merge upstream code

Merge remote-tracking branch 'upstream/araq-nir' into pr_ast2ir
NIR: implemented builtin
2026-08-31 19:03:42 +00:00 · 2023-10-04 15:07:11 +08:00 · 2023-10-04 15:03:36 +08:00 · 2023-10-03 23:57:38 +02:00 · 2023-10-03 22:27:19 +08:00 · 2023-10-03 09:08:20 +02:00
1589 changed files with 29213 additions and 83859 deletions
--- a/.github/ISSUE_TEMPLATE/bug_report.yml
+++ b/.github/ISSUE_TEMPLATE/bug_report.yml
@@ -7,26 +7,25 @@ body:
 - type: markdown
  attributes:
    value: |
-      Please provide a minimal code example that reproduces the bug if possible.
-      Reports with a reproducible example or detailed information will likely receive fixes faster.
-
- type: textarea
-  id: nim-version
-  attributes:
-    label: Nim Version
-    description: |
-      Can be obtained from `nim -v` on the command line along with the OS/architecture.
-      For development versions, including the commit hash may help.
-  validations:
-    required: true
+      - **Please provide a minimal code example that reproduces the Bug!** :bug:
+        Reports with a reproducible example and descriptive detailed information will likely receive fixes faster.

 - type: textarea
  id: description
  attributes:
    label: Description
    description: |
-      Describe the problem. Code example can be given here.
-    placeholder: Bug reports with reproducible code or detailed information will be fixed faster.
+      Use DETAILED DESCRIPTIVE information about the problem.
+      Here, you go into more details about your Bug report. This section can be a few paragraphs long.
+    placeholder: Bug reports with reproducible code and detailed information will be fixed faster.
+  validations:
+    required: true
+    
+- type: textarea
+  id: nim-version
+  attributes:
+    label: Nim Version
+    description: Copy and paste the output of `nim -v` on the command line. For development versions, make sure to include the commit hash.
  validations:
    required: true

@@ -35,7 +34,7 @@ body:
  attributes:
    label: Current Output
    description: Please copy and paste any relevant log output. This will be automatically formatted into code, so no need for backticks.
-    placeholder: Bug reports with reproducible code or detailed information will be fixed faster.
+    placeholder: Bug reports with reproducible code and detailed information will be fixed faster.
    render: text

 - type: textarea
@@ -43,14 +42,14 @@ body:
  attributes:
    label: Expected Output
    description: Please copy and paste any relevant log output. This will be automatically formatted into code, so no need for backticks.
-    placeholder: Bug reports with reproducible code or detailed information will be fixed faster.
+    placeholder: Bug reports with reproducible code and detailed information will be fixed faster.
    render: text

 - type: textarea
-  id: known-workarounds
+  id: possible-solution
  attributes:
-    label: Known Workarounds
-    description: Provide any known workarounds.
+    label: Possible Solution
+    description: Propose a possible solution.
  validations:
    required: false

@@ -65,9 +64,13 @@ body:
 - type: markdown
  attributes:
    value: |
-      - Please check whether the problem still exists in the devel branch, which can be installed via [choosenim](https://github.com/nim-lang/choosenim/), [nightlies](https://github.com/nim-lang/nightlies/), or by [creating a temporary build of the compiler](https://nim-lang.github.io/Nim/intern.html#debugging-the-compiler-building-an-instrumented-compiler).
+      - Thanks for your contributions!, your Bug report will receive feedback from the community soon...
+      - Please check whether the problem still exists in the devel branch, see [rebuilding the compiler](https://nim-lang.github.io/Nim/intern.html#rebuilding-the-compiler).
      - Consider writing a PR targetting devel branch after filing this, see [contributing](https://nim-lang.github.io/Nim/contributing.html).
-      - If it's a pre-existing compiler bug, see [debugging the compiler](https://nim-lang.github.io/Nim/intern.html#debugging-the-compiler) which should give more context on a compiler crash.
-      - If it's a regression, you can help us by identifying which version introduced the bug by [bisecting](https://nim-lang.github.io/Nim/intern.html#bisecting-for-regressions) or at least trying known past releases (e.g. `choosenim 2.0.0`).
-        The Nim repo also supports bisecting in issue comments by adding `!nim c`, `!nim js` etc. before a code block, see [nimrun-action](https://github.com/juancarlospaco/nimrun-action).
+      - If it's a pre-existing compiler bug, see [Debugging the compiler](https://nim-lang.github.io/Nim/intern.html#debugging-the-compiler)
+        which should give more context on a compiler crash.
+      - If it's a regression, you can help us by identifying which version introduced the bug,
+        see [Bisecting for regressions](https://nim-lang.github.io/Nim/intern.html#bisecting-for-regressions),
+        or at least try known past releases (e.g. `choosenim 2.0.0`). The Nim repo also supports online bisecting
+        via making a comment, which contains a code block starting by `!nim c`, `!nim js` etc. , see [nimrun-action](https://github.com/juancarlospaco/nimrun-action).
      - [Please, consider a Donation for the Nim project.](https://nim-lang.org/donate.html)
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -1,11 +0,0 @@
-# To get started with Dependabot version updates, you'll need to specify which
-# package ecosystems to update and where the package manifests are located.
-# Please see the documentation for all configuration options:
-# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
-
-version: 2
-updates:
-  - package-ecosystem: "github-actions" # See documentation for possible values
-    directory: "/" # Location of package manifests
-    schedule:
-      interval: "weekly"
--- a/.github/workflows/bisects.yml
+++ b/.github/workflows/bisects.yml
@@ -5,34 +5,19 @@ on:
    types: created

 jobs:
-  bisects:
-    if: |
-      github.event_name == 'issue_comment' && startsWith(github.event.comment.body, '!nim ') && github.event.issue.pull_request == null && github.event.comment.author_association != 'NONE'
-    strategy:
-      fail-fast: false
-      matrix:
-        platform: [ubuntu-latest, windows-latest, macos-latest]
-    name: ${{ matrix.platform }}-bisects
-    runs-on: ${{ matrix.platform }}
+  test:
+    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@v7
+    - uses: actions/checkout@v4

-      - name: Install OpenSSL (Windows)
-        if: |
-          runner.os == 'Windows'
-        run: choco install openssl.light --version=1.1.1.0  # OpenSSL 3.x removed SSL_library_init
-        shell: 'powershell'
+    # nimrun-action requires Nim installed.
+    - uses: jiro4989/setup-nim-action@v1
+      with:
+        nim-version: 'devel'

-      # v2 wont work here, because uses "hardcoded" nim versions, action "dynamically" finds version with bug.
-      - uses: jiro4989/setup-nim-action@v1  
-        with:
-          nim-version: 'devel'
+    - name: Install Dependencies
+      run: sudo apt-get install --no-install-recommends -yq valgrind

-      - uses: juancarlospaco/nimrun-action@nim
-        if: |
-          runner.os == 'Linux'   && contains(github.event.comment.body, '-d:linux'  ) ||
-          runner.os == 'Windows' && contains(github.event.comment.body, '-d:windows') ||
-          runner.os == 'macOS'   && contains(github.event.comment.body, '-d:osx'    ) ||
-          runner.os == 'Linux' && !contains(github.event.comment.body, '-d:linux') && !contains(github.event.comment.body, '-d:windows') && !contains(github.event.comment.body, '-d:osx')
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
+    - uses: juancarlospaco/nimrun-action@nim
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}
--- a/.github/workflows/ci_bench.yml
+++ b/.github/workflows/ci_bench.yml
@@ -0,0 +1,115 @@
+name: Benchmarks CI
+on:
+  pull_request:
+  push:
+    branches:
+      - 'devel'
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-20.04]
+        cpu: [amd64]
+    name: '${{ matrix.os }}'
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 60 # refs bug #18178
+    steps:
+      - name: 'Checkout'
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 2
+
+      - name: 'Install node.js 16.x'
+        uses: actions/setup-node@v3
+        with:
+          node-version: '16.x'
+
+      - name: 'Install dependencies (Linux amd64)'
+        if: runner.os == 'Linux' && matrix.cpu == 'amd64'
+        run: |
+          sudo apt-fast update -qq
+          DEBIAN_FRONTEND='noninteractive' \
+            sudo apt-fast install --no-install-recommends -yq \
+              libcurl4-openssl-dev libgc-dev libsdl1.2-dev libsfml-dev \
+              valgrind libc6-dbg libblas-dev xorg-dev
+
+      - name: 'Add build binaries to PATH'
+        shell: bash
+        run: echo "${{ github.workspace }}/bin" >> "${GITHUB_PATH}"
+
+      - name: 'Build csourcesAny'
+        shell: bash
+        run: . ci/funs.sh && nimBuildCsourcesIfNeeded CC=gcc ucpu='${{ matrix.cpu }}'
+
+      - name: 'Build koch'
+        shell: bash
+        run: nim c koch
+
+      - name: 'Build Nim'
+        shell: bash
+        run: ./koch boot -d:release -d:nimStrictMode --lib:lib
+
+      - name: 'Build Nimble'
+        shell: bash
+        run: ./koch nimble
+
+      - name: 'Action'
+        shell: bash
+        run: nim c -r -d:release ci/action.nim
+
+      - name: 'Checkout minimize'
+        uses: actions/checkout@v4
+        with:
+          repository: 'nim-lang/ci_bench'
+          path: minimize
+
+      - name: 'Run minimize benchmarks'
+        shell: bash
+        run: ./minimize/minimize ci-bench
+
+      - name: 'Restore minimize cached database'
+        uses: actions/cache/restore@v3
+        with:
+          path: minimize.csv
+          key: minimize-db-key
+
+      - name: 'Update minimize db'
+        shell: bash
+        run: ./minimize/minimize update-db
+
+      - name: 'Save minimize cached database'
+        if: |
+          github.event_name == 'push' && github.ref == 'refs/heads/devel' &&
+          matrix.target == 'linux'
+        uses: actions/cache/save@v3
+        with:
+          path: minimize.csv
+          key: minimize-db-key
+
+      - name: 'Generate minimize report'
+        shell: bash
+        run: ./minimize/minimize generate-report
+
+      - name: 'Archive minimize report'
+        uses: actions/upload-artifact@v3
+        with:
+          name: minimize-report
+          path: |
+            minimize/minimize.html
+            minimize/minimize.csv
+
+      # Requires additional permissions, see:
+      # https://github.com/nim-lang/Nim/actions/runs/4778177321/jobs/8494423792?pr=21566
+      # - name: 'Publish HTML report'
+      #   uses: rossjrw/pr-preview-action@v1
+      #   with:
+      #     source-dir: minimize
+      #     umbrella-dir: minimize
+      #   env:
+      #     GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract md summary
+        run: |
+          cat minimize/summary.md  >> $GITHUB_STEP_SUMMARY
--- a/.github/workflows/ci_docs.yml
+++ b/.github/workflows/ci_docs.yml
@@ -41,11 +41,11 @@ jobs:
        target: [linux, windows, osx]
        include:
          - target: linux
-            os: ubuntu-22.04
+            os: ubuntu-20.04
          - target: windows
-            os: windows-latest
+            os: windows-2019
          - target: osx
-            os: macos-15
+            os: macos-11

    name: ${{ matrix.target }}
    runs-on: ${{ matrix.os }}
@@ -53,7 +53,7 @@ jobs:

    steps:
      - name: 'Checkout'
-        uses: actions/checkout@v7
+        uses: actions/checkout@v4
        with:
          fetch-depth: 2

@@ -109,7 +109,7 @@ jobs:
        if: |
          github.event_name == 'push' && github.ref == 'refs/heads/devel' &&
          matrix.target == 'linux'
-        uses: crazy-max/ghaction-github-pages@v5
+        uses: crazy-max/ghaction-github-pages@v3
        with:
          build_dir: doc/html
        env:
--- a/.github/workflows/ci_packages.yml
+++ b/.github/workflows/ci_packages.yml
@@ -4,7 +4,6 @@ on:
  push:
    branches:
      - 'devel'
-      - 'version-2-2'
      - 'version-2-0'
      - 'version-1-6'
      - 'version-1-2'
@@ -18,13 +17,9 @@ jobs:
    strategy:
      fail-fast: false
      matrix:
-        os: [ubuntu-latest, macos-latest]
-        batch: ["0_3", "1_3", "2_3"] # list of `index_num`
-        include:
-          - os: ubuntu-latest
-            cpu: amd64
-          - os: macos-latest
-            cpu: arm64
+        os: [ubuntu-20.04, macos-11]
+        cpu: [amd64]
+        batch: ["allowed_failures", "0_3", "1_3", "2_3"] # list of `index_num`
    name: '${{ matrix.os }} (batch: ${{ matrix.batch }})'
    runs-on: ${{ matrix.os }}
    timeout-minutes: 60 # refs bug #18178
@@ -33,27 +28,26 @@ jobs:
      NIM_TESTAMENT_BATCH: ${{ matrix.batch }}
    steps:
      - name: 'Checkout'
-        uses: actions/checkout@v7
+        uses: actions/checkout@v4
        with:
          fetch-depth: 2

-      - name: 'Install node.js'
-        uses: actions/setup-node@v7
+      - name: 'Install node.js 16.x'
+        uses: actions/setup-node@v3
        with:
-          node-version: 24
+          node-version: '16.x'

      - name: 'Install dependencies (Linux amd64)'
        if: runner.os == 'Linux' && matrix.cpu == 'amd64'
        run: |
-          sudo apt-get update -qq
+          sudo apt-fast update -qq
          DEBIAN_FRONTEND='noninteractive' \
-            sudo apt-get install --no-install-recommends -yq \
+            sudo apt-fast install --no-install-recommends -yq \
              libcurl4-openssl-dev libgc-dev libsdl1.2-dev libsfml-dev \
-              valgrind libc6-dbg libblas-dev liblapack-dev libpcre3 xorg-dev
+              valgrind libc6-dbg libblas-dev xorg-dev
      - name: 'Install dependencies (macOS)'
        if: runner.os == 'macOS'
        run: brew install boehmgc make sfml gtk+3
-        # XXX can't find boehm and gtk on macos 13
      - name: 'Install dependencies (Windows)'
        if: runner.os == 'Windows'
        shell: bash
--- a/.github/workflows/ci_publish.yml
+++ b/.github/workflows/ci_publish.yml
@@ -11,20 +11,20 @@ jobs:
    strategy:
      fail-fast: false
      matrix:
-        os: [ubuntu-22.04]
+        os: [ubuntu-20.04]
        cpu: [amd64]
    name: '${{ matrix.os }}'
    runs-on: ${{ matrix.os }}
    steps:
      - name: 'Checkout'
-        uses: actions/checkout@v7
+        uses: actions/checkout@v4
        with:
          fetch-depth: 2

-      - name: 'Install node.js'
-        uses: actions/setup-node@v7
+      - name: 'Install node.js 16.x'
+        uses: actions/setup-node@v3
        with:
-          node-version: 24
+          node-version: '16.x'

      - name: 'Install dependencies (Linux amd64)'
        if: runner.os == 'Linux' && matrix.cpu == 'amd64'
@@ -34,6 +34,17 @@ jobs:
            sudo apt-fast install --no-install-recommends -yq \
              libcurl4-openssl-dev libgc-dev libsdl1.2-dev libsfml-dev \
              valgrind libc6-dbg libblas-dev xorg-dev
+      - name: 'Install dependencies (macOS)'
+        if: runner.os == 'macOS'
+        run: brew install boehmgc make sfml gtk+3
+      - name: 'Install dependencies (Windows)'
+        if: runner.os == 'Windows'
+        shell: bash
+        run: |
+          set -e
+          . ci/funs.sh
+          nimInternalInstallDepsWindows
+          echo_run echo "${{ github.workspace }}/dist/mingw64/bin" >> "${GITHUB_PATH}"

      - name: 'Add build binaries to PATH'
        shell: bash
@@ -60,7 +71,7 @@ jobs:
        run: nim c -r -d:release ci/action.nim

      - name: 'Comment'
-        uses: actions/github-script@v9
+        uses: actions/github-script@v6
        with:
          script: |
            const fs = require('fs');
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -9,7 +9,7 @@ jobs:
  stale:
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/stale@v10
+      - uses: actions/stale@v8
        with:
          days-before-pr-stale:    365
          days-before-pr-close:    30
--- a/.gitignore
+++ b/.gitignore
@@ -68,7 +68,6 @@ testament.db
 /csources
 /csources_v1
 /csources_v2
-/csources_v3

 /dist/
 # /lib/fusion # fusion is now unbundled; `git status` should reveal if it's there so users can act on it
@@ -87,7 +86,6 @@ tweeter_test.db

 /tests/megatest.nim
 /tests/ic/*_temp.nim
-/tests/ic/*_mm/
 /tests/navigator/*_temp.nim


--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -20,7 +20,7 @@ jobs:
  strategy:
    matrix:
      Linux_amd64:
-        vmImage: 'ubuntu-24.04'
+        vmImage: 'ubuntu-20.04'
        CPU: amd64
      # regularly breaks, refs bug #17325
 #       Linux_i386:
@@ -28,24 +28,24 @@ jobs:
 #         # g++-multilib : Depends: gcc-multilib (>= 4:5.3.1-1ubuntu1) but it is not going to be installed
 #         vmImage: 'ubuntu-18.04'
 #         CPU: i386
-      OSX_arm64:
-        vmImage: 'macos-15'
-        CPU: arm64
-      OSX_arm64_cpp:
-        vmImage: 'macos-15'
-        CPU: arm64
+      OSX_amd64:
+        vmImage: 'macOS-11'
+        CPU: amd64
+      OSX_amd64_cpp:
+        vmImage: 'macOS-11'
+        CPU: amd64
        NIM_COMPILE_TO_CPP: true
      Windows_amd64_batch0_3:
-        vmImage: 'windows-2025'
+        vmImage: 'windows-2019'
        CPU: amd64
        # see also: `NIM_TEST_PACKAGES`
        NIM_TESTAMENT_BATCH: "0_3"
      Windows_amd64_batch1_3:
-        vmImage: 'windows-2025'
+        vmImage: 'windows-2019'
        CPU: amd64
        NIM_TESTAMENT_BATCH: "1_3"
      Windows_amd64_batch2_3:
-        vmImage: 'windows-2025'
+        vmImage: 'windows-2019'
        CPU: amd64
        NIM_TESTAMENT_BATCH: "2_3"

@@ -73,19 +73,17 @@ jobs:

    - task: NodeTool@0
      inputs:
-        versionSpec: '20.x'
-      displayName: 'Install node.js 20.x'
+        versionSpec: '16.x'
+      displayName: 'Install node.js 16.x'
      condition: and(succeeded(), eq(variables['skipci'], 'false'))

    - bash: |
        set -e
        . ci/funs.sh
-        echo_run sudo add-apt-repository universe
-        echo_run sudo apt-get update -qq
+        echo_run sudo apt-fast update -qq
        DEBIAN_FRONTEND='noninteractive' \
-          echo_run sudo apt-get install --no-install-recommends -yq \
-            gcc-14 g++-14 libpcre3 liblapack-dev libpcre3 liblapack-dev libcurl4-openssl-dev libgc-dev libsdl1.2-dev libsfml-dev valgrind libc6-dbg
-        echo_run sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-14 60 --slave /usr/bin/g++ g++ /usr/bin/g++-14
+          echo_run sudo apt-fast install --no-install-recommends -yq \
+            libcurl4-openssl-dev libgc-dev libsdl1.2-dev libsfml-dev valgrind libc6-dbg
      displayName: 'Install dependencies (amd64 Linux)'
      condition: and(succeeded(), eq(variables['skipci'], 'false'), eq(variables['Agent.OS'], 'Linux'), eq(variables['CPU'], 'amd64'))

@@ -102,16 +100,15 @@ jobs:
        Pin-Priority: 1001
        EOF

-        # echo_run sudo apt-get update -qq
-        echo_run sudo apt-get update -qq || echo "failed, see bug #17343"
+        # echo_run sudo apt-fast update -qq
+        echo_run sudo apt-fast update -qq || echo "failed, see bug #17343"
        # `:i386` (e.g. in `libffi-dev:i386`) is needed otherwise you may get:
        # `could not load: libffi.so` during dynamic loading.
        DEBIAN_FRONTEND='noninteractive' \
-          echo_run sudo apt-get install --no-install-recommends --allow-downgrades -yq \
+          echo_run sudo apt-fast install --no-install-recommends --allow-downgrades -yq \
            g++-multilib gcc-multilib libcurl4-openssl-dev:i386 libgc-dev:i386 \
            libsdl1.2-dev:i386 libsfml-dev:i386 libglib2.0-dev:i386 libffi-dev:i386

-
        cat << EOF > bin/gcc
        #!/bin/bash

@@ -133,7 +130,6 @@ jobs:
    - bash: brew install boehmgc make sfml
      displayName: 'Install dependencies (OSX)'
      condition: and(succeeded(), eq(variables['skipci'], 'false'), eq(variables['Agent.OS'], 'Darwin'))
-      # XXX can't find boehm on macos 13

    - bash: |
        set -e
--- a/build_all.bat
+++ b/build_all.bat
@@ -24,6 +24,6 @@ if not exist %nim_csources% (
  cd ..
  copy /y bin\nim.exe  %nim_csources%
 )
-bin\nim.exe c --noNimblePath --skipUserCfg --skipParentCfg --hints:off koch
-koch boot -d:release --skipUserCfg --skipParentCfg --hints:off
-koch tools --skipUserCfg --skipParentCfg --hints:off
+ bin\nim.exe c --noNimblePath --skipUserCfg --skipParentCfg --hints:off koch
+ koch boot -d:release --skipUserCfg --skipParentCfg --hints:off
+ koch tools --skipUserCfg --skipParentCfg --hints:off
--- a/changelog.md
+++ b/changelog.md
@@ -1,155 +1,33 @@
-# v2.x.x - yyyy-mm-dd
+# v2.2.0 - yyyy-mm-dd


 ## Changes affecting backward compatibility

- `-d:nimPreviewFloatRoundtrip` becomes the default. `system.addFloat` and `system.$` now can produce string representations of
-floating point numbers that are minimal in size and possess round-trip and correct
-rounding guarantees (via the
-[Dragonbox](https://raw.githubusercontent.com/jk-jeon/dragonbox/master/other_files/Dragonbox.pdf) algorithm). Use `-d:nimLegacySprintf` to emulate old behaviors.
-
- The `default` parameter of `tables.getOrDefault` has been renamed to `def` to
-  avoid conflicts with `system.default`, so named argument usage for this
-  parameter like `getOrDefault(..., default = ...)` will have to be changed.
-
- With `-d:nimPreviewCheckedClose`, the `close` function in the `std/syncio` module now raises an IO exception in case of an error.
-
- Unknown warnings and hints now gives warnings `warnUnknownNotes` instead of
-errors.
-
- With `-d:nimPreviewAsmSemSymbol`, backticked symbols are type checked in the `asm/emit` statements.
-
- The bare `except:` now panics on `Defect`. Use `except Exception:` or `except Defect:` to catch `Defect`. `--legacy:noPanicOnExcept` is provided for a transition period.
-
- With `-d:nimPreviewCStringComparisons`, comparsions (`<`, `>`, `<=`, `>=`) between cstrings switch from reference semantics to value semantics like `==` and `!=`.
-
- `std/parsesql` has been moved to a nimble package, use `nimble` or `atlas` to install it.
-
- With `-d:nimPreviewDuplicateModuleError`, importing two modules that share the same name becomes a compile-time error. This includes importing the same module more than once. Use `import foo as foo1` (or other aliases) to avoid collisions.
-
- Adds the switch `--mangle:nim|cpp`, which selects `nim` or `cpp` style name mangling when used with `debuginfo` on, defaults to `cpp`.
-
- The second parameter of `succ`, `pred`, `inc`, and `dec` in `system` now accepts `SomeInteger` (previously `Ordinal`).
-
- Bitshift operators (`shl`, `shr`, `ashr`) now apply bitmasking to the right operand in the C/C++/VM/JS backends.
-
- Adds a new warning `--warning:ImplicitRangeConversion` that detects downsizing implicit conversions to range types (e.g., `int -> range[0..255]` or `range[1..256] -> range[0..255]`) that could cause runtime panics. Safe conversions like `range[0..255] -> range[0..65535]` and explicit casts do not trigger warnings. `int` to `Natural` and `Positive` conversions do not trigger warnings, which can be enabled with `--warning:systemRangeConversion`.
-
- Procedure compatibility also checks the backend representation of the
-parameter and result types, not just their source-level shape. Use
-`--legacy:procParamTypeBackendAliases` to restore the older behavior.

 ## Standard library additions and changes

-[//]: # "Additions:"
-
- Added `system.readRawDataStable`, a companion to `readRawData` that returns a
-  raw `ptr UncheckedArray[char]` into a string's character data which stays valid
-  across moves and copies of the string value. It is available under every string
-  implementation (refc, ARC/ORC and `--strings:sso`) with the same signature, so
-  code can pin an interior buffer pointer today and be ready for `--strings:sso`
-  without `when declared` guards. Under `--strings:sso` it promotes a small inline
-  string to its heap representation first; under the other implementations the data
-  is already heap-resident, so it is equivalent to `readRawData`.
-
- `setutils.symmetricDifference` along with its operator version
-  `` setutils.`-+-` `` and in-place version `setutils.toggle` have been added
-  to more efficiently calculate the symmetric difference of bitsets.
- `strutils.multiReplace` overload for character set replacements in a single pass.
-	Useful for string sanitation. Follows existing multiReplace semantics.
-
- `std/files` adds:
-  - Exports `CopyFlag` enum and `FilePermission` type for fine-grained control of file operations
-  - New file operation procs with `Path` support:
-    - `getFilePermissions`, `setFilePermissions` for managing permissions
-    - `tryRemoveFile` for file deletion
-    - `copyFile` with configurable buffer size and symlink handling
-    - `copyFileWithPermissions` to preserve file attributes
-    - `copyFileToDir` for copying files into directories
-
- `std/dirs` adds:
-  - New directory operation procs with `Path` support:
-    - `copyDir` with special file handling options
-    - `copyDirWithPermissions` to recursively preserve attributes
-
- `system.setLenUninit` now supports refc, JS and VM backends.
- `system.setLenUninit` for the `string` type. Allows setting length without initializing new memory on growth.
-
- `std/parseopt` now supports multiple parser modes via a `CliMode` enum.
-  Modes include `Nim` (default, fully compatible) and two new experimental modes:
-  `Lax` and `Gnu` for different option parsing behaviors.
-
- `std/symlinks.expandSymlink` now supports Windows symlinks and junctions with
-  POSIX-like single-hop `readlink` semantics.
- `std/nre2` is added to replace deprecated NRE.
-
- `system.typeof` adds a new parameter `modifierMode` to specify how type modifiers are handled.
-
 [//]: # "Changes:"

- `std/math` The `^` symbol now supports floating-point as exponent in addition to the Natural type.
- `min`, `max`, and `sequtils`' `minIndex`, `maxIndex` and `minmax` for `openArray`s now accept a comparison function.
- `system.substr` implementation now uses `copymem` (wrapped C `memcpy`) for copying data, if available at compilation.
- `system.newStringUninit` is now considered free of side-effects allowing it to be used with `--experimental:strictFuncs`.
- `std/re` and `std/nre` are deprecated as PCRE library is obsolete.
-  Use https://github.com/nitely/nim-regex or `std/nre2`.
-  See: https://github.com/nim-lang/Nim/issues/23668.
- `std/pegs` now correctly lexes UTF-8 bytes inside bare identifier-style
-  terminals, so case-insensitive matching of non-ASCII terms (e.g. ``\i café``)
-  works without single-quoting.
- `std/uri`: The `?` operator now appends query parameters to an existing query
-  string instead of replacing it. Fixes [#19782](https://github.com/nim-lang/Nim/issues/19782).
+
+[//]: # "Additions:"
+
+- Added `newStringUninit` to system, which creates a new string of length `len` like `newString` but with uninitialized content.
+- Added `hasDefaultValue` to `std/typetraits` to check if a type has a valid default value.
+
+[//]: # "Deprecations:"
+
+
+[//]: # "Removals:"
+

 ## Language changes

- An experimental option `--experimental:typeBoundOps` has been added that
-  implements the RFC https://github.com/nim-lang/RFCs/issues/380.
-  This makes the behavior of interfaces like `hash`, `$`, `==` etc. more
-  reliable for nominal types across indirect/restricted imports.

-  ```nim
-  # objs.nim
-  import std/hashes
-
-  type
-    Obj* = object
-      x*, y*: int
-      z*: string # to be ignored for equality
-
-  proc `==`*(a, b: Obj): bool =
-    a.x == b.x and a.y == b.y
-
-  proc hash*(a: Obj): Hash =
-    $!(hash(a.x) &! hash(a.y))
-  ```
-
-  ```nim
-  # main.nim
-  {.experimental: "typeBoundOps".}
-  from objs import Obj # objs.hash, objs.`==` not imported
-  import std/tables
-
-  var t: Table[Obj, int]
-  t[Obj(x: 3, y: 4, z: "debug")] = 34
-  echo t[Obj(x: 3, y: 4, z: "ignored")] # 34
-  ```
-
-  See the [experimental manual](https://nim-lang.github.io/Nim/manual_experimental.html#typeminusbound-overloads)
-  for more information.

 ## Compiler changes

- Fixed a bug where `sizeof(T)` inside a `typedesc` template called from a generic type's
-  `when` clause would error with "'sizeof' requires '.importc' types to be '.completeStruct'".
-  The issue was that `hasValuelessStatics` in `semtypinst.nim` didn't recognize
-  `tyTypeDesc(tyGenericParam)` as an unresolved generic parameter.

 ## Tool changes

- Added `--raw` flag when generating JSON docs to not render markup.
- Added `--stdinfile` flag to name of the file used when running program from stdin (defaults to `stdinfile.nim`)
- Added `--styleCheck:warning` flag to treat style check violations as warnings.
+- koch now allows bootstrapping with `-d:nimHasLibFFI`, replacing the older option of building the compiler directly w/ the `libffi` nimble package in tow.

-## Documentation changes
-
- Added documentation for the `completeStruct` pragma in the manual.
--- a/changelogs/changelog_0_18_1.md
+++ b/changelogs/changelog_0_18_1.md
@@ -53,7 +53,7 @@
  - [``joyent_http_parser``](https://github.com/nim-lang/joyent_http_parser)

 - Proc [toCountTable](https://nim-lang.org/docs/tables.html#toCountTable,openArray[A])
-  now produces a `CountTable` with values corresponding to the number of occurrences
+  now produces a `CountTable` with values correspoding to the number of occurrences
  of the key in the input. It used to produce a table with all values set to `1`.

  Counting occurrences in a sequence used to be:
@@ -339,7 +339,7 @@ for i in a..b:

 - Fixed "ReraiseError when using try/except within finally block"
  ([#5871](https://github.com/nim-lang/Nim/issues/5871))
- Fixed "Range type inference leads to counter-intuitive behaviour"
+- Fixed "Range type inference leads to counter-intuitive behvaiour"
  ([#5854](https://github.com/nim-lang/Nim/issues/5854))
 - Fixed "JSON % operator can fail in extern procs with dynamic types"
  ([#6385](https://github.com/nim-lang/Nim/issues/6385))
@@ -403,7 +403,7 @@ for i in a..b:
  ([#6589](https://github.com/nim-lang/Nim/issues/6589))
 - Fixed "Generated c code calls function twice"
  ([#6292](https://github.com/nim-lang/Nim/issues/6292))
- Fixed "Range type inference leads to counter-intuitive behaviour"
+- Fixed "Range type inference leads to counter-intuitive behvaiour"
  ([#5854](https://github.com/nim-lang/Nim/issues/5854))
 - Fixed "New backward indexing is too limited"
  ([#6631](https://github.com/nim-lang/Nim/issues/6631))
--- a/changelogs/changelog_1_0_0.md
+++ b/changelogs/changelog_1_0_0.md
@@ -22,7 +22,7 @@

 - We removed `unicode.Rune16` without any deprecation period as the name
  was wrong (see the [RFC](https://github.com/nim-lang/RFCs/issues/151) for details)
-  and we didn't find any usage of it in the wild. If you still need it, add this
+  and we didn't find any usages of it in the wild. If you still need it, add this
  piece of code to your project:
 ```nim
 type
--- a/changelogs/changelog_1_0_2.md
+++ b/changelogs/changelog_1_0_2.md
@@ -11,7 +11,7 @@
 * Fixed "Assertion error when running `nim check` on compiler/nim.nim" [#12281](https://github.com/nim-lang/Nim/issues/12281)
 * Fixed "Compiler crash with empty array and generic instantiation with int as parameter" [#12264](https://github.com/nim-lang/Nim/issues/12264)
 * Fixed "Regression in JS backend codegen "Error: request to generate code for .compileTime proc"" [#12240](https://github.com/nim-lang/Nim/issues/12240)
-* Fix how `relativePath` handles case sensitivity
+* Fix how `relativePath` handle case sensitiviy
 * Fixed "SIGSEGV in compiler when using generic types and seqs" [#12336](https://github.com/nim-lang/Nim/issues/12336)
 * Fixed "[1.0.0] weird interaction between `import os` and casting integer to char on macosx trigger bad codegen" [#12291](https://github.com/nim-lang/Nim/issues/12291)
 * VM: no special casing for big endian machines
@@ -43,7 +43,7 @@
 * threadpool: fix link in docs (#12258)
 * Fix spellings (#12277)
 * fix #12278, don't expose internal PCRE documentation
-* Fixed "Documentation of quitprocs is wrong" [#12279](https://github.com/nim-lang/Nim/issues/12279)
+* Fixed "Documentation of quitprocs is wrong" [#12279(https://github.com/nim-lang/Nim/issues/12279)
 * Fix typo in docs
 * Fix reference to parseSpec proc in readme
 * [doc/tut1] removed discard discussion in comments
--- a/changelogs/changelog_1_2_0.md
+++ b/changelogs/changelog_1_2_0.md
@@ -169,7 +169,7 @@ echo f
 - The Nim compiler now supports a new pragma called ``.localPassc`` to
  pass specific compiler options to the C(++) backend for the C(++) file
  that was produced from the current Nim module.
- The compiler now infers "sink parameters". To disable this for a specific routine,
+- The compiler now inferes "sink parameters". To disable this for a specific routine,
  annotate it with `.nosinks`. To disable it for a section of code, use
  `{.push sinkInference: off.}`...`{.pop.}`.
 - The compiler now supports a new switch `--panics:on` that turns runtime
@@ -261,7 +261,7 @@ echo f
  ([#12812](https://github.com/nim-lang/Nim/issues/12812))
 - Fixed "Produce static/const initializations for variables when possible"
  ([#12216](https://github.com/nim-lang/Nim/issues/12216))
- Fixed "Assigning discriminator field leads to internal assert with --gc:destructors"
+- Fixed "Assigning descriminator field leads to internal assert with --gc:destructors"
  ([#12821](https://github.com/nim-lang/Nim/issues/12821))
 - Fixed "nimsuggest `use` command does not return all instances of symbol"
  ([#12832](https://github.com/nim-lang/Nim/issues/12832))
--- a/changelogs/changelog_2_0_0.md
+++ b/changelogs/changelog_2_0_0.md
@@ -283,7 +283,7 @@ The definition of `"strictFuncs"` was changed.
 The old definition was roughly: "A store to a ref/ptr deref is forbidden unless it's coming from a `var T` parameter".
 The new definition is: "A store to a ref/ptr deref is forbidden."

-This new definition is much easier to understand, the price is some expressiveness. The following code used to be
+This new definition is much easier to understand, the price is some expressitivity. The following code used to be
 accepted:

 ```nim
--- a/changelogs/changelog_2_0_0_details.md
+++ b/changelogs/changelog_2_0_0_details.md
@@ -72,7 +72,7 @@
 - `shallowCopy` and `shallow` are removed for ARC/ORC. Use `move` when possible or combine assignment and
 `sink` for optimization purposes.

- The experimental `nimPreviewDotLikeOps` switch is going to be removed or deprecated because it didn't fulfill its promises.
+- The experimental `nimPreviewDotLikeOps` switch is going to be removed or deprecated because it didn't fullfill its promises.

 - The `{.this.}` pragma, deprecated since 0.19, has been removed.
 - `nil` literals can no longer be directly assigned to variables or fields of `distinct` pointer types. They must be converted instead.
@@ -205,7 +205,7 @@
  proc prc(): int =
    123

-  iterator iter(): int {.closure.} =
+  iterator iter(): int =
    yield 123

  proc takesProc[T: proc](x: T) = discard
--- a/changelogs/changelog_2_2_0.md
+++ b/changelogs/changelog_2_2_0.md
@@ -1,248 +1,12 @@
-# v2.2.0 - 2024-10-02
-
+# v2.2.0 - 2023-mm-dd

 ## Changes affecting backward compatibility

- `-d:nimStrictDelete` becomes the default. An index error is produced when the index passed to `system.delete` is out of bounds. Use `-d:nimAuditDelete` to mimic the old behavior for backward compatibility.
-
- The default user-agent in `std/httpclient` has been changed to `Nim-httpclient/<version>` instead of `Nim httpclient/<version>` which was incorrect according to the HTTP spec.
-
- Methods now support implementations based on a VTable by using `--experimental:vtables`. Methods are then confined to the same module where their type has been defined.
-
- With `-d:nimPreviewNonVarDestructor`, non-var destructors become the default.
-
- A bug where tuple unpacking assignment with a longer tuple on the RHS than the LHS was allowed has been fixed, i.e. code like:
-  ```nim
-  var a, b: int
-  (a, b) = (1, 2, 3, 4)
-  ```
-  will no longer compile.
-
- `internalNew` is removed from the `system` module, use `new` instead.
-
- `bindMethod` in `std/jsffi` is deprecated, don't use it with closures.
-
- The JS backend now supports lambda lifting for closures. Use `--legacy:jsNoLambdaLifting` to emulate old behaviors.
-
- The JS backend now supports closure iterators.
-
- `owner` in `std/macros` is deprecated.
-
- Ambiguous type symbols in generic procs and templates now generate symchoice nodes.
-  Previously; in templates they would error immediately at the template definition,
-  and in generic procs a type symbol would arbitrarily be captured, losing the
-  information of the other symbols. This means that generic code can now give
-  errors for ambiguous type symbols, and macros operating on generic proc AST
-  may encounter symchoice nodes instead of the arbitrarily resolved type symbol nodes.
-
- Partial generic instantiation of routines is no longer allowed. Previously
-  it compiled in niche situations due to bugs in the compiler.
-
-  ```nim
-  proc foo[T, U](x: T, y: U) = echo (x, y)
-  proc foo[T, U](x: var T, y: U) = echo "var ", (x, y)
-
-  proc bar[T]() =
-    foo[float](1, "abc")
-
-  bar[int]() # before: (1.0, "abc"), now: type mismatch, missing generic parameter
-  ```
-
- `const` values now open a new scope for each constant, meaning symbols
-  declared in them can no longer be used outside or in the value of
-  other constants.
-
-  ```nim
-  const foo = (var a = 1; a)
-  const bar = a # error
-  let baz = a # error
-  ```
-
- The following POSIX wrappers have had their types changed from signed to
-  unsigned types on OSX and FreeBSD/OpenBSD to correct codegen errors:
-  - `Gid` (was `int32`, is now `uint32`)
-  - `Uid` (was `int32`, is now `uint32`)
-  - `Dev` (was `int32`, is now `uint32` on FreeBSD)
-  - `Nlink` (was `int16`, is now `uint32` on OpenBSD and `uint16` on OSX/other BSD)
-  - `sin6_flowinfo` and `sin6_scope_id` fields of `Sockaddr_in6`
-    (were `int32`, are now `uint32`)
-  - `n_net` field of `Tnetent` (was `int32`, is now `uint32`)
-
- The `Atomic[T]` type on C++ now uses C11 primitives by default instead of
-  `std::atomic`. To use `std::atomic` instead, `-d:nimUseCppAtomics` can be defined.
-
-
-
-
-
-
 ## Standard library additions and changes

-[//]: # "Changes:"
-
- Changed `std/osfiles.copyFile` to allow specifying `bufferSize` instead of a hard-coded one.
- Changed `std/osfiles.copyFile` to use `POSIX_FADV_SEQUENTIAL` hints for kernel-level aggressive sequential read-aheads.
- `std/htmlparser` has been moved to a nimble package, use `nimble` or `atlas` to install it.
- Changed `std/os.copyDir` and `copyDirWithPermissions` to allow skipping special "file" objects like FIFOs, device files, etc on Unix by specifying a `skipSpecial` parameter.
-
-[//]: # "Additions:"
-
- Added `newStringUninit` to the `system` module, which creates a new string of length `len` like `newString` but with uninitialized content.
- Added `setLenUninit` to the `system` module, which doesn't initialize
-slots when enlarging a sequence.
- Added `hasDefaultValue` to `std/typetraits` to check if a type has a valid default value.
- Added `rangeBase` to `std/typetraits` to obtain the base type of a range type or
-  convert a value with a range type to its base type.
- Added Viewport API for the JavaScript targets in the `dom` module.
- Added `toSinglyLinkedRing` and `toDoublyLinkedRing` to `std/lists` to convert from `openArray`s.
- ORC: To be enabled via `nimOrcStats` there is a new API called `GC_orcStats` that can be used to query how many
-  objects the cyclic collector did free. If the number is zero that is a strong indicator that you can use `--mm:arc`
-  instead of `--mm:orc`.
- A `$` template is provided for `Path` in `std/paths`.
- `std/hashes.hash(x:string)` changed to produce a 64-bit string `Hash` (based
-on Google's Farm Hash) which is also often faster than the present one.  Define
-`nimStringHash2` to get the old values back.  `--jsbigint=off` mode always only
-produces the old values.  This may impact your automated tests if they depend
-on hash order in some obvious or indirect way.  Using `sorted` or `OrderedTable`
-is often an easy workaround.
-
-[//]: # "Deprecations:"
-
- Deprecates `system.newSeqUninitialized`, which is replaced by `newSeqUninit`.
-
-[//]: # "Removals:"
-
-
-
-
-
-
 ## Language changes

- `noInit` can be used in types and fields to disable member initializers in the C++ backend.
-
- C++ custom constructors initializers see https://nim-lang.org/docs/manual_experimental.html#constructor-initializer
-
- `member` can be used to attach a procedure to a C++ type.
-
- Inside a C++ constructor, `result` can be used to access the created object rather than `this`.
-
- Tuple unpacking changes:
-  - Tuple unpacking assignment now supports using underscores to discard values.
-    ```nim
-    var a, c: int
-    (a, _, c) = (1, 2, 3)
-    ```
-  - Tuple unpacking variable declarations now support type annotations, but
-    only for the entire tuple.
-    ```nim
-    let (a, b): (int, int) = (1, 2)
-    let (a, (b, c)): (byte, (float, cstring)) = (1, (2, "abc"))
-    ```
-
- The experimental option `--experimental:openSym` has been added to allow
-  captured symbols in generic routine and template bodies respectively to be
-  replaced by symbols injected locally by templates/macros at instantiation
-  time. `bind` may be used to keep the captured symbols over the injected ones
-  regardless of enabling the option, but other methods like renaming the
-  captured symbols should be used instead so that the code is not affected by
-  context changes.
-
-  Since this change may affect runtime behavior, the experimental switch
-  `openSym` needs to be enabled; and a warning is given in the case where an
-  injected symbol would replace a captured symbol not bound by `bind` and
-  the experimental switch isn't enabled.
-
-  ```nim
-  const value = "captured"
-  template foo(x: int, body: untyped): untyped =
-    let value {.inject.} = "injected"
-    body
-
-  proc old[T](): string =
-    foo(123):
-      return value # warning: a new `value` has been injected, use `bind` or turn on `experimental:openSym`
-  echo old[int]() # "captured"
-
-  template oldTempl(): string =
-    block:
-      foo(123):
-        value # warning: a new `value` has been injected, use `bind` or turn on `experimental:openSym`
-  echo oldTempl() # "captured"
-
-  {.experimental: "openSym".}
-
-  proc bar[T](): string =
-    foo(123):
-      return value
-  assert bar[int]() == "injected" # previously it would be "captured"
-
-  proc baz[T](): string =
-    bind value
-    foo(123):
-      return value
-  assert baz[int]() == "captured"
-
-  template barTempl(): string =
-    block:
-      foo(123):
-        value
-  assert barTempl() == "injected" # previously it would be "captured"
-
-  template bazTempl(): string =
-    bind value
-    block:
-      foo(123):
-        value
-  assert bazTempl() == "captured"
-  ```
-
-  This option also generates a new node kind `nnkOpenSym` which contains
-  exactly 1 `nnkSym` node. In the future this might be merged with a slightly
-  modified `nnkOpenSymChoice` node but macros that want to support the
-  experimental feature should still handle `nnkOpenSym`, as the node kind would
-  simply not be generated as opposed to being removed.
-
-  Another experimental switch `genericsOpenSym` exists that enables this behavior
-  at instantiation time, meaning templates etc can enable it specifically when
-  they are being called. However this does not generate `nnkOpenSym` nodes
-  (unless the other switch is enabled) and so doesn't reflect the regular
-  behavior of the switch.
-
-  ```nim
-  const value = "captured"
-  template foo(x: int, body: untyped): untyped =
-    let value {.inject.} = "injected"
-    {.push experimental: "genericsOpenSym".}
-    body
-    {.pop.}
-
-  proc bar[T](): string =
-    foo(123):
-      return value
-  echo bar[int]() # "injected"
-
-  template barTempl(): string =
-    block:
-      var res: string
-      foo(123):
-        res = value
-      res
-  assert barTempl() == "injected"
-  ```
-
-
-
-
-
 ## Compiler changes

- `--nimcache` using a relative path as the argument in a config file is now relative to the config file instead of the current directory.
-
-
-
-
-
 ## Tool changes

- koch now allows bootstrapping with `-d:nimHasLibFFI`, replacing the older option of building the compiler directly w/ the `libffi` nimble package.
--- a/changelogs/changelog_X_XX_X.md
+++ b/changelogs/changelog_X_XX_X.md
@@ -1,4 +1,4 @@
-# v2.xx.x - yyyy-mm-dd
+# v1.xx.x - yyyy-mm-dd

 This is an example file.
 The changes should go to changelog.md!
--- a/compiler/aliases.nim
+++ b/compiler/aliases.nim
@@ -10,9 +10,7 @@
 ## Simple alias analysis for the HLO and the code generators.

 import
-  ast, astalgo, types, trees
-
-import std/intsets
+  ast, astalgo, types, trees, intsets

 when defined(nimPreviewSlimSystem):
  import std/assertions
@@ -51,16 +49,14 @@ proc isPartOfAux(a, b: PType, marker: var IntSet): TAnalysisResult =
  if compareTypes(a, b, dcEqIgnoreDistinct): return arYes
  case a.kind
  of tyObject:
-    if a.baseClass != nil:
-      result = isPartOfAux(a.baseClass.skipTypes(skipPtrs), b, marker)
+    if a[0] != nil:
+      result = isPartOfAux(a[0].skipTypes(skipPtrs), b, marker)
    if result == arNo: result = isPartOfAux(a.n, b, marker)
  of tyGenericInst, tyDistinct, tyAlias, tySink:
-    result = isPartOfAux(skipModifier(a), b, marker)
-  of tySet, tyArray:
-    result = isPartOfAux(a.elementType, b, marker)
-  of tyTuple:
-    for aa in a.kids:
-      result = isPartOfAux(aa, b, marker)
+    result = isPartOfAux(lastSon(a), b, marker)
+  of tyArray, tySet, tyTuple:
+    for i in 0..<a.len:
+      result = isPartOfAux(a[i], b, marker)
      if result == arYes: return
  else: discard

--- a/compiler/ast.nim
+++ b/compiler/ast.nim
--- a/compiler/ast2nif.nim
+++ b/compiler/ast2nif.nim
--- a/compiler/astalgo.nim
+++ b/compiler/astalgo.nim
@@ -12,18 +12,23 @@
 # the data structures here are used in various places of the compiler.

 import
-  ast, astyaml, options, lineinfos, idents, rodutils,
+  ast, hashes, intsets, options, lineinfos, ropes, idents, rodutils,
  msgs

-import std/[hashes, intsets]
-import std/strutils except addf
-
-export astyaml.treeToYaml, astyaml.typeToYaml, astyaml.symToYaml, astyaml.lineInfoToStr
+import strutils except addf

 when defined(nimPreviewSlimSystem):
  import std/assertions

 proc hashNode*(p: RootRef): Hash
+proc treeToYaml*(conf: ConfigRef; n: PNode, indent: int = 0, maxRecDepth: int = - 1): Rope
+  # Convert a tree into its YAML representation; this is used by the
+  # YAML code generator and it is invaluable for debugging purposes.
+  # If maxRecDepht <> -1 then it won't print the whole graph.
+proc typeToYaml*(conf: ConfigRef; n: PType, indent: int = 0, maxRecDepth: int = - 1): Rope
+proc symToYaml*(conf: ConfigRef; n: PSym, indent: int = 0, maxRecDepth: int = - 1): Rope
+proc lineInfoToStr*(conf: ConfigRef; info: TLineInfo): Rope
+

 # these are for debugging only: They are not really deprecated, but I want
 # the warning so that release versions do not contain debugging statements:
@@ -31,6 +36,15 @@ proc debug*(n: PSym; conf: ConfigRef = nil) {.exportc: "debugSym", deprecated.}
 proc debug*(n: PType; conf: ConfigRef = nil) {.exportc: "debugType", deprecated.}
 proc debug*(n: PNode; conf: ConfigRef = nil) {.exportc: "debugNode", deprecated.}

+proc typekinds*(t: PType) {.deprecated.} =
+  var t = t
+  var s = ""
+  while t != nil and t.len > 0:
+    s.add $t.kind
+    s.add " "
+    t = t.lastSon
+  echo s
+
 template debug*(x: PSym|PType|PNode) {.deprecated.} =
  when compiles(c.config):
    debug(c.config, x)
@@ -65,9 +79,21 @@ template mdbg*: bool {.deprecated.} =
  else:
    error()

+# --------------------------- ident tables ----------------------------------
+proc idTableGet*(t: TIdTable, key: PIdObj): RootRef
+proc idTableGet*(t: TIdTable, key: int): RootRef
+proc idTablePut*(t: var TIdTable, key: PIdObj, val: RootRef)
+proc idTableHasObjectAsKey*(t: TIdTable, key: PIdObj): bool
+  # checks if `t` contains the `key` (compared by the pointer value, not only
+  # `key`'s id)
+proc idNodeTableGet*(t: TIdNodeTable, key: PIdObj): PNode
+proc idNodeTablePut*(t: var TIdNodeTable, key: PIdObj, val: PNode)
+
 # ---------------------------------------------------------------------------

 proc lookupInRecord*(n: PNode, field: PIdent): PSym
+proc mustRehash*(length, counter: int): bool
+proc nextTry*(h, maxHash: Hash): Hash {.inline.}

 # ------------- table[int, int] ---------------------------------------------
 const
@@ -214,7 +240,175 @@ proc getNamedParamFromList*(list: PNode, ident: PIdent): PSym =
 proc hashNode(p: RootRef): Hash =
  result = hash(cast[pointer](p))

-import std/tables
+proc mustRehash(length, counter: int): bool =
+  assert(length > counter)
+  result = (length * 2 < counter * 3) or (length - counter < 4)
+
+proc rspaces(x: int): Rope =
+  # returns x spaces
+  result = rope(spaces(x))
+
+proc toYamlChar(c: char): string =
+  case c
+  of '\0'..'\x1F', '\x7F'..'\xFF': result = "\\u" & strutils.toHex(ord(c), 4)
+  of '\'', '\"', '\\': result = '\\' & c
+  else: result = $c
+
+proc makeYamlString*(s: string): Rope =
+  # We have to split long strings into many ropes. Otherwise
+  # this could trigger InternalError(111). See the ropes module for
+  # further information.
+  const MaxLineLength = 64
+  result = ""
+  var res = "\""
+  for i in 0..<s.len:
+    if (i + 1) mod MaxLineLength == 0:
+      res.add('\"')
+      res.add("\n")
+      result.add(rope(res))
+      res = "\""              # reset
+    res.add(toYamlChar(s[i]))
+  res.add('\"')
+  result.add(rope(res))
+
+proc flagsToStr[T](flags: set[T]): Rope =
+  if flags == {}:
+    result = rope("[]")
+  else:
+    result = ""
+    for x in items(flags):
+      if result != "": result.add(", ")
+      result.add(makeYamlString($x))
+    result = "[" & result & "]"
+
+proc lineInfoToStr(conf: ConfigRef; info: TLineInfo): Rope =
+  result = "[$1, $2, $3]" % [makeYamlString(toFilename(conf, info)),
+                             rope(toLinenumber(info)),
+                             rope(toColumn(info))]
+
+proc treeToYamlAux(conf: ConfigRef; n: PNode, marker: var IntSet,
+                   indent, maxRecDepth: int): Rope
+proc symToYamlAux(conf: ConfigRef; n: PSym, marker: var IntSet,
+                  indent, maxRecDepth: int): Rope
+proc typeToYamlAux(conf: ConfigRef; n: PType, marker: var IntSet,
+                   indent, maxRecDepth: int): Rope
+
+proc symToYamlAux(conf: ConfigRef; n: PSym, marker: var IntSet, indent: int,
+                  maxRecDepth: int): Rope =
+  if n == nil:
+    result = rope("null")
+  elif containsOrIncl(marker, n.id):
+    result = "\"$1\"" % [rope(n.name.s)]
+  else:
+    var ast = treeToYamlAux(conf, n.ast, marker, indent + 2, maxRecDepth - 1)
+                                 #rope("typ"), typeToYamlAux(conf, n.typ, marker,
+                                 #  indent + 2, maxRecDepth - 1),
+    let istr = rspaces(indent + 2)
+    result = rope("{")
+    result.addf("$N$1\"kind\": $2", [istr, makeYamlString($n.kind)])
+    result.addf("$N$1\"name\": $2", [istr, makeYamlString(n.name.s)])
+    result.addf("$N$1\"typ\": $2", [istr, typeToYamlAux(conf, n.typ, marker, indent + 2, maxRecDepth - 1)])
+    if conf != nil:
+      # if we don't pass the config, we probably don't care about the line info
+      result.addf("$N$1\"info\": $2", [istr, lineInfoToStr(conf, n.info)])
+    if card(n.flags) > 0:
+      result.addf("$N$1\"flags\": $2", [istr, flagsToStr(n.flags)])
+    result.addf("$N$1\"magic\": $2", [istr, makeYamlString($n.magic)])
+    result.addf("$N$1\"ast\": $2", [istr, ast])
+    result.addf("$N$1\"options\": $2", [istr, flagsToStr(n.options)])
+    result.addf("$N$1\"position\": $2", [istr, rope(n.position)])
+    result.addf("$N$1\"k\": $2", [istr, makeYamlString($n.loc.k)])
+    result.addf("$N$1\"storage\": $2", [istr, makeYamlString($n.loc.storage)])
+    if card(n.loc.flags) > 0:
+      result.addf("$N$1\"flags\": $2", [istr, makeYamlString($n.loc.flags)])
+    result.addf("$N$1\"r\": $2", [istr, n.loc.r])
+    result.addf("$N$1\"lode\": $2", [istr, treeToYamlAux(conf, n.loc.lode, marker, indent + 2, maxRecDepth - 1)])
+    result.addf("$N$1}", [rspaces(indent)])
+
+proc typeToYamlAux(conf: ConfigRef; n: PType, marker: var IntSet, indent: int,
+                   maxRecDepth: int): Rope =
+  var sonsRope: Rope
+  if n == nil:
+    result = ""
+    sonsRope = rope("null")
+  elif containsOrIncl(marker, n.id):
+    result = ""
+    sonsRope = "\"$1 @$2\"" % [rope($n.kind), rope(
+        strutils.toHex(cast[int](n), sizeof(n) * 2))]
+  else:
+    if n.len > 0:
+      sonsRope = rope("[")
+      for i in 0..<n.len:
+        if i > 0: sonsRope.add(",")
+        sonsRope.addf("$N$1$2", [rspaces(indent + 4), typeToYamlAux(conf, n[i],
+            marker, indent + 4, maxRecDepth - 1)])
+      sonsRope.addf("$N$1]", [rspaces(indent + 2)])
+    else:
+      sonsRope = rope("null")
+
+    let istr = rspaces(indent + 2)
+    result = rope("{")
+    result.addf("$N$1\"kind\": $2", [istr, makeYamlString($n.kind)])
+    result.addf("$N$1\"sym\": $2",  [istr, symToYamlAux(conf, n.sym, marker, indent + 2, maxRecDepth - 1)])
+    result.addf("$N$1\"n\": $2",     [istr, treeToYamlAux(conf, n.n, marker, indent + 2, maxRecDepth - 1)])
+    if card(n.flags) > 0:
+      result.addf("$N$1\"flags\": $2", [istr, flagsToStr(n.flags)])
+    result.addf("$N$1\"callconv\": $2", [istr, makeYamlString($n.callConv)])
+    result.addf("$N$1\"size\": $2", [istr, rope(n.size)])
+    result.addf("$N$1\"align\": $2", [istr, rope(n.align)])
+    result.addf("$N$1\"sons\": $2", [istr, sonsRope])
+
+proc treeToYamlAux(conf: ConfigRef; n: PNode, marker: var IntSet, indent: int,
+                   maxRecDepth: int): Rope =
+  if n == nil:
+    result = rope("null")
+  else:
+    var istr = rspaces(indent + 2)
+    result = "{$N$1\"kind\": $2" % [istr, makeYamlString($n.kind)]
+    if maxRecDepth != 0:
+      if conf != nil:
+        result.addf(",$N$1\"info\": $2", [istr, lineInfoToStr(conf, n.info)])
+      case n.kind
+      of nkCharLit..nkInt64Lit:
+        result.addf(",$N$1\"intVal\": $2", [istr, rope(n.intVal)])
+      of nkFloatLit, nkFloat32Lit, nkFloat64Lit:
+        result.addf(",$N$1\"floatVal\": $2",
+            [istr, rope(n.floatVal.toStrMaxPrecision)])
+      of nkStrLit..nkTripleStrLit:
+        result.addf(",$N$1\"strVal\": $2", [istr, makeYamlString(n.strVal)])
+      of nkSym:
+        result.addf(",$N$1\"sym\": $2",
+             [istr, symToYamlAux(conf, n.sym, marker, indent + 2, maxRecDepth)])
+      of nkIdent:
+        if n.ident != nil:
+          result.addf(",$N$1\"ident\": $2", [istr, makeYamlString(n.ident.s)])
+        else:
+          result.addf(",$N$1\"ident\": null", [istr])
+      else:
+        if n.len > 0:
+          result.addf(",$N$1\"sons\": [", [istr])
+          for i in 0..<n.len:
+            if i > 0: result.add(",")
+            result.addf("$N$1$2", [rspaces(indent + 4), treeToYamlAux(conf, n[i],
+                marker, indent + 4, maxRecDepth - 1)])
+          result.addf("$N$1]", [istr])
+      result.addf(",$N$1\"typ\": $2",
+           [istr, typeToYamlAux(conf, n.typ, marker, indent + 2, maxRecDepth)])
+    result.addf("$N$1}", [rspaces(indent)])
+
+proc treeToYaml(conf: ConfigRef; n: PNode, indent: int = 0, maxRecDepth: int = - 1): Rope =
+  var marker = initIntSet()
+  result = treeToYamlAux(conf, n, marker, indent, maxRecDepth)
+
+proc typeToYaml(conf: ConfigRef; n: PType, indent: int = 0, maxRecDepth: int = - 1): Rope =
+  var marker = initIntSet()
+  result = typeToYamlAux(conf, n, marker, indent, maxRecDepth)
+
+proc symToYaml(conf: ConfigRef; n: PSym, indent: int = 0, maxRecDepth: int = - 1): Rope =
+  var marker = initIntSet()
+  result = symToYamlAux(conf, n, marker, indent, maxRecDepth)
+
+import tables

 const backrefStyle = "\e[90m"
 const enumStyle = "\e[34m"
@@ -378,12 +572,14 @@ proc value(this: var DebugPrinter; value: PType) =
    this.key "n"
    this.value value.n

-  this.key "sons"
-  this.openBracket
-  for i, a in value.ikids:
-    if i > 0: this.comma
-    this.value a
-  this.closeBracket
+  if value.len > 0:
+    this.key "sons"
+    this.openBracket
+    for i in 0..<value.len:
+      this.value value[i]
+      if i != value.len - 1:
+        this.comma
+    this.closeBracket

  if value.n != nil:
    this.key "n"
@@ -452,32 +648,35 @@ proc value(this: var DebugPrinter; value: PNode) =


 proc debug(n: PSym; conf: ConfigRef) =
-  var this = DebugPrinter(
-    visited: initTable[pointer, int](),
-    renderSymType: true,
-    useColor: not defined(windows)
-  )
+  var this: DebugPrinter
+  this.visited = initTable[pointer, int]()
+  this.renderSymType = true
+  this.useColor = not defined(windows)
  this.value(n)
  echo($this.res)

 proc debug(n: PType; conf: ConfigRef) =
-  var this = DebugPrinter(
-    visited: initTable[pointer, int](),
-    renderSymType: true,
-    useColor: not defined(windows)
-  )
+  var this: DebugPrinter
+  this.visited = initTable[pointer, int]()
+  this.renderSymType = true
+  this.useColor = not defined(windows)
  this.value(n)
  echo($this.res)

 proc debug(n: PNode; conf: ConfigRef) =
-  var this = DebugPrinter(
-    visited: initTable[pointer, int](),
-    renderSymType: false,
-    useColor: not defined(windows)
-  )
+  var this: DebugPrinter
+  this.visited = initTable[pointer, int]()
+  #this.renderSymType = true
+  this.useColor = not defined(windows)
  this.value(n)
  echo($this.res)

+proc nextTry(h, maxHash: Hash): Hash =
+  result = ((5 * h) + 1) and maxHash
+  # For any initial h in range(maxHash), repeating that maxHash times
+  # generates each int in range(maxHash) exactly once (see any text on
+  # random-number generation for proof).
+
 proc objectSetContains*(t: TObjectSet, obj: RootRef): bool =
  # returns true whether n is in t
  var h: Hash = hashNode(obj) and high(t.data) # start with real hash value
@@ -525,6 +724,95 @@ proc objectSetContainsOrIncl*(t: var TObjectSet, obj: RootRef): bool =
  inc(t.counter)
  result = false

+proc strTableContains*(t: TStrTable, n: PSym): bool =
+  var h: Hash = n.name.h and high(t.data) # start with real hash value
+  while t.data[h] != nil:
+    if (t.data[h] == n):
+      return true
+    h = nextTry(h, high(t.data))
+  result = false
+
+proc strTableRawInsert(data: var seq[PSym], n: PSym) =
+  var h: Hash = n.name.h and high(data)
+  while data[h] != nil:
+    if data[h] == n:
+      # allowed for 'export' feature:
+      #InternalError(n.info, "StrTableRawInsert: " & n.name.s)
+      return
+    h = nextTry(h, high(data))
+  assert(data[h] == nil)
+  data[h] = n
+
+proc symTabReplaceRaw(data: var seq[PSym], prevSym: PSym, newSym: PSym) =
+  assert prevSym.name.h == newSym.name.h
+  var h: Hash = prevSym.name.h and high(data)
+  while data[h] != nil:
+    if data[h] == prevSym:
+      data[h] = newSym
+      return
+    h = nextTry(h, high(data))
+  assert false
+
+proc symTabReplace*(t: var TStrTable, prevSym: PSym, newSym: PSym) =
+  symTabReplaceRaw(t.data, prevSym, newSym)
+
+proc strTableEnlarge(t: var TStrTable) =
+  var n: seq[PSym]
+  newSeq(n, t.data.len * GrowthFactor)
+  for i in 0..high(t.data):
+    if t.data[i] != nil: strTableRawInsert(n, t.data[i])
+  swap(t.data, n)
+
+proc strTableAdd*(t: var TStrTable, n: PSym) =
+  if mustRehash(t.data.len, t.counter): strTableEnlarge(t)
+  strTableRawInsert(t.data, n)
+  inc(t.counter)
+
+proc strTableInclReportConflict*(t: var TStrTable, n: PSym;
+                                 onConflictKeepOld = false): PSym =
+  # if `t` has a conflicting symbol (same identifier as `n`), return it
+  # otherwise return `nil`. Incl `n` to `t` unless `onConflictKeepOld = true`
+  # and a conflict was found.
+  assert n.name != nil
+  var h: Hash = n.name.h and high(t.data)
+  var replaceSlot = -1
+  while true:
+    var it = t.data[h]
+    if it == nil: break
+    # Semantic checking can happen multiple times thanks to templates
+    # and overloading: (var x=@[]; x).mapIt(it).
+    # So it is possible the very same sym is added multiple
+    # times to the symbol table which we allow here with the 'it == n' check.
+    if it.name.id == n.name.id:
+      if it == n: return nil
+      replaceSlot = h
+    h = nextTry(h, high(t.data))
+  if replaceSlot >= 0:
+    result = t.data[replaceSlot] # found it
+    if not onConflictKeepOld:
+      t.data[replaceSlot] = n # overwrite it with newer definition!
+    return result # but return the old one
+  elif mustRehash(t.data.len, t.counter):
+    strTableEnlarge(t)
+    strTableRawInsert(t.data, n)
+  else:
+    assert(t.data[h] == nil)
+    t.data[h] = n
+  inc(t.counter)
+  result = nil
+
+proc strTableIncl*(t: var TStrTable, n: PSym;
+                   onConflictKeepOld = false): bool {.discardable.} =
+  result = strTableInclReportConflict(t, n, onConflictKeepOld) != nil
+
+proc strTableGet*(t: TStrTable, name: PIdent): PSym =
+  var h: Hash = name.h and high(t.data)
+  while true:
+    result = t.data[h]
+    if result == nil: break
+    if result.name.id == name.id: break
+    h = nextTry(h, high(t.data))
+

 type
  TIdentIter* = object # iterator over all syms with same identifier
@@ -606,75 +894,124 @@ proc initTabIter*(ti: var TTabIter, tab: TStrTable): PSym =
    result = nextIter(ti, tab)

 iterator items*(tab: TStrTable): PSym =
-  var it: TTabIter = default(TTabIter)
+  var it: TTabIter
  var s = initTabIter(it, tab)
  while s != nil:
    yield s
    s = nextIter(it, tab)

-proc isNil(x: ItemId): bool {.inline.} =
-  x.module == 0 and x.item == 0
-
-proc hasEmptySlot[T](data: TIdPairSeq[T]): bool =
+proc hasEmptySlot(data: TIdPairSeq): bool =
  for h in 0..high(data):
-    if isNil(data[h].key):
+    if data[h].key == nil:
      return true
  result = false

-proc idTableRawGet[T](t: TIdTable[T], key: int): int =
+proc idTableRawGet(t: TIdTable, key: int): int =
  var h: Hash
  h = key and high(t.data)    # start with real hash value
-  while not isNil(t.data[h].key):
-    if toId(t.data[h].key) == key:
+  while t.data[h].key != nil:
+    if t.data[h].key.id == key:
      return h
    h = nextTry(h, high(t.data))
  result = - 1

-proc getOrDefault*[T](t: TIdTable[T], key: ItemId): T =
-  var index = idTableRawGet(t, toId(key))
+proc idTableHasObjectAsKey(t: TIdTable, key: PIdObj): bool =
+  var index = idTableRawGet(t, key.id)
+  if index >= 0: result = t.data[index].key == key
+  else: result = false
+
+proc idTableGet(t: TIdTable, key: PIdObj): RootRef =
+  var index = idTableRawGet(t, key.id)
  if index >= 0: result = t.data[index].val
-  else: result = default(T)
+  else: result = nil

-template idTableGet*[T](t: TIdTable[T], key: PType | PSym): T =
-  getOrDefault(t, key.itemId)
+proc idTableGet(t: TIdTable, key: int): RootRef =
+  var index = idTableRawGet(t, key)
+  if index >= 0: result = t.data[index].val
+  else: result = nil

-proc idTableRawInsert[T](data: var TIdPairSeq[T], key: ItemId, val: T) =
+iterator pairs*(t: TIdTable): tuple[key: int, value: RootRef] =
+  for i in 0..high(t.data):
+    if t.data[i].key != nil:
+      yield (t.data[i].key.id, t.data[i].val)
+
+proc idTableRawInsert(data: var TIdPairSeq, key: PIdObj, val: RootRef) =
  var h: Hash
-  let keyId = toId(key)
-  h = keyId and high(data)
-  while not isNil(data[h].key):
-    assert(toId(data[h].key) != keyId)
+  h = key.id and high(data)
+  while data[h].key != nil:
+    assert(data[h].key.id != key.id)
    h = nextTry(h, high(data))
-  assert(isNil(data[h].key))
+  assert(data[h].key == nil)
  data[h].key = key
  data[h].val = val

-proc `[]=`*[T](t: var TIdTable[T], key: ItemId, val: T) =
+proc idTablePut(t: var TIdTable, key: PIdObj, val: RootRef) =
  var
    index: int
-    n: TIdPairSeq[T]
-  index = idTableRawGet(t, toId(key))
+    n: TIdPairSeq
+  index = idTableRawGet(t, key.id)
  if index >= 0:
-    assert(not isNil(t.data[index].key))
+    assert(t.data[index].key != nil)
    t.data[index].val = val
  else:
    if mustRehash(t.data.len, t.counter):
      newSeq(n, t.data.len * GrowthFactor)
      for i in 0..high(t.data):
-        if not isNil(t.data[i].key):
+        if t.data[i].key != nil:
          idTableRawInsert(n, t.data[i].key, t.data[i].val)
      assert(hasEmptySlot(n))
      swap(t.data, n)
    idTableRawInsert(t.data, key, val)
    inc(t.counter)

-template idTablePut*[T](t: var TIdTable[T], key: PType | PSym, val: T) =
-  t[key.itemId] = val
-
-iterator idTablePairs*[T](t: TIdTable[T]): tuple[key: ItemId, val: T] =
+iterator idTablePairs*(t: TIdTable): tuple[key: PIdObj, val: RootRef] =
  for i in 0..high(t.data):
-    if not isNil(t.data[i].key):
-      yield (t.data[i].key, t.data[i].val)
+    if not isNil(t.data[i].key): yield (t.data[i].key, t.data[i].val)
+
+proc idNodeTableRawGet(t: TIdNodeTable, key: PIdObj): int =
+  var h: Hash
+  h = key.id and high(t.data) # start with real hash value
+  while t.data[h].key != nil:
+    if t.data[h].key.id == key.id:
+      return h
+    h = nextTry(h, high(t.data))
+  result = - 1
+
+proc idNodeTableGet(t: TIdNodeTable, key: PIdObj): PNode =
+  var index: int
+  index = idNodeTableRawGet(t, key)
+  if index >= 0: result = t.data[index].val
+  else: result = nil
+
+proc idNodeTableRawInsert(data: var TIdNodePairSeq, key: PIdObj, val: PNode) =
+  var h: Hash
+  h = key.id and high(data)
+  while data[h].key != nil:
+    assert(data[h].key.id != key.id)
+    h = nextTry(h, high(data))
+  assert(data[h].key == nil)
+  data[h].key = key
+  data[h].val = val
+
+proc idNodeTablePut(t: var TIdNodeTable, key: PIdObj, val: PNode) =
+  var index = idNodeTableRawGet(t, key)
+  if index >= 0:
+    assert(t.data[index].key != nil)
+    t.data[index].val = val
+  else:
+    if mustRehash(t.data.len, t.counter):
+      var n: TIdNodePairSeq
+      newSeq(n, t.data.len * GrowthFactor)
+      for i in 0..high(t.data):
+        if t.data[i].key != nil:
+          idNodeTableRawInsert(n, t.data[i].key, t.data[i].val)
+      swap(t.data, n)
+    idNodeTableRawInsert(t.data, key, val)
+    inc(t.counter)
+
+iterator pairs*(t: TIdNodeTable): tuple[key: PIdObj, val: PNode] =
+  for i in 0..high(t.data):
+    if not isNil(t.data[i].key): yield (t.data[i].key, t.data[i].val)

 proc initIITable(x: var TIITable) =
  x.counter = 0
@@ -721,6 +1058,14 @@ proc iiTablePut(t: var TIITable, key, val: int) =
    iiTableRawInsert(t.data, key, val)
    inc(t.counter)

+proc isAddrNode*(n: PNode): bool =
+  case n.kind
+    of nkAddr, nkHiddenAddr: true
+    of nkCallKinds:
+      if n[0].kind == nkSym and n[0].sym.magic == mAddr: true
+      else: false
+    else: false
+
 proc listSymbolNames*(symbols: openArray[PSym]): string =
  result = ""
  for sym in symbols:
--- a/compiler/astdef.nim
+++ b/compiler/astdef.nim
--- a/compiler/astmsgs.nim
+++ b/compiler/astmsgs.nim
@@ -5,7 +5,7 @@ import options, ast, msgs
 proc typSym*(t: PType): PSym =
  result = t.sym
  if result == nil and t.kind == tyGenericInst: # this might need to be refined
-    result = t.genericHead.sym
+    result = t[0].sym

 proc addDeclaredLoc*(result: var string, conf: ConfigRef; sym: PSym) =
  result.add " [$1 declared in $2]" % [sym.kind.toHumanStr, toFileLineCol(conf, sym.info)]
@@ -24,12 +24,6 @@ proc addDeclaredLoc*(result: var string, conf: ConfigRef; typ: PType) =
    result.add " declared in " & toFileLineCol(conf, typ.sym.info)
  result.add "]"

-proc addTypeNodeDeclaredLoc*(result: var string, conf: ConfigRef; typ: PType) =
-  result.add " [$1" % typ.kind.toHumanStr
-  if typ.sym != nil:
-    result.add " declared in " & toFileLineCol(conf, typ.sym.info)
-  result.add "]"
-
 proc addDeclaredLocMaybe*(result: var string, conf: ConfigRef; typ: PType) =
  if optDeclaredLocs in conf.globalOptions: addDeclaredLoc(result, conf, typ)

--- a/compiler/astyaml.nim
+++ b/compiler/astyaml.nim
@@ -1,160 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2012 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-# AST YAML printing
-
-import "."/[ast, lineinfos, msgs, options, rodutils]
-import std/[intsets, strutils]
-
-proc addYamlString*(res: var string; s: string) =
-  res.add "\""
-  for c in s:
-    case c
-    of '\0' .. '\x1F', '\x7F' .. '\xFF':
-      res.add("\\u" & strutils.toHex(ord(c), 4))
-    of '\"', '\\':
-      res.add '\\' & c
-    else:
-      res.add c
-
-  res.add('\"')
-
-proc makeYamlString(s: string): string =
-  result = ""
-  result.addYamlString(s)
-
-proc flagsToStr[T](flags: set[T]): string =
-  if flags == {}:
-    result = "[]"
-  else:
-    result = ""
-    for x in items(flags):
-      if result != "":
-        result.add(", ")
-      result.addYamlString($x)
-    result = "[" & result & "]"
-
-proc lineInfoToStr*(conf: ConfigRef; info: TLineInfo): string =
-  result = "["
-  result.addYamlString(toFilename(conf, info))
-  result.addf ", $1, $2]", toLinenumber(info), toColumn(info)
-
-proc treeToYamlAux(res: var string; conf: ConfigRef; n: PNode; marker: var IntSet; nl: bool, indent, maxRecDepth: int)
-proc symToYamlAux(res: var string; conf: ConfigRef; n: PSym; marker: var IntSet; nl: bool, indent, maxRecDepth: int)
-proc typeToYamlAux(res: var string; conf: ConfigRef; n: PType; marker: var IntSet; nl: bool, indent, maxRecDepth: int)
-
-proc symToYamlAux(res: var string; conf: ConfigRef; n: PSym; marker: var IntSet; nl: bool, indent: int; maxRecDepth: int) =
-  if n == nil:
-    res.add("null")
-  elif containsOrIncl(marker, n.id):
-    res.addYamlString(n.name.s)
-  else:
-    let istr = spaces(indent * 4)
-
-    if nl:
-      res.addf("\n$1", istr)
-    res.addf("kind: $1", [makeYamlString($n.kind)])
-    res.addf("\n$1name: $2", [istr, makeYamlString(n.name.s)])
-    res.addf("\n$1typ: ", [istr])
-    res.typeToYamlAux(conf, n.typ, marker, true, indent + 1, maxRecDepth - 1)
-    if conf != nil:
-      # if we don't pass the config, we probably don't care about the line info
-      res.addf("\n$1info: $2", [istr, lineInfoToStr(conf, n.info)])
-    if card(n.flags) > 0:
-      res.addf("\n$1flags: $2", [istr, flagsToStr(n.flags)])
-    res.addf("\n$1magic: $2", [istr, makeYamlString($n.magic)])
-    res.addf("\n$1ast: ", [istr])
-    res.treeToYamlAux(conf, n.ast, marker, true, indent + 1, maxRecDepth - 1)
-    res.addf("\n$1options: $2", [istr, flagsToStr(n.options)])
-    res.addf("\n$1position: $2", [istr, $n.position])
-    res.addf("\n$1k: $2", [istr, makeYamlString($n.loc.k)])
-    res.addf("\n$1storage: $2", [istr, makeYamlString($n.loc.storage)])
-    if card(n.loc.flags) > 0:
-      res.addf("\n$1flags: $2", [istr, makeYamlString($n.loc.flags)])
-    res.addf("\n$1snippet: $2", [istr, n.loc.snippet])
-    res.addf("\n$1lode: ", [istr])
-    res.treeToYamlAux(conf, n.loc.lode, marker, true, indent + 1, maxRecDepth - 1)
-
-proc typeToYamlAux(res: var string; conf: ConfigRef; n: PType; marker: var IntSet; nl: bool, indent: int; maxRecDepth: int) =
-  if n == nil:
-    res.add("null")
-  elif containsOrIncl(marker, n.id):
-    res.addf "\"$1 @$2\"" % [$n.kind, strutils.toHex(cast[uint](n), sizeof(n) * 2)]
-  else:
-    let istr = spaces(indent * 4)
-    if nl:
-      res.addf("\n$1", istr)
-    res.addf("kind: $2", [istr, makeYamlString($n.kind)])
-    res.addf("\n$1sym: ", istr)
-    res.symToYamlAux(conf, n.sym, marker, true, indent + 1, maxRecDepth - 1)
-    res.addf("\n$1n: ", istr)
-    res.treeToYamlAux(conf, n.n, marker, true, indent + 1, maxRecDepth - 1)
-    if card(n.flags) > 0:
-      res.addf("\n$1flags: $2", [istr, flagsToStr(n.flags)])
-    res.addf("\n$1callconv: $2", [istr, makeYamlString($n.callConv)])
-    res.addf("\n$1size: $2", [istr, $(n.size)])
-    res.addf("\n$1align: $2", [istr, $(n.align)])
-    if n.hasElementType:
-      res.addf("\n$1sons:", istr)
-      for a in n.kids:
-        res.addf("\n$1  - ", istr)
-        res.typeToYamlAux(conf, a, marker, false, indent + 1, maxRecDepth - 1)
-
-proc treeToYamlAux(res: var string; conf: ConfigRef; n: PNode; marker: var IntSet; nl: bool, indent: int;
-                   maxRecDepth: int) =
-  if n == nil:
-    res.add("null")
-  else:
-    var istr = spaces(indent * 4)
-    if nl:
-      res.addf("\n$1", istr)
-    res.addf("kind: $1" % [makeYamlString($n.kind)])
-
-    if maxRecDepth != 0:
-      if conf != nil:
-        res.addf("\n$1info: $2", [istr, lineInfoToStr(conf, n.info)])
-      case n.kind
-      of nkCharLit .. nkUInt64Lit:
-        res.addf("\n$1intVal: $2", [istr, $(n.intVal)])
-      of nkFloatLit .. nkFloat128Lit:
-        res.addf("\n$1floatVal: $2", [istr, n.floatVal.toStrMaxPrecision])
-      of nkStrLit .. nkTripleStrLit:
-        res.addf("\n$1strVal: $2", [istr, makeYamlString(n.strVal)])
-      of nkSym:
-        res.addf("\n$1sym: ", [istr])
-        res.symToYamlAux(conf, n.sym, marker, true, indent + 1, maxRecDepth)
-      of nkIdent:
-        if n.ident != nil:
-          res.addf("\n$1ident: $2", [istr, makeYamlString(n.ident.s)])
-        else:
-          res.addf("\n$1ident: null", [istr])
-      else:
-        if n.len > 0:
-          res.addf("\n$1sons: ", [istr])
-          for i in 0 ..< n.len:
-            res.addf("\n$1  - ", [istr])
-            res.treeToYamlAux(conf, n[i], marker, false, indent + 1, maxRecDepth - 1)
-      if n.typ != nil:
-        res.addf("\n$1typ: ", [istr])
-        res.typeToYamlAux(conf, n.typ, marker, true, indent + 1, maxRecDepth)
-
-proc treeToYaml*(conf: ConfigRef; n: PNode; indent: int = 0; maxRecDepth: int = -1): string =
-  var marker = initIntSet()
-  result = newStringOfCap(1024)
-  result.treeToYamlAux(conf, n, marker, false, indent, maxRecDepth)
-
-proc typeToYaml*(conf: ConfigRef; n: PType; indent: int = 0; maxRecDepth: int = -1): string =
-  var marker = initIntSet()
-  result = newStringOfCap(1024)
-  result.typeToYamlAux(conf, n, marker, false, indent, maxRecDepth)
-
-proc symToYaml*(conf: ConfigRef; n: PSym; indent: int = 0; maxRecDepth: int = -1): string =
-  var marker = initIntSet()
-  result = newStringOfCap(1024)
-  result.symToYamlAux(conf, n, marker, false, indent, maxRecDepth)
--- a/compiler/backendpragmas.nim
+++ b/compiler/backendpragmas.nim
@@ -0,0 +1,25 @@
+import pragmas, options, ast, trees
+
+proc pushBackendOption(optionsStack: var seq[TOptions], options: var TOptions) =
+  optionsStack.add options
+
+proc popBackendOption(optionsStack: var seq[TOptions], options: var TOptions) =
+  options = optionsStack[^1]
+  optionsStack.setLen(optionsStack.len-1)
+
+proc processPushBackendOption*(optionsStack: var seq[TOptions], options: var TOptions,
+                           n: PNode, start: int) =
+  pushBackendOption(optionsStack, options)
+  for i in start..<n.len:
+    let it = n[i]
+    if it.kind in nkPragmaCallKinds and it.len == 2 and it[1].kind == nkIntLit:
+      let sw = whichPragma(it[0])
+      let opts = pragmaToOptions(sw)
+      if opts != {}:
+        if it[1].intVal != 0:
+          options.incl opts
+        else:
+          options.excl opts
+
+template processPopBackendOption*(optionsStack: var seq[TOptions], options: var TOptions) =
+  popBackendOption(optionsStack, options)
--- a/compiler/bitsets.nim
+++ b/compiler/bitsets.nim
@@ -90,8 +90,3 @@ proc bitSetCard*(x: TBitSet): BiggestInt =
  result = 0
  for it in x:
    result.inc int(populationCount[it])
-
-proc bitSetToWord*(s: TBitSet; size: int): BiggestUInt =
-  result = 0
-  for j in 0..<size:
-    if j < s.len: result = result or (BiggestUInt(s[j]) shl (j * 8))
--- a/compiler/btrees.nim
+++ b/compiler/btrees.nim
@@ -69,7 +69,7 @@ proc copyHalf[Key, Val](h, result: Node[Key, Val]) =
      result.links[j] = h.links[Mhalf + j]
  else:
    for j in 0..<Mhalf:
-      when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc) or defined(gcYrc):
+      when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc):
        result.vals[j] = move h.vals[Mhalf + j]
      else:
        shallowCopy(result.vals[j], h.vals[Mhalf + j])
@@ -92,7 +92,7 @@ proc insert[Key, Val](h: Node[Key, Val], key: Key, val: Val): Node[Key, Val] =
      if less(key, h.keys[j]): break
      inc j
    for i in countdown(h.entries, j+1):
-      when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc) or defined(gcYrc):
+      when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc):
        h.vals[i] = move h.vals[i-1]
      else:
        shallowCopy(h.vals[i], h.vals[i-1])
--- a/compiler/cbuilderbase.nim
+++ b/compiler/cbuilderbase.nim
@@ -1,164 +0,0 @@
-import ropes, int128
-
-type
-  Snippet* = string
-  Builder* = object
-    buf*: string
-    indents*: int
-
-template newBuilder*(s: string): Builder =
-  Builder(buf: s)
-
-proc extract*(builder: Builder): Snippet =
-  builder.buf
-
-proc add*(builder: var Builder, s: string) =
-  builder.buf.add(s)
-
-proc add*(builder: var Builder, s: char) =
-  builder.buf.add(s)
-
-proc addNewline*(builder: var Builder) =
-  builder.add('\n')
-  for i in 0 ..< builder.indents:
-    builder.add('\t')
-
-proc addLineEnd*(builder: var Builder, s: string) =
-  builder.add(s)
-  builder.addNewline()
-
-proc addLineEndIndent*(builder: var Builder, s: string) =
-  inc builder.indents
-  builder.add(s)
-  builder.addNewline()
-
-proc addDedent*(builder: var Builder, s: string) =
-  if builder.buf.len > 0 and builder.buf[^1] == '\t':
-    builder.buf.setLen(builder.buf.len - 1)
-  builder.add(s)
-  dec builder.indents
-
-proc addLineEndDedent*(builder: var Builder, s: string) =
-  builder.addDedent(s)
-  builder.addNewline()
-
-proc addLineComment*(builder: var Builder, comment: string) =
-  # probably no-op on nifc
-  builder.add("// ")
-  builder.add(comment)
-  builder.addNewline()
-
-proc addIntValue*(builder: var Builder, val: int) =
-  builder.buf.addInt(val)
-
-proc addIntValue*(builder: var Builder, val: int64) =
-  builder.buf.addInt(val)
-
-proc addIntValue*(builder: var Builder, val: uint64) =
-  builder.buf.addInt(val)
-
-proc addIntValue*(builder: var Builder, val: Int128) =
-  builder.buf.addInt128(val)
-
-template cIntValue*(val: int): Snippet = $val
-template cIntValue*(val: int64): Snippet = $val
-template cIntValue*(val: uint64): Snippet = $val
-template cIntValue*(val: Int128): Snippet = $val
-
-template cUintValue*(val: uint): Snippet = $val & "U"
-
-import std/formatfloat
-
-proc addFloatValue*(builder: var Builder, val: float) =
-  builder.buf.addFloat(val)
-
-template cFloatValue*(val: float): Snippet = $val
-
-proc addInt64Literal*(result: var Builder; i: BiggestInt) =
-  if i > low(int64):
-    result.add "IL64($1)" % [rope(i)]
-  else:
-    result.add "(IL64(-9223372036854775807) - IL64(1))"
-
-proc addUint64Literal*(result: var Builder; i: uint64) =
-  result.add rope($i & "ULL")
-
-proc addIntLiteral*(result: var Builder; i: BiggestInt) =
-  if i > low(int32) and i <= high(int32):
-    result.addIntValue(i)
-  elif i == low(int32):
-    # Nim has the same bug for the same reasons :-)
-    result.add "(-2147483647 -1)"
-  elif i > low(int64):
-    result.add "IL64($1)" % [rope(i)]
-  else:
-    result.add "(IL64(-9223372036854775807) - IL64(1))"
-
-proc addIntLiteral*(result: var Builder; i: Int128) =
-  addIntLiteral(result, toInt64(i))
-
-proc cInt64Literal*(i: BiggestInt): Snippet =
-  if i > low(int64):
-    result = "IL64($1)" % [rope(i)]
-  else:
-    result = "(IL64(-9223372036854775807) - IL64(1))"
-
-proc cUint64Literal*(i: uint64): Snippet =
-  result = $i & "ULL"
-
-proc cIntLiteral*(i: BiggestInt): Snippet =
-  if i > low(int32) and i <= high(int32):
-    result = rope(i)
-  elif i == low(int32):
-    # Nim has the same bug for the same reasons :-)
-    result = "(-2147483647 -1)"
-  elif i > low(int64):
-    result = "IL64($1)" % [rope(i)]
-  else:
-    result = "(IL64(-9223372036854775807) - IL64(1))"
-
-proc cIntLiteral*(i: Int128): Snippet =
-  result = cIntLiteral(toInt64(i))
-
-const
-  NimInt* = "NI"
-  NimInt8* = "NI8"
-  NimInt16* = "NI16"
-  NimInt32* = "NI32"
-  NimInt64* = "NI64"
-  CInt* = "int"
-  NimUint* = "NU"
-  NimUint8* = "NU8"
-  NimUint16* = "NU16"
-  NimUint32* = "NU32"
-  NimUint64* = "NU64"
-  NimFloat* = "NF"
-  NimFloat32* = "NF32"
-  NimFloat64* = "NF64"
-  NimFloat128* = "NF128" # not actually defined
-  NimNan* = "NAN"
-  NimInf* = "INF"
-  NimBool* = "NIM_BOOL"
-  NimTrue* = "NIM_TRUE"
-  NimFalse* = "NIM_FALSE"
-  NimChar* = "NIM_CHAR"
-  CChar* = "char"
-  NimCstring* = "NCSTRING"
-  NimNil* = "NIM_NIL"
-  CNil* = "NULL"
-  NimStrlitFlag* = "NIM_STRLIT_FLAG"
-  CVoid* = "void"
-  CPointer* = "void*"
-  CConstPointer* = "NIM_CONST void*"
-
-proc cIntType*(bits: BiggestInt): Snippet =
-  "NI" & $bits
-
-proc cUintType*(bits: BiggestInt): Snippet =
-  "NU" & $bits
-
-type
-  IfBuilderState* = enum
-    WaitingIf, WaitingElseIf, InBlock
-  IfBuilder* = object
-    state*: IfBuilderState
--- a/compiler/cbuilderdecls.nim
+++ b/compiler/cbuilderdecls.nim
@@ -1,668 +0,0 @@
-type VarKind = enum
-  Local
-  Global
-  Threadvar
-  Const
-  AlwaysConst ## const even on C++
-
-proc addVarHeader(builder: var Builder, kind: VarKind) =
-  ## adds modifiers for given var kind:
-  ## Local has no modifier
-  ## Global has `static` modifier
-  ## Const has `static NIM_CONST` modifier
-  ## AlwaysConst has `static const` modifier (NIM_CONST is no-op on C++)
-  ## Threadvar is unimplemented
-  case kind
-  of Local: discard
-  of Global:
-    builder.add("static ")
-  of Const:
-    builder.add("static NIM_CONST ")
-  of AlwaysConst:
-    builder.add("static const ")
-  of Threadvar:
-    doAssert false, "unimplemented"
-
-proc addVar(builder: var Builder, kind: VarKind = Local, name: string, typ: Snippet, initializer: Snippet = "") =
-  ## adds a variable declaration to the builder
-  builder.addVarHeader(kind)
-  builder.add(typ)
-  builder.add(" ")
-  builder.add(name)
-  if initializer.len != 0:
-    builder.add(" = ")
-    builder.add(initializer)
-  builder.addLineEnd(";")
-
-template addVarWithType(builder: var Builder, kind: VarKind = Local, name: string, body: typed) =
-  ## adds a variable declaration to the builder, with the `body` building the type
-  builder.addVarHeader(kind)
-  body
-  builder.add(" ")
-  builder.add(name)
-  builder.addLineEnd(";")
-
-template addVarWithInitializer(builder: var Builder, kind: VarKind = Local, name: string,
-                               typ: Snippet, initializerBody: typed) =
-  ## adds a variable declaration to the builder, with
-  ## `initializerBody` building the initializer. initializer must be provided
-  builder.addVarHeader(kind)
-  builder.add(typ)
-  builder.add(" ")
-  builder.add(name)
-  builder.add(" = ")
-  initializerBody
-  builder.addLineEnd(";")
-
-template addVarWithTypeAndInitializer(builder: var Builder, kind: VarKind = Local, name: string,
-                                      typeBody, initializerBody: typed) =
-  ## adds a variable declaration to the builder, with `typeBody` building the type, and
-  ## `initializerBody` building the initializer. initializer must be provided
-  builder.addVarHeader(kind)
-  typeBody
-  builder.add(" ")
-  builder.add(name)
-  builder.add(" = ")
-  initializerBody
-  builder.addLineEnd(";")
-
-proc addArrayVar(builder: var Builder, kind: VarKind = Local, name: string, elementType: Snippet, len: int, initializer: Snippet = "") =
-  ## adds an array variable declaration to the builder
-  builder.addVarHeader(kind)
-  builder.add(elementType)
-  builder.add(" ")
-  builder.add(name)
-  builder.add("[")
-  builder.addIntValue(len)
-  builder.add("]")
-  if initializer.len != 0:
-    builder.add(" = ")
-    builder.add(initializer)
-  builder.addLineEnd(";")
-
-template addArrayVarWithInitializer(builder: var Builder, kind: VarKind = Local, name: string, elementType: Snippet, len: int, body: typed) =
-  ## adds an array variable declaration to the builder with the initializer built according to `body`
-  builder.addVarHeader(kind)
-  builder.add(elementType)
-  builder.add(" ")
-  builder.add(name)
-  builder.add("[")
-  builder.addIntValue(len)
-  builder.add("] = ")
-  body
-  builder.addLineEnd(";")
-
-template addTypedef(builder: var Builder, name: string, typeBody: typed) =
-  ## adds a typedef declaration to the builder with name `name` and type as
-  ## built in `typeBody`
-  builder.add("typedef ")
-  typeBody
-  builder.add(" ")
-  builder.add(name)
-  builder.addLineEnd(";")
-
-proc addProcTypedef(builder: var Builder, callConv: TCallingConvention, name: string, rettype, params: Snippet) =
-  builder.add("typedef ")
-  builder.add(CallingConvToStr[callConv])
-  builder.add("_PTR(")
-  builder.add(rettype)
-  builder.add(", ")
-  builder.add(name)
-  builder.add(")")
-  builder.add(params)
-  builder.addLineEnd(";")
-
-template addArrayTypedef(builder: var Builder, name: string, len: BiggestInt, typeBody: typed) =
-  ## adds an array typedef declaration to the builder with name `name`,
-  ## length `len`, and element type as built in `typeBody`
-  builder.add("typedef ")
-  typeBody
-  builder.add(" ")
-  builder.add(name)
-  builder.add("[")
-  builder.addIntValue(len)
-  builder.addLineEnd("];")
-
-type
-  StructInitializerKind = enum
-    siOrderedStruct ## struct constructor, but without named fields on C
-    siNamedStruct ## struct constructor, with named fields i.e. C99 designated initializer
-    siArray ## array constructor
-    siWrapper ## wrapper for a single field, generates it verbatim
-
-  StructInitializer = object
-    ## context for building struct initializers, i.e. `{ field1, field2 }`
-    kind: StructInitializerKind
-      ## if true, fields will not be named, instead values are placed in order
-    needsComma: bool
-
-proc initStructInitializer(builder: var Builder, kind: StructInitializerKind): StructInitializer =
-  ## starts building a struct initializer, i.e. braced initializer list
-  result = StructInitializer(kind: kind, needsComma: false)
-  if kind != siWrapper:
-    builder.add("{")
-
-template addField(builder: var Builder, constr: var StructInitializer, name: string, valueBody: typed) =
-  ## adds a field to a struct initializer, with the value built in `valueBody`
-  if constr.needsComma:
-    assert constr.kind != siWrapper, "wrapper constructor cannot have multiple fields"
-    builder.add(", ")
-  else:
-    constr.needsComma = true
-  case constr.kind
-  of siArray, siWrapper:
-    # no name, can just add value
-    valueBody
-  of siOrderedStruct:
-    # positional init - name not used in output (empty allowed for anonymous unions)
-    valueBody
-  of siNamedStruct:
-    # designated init - empty name for anonymous unions (skips .name = prefix)
-    if name.len != 0:
-      builder.add(".")
-      builder.add(name)
-      builder.add(" = ")
-    valueBody
-
-proc finishStructInitializer(builder: var Builder, constr: StructInitializer) =
-  ## finishes building a struct initializer
-  if constr.kind != siWrapper:
-    builder.add("}")
-
-template addStructInitializer(builder: var Builder, constr: out StructInitializer, kind: StructInitializerKind, body: typed) =
-  ## builds a struct initializer, i.e. `{ field1, field2 }`
-  ## a `var StructInitializer` must be declared and passed as a parameter so
-  ## that it can be used with `addField`
-  constr = builder.initStructInitializer(kind)
-  body
-  builder.finishStructInitializer(constr)
-
-proc addField(obj: var Builder; name, typ: Snippet; isFlexArray: bool = false; initializer: Snippet = "") =
-  ## adds a field inside a struct/union type
-  obj.add('\t')
-  obj.add(typ)
-  obj.add(" ")
-  obj.add(name)
-  if isFlexArray:
-    obj.add("[SEQ_DECL_SIZE]")
-  if initializer.len != 0:
-    obj.add(initializer)
-  obj.add(";\n")
-
-proc addArrayField(obj: var Builder; name, elementType: Snippet; len: int; initializer: Snippet = "") =
-  ## adds an array field inside a struct/union type
-  obj.add('\t')
-  obj.add(elementType)
-  obj.add(" ")
-  obj.add(name)
-  obj.add("[")
-  obj.addIntValue(len)
-  obj.add("]")
-  if initializer.len != 0:
-    obj.add(initializer)
-  obj.add(";\n")
-
-proc addField(obj: var Builder; field: PSym; name, typ: Snippet; isFlexArray: bool = false; initializer: Snippet = "") =
-  ## adds an field inside a struct/union type, based on an `skField` symbol
-  obj.add('\t')
-  if field.alignment > 0:
-    obj.add("NIM_ALIGN(")
-    obj.addIntValue(field.alignment)
-    obj.add(") ")
-  obj.add(typ)
-  if sfNoalias in field.flags:
-    obj.add(" NIM_NOALIAS")
-  obj.add(" ")
-  obj.add(name)
-  if isFlexArray:
-    obj.add("[SEQ_DECL_SIZE]")
-  if field.bitsize != 0:
-    obj.add(":")
-    obj.addIntValue(field.bitsize)
-  if initializer.len != 0:
-    obj.add(initializer)
-  obj.add(";\n")
-
-proc addProcField(obj: var Builder, callConv: TCallingConvention, name: string, rettype, params: Snippet) =
-  obj.add(CallingConvToStr[callConv])
-  obj.add("_PTR(")
-  obj.add(rettype)
-  obj.add(", ")
-  obj.add(name)
-  obj.add(")")
-  obj.add(params)
-  obj.add(";\n")
-
-type
-  BaseClassKind = enum
-    ## denotes how and whether or not the base class/RTTI should be stored
-    bcNone, bcCppInherit, bcSupField, bcNoneRtti, bcNoneTinyRtti
-  StructBuilderInfo = object
-    ## context for building `struct` types
-    baseKind: BaseClassKind
-    named: bool
-    preFieldsLen: int
-
-proc structOrUnion(t: PType): Snippet =
-  let t = t.skipTypes({tyAlias, tySink})
-  if tfUnion in t.flags: "union"
-  else: "struct"
-
-proc startSimpleStruct(obj: var Builder; m: BModule; name: string; baseType: Snippet): StructBuilderInfo =
-  result = StructBuilderInfo(baseKind: bcNone, named: name.len != 0)
-  obj.add("struct")
-  if result.named:
-    obj.add(" ")
-    obj.add(name)
-  if baseType.len != 0:
-    if m.compileToCpp:
-      result.baseKind = bcCppInherit
-    else:
-      result.baseKind = bcSupField
-  if result.baseKind == bcCppInherit:
-    obj.add(" : public ")
-    obj.add(baseType)
-  obj.add(" ")
-  obj.add("{\n")
-  result.preFieldsLen = obj.buf.len
-  if result.baseKind == bcSupField:
-    obj.addField(name = "Sup", typ = baseType)
-
-proc finishSimpleStruct(obj: var Builder; m: BModule; info: StructBuilderInfo) =
-  if info.baseKind == bcNone and info.preFieldsLen == obj.buf.len:
-    # no fields were added, add dummy field
-    obj.addField(name = "dummy", typ = CChar)
-  if info.named:
-    obj.add("};\n")
-  else:
-    obj.add("}")
-
-template addSimpleStruct(obj: var Builder; m: BModule; name: string; baseType: Snippet; body: typed) =
-  ## builds a struct type not based on a Nim type with fields according to `body`,
-  ## `name` can be empty to build as a type expression and not a statement
-  let info = startSimpleStruct(obj, m, name, baseType)
-  body
-  finishSimpleStruct(obj, m, info)
-
-proc startStruct(obj: var Builder; m: BModule; t: PType; name: string; baseType: Snippet): StructBuilderInfo =
-  result = StructBuilderInfo(baseKind: bcNone, named: name.len != 0)
-  if tfPacked in t.flags:
-    if hasAttribute in CC[m.config.cCompiler].props:
-      obj.add(structOrUnion(t))
-      obj.add(" __attribute__((__packed__))")
-    else:
-      obj.add("#pragma pack(push, 1)\n")
-      obj.add(structOrUnion(t))
-  else:
-    obj.add(structOrUnion(t))
-  if result.named:
-    obj.add(" ")
-    obj.add(name)
-  if t.kind == tyObject:
-    if t.baseClass == nil:
-      if lacksMTypeField(t):
-        result.baseKind = bcNone
-      elif optTinyRtti in m.config.globalOptions:
-        result.baseKind = bcNoneTinyRtti
-      else:
-        result.baseKind = bcNoneRtti
-    elif m.compileToCpp:
-      result.baseKind = bcCppInherit
-    else:
-      result.baseKind = bcSupField
-  elif baseType.len != 0:
-    if m.compileToCpp:
-      result.baseKind = bcCppInherit
-    else:
-      result.baseKind = bcSupField
-  if result.baseKind == bcCppInherit:
-    obj.add(" : public ")
-    obj.add(baseType)
-  obj.add(" ")
-  obj.add("{\n")
-  result.preFieldsLen = obj.buf.len
-  case result.baseKind
-  of bcNone:
-    # rest of the options add a field or don't need it due to inheritance,
-    # we need to add the dummy field for uncheckedarray ahead of time
-    # so that it remains trailing
-    if t.itemId notin m.g.graph.memberProcsPerType and
-        t.n != nil and t.n.len == 1 and t.n[0].kind == nkSym and
-        t.n[0].sym.typ.skipTypes(abstractInst).kind == tyUncheckedArray:
-      # only consists of flexible array field, add *initial* dummy field
-      obj.addField(name = "dummy", typ = CChar)
-  of bcCppInherit: discard
-  of bcNoneRtti:
-    obj.addField(name = "m_type", typ = ptrType(cgsymValue(m, "TNimType")))
-  of bcNoneTinyRtti:
-    obj.addField(name = "m_type", typ = ptrType(cgsymValue(m, "TNimTypeV2")))
-  of bcSupField:
-    obj.addField(name = "Sup", typ = baseType)
-
-proc finishStruct(obj: var Builder; m: BModule; t: PType; info: StructBuilderInfo) =
-  if info.baseKind == bcNone and info.preFieldsLen == obj.buf.len and
-      t.itemId notin m.g.graph.memberProcsPerType:
-    # no fields were added, add dummy field
-    obj.addField(name = "dummy", typ = CChar)
-  if info.named:
-    obj.add("};\n")
-  else:
-    obj.add("}")
-  if tfPacked in t.flags and hasAttribute notin CC[m.config.cCompiler].props:
-    obj.add("#pragma pack(pop)\n")
-
-template addStruct(obj: var Builder; m: BModule; typ: PType; name: string; baseType: Snippet; body: typed) =
-  ## builds a struct type directly based on `typ` with fields according to `body`,
-  ## `name` can be empty to build as a type expression and not a statement
-  let info = startStruct(obj, m, typ, name, baseType)
-  body
-  finishStruct(obj, m, typ, info)
-
-template addFieldWithStructType(obj: var Builder; m: BModule; parentTyp: PType; fieldName: string, body: typed) =
-  ## adds a field with a `struct { ... }` type, building the fields according to `body`
-  obj.add('\t')
-  if tfPacked in parentTyp.flags:
-    if hasAttribute in CC[m.config.cCompiler].props:
-      obj.add("struct __attribute__((__packed__)) {\n")
-    else:
-      obj.add("#pragma pack(push, 1)\nstruct {")
-  else:
-    obj.add("struct {\n")
-  body
-  obj.add("} ")
-  obj.add(fieldName)
-  obj.add(";\n")
-  if tfPacked in parentTyp.flags and hasAttribute notin CC[m.config.cCompiler].props:
-    obj.add("#pragma pack(pop)\n")
-
-template addAnonUnion(obj: var Builder; body: typed) =
-  ## adds an anonymous union i.e. `union { ... };` with fields according to `body`
-  obj.add "union{\n"
-  body
-  obj.add("};\n")
-
-template addUnionType(obj: var Builder; body: typed) =
-  ## adds a union type i.e. `union { ... }` with fields according to `body`
-  obj.add "union{\n"
-  body
-  obj.add("}")
-
-type DeclVisibility = enum
-  None
-  Extern
-  ExternC
-  ImportLib
-  ExportLib
-  ExportLibVar
-  Private
-  StaticProc
-
-proc addVisibilityPrefix(builder: var Builder, visibility: DeclVisibility) =
-  # internal proc
-  case visibility
-  of None: discard
-  of Extern:
-    builder.add("extern ")
-  of ExternC:
-    builder.add("NIM_EXTERNC ")
-  of ImportLib:
-    builder.add("N_LIB_IMPORT ")
-  of ExportLib:
-    builder.add("N_LIB_EXPORT ")
-  of ExportLibVar:
-    builder.add("N_LIB_EXPORT_VAR ")
-  of Private:
-    builder.add("N_LIB_PRIVATE ")
-  of StaticProc:
-    builder.add("static ")
-
-template addDeclWithVisibility(builder: var Builder, visibility: DeclVisibility, declBody: typed) =
-  ## adds a declaration as in `declBody` with the given visibility
-  builder.addVisibilityPrefix(visibility)
-  declBody
-
-type ProcParamBuilder = object
-  needsComma: bool
-
-proc initProcParamBuilder(builder: var Builder): ProcParamBuilder =
-  result = ProcParamBuilder(needsComma: false)
-  builder.add("(")
-
-proc finishProcParamBuilder(builder: var Builder, params: ProcParamBuilder) =
-  if params.needsComma:
-    builder.add(")")
-  else:
-    builder.add("void)")
-
-template cgDeclFrmt*(s: PSym): string =
-  s.constraint.strVal
-
-proc addParam(builder: var Builder, params: var ProcParamBuilder, name: string, typ: Snippet) =
-  if params.needsComma:
-    builder.add(", ")
-  else:
-    params.needsComma = true
-  builder.add(typ)
-  builder.add(" ")
-  builder.add(name)
-
-proc addParam(builder: var Builder, params: var ProcParamBuilder, param: PSym, typ: Snippet) =
-  if params.needsComma:
-    builder.add(", ")
-  else:
-    params.needsComma = true
-  var modifiedTyp = typ
-  if sfNoalias in param.flags:
-    modifiedTyp.add(" NIM_NOALIAS")
-  if sfCodegenDecl notin param.flags:
-    builder.add(modifiedTyp)
-    builder.add(" ")
-    builder.add(param.loc.snippet)
-  else:
-    builder.add runtimeFormat(param.cgDeclFrmt, [modifiedTyp, param.loc.snippet])
-
-proc addUnnamedParam(builder: var Builder, params: var ProcParamBuilder, typ: Snippet) =
-  if params.needsComma:
-    builder.add(", ")
-  else:
-    params.needsComma = true
-  builder.add(typ)
-
-proc addProcTypedParam(builder: var Builder, paramBuilder: var ProcParamBuilder, callConv: TCallingConvention, name: string, rettype, params: Snippet) =
-  if paramBuilder.needsComma:
-    builder.add(", ")
-  else:
-    paramBuilder.needsComma = true
-  builder.add(CallingConvToStr[callConv])
-  builder.add("_PTR(")
-  builder.add(rettype)
-  builder.add(", ")
-  builder.add(name)
-  builder.add(")")
-  builder.add(params)
-
-proc addVarargsParam(builder: var Builder, params: var ProcParamBuilder) =
-  # does not exist in NIFC, needs to be proc pragma
-  if params.needsComma:
-    builder.add(", ")
-  else:
-    params.needsComma = true
-  builder.add("...")
-
-template addProcParams(builder: var Builder, params: out ProcParamBuilder, body: typed) =
-  params = initProcParamBuilder(builder)
-  body
-  finishProcParamBuilder(builder, params)
-
-type SimpleProcParam = tuple
-  name, typ: string
-
-proc cProcParams(params: varargs[SimpleProcParam]): Snippet =
-  if params.len == 0: return "(void)"
-  result = "("
-  for i in 0 ..< params.len:
-    if i != 0: result.add(", ")
-    result.add(params[i].typ)
-    if params[i].name.len != 0:
-      result.add(" ")
-      result.add(params[i].name)
-  result.add(")")
-
-template addProcHeaderWithParams(builder: var Builder, callConv: TCallingConvention,
-                                 name: string, rettype: Snippet, paramBuilder: typed) =
-  # on nifc should build something like (proc name params type pragmas
-  # with no body given
-  # or enforce this with secondary builder object
-  builder.add(CallingConvToStr[callConv])
-  builder.add("(")
-  builder.add(rettype)
-  builder.add(", ")
-  builder.add(name)
-  builder.add(")")
-  paramBuilder
-
-proc addProcHeader(builder: var Builder, callConv: TCallingConvention,
-                   name: string, rettype, params: Snippet) =
-  # on nifc should build something like (proc name params type pragmas
-  # with no body given
-  # or enforce this with secondary builder object
-  addProcHeaderWithParams(builder, callConv, name, rettype):
-    builder.add(params)
-
-proc addProcHeader(builder: var Builder, name: string, rettype, params: Snippet, isConstructor = false) =
-  # no callconv
-  builder.add(rettype)
-  builder.add(" ")
-  if isConstructor:
-    builder.add("__attribute__((constructor)) ")
-  builder.add(name)
-  builder.add(params)
-
-proc addProcHeader(builder: var Builder, m: BModule, prc: PSym, name: string, params, rettype: Snippet, addAttributes: bool) =
-  # on nifc should build something like (proc name params type pragmas
-  # with no body given
-  # or enforce this with secondary builder object
-  let noreturn = isNoReturn(m, prc)
-  if sfPure in prc.flags and hasDeclspec in extccomp.CC[m.config.cCompiler].props:
-    builder.add("__declspec(naked) ")
-  if noreturn and hasDeclspec in extccomp.CC[m.config.cCompiler].props:
-    builder.add("__declspec(noreturn) ")
-  builder.add(CallingConvToStr[prc.typ.callConv])
-  builder.add("(")
-  builder.add(rettype)
-  builder.add(", ")
-  builder.add(name)
-  builder.add(")")
-  builder.add(params)
-  if addAttributes:
-    if sfPure in prc.flags and hasAttribute in extccomp.CC[m.config.cCompiler].props:
-      builder.add(" __attribute__((naked))")
-    if noreturn and hasAttribute in extccomp.CC[m.config.cCompiler].props:
-      builder.add(" __attribute__((noreturn))")
-
-proc finishProcHeaderAsProto(builder: var Builder) =
-  builder.addLineEnd(";")
-
-template finishProcHeaderWithBody(builder: var Builder, body: typed) =
-  builder.addLineEndIndent(" {")
-  body
-  builder.addLineEndDedent("}")
-  builder.addNewline
-
-proc addProcVar(builder: var Builder, m: BModule, prc: PSym, name: string, params, rettype: Snippet,
-                isStatic = false, ignoreAttributes = false) =
-  # on nifc, builds full variable
-  if isStatic:
-    builder.add("static ")
-  let noreturn = isNoReturn(m, prc)
-  if not ignoreAttributes:
-    if sfPure in prc.flags and hasDeclspec in extccomp.CC[m.config.cCompiler].props:
-      builder.add("__declspec(naked) ")
-    if noreturn and hasDeclspec in extccomp.CC[m.config.cCompiler].props:
-      builder.add("__declspec(noreturn) ")
-  builder.add(CallingConvToStr[prc.typ.callConv])
-  builder.add("_PTR(")
-  builder.add(rettype)
-  builder.add(", ")
-  builder.add(name)
-  builder.add(")")
-  builder.add(params)
-  if not ignoreAttributes:
-    if sfPure in prc.flags and hasAttribute in extccomp.CC[m.config.cCompiler].props:
-      builder.add(" __attribute__((naked))")
-    if noreturn and hasAttribute in extccomp.CC[m.config.cCompiler].props:
-      builder.add(" __attribute__((noreturn))")
-  # ensure we are just adding a variable:
-  builder.addLineEnd(";")
-
-proc addProcVar(builder: var Builder, callConv: TCallingConvention,
-                name: string, params, rettype: Snippet,
-                isStatic = false, isVolatile = false) =
-  # on nifc, builds full variable
-  if isStatic:
-    builder.add("static ")
-  builder.add(CallingConvToStr[callConv])
-  builder.add("_PTR(")
-  builder.add(rettype)
-  builder.add(", ")
-  if isVolatile:
-    builder.add("volatile ")
-  builder.add(name)
-  builder.add(")")
-  builder.add(params)
-  # ensure we are just adding a variable:
-  builder.addLineEnd(";")
-
-proc addProcVar(builder: var Builder,
-                name: string, params, rettype: Snippet,
-                isStatic = false, isVolatile = false) =
-  # no callconv
-  if isStatic:
-    builder.add("static ")
-  builder.add(rettype)
-  builder.add(" (*")
-  if isVolatile:
-    builder.add("volatile ")
-  builder.add(name)
-  builder.add(")")
-  builder.add(params)
-  # ensure we are just adding a variable:
-  builder.addLineEnd(";")
-
-type VarInitializerKind = enum
-  Assignment, CppConstructor
-
-proc addVar(builder: var Builder, m: BModule, s: PSym, name: string, typ: Snippet, kind = Local, visibility: DeclVisibility = None, initializer: Snippet = "", initializerKind: VarInitializerKind = Assignment) =
-  if sfCodegenDecl in s.flags:
-    builder.add(runtimeFormat(s.cgDeclFrmt, [typ, name]))
-    if initializer.len != 0:
-      if initializerKind == Assignment:
-        builder.add(" = ")
-      builder.add(initializer)
-    builder.addLineEnd(";")
-    return
-  if s.kind in {skLet, skVar, skField, skForVar} and s.alignment > 0:
-    builder.add("NIM_ALIGN(" & $s.alignment & ") ")
-  builder.addVisibilityPrefix(visibility)
-  if kind == Threadvar:
-    if optThreads in m.config.globalOptions:
-      let sym = s.typ.sym
-      if sym != nil and sfCppNonPod in sym.flags:
-        builder.add("NIM_THREAD_LOCAL ")
-      else: builder.add("NIM_THREADVAR ")
-  else:
-    builder.addVarHeader(kind)
-  builder.add(typ)
-  if sfRegister in s.flags: builder.add(" register")
-  if sfVolatile in s.flags: builder.add(" volatile")
-  if sfNoalias in s.flags: builder.add(" NIM_NOALIAS")
-  builder.add(" ")
-  builder.add(name)
-  if initializer.len != 0:
-    if initializerKind == Assignment:
-      builder.add(" = ")
-    builder.add(initializer)
-  builder.addLineEnd(";")
-
-proc addInclude(builder: var Builder, value: Snippet) =
-  builder.addLineEnd("#include " & value)
--- a/compiler/cbuilderexprs.nim
+++ b/compiler/cbuilderexprs.nim
@@ -1,259 +0,0 @@
-proc constType(t: Snippet): Snippet =
-  # needs manipulation of `t` in nifc
-  "NIM_CONST " & t
-
-proc constPtrType(t: Snippet): Snippet =
-  t & "* NIM_CONST"
-
-proc ptrConstType(t: Snippet): Snippet =
-  "NIM_CONST " & t & "*"
-
-proc ptrType(t: Snippet): Snippet =
-  t & "*"
-
-proc cppRefType(t: Snippet): Snippet =
-  t & "&"
-
-const
-  CallingConvToStr: array[TCallingConvention, string] = ["N_NIMCALL",
-    "N_STDCALL", "N_CDECL", "N_SAFECALL",
-    "N_SYSCALL", # this is probably not correct for all platforms,
-                 # but one can #define it to what one wants
-    "N_INLINE", "N_NOINLINE", "N_FASTCALL", "N_THISCALL", "N_CLOSURE", "N_NOCONV",
-    "N_NOCONV" #ccMember is N_NOCONV
-    ]
-
-proc procPtrTypeUnnamed(rettype, params: Snippet): Snippet =
-  rettype & "(*)" & params
-
-proc procPtrTypeUnnamedNimCall(rettype, params: Snippet): Snippet =
-  rettype & "(N_RAW_NIMCALL*)" & params
-
-proc procPtrTypeUnnamed(callConv: TCallingConvention, rettype, params: Snippet): Snippet =
-  CallingConvToStr[callConv] & "_PTR(" & rettype & ", )" & params
-
-type CppCaptureKind = enum None, ByReference, ByCopy
-
-template addCppLambda(builder: var Builder, captures: CppCaptureKind, params: Snippet, body: typed) =
-  builder.add("[")
-  case captures
-  of None: discard
-  of ByReference: builder.add("&")
-  of ByCopy: builder.add("=")
-  builder.add("] ")
-  builder.add(params)
-  builder.addLineEndIndent(" {")
-  body
-  builder.addLineEndDedent("}")
-
-proc cCast(typ, value: Snippet): Snippet =
-  "((" & typ & ") " & value & ")"
-
-proc wrapPar(value: Snippet): Snippet =
-  # used for expression group, no-op on sexp
-  "(" & value & ")"
-
-proc removeSinglePar(value: Snippet): Snippet =
-  # removes a single paren layer expected to exist, to silence Wparentheses-equality
-  assert value[0] == '(' and value[^1] == ')'
-  value[1..^2]
-
-template addCast(builder: var Builder, typ: Snippet, valueBody: typed) =
-  ## adds a cast to `typ` with value built by `valueBody`
-  builder.add "(("
-  builder.add typ
-  builder.add ") "
-  valueBody
-  builder.add ")"
-
-proc cAddr(value: Snippet): Snippet =
-  "(&" & value & ")"
-
-proc cLabelAddr(value: TLabel): Snippet =
-  "&&" & value
-
-proc cDeref(value: Snippet): Snippet =
-  "(*" & value & ")"
-
-proc subscript(a, b: Snippet): Snippet =
-  a & "[" & b & "]"
-
-proc dotField(a, b: Snippet): Snippet =
-  a & "." & b
-
-proc derefField(a, b: Snippet): Snippet =
-  a & "->" & b
-
-type CallBuilder = object
-  needsComma: bool
-
-proc initCallBuilder(builder: var Builder, callee: Snippet): CallBuilder =
-  result = CallBuilder(needsComma: false)
-  builder.add(callee)
-  builder.add("(")
-
-const cArgumentSeparator = ", "
-
-proc addArgumentSeparator(builder: var Builder) =
-  # no-op on NIFC
-  # used by "single argument" builders
-  builder.add(cArgumentSeparator)
-
-template addArgument(builder: var Builder, call: var CallBuilder, valueBody: typed) =
-  if call.needsComma:
-    builder.addArgumentSeparator()
-  else:
-    call.needsComma = true
-  valueBody
-
-proc finishCallBuilder(builder: var Builder, call: CallBuilder) =
-  builder.add(")")
-
-template addCall(builder: var Builder, call: out CallBuilder, callee: Snippet, body: typed) =
-  call = initCallBuilder(builder, callee)
-  body
-  finishCallBuilder(builder, call)
-
-proc addCall(builder: var Builder, callee: Snippet, args: varargs[Snippet]) =
-  builder.add(callee)
-  builder.add("(")
-  if args.len != 0:
-    builder.add(args[0])
-    for i in 1 ..< args.len:
-      builder.add(", ")
-      builder.add(args[i])
-  builder.add(")")
-
-proc cCall(callee: Snippet, args: varargs[Snippet]): Snippet =
-  result = callee
-  result.add("(")
-  if args.len != 0:
-    result.add(args[0])
-    for i in 1 ..< args.len:
-      result.add(", ")
-      result.add(args[i])
-  result.add(")")
-
-proc addSizeof(builder: var Builder, val: Snippet) =
-  builder.add("sizeof(")
-  builder.add(val)
-  builder.add(")")
-
-proc addAlignof(builder: var Builder, val: Snippet) =
-  builder.add("NIM_ALIGNOF(")
-  builder.add(val)
-  builder.add(")")
-
-proc addOffsetof(builder: var Builder, val, member: Snippet) =
-  builder.add("offsetof(")
-  builder.add(val)
-  builder.add(", ")
-  builder.add(member)
-  builder.add(")")
-
-template cSizeof(val: Snippet): Snippet =
-  "sizeof(" & val & ")"
-
-template cAlignof(val: Snippet): Snippet =
-  "NIM_ALIGNOF(" & val & ")"
-
-template cOffsetof(val, member: Snippet): Snippet =
-  "offsetof(" & val & ", " & member & ")"
-
-type TypedBinaryOp = enum
-  Add, Sub, Mul, Div, Mod
-  Shr, Shl, BitAnd, BitOr, BitXor
-
-const typedBinaryOperators: array[TypedBinaryOp, string] = [
-  Add: "+",
-  Sub: "-",
-  Mul: "*",
-  Div: "/",
-  Mod: "%",
-  Shr: ">>",
-  Shl: "<<",
-  BitAnd: "&",
-  BitOr: "|",
-  BitXor: "^"
-]
-
-type TypedUnaryOp = enum
-  Neg, BitNot
-
-const typedUnaryOperators: array[TypedUnaryOp, string] = [
-  Neg: "-",
-  BitNot: "~",
-]
-
-type UntypedBinaryOp = enum
-  LessEqual, LessThan, GreaterEqual, GreaterThan, Equal, NotEqual
-  And, Or
-
-const untypedBinaryOperators: array[UntypedBinaryOp, string] = [
-  LessEqual: "<=",
-  LessThan: "<",
-  GreaterEqual: ">=",
-  GreaterThan: ">",
-  Equal: "==",
-  NotEqual: "!=",
-  And: "&&",
-  Or: "||"
-]
-
-type UntypedUnaryOp = enum
-  Not
-
-const untypedUnaryOperators: array[UntypedUnaryOp, string] = [
-  Not: "!"
-]
-
-proc addOp(builder: var Builder, binOp: TypedBinaryOp, t: Snippet, a, b: Snippet) =
-  builder.add('(')
-  builder.add(a)
-  builder.add(' ')
-  builder.add(typedBinaryOperators[binOp])
-  builder.add(' ')
-  builder.add(b)
-  builder.add(')')
-
-proc addOp(builder: var Builder, unOp: TypedUnaryOp, t: Snippet, a: Snippet) =
-  builder.add('(')
-  builder.add(typedUnaryOperators[unOp])
-  builder.add('(')
-  builder.add(a)
-  builder.add("))")
-
-proc addOp(builder: var Builder, binOp: UntypedBinaryOp, a, b: Snippet) =
-  builder.add('(')
-  builder.add(a)
-  builder.add(' ')
-  builder.add(untypedBinaryOperators[binOp])
-  builder.add(' ')
-  builder.add(b)
-  builder.add(')')
-
-proc addOp(builder: var Builder, unOp: UntypedUnaryOp, a: Snippet) =
-  builder.add('(')
-  builder.add(untypedUnaryOperators[unOp])
-  builder.add('(')
-  builder.add(a)
-  builder.add("))")
-
-template cOp(binOp: TypedBinaryOp, t: Snippet, a, b: Snippet): Snippet =
-  '(' & a & ' ' & typedBinaryOperators[binOp] & ' ' & b & ')'
-
-template cOp(binOp: TypedUnaryOp, t: Snippet, a: Snippet): Snippet =
-  '(' & typedUnaryOperators[binOp] & '(' & a & "))"
-
-template cOp(binOp: UntypedBinaryOp, a, b: Snippet): Snippet =
-  '(' & a & ' ' & untypedBinaryOperators[binOp] & ' ' & b & ')'
-
-template cOp(binOp: UntypedUnaryOp, a: Snippet): Snippet =
-  '(' & untypedUnaryOperators[binOp] & '(' & a & "))"
-
-template cIfExpr(cond, a, b: Snippet): Snippet =
-  # XXX used for `min` and `max`, maybe add nifc primitives for these
-  "(" & cond & " ? " & a & " : " & b & ")"
-
-template cUnlikely(val: Snippet): Snippet =
-  "NIM_UNLIKELY(" & val & ")"
--- a/compiler/cbuilderstmts.nim
+++ b/compiler/cbuilderstmts.nim
@@ -1,329 +0,0 @@
-template addAssignmentWithValue(builder: var Builder, lhs: Snippet, valueBody: typed) =
-  builder.add(lhs)
-  builder.add(" = ")
-  valueBody
-  builder.addLineEnd(";")
-
-template addFieldAssignmentWithValue(builder: var Builder, lhs: Snippet, name: string, valueBody: typed) =
-  builder.add(lhs)
-  builder.add("." & name & " = ")
-  valueBody
-  builder.addLineEnd(";")
-
-template addAssignment(builder: var Builder, lhs, rhs: Snippet) =
-  builder.addAssignmentWithValue(lhs):
-    builder.add(rhs)
-
-template addFieldAssignment(builder: var Builder, lhs: Snippet, name: string, rhs: Snippet) =
-  builder.addFieldAssignmentWithValue(lhs, name):
-    builder.add(rhs)
-
-template addMutualFieldAssignment(builder: var Builder, lhs, rhs: Snippet, name: string) =
-  builder.addFieldAssignmentWithValue(lhs, name):
-    builder.add(rhs)
-    builder.add("." & name)
-
-template addAssignment(builder: var Builder, lhs: Snippet, rhs: int | int64 | uint64 | Int128) =
-  builder.addAssignmentWithValue(lhs):
-    builder.addIntValue(rhs)
-
-template addFieldAssignment(builder: var Builder, lhs: Snippet, name: string, rhs: int | int64 | uint64 | Int128) =
-  builder.addFieldAssignmentWithValue(lhs, name):
-    builder.addIntValue(rhs)
-
-template addDerefFieldAssignment(builder: var Builder, lhs: Snippet, name: string, rhs: Snippet) =
-  builder.add(lhs)
-  builder.add("->" & name & " = ")
-  builder.add(rhs)
-  builder.addLineEnd(";")
-
-template addSubscriptAssignment(builder: var Builder, lhs: Snippet, index: Snippet, rhs: Snippet) =
-  builder.add(lhs)
-  builder.add("[" & index & "] = ")
-  builder.add(rhs)
-  builder.addLineEnd(";")
-
-template addStmt(builder: var Builder, stmtBody: typed) =
-  ## makes an expression built by `stmtBody` into a statement
-  stmtBody
-  builder.addLineEnd(";")
-
-proc addCallStmt(builder: var Builder, callee: Snippet, args: varargs[Snippet]) =
-  builder.addStmt():
-    builder.addCall(callee, args)
-
-# XXX blocks need indent tracker in `Builder` object
-
-template addSingleIfStmt(builder: var Builder, cond: Snippet, body: typed) =
-  builder.add("if (")
-  builder.add(cond)
-  builder.addLineEndIndent(") {")
-  body
-  builder.addLineEndDedent("}")
-
-template addSingleIfStmtWithCond(builder: var Builder, condBody: typed, body: typed) =
-  builder.add("if (")
-  condBody
-  builder.addLineEndIndent(") {")
-  body
-  builder.addLineEndDedent("}")
-
-proc initIfStmt(builder: var Builder): IfBuilder =
-  IfBuilder(state: WaitingIf)
-
-proc finishIfStmt(builder: var Builder, stmt: IfBuilder) =
-  assert stmt.state != InBlock
-  builder.addNewline()
-
-template addIfStmt(builder: var Builder, stmt: out IfBuilder, body: typed) =
-  stmt = initIfStmt(builder)
-  body
-  finishIfStmt(builder, stmt)
-
-proc initElifBranch(builder: var Builder, stmt: var IfBuilder, cond: Snippet) =
-  case stmt.state
-  of WaitingIf:
-    builder.add("if (")
-  of WaitingElseIf:
-    builder.add(" else if (")
-  else: assert false, $stmt.state
-  builder.add(cond)
-  builder.addLineEndIndent(") {")
-  stmt.state = InBlock
-
-proc initElseBranch(builder: var Builder, stmt: var IfBuilder) =
-  assert stmt.state == WaitingElseIf, $stmt.state
-  builder.addLineEndIndent(" else {")
-  stmt.state = InBlock
-
-proc finishBranch(builder: var Builder, stmt: var IfBuilder) =
-  builder.addDedent("}")
-  stmt.state = WaitingElseIf
-
-template addElifBranch(builder: var Builder, stmt: var IfBuilder, cond: Snippet, body: typed) =
-  initElifBranch(builder, stmt, cond)
-  body
-  finishBranch(builder, stmt)
-
-template addElseBranch(builder: var Builder, stmt: var IfBuilder, body: typed) =
-  initElseBranch(builder, stmt)
-  body
-  finishBranch(builder, stmt)
-
-proc initForRange(builder: var Builder, i, start, bound: Snippet, inclusive: bool = false) =
-  builder.add("for (")
-  builder.add(i)
-  builder.add(" = ")
-  builder.add(start)
-  builder.add("; ")
-  builder.add(i)
-  if inclusive:
-    builder.add(" <= ")
-  else:
-    builder.add(" < ")
-  builder.add(bound)
-  builder.add("; ")
-  builder.add(i)
-  builder.addLineEndIndent("++) {")
-
-proc initForStep(builder: var Builder, i, start, bound, step: Snippet, inclusive: bool = false) =
-  builder.add("for (")
-  builder.add(i)
-  builder.add(" = ")
-  builder.add(start)
-  builder.add("; ")
-  builder.add(i)
-  if inclusive:
-    builder.add(" <= ")
-  else:
-    builder.add(" < ")
-  builder.add(bound)
-  builder.add("; ")
-  builder.add(i)
-  builder.add(" += ")
-  builder.add(step)
-  builder.addLineEndIndent(") {")
-
-proc finishFor(builder: var Builder) {.inline.} =
-  builder.addLineEndDedent("}")
-
-template addForRangeExclusive(builder: var Builder, i, start, bound: Snippet, body: typed) =
-  initForRange(builder, i, start, bound, false)
-  body
-  finishFor(builder)
-
-template addForRangeInclusive(builder: var Builder, i, start, bound: Snippet, body: typed) =
-  initForRange(builder, i, start, bound, true)
-  body
-  finishFor(builder)
-
-template addSwitchStmt(builder: var Builder, val: Snippet, body: typed) =
-  builder.add("switch (")
-  builder.add(val)
-  builder.addLineEnd(") {") # no indent
-  body
-  builder.addLineEnd("}")
-
-template addSingleSwitchCase(builder: var Builder, val: Snippet, body: typed) =
-  builder.add("case ")
-  builder.add(val)
-  builder.addLineEndIndent(":")
-  body
-  builder.addLineEndDedent("")
-
-type
-  SwitchCaseState = enum
-    None, Of, Else, Finished
-  SwitchCaseBuilder = object
-    state: SwitchCaseState
-
-proc addCase(builder: var Builder, info: var SwitchCaseBuilder, val: Snippet) =
-  if info.state != Of:
-    assert info.state == None
-    info.state = Of
-  builder.add("case ")
-  builder.add(val)
-  builder.addLineEndIndent(":")
-
-proc addCaseRange(builder: var Builder, info: var SwitchCaseBuilder, first, last: Snippet) =
-  if info.state != Of:
-    assert info.state == None
-    info.state = Of
-  builder.add("case ")
-  builder.add(first)
-  builder.add(" ... ")
-  builder.add(last)
-  builder.addLineEndIndent(":")
-
-proc addCaseElse(builder: var Builder, info: var SwitchCaseBuilder) =
-  assert info.state == None
-  info.state = Else
-  builder.addLineEndIndent("default:")
-
-template addSwitchCase(builder: var Builder, info: out SwitchCaseBuilder, caseBody, body: typed) =
-  info = SwitchCaseBuilder(state: None)
-  caseBody
-  info.state = Finished
-  body
-  builder.addLineEndDedent("")
-
-template addSwitchElse(builder: var Builder, body: typed) =
-  builder.addLineEndIndent("default:")
-  body
-  builder.addLineEndDedent("")
-
-proc addBreak(builder: var Builder) =
-  builder.addLineEnd("break;")
-
-type ScopeBuilder = object
-  inside: bool
-
-proc initScope(builder: var Builder): ScopeBuilder =
-  builder.addLineEndIndent("{")
-  result = ScopeBuilder(inside: true)
-
-proc finishScope(builder: var Builder, scope: var ScopeBuilder) =
-  assert scope.inside, "scope not inited"
-  builder.addLineEndDedent("}")
-  scope.inside = false
-
-template addScope(builder: var Builder, body: typed) =
-  builder.addLineEndIndent("{")
-  body
-  builder.addLineEndDedent("}")
-
-type WhileBuilder = object
-  inside: bool
-
-proc initWhileStmt(builder: var Builder, cond: Snippet): WhileBuilder =
-  builder.add("while (")
-  builder.add(cond)
-  builder.addLineEndIndent(") {")
-  result = WhileBuilder(inside: true)
-
-proc finishWhileStmt(builder: var Builder, stmt: var WhileBuilder) =
-  assert stmt.inside, "while stmt not inited"
-  builder.addLineEndDedent("}")
-  stmt.inside = false
-
-template addWhileStmt(builder: var Builder, cond: Snippet, body: typed) =
-  builder.add("while (")
-  builder.add(cond)
-  builder.addLineEndIndent(") {")
-  body
-  builder.addLineEndDedent("}")
-
-proc addLabel(builder: var Builder, name: TLabel) =
-  builder.add(name)
-  builder.addLineEnd(": ;")
-
-proc addReturn(builder: var Builder) =
-  builder.addLineEnd("return;")
-
-proc addReturn(builder: var Builder, value: Snippet) =
-  builder.add("return ")
-  builder.add(value)
-  builder.addLineEnd(";")
-
-proc addGoto(builder: var Builder, label: TLabel) =
-  builder.add("goto ")
-  builder.add(label)
-  builder.addLineEnd(";")
-
-proc addComputedGoto(builder: var Builder, value: Snippet) =
-  builder.add("goto *")
-  builder.add(value)
-  builder.addLineEnd(";")
-
-proc addIncr(builder: var Builder, val: Snippet) =
-  builder.add(val)
-  builder.addLineEnd("++;")
-
-proc addDecr(builder: var Builder, val: Snippet) =
-  builder.add(val)
-  builder.addLineEnd("--;")
-
-proc addInPlaceOp(builder: var Builder, binOp: TypedBinaryOp, t: Snippet, a, b: Snippet) =
-  builder.add(a)
-  builder.add(' ')
-  builder.add(typedBinaryOperators[binOp])
-  builder.add("= ")
-  builder.add(b)
-  builder.addLineEnd(";")
-
-proc addInPlaceOp(builder: var Builder, binOp: UntypedBinaryOp, a, b: Snippet) =
-  builder.add(a)
-  builder.add(' ')
-  builder.add(untypedBinaryOperators[binOp])
-  builder.add("= ")
-  builder.add(b)
-  builder.addLineEnd(";")
-
-proc cInPlaceOp(binOp: TypedBinaryOp, t: Snippet, a, b: Snippet): Snippet =
-  result = ""
-  result.add(a)
-  result.add(' ')
-  result.add(typedBinaryOperators[binOp])
-  result.add("= ")
-  result.add(b)
-  result.add(";\n")
-
-proc cInPlaceOp(binOp: UntypedBinaryOp, a, b: Snippet): Snippet =
-  result = ""
-  result.add(a)
-  result.add(' ')
-  result.add(untypedBinaryOperators[binOp])
-  result.add("= ")
-  result.add(b)
-  result.add(";\n")
-
-template addCPragma(builder: var Builder, val: Snippet) =
-  builder.addNewline()
-  builder.add("#pragma ")
-  builder.add(val)
-  builder.addNewline()
-
-proc addDiscard(builder: var Builder, val: Snippet) =
-  builder.add("(void)")
-  builder.add(val)
-  builder.addLineEnd(";")
--- a/compiler/ccgcalls.nim
+++ b/compiler/ccgcalls.nim
@@ -76,119 +76,78 @@ proc isHarmlessStore(p: BProc; canRaise: bool; d: TLoc): bool =
  else:
    result = false

-proc cleanupTemp(p: BProc; returnType: PType, tmp: TLoc): bool =
-  if returnType.kind in {tyVar, tyLent}:
-    # we don't need to worry about var/lent return types
-    result = false
-  elif hasDestructor(returnType) and getAttachedOp(p.module.g.graph, returnType, attachedDestructor) != nil:
-    let dtor = getAttachedOp(p.module.g.graph, returnType, attachedDestructor)
-    var op = initLocExpr(p, newSymNode(dtor))
-    var callee = rdLoc(op)
-    let destroyArg =
-      if dtor.typ.firstParamType.kind == tyVar:
-        cAddr(rdLoc(tmp))
-      else:
-        rdLoc(tmp)
-    let destroy = cCall(callee, destroyArg)
-    raiseExitCleanup(p, destroy)
-    result = true
-  else:
-    result = false
-
 proc fixupCall(p: BProc, le, ri: PNode, d: var TLoc,
-               result: var Builder, call: var CallBuilder) =
+               callee, params: Rope) =
  let canRaise = p.config.exc == excGoto and canRaiseDisp(p, ri[0])
  genLineDir(p, ri)
+  var pl = callee & "(" & params
  # getUniqueType() is too expensive here:
  var typ = skipTypes(ri[0].typ, abstractInst)
-  if typ.returnType != nil:
-    var flags: TAssignmentFlags = {}
-    if typ.returnType.kind in {tyOpenArray, tyVarargs}:
-      # perhaps generate no temp if the call doesn't have side effects
-      flags.incl needTempForOpenArray
+  if typ[0] != nil:
    if isInvalidReturnType(p.config, typ):
+      if params.len != 0: pl.add(", ")
      # beware of 'result = p(result)'. We may need to allocate a temporary:
      if d.k in {locTemp, locNone} or not preventNrvo(p, d.lode, le, ri):
        # Great, we can use 'd':
-        if d.k == locNone: d = getTemp(p, typ.returnType, needsInit=true)
+        if d.k == locNone: d = getTemp(p, typ[0], needsInit=true)
        elif d.k notin {locTemp} and not hasNoInit(ri):
          # reset before pass as 'result' var:
          discard "resetLoc(p, d)"
-        let rad = addrLoc(p.config, d)
-        result.addArgument(call):
-          result.add(rad)
-        result.finishCallBuilder(call)
-        p.s(cpsStmts).addStmt():
-          p.s(cpsStmts).add(extract(result))
+        pl.add(addrLoc(p.config, d))
+        pl.add(");\n")
+        line(p, cpsStmts, pl)
      else:
-        var tmp: TLoc = getTemp(p, typ.returnType, needsInit=true)
-        let ratmp = addrLoc(p.config, tmp)
-        result.addArgument(call):
-          result.add(ratmp)
-        result.finishCallBuilder(call)
-        p.s(cpsStmts).addStmt():
-          p.s(cpsStmts).add(extract(result))
+        var tmp: TLoc = getTemp(p, typ[0], needsInit=true)
+        pl.add(addrLoc(p.config, tmp))
+        pl.add(");\n")
+        line(p, cpsStmts, pl)
        genAssignment(p, d, tmp, {}) # no need for deep copying
      if canRaise: raiseExit(p)
    else:
-      result.finishCallBuilder(call)
+      pl.add(")")
      if p.module.compileToCpp:
        if lfSingleUse in d.flags:
          # do not generate spurious temporaries for C++! For C we're better off
          # with them to prevent undefined behaviour and because the codegen
          # is free to emit expressions multiple times!
          d.k = locCall
-          d.snippet = extract(result)
+          d.r = pl
          excl d.flags, lfSingleUse
        else:
-          if d.k == locNone and p.splitDecls == 0 and p.config.exc != excGoto:
-            d = getTempCpp(p, typ.returnType, extract(result))
+          if d.k == locNone and p.splitDecls == 0:
+            d = getTempCpp(p, typ[0], pl)
          else:
-            if d.k == locNone: d = getTemp(p, typ.returnType)
+            if d.k == locNone: d = getTemp(p, typ[0])
            var list = initLoc(locCall, d.lode, OnUnknown)
-            list.snippet = extract(result)
-            genAssignment(p, d, list, {needAssignCall}) # no need for deep copying
+            list.r = pl
+            genAssignment(p, d, list, {}) # no need for deep copying
            if canRaise: raiseExit(p)

      elif isHarmlessStore(p, canRaise, d):
-        var useTemp = false
-        if d.k == locNone:
-          useTemp = true
-          d = getTemp(p, typ.returnType)
+        if d.k == locNone: d = getTemp(p, typ[0])
        assert(d.t != nil)        # generate an assignment to d:
        var list = initLoc(locCall, d.lode, OnUnknown)
-        list.snippet = extract(result)
-        genAssignment(p, d, list, flags+{needAssignCall}) # no need for deep copying
-        if canRaise:
-          if not (useTemp and cleanupTemp(p, typ.returnType, d)):
-            raiseExit(p)
+        list.r = pl
+        genAssignment(p, d, list, {}) # no need for deep copying
+        if canRaise: raiseExit(p)
      else:
-        var tmp: TLoc = getTemp(p, typ.returnType, needsInit=true)
+        var tmp: TLoc = getTemp(p, typ[0], needsInit=true)
        var list = initLoc(locCall, d.lode, OnUnknown)
-        list.snippet = extract(result)
-        genAssignment(p, tmp, list, flags+{needAssignCall}) # no need for deep copying
-        if canRaise:
-          if not cleanupTemp(p, typ.returnType, tmp):
-            raiseExit(p)
+        list.r = pl
+        genAssignment(p, tmp, list, {}) # no need for deep copying
+        if canRaise: raiseExit(p)
        genAssignment(p, d, tmp, {})
  else:
-    finishCallBuilder(result, call)
-    p.s(cpsStmts).addStmt():
-      p.s(cpsStmts).add(extract(result))
+    pl.add(");\n")
+    line(p, cpsStmts, pl)
    if canRaise: raiseExit(p)

-proc genBoundsCheck(p: BProc; arr, a, b: TLoc; arrTyp: PType)
+proc genBoundsCheck(p: BProc; arr, a, b: TLoc)

 proc reifiedOpenArray(n: PNode): bool {.inline.} =
  var x = n
-  while true:
-    case x.kind
-    of {nkAddr, nkHiddenAddr, nkHiddenDeref}:
-      x = x[0]
-    of nkHiddenStdConv:
-      x = x[1]
-    else:
-      break
+  while x.kind in {nkAddr, nkHiddenAddr, nkHiddenStdConv, nkHiddenDeref}:
+    x = x[0]
  if x.kind == nkSym and x.sym.kind == skParam:
    result = false
  else:
@@ -198,66 +157,54 @@ proc genOpenArraySlice(p: BProc; q: PNode; formalType, destType: PType; prepareF
  var a = initLocExpr(p, q[1])
  var b = initLocExpr(p, q[2])
  var c = initLocExpr(p, q[3])
-  # bug #23321: In the function mapType, ptrs (tyPtr, tyVar, tyLent, tyRef)
-  # are mapped into ctPtrToArray, the dereference of which is skipped
-  # in the `genDeref`. We need to skip these ptrs here
-  let ty = skipTypes(a.t, abstractVar+{tyPtr, tyRef})
  # but first produce the required index checks:
  if optBoundsCheck in p.options:
-    genBoundsCheck(p, a, b, c, ty)
+    genBoundsCheck(p, a, b, c)
  if prepareForMutation:
-    let bra = byRefLoc(p, a)
-    p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimPrepareStrMutationV2"),
-      bra)
+    linefmt(p, cpsStmts, "#nimPrepareStrMutationV2($1);$n", [byRefLoc(p, a)])
+  let ty = skipTypes(a.t, abstractVar+{tyPtr})
  let dest = getTypeDesc(p.module, destType)
-  let ra = rdLoc(a)
-  let rb = rdLoc(b)
-  let rc = rdLoc(c)
-  let lengthExpr = cOp(Add, NimInt, cOp(Sub, NimInt, rc, rb), cIntValue(1))
+  let lengthExpr = "($1)-($2)+1" % [rdLoc(c), rdLoc(b)]
  case ty.kind
  of tyArray:
    let first = toInt64(firstOrd(p.config, ty))
    if first == 0:
-      result = (cCast(ptrType(dest), cOp(Add, NimInt, ra, rb)), lengthExpr)
+      result = ("($3*)(($1)+($2))" % [rdLoc(a), rdLoc(b), dest],
+                lengthExpr)
    else:
-      let lit = cIntLiteral(first)
-      result = (cCast(ptrType(dest), cOp(Add, NimInt, ra, cOp(Sub, NimInt, rb, lit))), lengthExpr)
+      var lit = newRopeAppender()
+      intLiteral(first, lit)
+      result = ("($4*)($1)+(($2)-($3))" %
+        [rdLoc(a), rdLoc(b), lit, dest],
+        lengthExpr)
  of tyOpenArray, tyVarargs:
-    let data = if reifiedOpenArray(q[1]): dotField(ra, "Field0") else: ra
-    result = (cCast(ptrType(dest), cOp(Add, NimInt, data, rb)), lengthExpr)
+    if reifiedOpenArray(q[1]):
+      result = ("($3*)($1.Field0)+($2)" % [rdLoc(a), rdLoc(b), dest],
+                lengthExpr)
+    else:
+      result = ("($3*)($1)+($2)" % [rdLoc(a), rdLoc(b), dest],
+                lengthExpr)
  of tyUncheckedArray, tyCstring:
-    result = (cCast(ptrType(dest), cOp(Add, NimInt, ra, rb)), lengthExpr)
+    result = ("($3*)($1)+($2)" % [rdLoc(a), rdLoc(b), dest],
+              lengthExpr)
  of tyString, tySequence:
    let atyp = skipTypes(a.t, abstractInst)
    if formalType.skipTypes(abstractInst).kind in {tyVar} and atyp.kind == tyString and
-        optSeqDestructors in p.config.globalOptions and not p.config.usesSso():
-      let bra = byRefLoc(p, a)
-      p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimPrepareStrMutationV2"),
-        bra)
-    if p.config.usesSso() and
-        skipTypes(a.t, abstractVar + abstractInst).kind == tyString:
-      let strPtr = if atyp.kind in {tyVar} and not compileToCpp(p.module): ra
-                   else: addrLoc(p.config, a)
-      result = (
-        cCast(ptrType(dest), cOp(Add, NimInt,
-          cCall(cgsymValue(p.module, "nimStrData"), strPtr), rb)),
-        lengthExpr)
+        optSeqDestructors in p.config.globalOptions:
+      linefmt(p, cpsStmts, "#nimPrepareStrMutationV2($1);$n", [byRefLoc(p, a)])
+    if atyp.kind in {tyVar} and not compileToCpp(p.module):
+      result = ("(($5) ? (($4*)(*$1)$3+($2)) : NIM_NIL)" %
+                  [rdLoc(a), rdLoc(b), dataField(p), dest, dataFieldAccessor(p, "*" & rdLoc(a))],
+                lengthExpr)
    else:
-      var val: Snippet
-      if atyp.kind in {tyVar} and not compileToCpp(p.module):
-        val = cDeref(ra)
-      else:
-        val = ra
-      result = (
-        cIfExpr(dataFieldAccessor(p, val),
-          cCast(ptrType(dest), cOp(Add, NimInt, dataField(p, val), rb)),
-          NimNil),
-        lengthExpr)
+      result = ("(($5) ? (($4*)$1$3+($2)) : NIM_NIL)" %
+                  [rdLoc(a), rdLoc(b), dataField(p), dest, dataFieldAccessor(p, rdLoc(a))],
+                lengthExpr)
  else:
    result = ("", "")
    internalError(p.config, "openArrayLoc: " & typeToString(a.t))

-proc openArrayLoc(p: BProc, formalType: PType, n: PNode; result: var Builder) =
+proc openArrayLoc(p: BProc, formalType: PType, n: PNode; result: var Rope) =
  var q = skipConv(n)
  var skipped = false
  while q.kind == nkStmtListExpr and q.len > 0:
@@ -271,83 +218,45 @@ proc openArrayLoc(p: BProc, formalType: PType, n: PNode; result: var Builder) =
        for i in 0..<q.len-1:
          genStmts(p, q[i])
        q = q.lastSon
-    let (x, y) = genOpenArraySlice(p, q, formalType, n.typ.elementType)
-    result.add(x)
-    result.addArgumentSeparator()
-    result.add(y)
+    let (x, y) = genOpenArraySlice(p, q, formalType, n.typ[0])
+    result.add x & ", " & y
  else:
-    var a = initLocExpr(p, if n.kind == nkHiddenStdConv: n[1] else: n)
+    var a: TLoc = initLocExpr(p, if n.kind == nkHiddenStdConv: n[1] else: n)
    case skipTypes(a.t, abstractVar+{tyStatic}).kind
    of tyOpenArray, tyVarargs:
-      let ra = rdLoc(a)
      if reifiedOpenArray(n):
        if a.t.kind in {tyVar, tyLent}:
-          result.add(derefField(ra, "Field0"))
-          result.addArgumentSeparator()
-          result.add(derefField(ra, "Field1"))
+          result.add "$1->Field0, $1->Field1" % [rdLoc(a)]
        else:
-          result.add(dotField(ra, "Field0"))
-          result.addArgumentSeparator()
-          result.add(dotField(ra, "Field1"))
+          result.add "$1.Field0, $1.Field1" % [rdLoc(a)]
      else:
-        result.add(ra)
-        result.addArgumentSeparator()
-        result.add(ra & "Len_0")
+        result.add "$1, $1Len_0" % [rdLoc(a)]
    of tyString, tySequence:
      let ntyp = skipTypes(n.typ, abstractInst)
      if formalType.skipTypes(abstractInst).kind in {tyVar} and ntyp.kind == tyString and
-          optSeqDestructors in p.config.globalOptions and not p.config.usesSso():
-        let bra = byRefLoc(p, a)
-        p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimPrepareStrMutationV2"),
-          bra)
-      if p.config.usesSso() and
-          skipTypes(n.typ, abstractVar + abstractInst).kind == tyString:
-        if ntyp.kind in {tyVar} and not compileToCpp(p.module):
-          let ra = a.rdLoc
-          result.add(cCall(cgsymValue(p.module, "nimStrData"), ra))
-          result.addArgumentSeparator()
-          result.add(cCall(cgsymValue(p.module, "nimStrLen"), cDeref(ra)))
-        else:
-          result.add(cCall(cgsymValue(p.module, "nimStrData"), addrLoc(p.config, a)))
-          result.addArgumentSeparator()
-          result.add(lenExpr(p, a))
-      elif ntyp.kind in {tyVar} and not compileToCpp(p.module):
-        let ra = a.rdLoc
-        var t = TLoc(snippet: cDeref(ra))
-        let lt = lenExpr(p, t)
-        result.add(cIfExpr(dataFieldAccessor(p, t.snippet), dataField(p, t.snippet), NimNil))
-        result.addArgumentSeparator()
-        result.add(lt)
+          optSeqDestructors in p.config.globalOptions:
+        linefmt(p, cpsStmts, "#nimPrepareStrMutationV2($1);$n", [byRefLoc(p, a)])
+      if ntyp.kind in {tyVar} and not compileToCpp(p.module):
+        var t: TLoc
+        t.r = "(*$1)" % [a.rdLoc]
+        result.add "($4) ? ((*$1)$3) : NIM_NIL, $2" %
+                     [a.rdLoc, lenExpr(p, t), dataField(p),
+                      dataFieldAccessor(p, "*" & a.rdLoc)]
      else:
-        let ra = a.rdLoc
-        let la = lenExpr(p, a)
-        result.add(cIfExpr(dataFieldAccessor(p, ra), dataField(p, ra), NimNil))
-        result.addArgumentSeparator()
-        result.add(la)
+        result.add "($4) ? ($1$3) : NIM_NIL, $2" %
+                     [a.rdLoc, lenExpr(p, a), dataField(p), dataFieldAccessor(p, a.rdLoc)]
    of tyArray:
-      let ra = rdLoc(a)
-      result.add(ra)
-      result.addArgumentSeparator()
-      result.addIntValue(lengthOrd(p.config, a.t))
+      result.add "$1, $2" % [rdLoc(a), rope(lengthOrd(p.config, a.t))]
    of tyPtr, tyRef:
-      case elementType(a.t).kind
+      case lastSon(a.t).kind
      of tyString, tySequence:
-        let ra = a.rdLoc
-        var t = TLoc(snippet: cDeref(ra))
-        let lt = lenExpr(p, t)
-        if p.config.usesSso():
-          result.add(cCall(cgsymValue(p.module, "nimStrData"), ra))
-          result.addArgumentSeparator()
-          result.add(cCall(cgsymValue(p.module, "nimStrLen"), t.snippet))
-        else:
-          result.add(cIfExpr(dataFieldAccessor(p, t.snippet), dataField(p, t.snippet), NimNil))
-          result.addArgumentSeparator()
-          result.add(lt)
+        var t: TLoc
+        t.r = "(*$1)" % [a.rdLoc]
+        result.add "($4) ? ((*$1)$3) : NIM_NIL, $2" %
+                     [a.rdLoc, lenExpr(p, t), dataField(p),
+                      dataFieldAccessor(p, "*" & a.rdLoc)]
      of tyArray:
-        let ra = rdLoc(a)
-        result.add(ra)
-        result.addArgumentSeparator()
-        result.addIntValue(lengthOrd(p.config, elementType(a.t)))
+        result.add "$1, $2" % [rdLoc(a), rope(lengthOrd(p.config, lastSon(a.t)))]
      else:
        internalError(p.config, "openArrayLoc: " & typeToString(a.t))
    else: internalError(p.config, "openArrayLoc: " & typeToString(a.t))
@@ -356,69 +265,53 @@ proc withTmpIfNeeded(p: BProc, a: TLoc, needsTmp: bool): TLoc =
  # Bug https://github.com/status-im/nimbus-eth2/issues/1549
  # Aliasing is preferred over stack overflows.
  # Also don't regress for non ARC-builds, too risky.
-  if needsTmp and a.lode.typ != nil and p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc} and
+  if needsTmp and a.lode.typ != nil and p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc} and
      getSize(p.config, a.lode.typ) < 1024:
    result = getTemp(p, a.lode.typ, needsInit=false)
    genAssignment(p, result, a, {})
  else:
    result = a

-proc expressionsNeedsTmp(p: BProc, a: TLoc): TLoc =
+proc literalsNeedsTmp(p: BProc, a: TLoc): TLoc =
  result = getTemp(p, a.lode.typ, needsInit=false)
  genAssignment(p, result, a, {})

-proc genArgStringToCString(p: BProc, n: PNode; result: var Builder; needsTmp: bool) {.inline.} =
-  var a = initLocExpr(p, n[0])
-  let tmp = withTmpIfNeeded(p, a, needsTmp)
-  let ra = if p.config.usesSso(): byRefLoc(p, tmp) else: tmp.rdLoc
-  result.addCall(cgsymValue(p.module, "nimToCStringConv"), ra)
+proc genArgStringToCString(p: BProc, n: PNode; result: var Rope; needsTmp: bool) {.inline.} =
+  var a: TLoc = initLocExpr(p, n[0])
+  appcg(p.module, result, "#nimToCStringConv($1)", [withTmpIfNeeded(p, a, needsTmp).rdLoc])

-proc genArg(p: BProc, n: PNode, param: PSym; call: PNode; result: var Builder; needsTmp = false) =
+proc genArg(p: BProc, n: PNode, param: PSym; call: PNode; result: var Rope; needsTmp = false) =
  var a: TLoc
  if n.kind == nkStringToCString:
    genArgStringToCString(p, n, result, needsTmp)
  elif skipTypes(param.typ, abstractVar).kind in {tyOpenArray, tyVarargs}:
    var n = if n.kind != nkHiddenAddr: n else: n[0]
    openArrayLoc(p, param.typ, n, result)
-  elif ccgIntroducedPtr(p.config, param, call[0].typ.returnType) and
+  elif ccgIntroducedPtr(p.config, param, call[0].typ[0]) and 
    (optByRef notin param.options or not p.module.compileToCpp):
    a = initLocExpr(p, n)
    if n.kind in {nkCharLit..nkNilLit}:
-      addAddrLoc(p.config, expressionsNeedsTmp(p, a), result)
+      addAddrLoc(p.config, literalsNeedsTmp(p, a), result)
    else:
      addAddrLoc(p.config, withTmpIfNeeded(p, a, needsTmp), result)
  elif p.module.compileToCpp and param.typ.kind in {tyVar} and
      n.kind == nkHiddenAddr:
-    # bug #23748: we need to introduce a temporary here. The expression type
-    # will be a reference in C++ and we cannot create a temporary reference
-    # variable. Thus, we create a temporary pointer variable instead.
-    let needsIndirect = mapType(p.config, n[0].typ, mapTypeChooser(n[0]) == skParam) != ctArray
-    if needsIndirect:
-      n.typ = n.typ.exactReplica(p.module.idgen)
-      n.typ.incl tfVarIsPtr
-    a = initLocExprSingleUse(p, n)
-    a = withTmpIfNeeded(p, a, needsTmp)
-    if needsIndirect: a.flags.incl lfIndirect
+    a = initLocExprSingleUse(p, n[0])
    # if the proc is 'importc'ed but not 'importcpp'ed then 'var T' still
    # means '*T'. See posix.nim for lots of examples that do that in the wild.
    let callee = call[0]
    if callee.kind == nkSym and
        {sfImportc, sfInfixCall, sfCompilerProc} * callee.sym.flags == {sfImportc} and
-        {lfHeader, lfNoDecl} * callee.sym.loc.flags != {} and
-        needsIndirect:
+        {lfHeader, lfNoDecl} * callee.sym.loc.flags != {}:
      addAddrLoc(p.config, a, result)
    else:
      addRdLoc(a, result)
  else:
    a = initLocExprSingleUse(p, n)
-    if param.typ.kind in {tyVar, tyPtr, tyRef, tySink}:
-      let typ = skipTypes(param.typ, abstractPtrs)
-      if not sameBackendTypePickyAliases(typ, n.typ.skipTypes(abstractPtrs)):
-        a.snippet = cCast(getTypeDesc(p.module, param.typ), rdCharLoc(a))
    addRdLoc(withTmpIfNeeded(p, a, needsTmp), result)
  #assert result != nil

-proc genArgNoParam(p: BProc, n: PNode; result: var Builder; needsTmp = false) =
+proc genArgNoParam(p: BProc, n: PNode; result: var Rope; needsTmp = false) =
  var a: TLoc
  if n.kind == nkStringToCString:
    genArgStringToCString(p, n, result, needsTmp)
@@ -444,6 +337,35 @@ proc skipTrivialIndirections(n: PNode): PNode =
      result = result[1]
    else: break

+proc getPotentialWrites(n: PNode; mutate: bool; result: var seq[PNode]) =
+  case n.kind:
+  of nkLiterals, nkIdent, nkFormalParams: discard
+  of nkSym:
+    if mutate: result.add n
+  of nkAsgn, nkFastAsgn, nkSinkAsgn:
+    getPotentialWrites(n[0], true, result)
+    getPotentialWrites(n[1], mutate, result)
+  of nkAddr, nkHiddenAddr:
+    getPotentialWrites(n[0], true, result)
+  of nkBracketExpr, nkDotExpr, nkCheckedFieldExpr:
+    getPotentialWrites(n[0], mutate, result)
+  of nkCallKinds:
+    case n.getMagic:
+    of mIncl, mExcl, mInc, mDec, mAppendStrCh, mAppendStrStr, mAppendSeqElem,
+        mAddr, mNew, mNewFinalize, mWasMoved, mDestroy, mReset:
+      getPotentialWrites(n[1], true, result)
+      for i in 2..<n.len:
+        getPotentialWrites(n[i], mutate, result)
+    of mSwap:
+      for i in 1..<n.len:
+        getPotentialWrites(n[i], true, result)
+    else:
+      for i in 1..<n.len:
+        getPotentialWrites(n[i], mutate, result)
+  else:
+    for s in n:
+      getPotentialWrites(s, mutate, result)
+
 proc getPotentialReads(n: PNode; result: var seq[PNode]) =
  case n.kind:
  of nkLiterals, nkIdent, nkFormalParams: discard
@@ -452,7 +374,7 @@ proc getPotentialReads(n: PNode; result: var seq[PNode]) =
    for s in n:
      getPotentialReads(s, result)

-proc genParams(p: BProc, ri: PNode, typ: PType; result: var Builder, argBuilder: var CallBuilder) =
+proc genParams(p: BProc, ri: PNode, typ: PType; result: var Rope) =
  # We must generate temporaries in cases like #14396
  # to keep the strict Left-To-Right evaluation
  var needTmp = newSeq[bool](ri.len - 1)
@@ -468,28 +390,25 @@ proc genParams(p: BProc, ri: PNode, typ: PType; result: var Builder, argBuilder:
        if not needTmp[i - 1]:
          needTmp[i - 1] = potentialAlias(n, potentialWrites)
      getPotentialWrites(ri[i], false, potentialWrites)
-    when false:
-      # this optimization is wrong, see bug #23748
-      if ri[i].kind in {nkHiddenAddr, nkAddr}:
-        # Optimization: don't use a temp, if we would only take the address anyway
-        needTmp[i - 1] = false
+    if ri[i].kind in {nkHiddenAddr, nkAddr}:
+      # Optimization: don't use a temp, if we would only take the address anyway
+      needTmp[i - 1] = false

+  var oldLen = result.len
  for i in 1..<ri.len:
-    if i < typ.n.len:
+    if i < typ.len:
      assert(typ.n[i].kind == nkSym)
      let paramType = typ.n[i]
      if not paramType.typ.isCompileTimeOnly:
-        var arg = newBuilder("")
-        genArg(p, ri[i], paramType.sym, ri, arg, needTmp[i-1])
-        if arg.buf.len != 0:
-          result.addArgument(argBuilder):
-            result.add(extract(arg))
+        if oldLen != result.len:
+          result.add(", ")
+          oldLen = result.len
+        genArg(p, ri[i], paramType.sym, ri, result, needTmp[i-1])
    else:
-      var arg = newBuilder("")
-      genArgNoParam(p, ri[i], arg, needTmp[i-1])
-      if arg.buf.len != 0:
-        result.addArgument(argBuilder):
-          result.add(extract(arg))
+      if oldLen != result.len:
+        result.add(", ")
+        oldLen = result.len
+      genArgNoParam(p, ri[i], result, needTmp[i-1])

 proc addActualSuffixForHCR(res: var Rope, module: PSym, sym: PSym) =
  if sym.flags * {sfImportc, sfNonReloadable} == {} and sym.loc.k == locProc and
@@ -498,109 +417,84 @@ proc addActualSuffixForHCR(res: var Rope, module: PSym, sym: PSym) =

 proc genPrefixCall(p: BProc, le, ri: PNode, d: var TLoc) =
  # this is a hotspot in the compiler
-  var op = initLocExpr(p, ri[0])
+  var op: TLoc = initLocExpr(p, ri[0])
  # getUniqueType() is too expensive here:
  var typ = skipTypes(ri[0].typ, abstractInstOwned)
  assert(typ.kind == tyProc)
+  assert(typ.len == typ.n.len)
+
+  var params = newRopeAppender()
+  genParams(p, ri, typ, params)

  var callee = rdLoc(op)
  if p.hcrOn and ri[0].kind == nkSym:
    callee.addActualSuffixForHCR(p.module.module, ri[0].sym)
-
-  var res = newBuilder("")
-  var call = initCallBuilder(res, callee)
-  genParams(p, ri, typ, res, call)
-  fixupCall(p, le, ri, d, res, call)
+  fixupCall(p, le, ri, d, callee, params)

 proc genClosureCall(p: BProc, le, ri: PNode, d: var TLoc) =

-  template callProc(rp, params, pTyp: Snippet): Snippet =
-    let e = dotField(rp, "ClE_0")
-    let p = dotField(rp, "ClP_0")
-    let eCall =
-      # note `params` here is actually multiple params
-      if params.len == 0:
-        cCall(p, e)
-      else:
-        cCall(p, params, e)
-    cIfExpr(e,
-      eCall,
-      cCall(cCast(pTyp, p), params))
+  proc addComma(r: Rope): Rope =
+    if r.len == 0: r else: r & ", "

-  template callIter(rp, params: Snippet): Snippet =
-    # we know the env exists
-    let e = dotField(rp, "ClE_0")
-    let p = dotField(rp, "ClP_0")
-    # note `params` here is actually multiple params
-    if params.len == 0:
-      cCall(p, e)
-    else:
-      cCall(p, params, e)
+  const PatProc = "$1.ClE_0? $1.ClP_0($3$1.ClE_0):(($4)($1.ClP_0))($2)"
+  const PatIter = "$1.ClP_0($3$1.ClE_0)" # we know the env exists

-  var op = initLocExpr(p, ri[0])
+  var op: TLoc = initLocExpr(p, ri[0])

  # getUniqueType() is too expensive here:
  var typ = skipTypes(ri[0].typ, abstractInstOwned)
  assert(typ.kind == tyProc)
+  assert(typ.len == typ.n.len)

-  var params = newBuilder("")
-  var argBuilder = default(CallBuilder) # not initCallBuilder, we just want the params
-  genParams(p, ri, typ, params, argBuilder)
+  var pl = newRopeAppender()
+  genParams(p, ri, typ, pl)

  template genCallPattern {.dirty.} =
-    let rp = rdLoc(op)
-    let pars = extract(params)
-    p.s(cpsStmts).addStmt():
-      if tfIterator in typ.flags:
-        p.s(cpsStmts).add(callIter(rp, pars))
-      else:
-        p.s(cpsStmts).add(callProc(rp, pars, rawProc))
+    if tfIterator in typ.flags:
+      lineF(p, cpsStmts, PatIter & ";$n", [rdLoc(op), pl, pl.addComma, rawProc])
+    else:
+      lineF(p, cpsStmts, PatProc & ";$n", [rdLoc(op), pl, pl.addComma, rawProc])

  let rawProc = getClosureType(p.module, typ, clHalf)
  let canRaise = p.config.exc == excGoto and canRaiseDisp(p, ri[0])
-  if typ.returnType != nil:
+  if typ[0] != nil:
    if isInvalidReturnType(p.config, typ):
+      if ri.len > 1: pl.add(", ")
      # beware of 'result = p(result)'. We may need to allocate a temporary:
      if d.k in {locTemp, locNone} or not preventNrvo(p, d.lode, le, ri):
        # Great, we can use 'd':
        if d.k == locNone:
-          d = getTemp(p, typ.returnType, needsInit=true)
+          d = getTemp(p, typ[0], needsInit=true)
        elif d.k notin {locTemp} and not hasNoInit(ri):
          # reset before pass as 'result' var:
          discard "resetLoc(p, d)"
-        params.addArgument(argBuilder):
-          params.add(addrLoc(p.config, d))
+        pl.add(addrLoc(p.config, d))
        genCallPattern()
        if canRaise: raiseExit(p)
      else:
-        var tmp: TLoc = getTemp(p, typ.returnType, needsInit=true)
-        params.addArgument(argBuilder):
-          params.add(addrLoc(p.config, tmp))
+        var tmp: TLoc = getTemp(p, typ[0], needsInit=true)
+        pl.add(addrLoc(p.config, tmp))
        genCallPattern()
        if canRaise: raiseExit(p)
        genAssignment(p, d, tmp, {}) # no need for deep copying
    elif isHarmlessStore(p, canRaise, d):
-      if d.k == locNone: d = getTemp(p, typ.returnType)
+      if d.k == locNone: d = getTemp(p, typ[0])
      assert(d.t != nil)        # generate an assignment to d:
      var list: TLoc = initLoc(locCall, d.lode, OnUnknown)
-      let rp = rdLoc(op)
-      let pars = extract(params)
      if tfIterator in typ.flags:
-        list.snippet = callIter(rp, pars)
+        list.r = PatIter % [rdLoc(op), pl, pl.addComma, rawProc]
      else:
-        list.snippet = callProc(rp, pars, rawProc)
+        list.r = PatProc % [rdLoc(op), pl, pl.addComma, rawProc]
      genAssignment(p, d, list, {}) # no need for deep copying
      if canRaise: raiseExit(p)
    else:
-      var tmp: TLoc = getTemp(p, typ.returnType)
+      var tmp: TLoc = getTemp(p, typ[0])
      assert(d.t != nil)        # generate an assignment to d:
      var list: TLoc = initLoc(locCall, d.lode, OnUnknown)
-      let rp = rdLoc(op)
-      let pars = extract(params)
      if tfIterator in typ.flags:
-        list.snippet = callIter(rp, pars)
+        list.r = PatIter % [rdLoc(op), pl, pl.addComma, rawProc]
      else:
-        list.snippet = callProc(rp, pars, rawProc)
+        list.r = PatProc % [rdLoc(op), pl, pl.addComma, rawProc]
      genAssignment(p, tmp, list, {})
      if canRaise: raiseExit(p)
      genAssignment(p, d, tmp, {})
@@ -608,27 +502,30 @@ proc genClosureCall(p: BProc, le, ri: PNode, d: var TLoc) =
    genCallPattern()
    if canRaise: raiseExit(p)

-proc genOtherArg(p: BProc; ri: PNode; i: int; typ: PType; result: var Builder;
-                 argBuilder: var CallBuilder) =
-  if i < typ.n.len:
+proc genOtherArg(p: BProc; ri: PNode; i: int; typ: PType; result: var Rope;
+                 argsCounter: var int) =
+  if i < typ.len:
    # 'var T' is 'T&' in C++. This means we ignore the request of
    # any nkHiddenAddr when it's a 'var T'.
    let paramType = typ.n[i]
    assert(paramType.kind == nkSym)
    if paramType.typ.isCompileTimeOnly:
      discard
-    elif paramType.typ.kind in {tyVar} and ri[i].kind == nkHiddenAddr:
-      result.addArgument(argBuilder):
-        genArgNoParam(p, ri[i][0], result)
+    elif typ[i].kind in {tyVar} and ri[i].kind == nkHiddenAddr:
+      if argsCounter > 0: result.add ", "
+      genArgNoParam(p, ri[i][0], result)
+      inc argsCounter
    else:
-      result.addArgument(argBuilder):
-        genArgNoParam(p, ri[i], result) #, typ.n[i].sym)
+      if argsCounter > 0: result.add ", "
+      genArgNoParam(p, ri[i], result) #, typ.n[i].sym)
+      inc argsCounter
  else:
    if tfVarargs notin typ.flags:
      localError(p.config, ri.info, "wrong argument count")
    else:
-      result.addArgument(argBuilder):
-        genArgNoParam(p, ri[i], result)
+      if argsCounter > 0: result.add ", "
+      genArgNoParam(p, ri[i], result)
+      inc argsCounter

 discard """
 Dot call syntax in C++
@@ -685,11 +582,11 @@ proc skipAddrDeref(node: PNode): PNode =
  else:
    result = node

-proc genThisArg(p: BProc; ri: PNode; i: int; typ: PType; result: var Builder) =
+proc genThisArg(p: BProc; ri: PNode; i: int; typ: PType; result: var Rope) =
  # for better or worse c2nim translates the 'this' argument to a 'var T'.
  # However manual wrappers may also use 'ptr T'. In any case we support both
  # for convenience.
-  internalAssert p.config, i < typ.n.len
+  internalAssert p.config, i < typ.len
  assert(typ.n[i].kind == nkSym)
  # if the parameter is lying (tyVar) and thus we required an additional deref,
  # skip the deref:
@@ -720,15 +617,15 @@ proc genThisArg(p: BProc; ri: PNode; i: int; typ: PType; result: var Builder) =
    genArgNoParam(p, ri, result) #, typ.n[i].sym)
    result.add(".")

-proc genPatternCall(p: BProc; ri: PNode; pat: string; typ: PType; result: var Builder) =
+proc genPatternCall(p: BProc; ri: PNode; pat: string; typ: PType; result: var Rope) =
  var i = 0
  var j = 1
  while i < pat.len:
    case pat[i]
    of '@':
-      var callBuilder = default(CallBuilder) # not init call builder
+      var argsCounter = 0
      for k in j..<ri.len:
-        genOtherArg(p, ri, k, typ, result, callBuilder)
+        genOtherArg(p, ri, k, typ, result, argsCounter)
      inc i
    of '#':
      if i+1 < pat.len and pat[i+1] in {'+', '@'}:
@@ -738,11 +635,11 @@ proc genPatternCall(p: BProc; ri: PNode; pat: string; typ: PType; result: var Bu
          if pat[i+1] == '+': genArgNoParam(p, ri[0], result)
          result.add("(")
          if 1 < ri.len:
-            var callBuilder: CallBuilder = default(CallBuilder)
-            genOtherArg(p, ri, 1, typ, result, callBuilder)
+            var argsCounterB = 0
+            genOtherArg(p, ri, 1, typ, result, argsCounterB)
          for k in j+1..<ri.len:
-            var callBuilder: CallBuilder = default(CallBuilder)
-            genOtherArg(p, ri, k, typ, result, callBuilder)
+            var argsCounterB = 0
+            genOtherArg(p, ri, k, typ, result, argsCounterB)
          result.add(")")
        else:
          localError(p.config, ri.info, "call expression expected for C++ pattern")
@@ -756,15 +653,15 @@ proc genPatternCall(p: BProc; ri: PNode; pat: string; typ: PType; result: var Bu
        genArgNoParam(p, arg, result)
        #result.add debugTree(arg, 0, 10)
      else:
-        var callBuilder = default(CallBuilder) # not init call builder
-        genOtherArg(p, ri, j, typ, result, callBuilder)
+        var argsCounter = 0
+        genOtherArg(p, ri, j, typ, result, argsCounter)
      inc j
      inc i
    of '\'':
      var idx, stars: int = 0
      if scanCppGenericSlot(pat, i, idx, stars):
        var t = resolveStarsInCppType(typ, idx, stars)
-        if t == nil: result.add(CVoid)
+        if t == nil: result.add("void")
        else: result.add(getTypeDesc(p.module, t))
    else:
      let start = i
@@ -775,61 +672,64 @@ proc genPatternCall(p: BProc; ri: PNode; pat: string; typ: PType; result: var Bu
        result.add(substr(pat, start, i - 1))

 proc genInfixCall(p: BProc, le, ri: PNode, d: var TLoc) =
-  var op = initLocExpr(p, ri[0])
+  var op: TLoc = initLocExpr(p, ri[0])
  # getUniqueType() is too expensive here:
  var typ = skipTypes(ri[0].typ, abstractInst)
  assert(typ.kind == tyProc)
+  assert(typ.len == typ.n.len)
  # don't call '$' here for efficiency:
-  let pat = $ri[0].sym.loc.snippet
+  let pat = $ri[0].sym.loc.r
  internalAssert p.config, pat.len > 0
  if pat.contains({'#', '(', '@', '\''}):
-    var pl = newBuilder("")
+    var pl = newRopeAppender()
    genPatternCall(p, ri, pat, typ, pl)
    # simpler version of 'fixupCall' that works with the pl+params combination:
    var typ = skipTypes(ri[0].typ, abstractInst)
-    if typ.returnType != nil:
+    if typ[0] != nil:
      if p.module.compileToCpp and lfSingleUse in d.flags:
        # do not generate spurious temporaries for C++! For C we're better off
        # with them to prevent undefined behaviour and because the codegen
        # is free to emit expressions multiple times!
        d.k = locCall
-        d.snippet = extract(pl)
+        d.r = pl
        excl d.flags, lfSingleUse
      else:
-        if d.k == locNone: d = getTemp(p, typ.returnType)
+        if d.k == locNone: d = getTemp(p, typ[0])
        assert(d.t != nil)        # generate an assignment to d:
        var list: TLoc = initLoc(locCall, d.lode, OnUnknown)
-        list.snippet = extract(pl)
+        list.r = pl
        genAssignment(p, d, list, {}) # no need for deep copying
    else:
-      p.s(cpsStmts).addStmt():
-        p.s(cpsStmts).add(extract(pl))
+      pl.add(";\n")
+      line(p, cpsStmts, pl)
  else:
-    var pl = newBuilder("")
+    var pl = newRopeAppender()
+    var argsCounter = 0
    if 1 < ri.len:
      genThisArg(p, ri, 1, typ, pl)
-    pl.add(op.snippet)
-    var res = newBuilder("")
-    var call = initCallBuilder(res, extract(pl))
+    pl.add(op.r)
+    var params = newRopeAppender()
    for i in 2..<ri.len:
-      genOtherArg(p, ri, i, typ, res, call)
-    fixupCall(p, le, ri, d, res, call)
+      assert(typ.len == typ.n.len)
+      genOtherArg(p, ri, i, typ, params, argsCounter)
+    fixupCall(p, le, ri, d, pl, params)

 proc genNamedParamCall(p: BProc, ri: PNode, d: var TLoc) =
  # generates a crappy ObjC call
-  var op = initLocExpr(p, ri[0])
-  var pl = newBuilder("[")
+  var op: TLoc = initLocExpr(p, ri[0])
+  var pl = "["
  # getUniqueType() is too expensive here:
  var typ = skipTypes(ri[0].typ, abstractInst)
  assert(typ.kind == tyProc)
+  assert(typ.len == typ.n.len)

  # don't call '$' here for efficiency:
-  let pat = $ri[0].sym.loc.snippet
+  let pat = $ri[0].sym.loc.r
  internalAssert p.config, pat.len > 0
  var start = 3
  if ' ' in pat:
    start = 1
-    pl.add(op.snippet)
+    pl.add(op.r)
    if ri.len > 1:
      pl.add(": ")
      genArg(p, ri[1], typ.n[1].sym, ri, pl)
@@ -838,12 +738,13 @@ proc genNamedParamCall(p: BProc, ri: PNode, d: var TLoc) =
    if ri.len > 1:
      genArg(p, ri[1], typ.n[1].sym, ri, pl)
      pl.add(" ")
-    pl.add(op.snippet)
+    pl.add(op.r)
    if ri.len > 2:
      pl.add(": ")
      genArg(p, ri[2], typ.n[2].sym, ri, pl)
  for i in start..<ri.len:
-    if i >= typ.n.len:
+    assert(typ.len == typ.n.len)
+    if i >= typ.len:
      internalError(p.config, ri.info, "varargs for objective C method?")
    assert(typ.n[i].kind == nkSym)
    var param = typ.n[i].sym
@@ -851,36 +752,33 @@ proc genNamedParamCall(p: BProc, ri: PNode, d: var TLoc) =
    pl.add(param.name.s)
    pl.add(": ")
    genArg(p, ri[i], param, ri, pl)
-  if typ.returnType != nil:
+  if typ[0] != nil:
    if isInvalidReturnType(p.config, typ):
      if ri.len > 1: pl.add(" ")
      # beware of 'result = p(result)'. We always allocate a temporary:
      if d.k in {locTemp, locNone}:
        # We already got a temp. Great, special case it:
-        if d.k == locNone: d = getTemp(p, typ.returnType, needsInit=true)
+        if d.k == locNone: d = getTemp(p, typ[0], needsInit=true)
        pl.add("Result: ")
        pl.add(addrLoc(p.config, d))
-        pl.add("]")
-        p.s(cpsStmts).addStmt():
-          p.s(cpsStmts).add(extract(pl))
+        pl.add("];\n")
+        line(p, cpsStmts, pl)
      else:
-        var tmp: TLoc = getTemp(p, typ.returnType, needsInit=true)
+        var tmp: TLoc = getTemp(p, typ[0], needsInit=true)
        pl.add(addrLoc(p.config, tmp))
-        pl.add("]")
-        p.s(cpsStmts).addStmt():
-          p.s(cpsStmts).add(extract(pl))
+        pl.add("];\n")
+        line(p, cpsStmts, pl)
        genAssignment(p, d, tmp, {}) # no need for deep copying
    else:
      pl.add("]")
-      if d.k == locNone: d = getTemp(p, typ.returnType)
+      if d.k == locNone: d = getTemp(p, typ[0])
      assert(d.t != nil)        # generate an assignment to d:
      var list: TLoc = initLoc(locCall, ri, OnUnknown)
-      list.snippet = extract(pl)
+      list.r = pl
      genAssignment(p, d, list, {}) # no need for deep copying
  else:
-    pl.add("]")
-    p.s(cpsStmts).addStmt():
-      p.s(cpsStmts).add(extract(pl))
+    pl.add("];\n")
+    line(p, cpsStmts, pl)

 proc notYetAlive(n: PNode): bool {.inline.} =
  let r = getRoot(n)
@@ -909,16 +807,6 @@ proc isInactiveDestructorCall(p: BProc, e: PNode): bool =
 proc genAsgnCall(p: BProc, le, ri: PNode, d: var TLoc) =
  if p.withinBlockLeaveActions > 0 and isInactiveDestructorCall(p, ri):
    return
-  when defined(icDbgHash):
-    if ri[0].typ == nil:
-      echo "NILCALLEE kind=", ri[0].kind,
-        " sym=", (if ri[0].kind == nkSym: ri[0].sym.name.s else: "-"),
-        " symKind=", (if ri[0].kind == nkSym: $ri[0].sym.kind else: "-"),
-        " flags=", (if ri[0].kind == nkSym: $ri[0].sym.flags else: "-"),
-        " lazy=", nfLazyType in ri[0].flags,
-        " inProc=", (if p.prc != nil: p.prc.name.s else: "NIL"),
-        " module=", p.module.module.name.s
-      raiseAssert "nil callee type, see NILCALLEE above"
  if ri[0].typ.skipTypes({tyGenericInst, tyAlias, tySink, tyOwned}).callConv == ccClosure:
    genClosureCall(p, le, ri, d)
  elif ri[0].kind == nkSym and sfInfixCall in ri[0].sym.flags:
--- a/compiler/ccgexprs.nim
+++ b/compiler/ccgexprs.nim
--- a/compiler/ccgliterals.nim
+++ b/compiler/ccgliterals.nim
@@ -16,17 +16,16 @@
 ## implementation.

 template detectVersion(field, corename) =
-  if m.g.config.selectedGC in {gcArc, gcOrc, gcYrc, gcAtomicArc, gcHooks}:
-    result = 2
-  else:
-    result = 1
+  if m.g.field == 0:
+    let core = getCompilerProc(m.g.graph, corename)
+    if core == nil or core.kind != skConst:
+      m.g.field = 1
+    else:
+      m.g.field = toInt(ast.getInt(core.astdef))
+  result = m.g.field

 proc detectStrVersion(m: BModule): int =
-  if m.g.config.usesSso() and
-      m.g.config.selectedGC in {gcArc, gcOrc, gcYrc, gcAtomicArc, gcHooks}:
-    result = 3
-  else:
-    detectVersion(strVersion, "nimStrVersion")
+  detectVersion(strVersion, "nimStrVersion")

 proc detectSeqVersion(m: BModule): int =
  detectVersion(seqVersion, "nimSeqVersion")
@@ -37,84 +36,52 @@ proc genStringLiteralDataOnlyV1(m: BModule, s: string; result: var Rope) =
  cgsym(m, "TGenericSeq")
  let tmp = getTempName(m)
  result.add tmp
-  var res = newBuilder("")
-  res.addVarWithTypeAndInitializer(AlwaysConst, name = tmp):
-    res.addSimpleStruct(m, name = "", baseType = ""):
-      res.addField(name = "Sup", typ = "TGenericSeq")
-      res.addArrayField(name = "data", elementType = NimChar, len = s.len + 1)
-  do:
-    var strInit: StructInitializer
-    res.addStructInitializer(strInit, kind = siOrderedStruct):
-      res.addField(strInit, name = "Sup"):
-        var seqInit: StructInitializer
-        res.addStructInitializer(seqInit, kind = siOrderedStruct):
-          res.addField(seqInit, name = "len"):
-            res.addIntValue(s.len)
-          res.addField(seqInit, name = "reserved"):
-            res.add(cCast(NimInt, cOp(BitOr, NimUint, cCast(NimUint, cIntValue(s.len)), NimStrlitFlag)))
-      res.addField(strInit, name = "data"):
-        res.add(makeCString(s))
-  m.s[cfsStrData].add(extract(res))
+  m.s[cfsStrData].addf("STRING_LITERAL($1, $2, $3);$n",
+       [tmp, makeCString(s), rope(s.len)])

-proc genStringLiteralV1(m: BModule; n: PNode; result: var Builder) =
+proc genStringLiteralV1(m: BModule; n: PNode; result: var Rope) =
  if s.isNil:
-    result.add(cCast(ptrType(cgsymValue(m, "NimStringDesc")), NimNil))
+    appcg(m, result, "((#NimStringDesc*) NIM_NIL)", [])
  else:
    let id = nodeTableTestOrSet(m.dataCache, n, m.labels)
-    var name: string = ""
    if id == m.labels:
      # string literal not found in the cache:
-      genStringLiteralDataOnlyV1(m, n.strVal, name)
+      appcg(m, result, "((#NimStringDesc*) &", [])
+      genStringLiteralDataOnlyV1(m, n.strVal, result)
+      result.add ")"
    else:
-      name = m.tmpBase & $id
-    result.add(cCast(ptrType(cgsymValue(m, "NimStringDesc")), cAddr(name)))
+      appcg(m, result, "((#NimStringDesc*) &$1$2)",
+                      [m.tmpBase, id])

 # ------ Version 2: destructor based strings and seqs -----------------------

 proc genStringLiteralDataOnlyV2(m: BModule, s: string; result: Rope; isConst: bool) =
-  var res = newBuilder("")
-  res.addVarWithTypeAndInitializer(
-      if isConst: AlwaysConst else: Global,
-      name = result):
-    res.addSimpleStruct(m, name = "", baseType = ""):
-      res.addField(name = "cap", typ = NimInt)
-      res.addArrayField(name = "data", elementType = NimChar, len = s.len + 1)
-  do:
-    var structInit: StructInitializer
-    res.addStructInitializer(structInit, kind = siOrderedStruct):
-      res.addField(structInit, name = "cap"):
-        res.add(cOp(BitOr, NimInt, cIntValue(s.len), NimStrlitFlag))
-      res.addField(structInit, name = "data"):
-        res.add(makeCString(s))
-  m.s[cfsStrData].add(extract(res))
+  m.s[cfsStrData].addf("static $4 struct {$n" &
+       "  NI cap; NIM_CHAR data[$2+1];$n" &
+       "} $1 = { $2 | NIM_STRLIT_FLAG, $3 };$n",
+       [result, rope(s.len), makeCString(s),
+       rope(if isConst: "const" else: "")])

-proc genStringLiteralV2(m: BModule; n: PNode; isConst: bool; result: var Builder) =
+proc genStringLiteralV2(m: BModule; n: PNode; isConst: bool; result: var Rope) =
  let id = nodeTableTestOrSet(m.dataCache, n, m.labels)
-  var litName: string
  if id == m.labels:
+    let pureLit = getTempName(m)
+    genStringLiteralDataOnlyV2(m, n.strVal, pureLit, isConst)
+    let tmp = getTempName(m)
+    result.add tmp
    cgsym(m, "NimStrPayload")
    cgsym(m, "NimStringV2")
    # string literal not found in the cache:
-    litName = getTempName(m)
-    genStringLiteralDataOnlyV2(m, n.strVal, litName, isConst)
+    m.s[cfsStrData].addf("static $4 NimStringV2 $1 = {$2, (NimStrPayload*)&$3};$n",
+          [tmp, rope(n.strVal.len), pureLit, rope(if isConst: "const" else: "")])
  else:
-    litName = m.tmpBase & $id
-  let tmp = getTempName(m)
-  result.add tmp
-  var res = newBuilder("")
-  res.addVarWithInitializer(
-      if isConst: AlwaysConst else: Global,
-      name = tmp,
-      typ = "NimStringV2"):
-    var strInit: StructInitializer
-    res.addStructInitializer(strInit, kind = siOrderedStruct):
-      res.addField(strInit, name = "len"):
-        res.addIntValue(n.strVal.len)
-      res.addField(strInit, name = "p"):
-        res.add(cCast(ptrType("NimStrPayload"), cAddr(litName)))
-  m.s[cfsStrData].add(extract(res))
+    let tmp = getTempName(m)
+    result.add tmp
+    m.s[cfsStrData].addf("static $4 NimStringV2 $1 = {$2, (NimStrPayload*)&$3};$n",
+          [tmp, rope(n.strVal.len), m.tmpBase & rope(id),
+          rope(if isConst: "const" else: "")])

-proc genStringLiteralV2Const(m: BModule; n: PNode; isConst: bool; result: var Builder) =
+proc genStringLiteralV2Const(m: BModule; n: PNode; isConst: bool; result: var Rope) =
  let id = nodeTableTestOrSet(m.dataCache, n, m.labels)
  var pureLit: Rope
  if id == m.labels:
@@ -125,198 +92,7 @@ proc genStringLiteralV2Const(m: BModule; n: PNode; isConst: bool; result: var Bu
    genStringLiteralDataOnlyV2(m, n.strVal, pureLit, isConst)
  else:
    pureLit = m.tmpBase & rope(id)
-  var strInit: StructInitializer
-  result.addStructInitializer(strInit, kind = siOrderedStruct):
-    result.addField(strInit, name = "len"):
-      result.addIntValue(n.strVal.len)
-    result.addField(strInit, name = "p"):
-      result.add(cCast(ptrType("NimStrPayload"), cAddr(pureLit)))
-
-proc ssoCharLit(ch: char): string =
-  ## Return a C char literal for ch, with proper escaping.
-  const hexDigits = "0123456789abcdef"
-  result = "'"
-  case ch
-  of '\'': result.add("\\'")
-  of '\\': result.add("\\\\")
-  of '\0': result.add("\\0")
-  of '\n': result.add("\\n")
-  of '\r': result.add("\\r")
-  of '\t': result.add("\\t")
-  elif ch.ord < 32 or ch.ord == 127:
-    result.add("\\x")
-    result.add(hexDigits[ch.ord shr 4])
-    result.add(hexDigits[ch.ord and 0xf])
-  else:
-    result.add(ch)
-  result.add('\'')
-
-proc ssoBytesLit(m: BModule; s: string; slen: int): string =
-  ## Compute the `bytes` field value for the new SmallString layout.
-  ## byte 0 = slen, bytes 1-7 = inline chars 0-6 (zero-padded).
-  ## On LE: slen in bits 0-7, char[i] in bits (i+1)*8..(i+1)*8+7.
-  ## On BE: slen in bits 56-63, char[i] in bits (6-i)*8..(6-i)*8+7.
-  const AlwaysAvail = 7
-  var val: uint64
-  if CPU[m.g.config.target.targetCPU].endian == littleEndian:
-    val = uint64(slen)
-    for i in 0..<min(s.len, AlwaysAvail):
-      val = val or (uint64(s[i]) shl (uint(i + 1) * 8))
-  else:
-    val = uint64(slen) shl 56
-    for i in 0..<min(s.len, AlwaysAvail):
-      val = val or (uint64(s[i]) shl (uint(AlwaysAvail - 1 - i) * 8))
-  # Cast to NU (C name for Nim's uint, = NU64 on 64-bit). NU64 = uint64_t.
-  result = cCast("NU", $val & "ULL")
-
-proc ssoMoreLit(m: BModule; s: string): string =
-  ## For medium string literals (AlwaysAvail < len <= PayloadSize), encode
-  ## chars[AlwaysAvail..ptrSize-1] in the 'more' pointer field bit-pattern.
-  ## The last pointer byte is always '\0' (null terminator), guaranteed by
-  ## PayloadSize = AlwaysAvail + ptrSize - 1.  slen <= PayloadSize guards
-  ## prevent any code from dereferencing this as an actual pointer.
-  const AlwaysAvail = 7
-  let ptrSize = m.g.config.target.ptrSize
-  var val: uint64 = 0
-  for i in 0..<ptrSize:
-    let ch: uint64 = if AlwaysAvail + i < s.len: uint64(s[AlwaysAvail + i]) else: 0
-    if CPU[m.g.config.target.targetCPU].endian == littleEndian:
-      val = val or (ch shl (uint(i) * 8))
-    else:
-      val = val or (ch shl (uint(ptrSize - 1 - i) * 8))
-  result = cCast(ptrType("LongString"), "(uintptr_t)" & $val)
-
-proc genStringLiteralV3Const(m: BModule; n: PNode; isConst: bool; result: var Builder) =
-  # Inline SmallString struct initializer for use inside const aggregate types.
-  # Layout: {bytes: NimUint, more: ptr LongString}
-  # bytes = slen (low byte) | char[0]<<8 | char[1]<<16 | ... | char[6]<<56
-  const AlwaysAvail = 7
-  let s = n.strVal
-
-  cgsym(m, "SmallString")
-  cgsym(m, "LongString")
-
-  let payloadSize = AlwaysAvail + m.g.config.target.ptrSize - 1
-  var si: StructInitializer
-  result.addStructInitializer(si, kind = siOrderedStruct):
-    if s.len <= AlwaysAvail:
-      result.addField(si, name = "bytes"):
-        result.add(ssoBytesLit(m, s, s.len))
-      result.addField(si, name = "more"):
-        result.add(NimNil)
-    elif s.len <= payloadSize:
-      # Medium string: bytes holds slen + chars 0-6; more holds chars 7..PayloadSize-1.
-      result.addField(si, name = "bytes"):
-        result.add(ssoBytesLit(m, s, s.len))
-      result.addField(si, name = "more"):
-        result.add(ssoMoreLit(m, s))
-    else:
-      # Emit the LongString block into cfsStrData and reference it inline.
-      let dataName = getTempName(m)
-      var res = newBuilder("")
-      res.addVarWithTypeAndInitializer(
-          if isConst: AlwaysConst else: Global,
-          name = dataName):
-        res.addSimpleStruct(m, name = "", baseType = ""):
-          res.addField(name = "rc", typ = NimInt)
-          res.addField(name = "fullLen", typ = NimInt)
-          res.addField(name = "capImpl", typ = NimInt)
-          res.addArrayField(name = "data", elementType = NimChar, len = s.len + 1)
-      do:
-        var di: StructInitializer
-        res.addStructInitializer(di, kind = siOrderedStruct):
-          res.addField(di, name = "fullLen"):
-            res.addIntValue(s.len)
-          res.addField(di, name = "rc"):
-            res.addIntValue(1)
-          res.addField(di, name = "capImpl"):
-            res.addIntValue(0)  # static, never freed
-          res.addField(di, name = "data"):
-            res.add(makeCString(s))
-      m.s[cfsStrData].add(extract(res))
-      # slen = StaticSlen (254): marks this as a static (never-freed) long string.
-      result.addField(si, name = "bytes"):
-        result.add(ssoBytesLit(m, s, 254))
-      result.addField(si, name = "more"):
-        result.add(cCast(ptrType("LongString"), cAddr(dataName)))
-
-# ------ Version 3: SmallString (SSO) strings --------------------------------
-
-proc genStringLiteralV3(m: BModule; n: PNode; isConst: bool; result: var Builder) =
-  # SmallString literal. Always generate a fresh SmallString variable (like v2
-  # always generates a fresh outer NimStringV2). For long strings, cache the
-  # LongString payload to avoid duplicates within a module.
-  const AlwaysAvail = 7  # must match strs_v3.nim
-  let s = n.strVal
-  let tmp = getTempName(m)
-  result.add tmp
-
-  cgsym(m, "SmallString")
-  cgsym(m, "LongString")
-
-  let payloadSize = AlwaysAvail + m.g.config.target.ptrSize - 1
-  var res = newBuilder("")
-  if s.len <= AlwaysAvail:
-    # Short: bytes holds slen + all chars (zero-padded), more = NULL.
-    res.addVarWithInitializer(
-        if isConst: AlwaysConst else: Global,
-        name = tmp, typ = "SmallString"):
-      var si: StructInitializer
-      res.addStructInitializer(si, kind = siOrderedStruct):
-        res.addField(si, name = "bytes"):
-          res.add(ssoBytesLit(m, s, s.len))
-        res.addField(si, name = "more"):
-          res.add(NimNil)
-  elif s.len <= payloadSize:
-    # Medium: bytes holds slen + chars 0-6; more holds chars 7..PayloadSize-1 as raw bits.
-    res.addVarWithInitializer(
-        if isConst: AlwaysConst else: Global,
-        name = tmp, typ = "SmallString"):
-      var si: StructInitializer
-      res.addStructInitializer(si, kind = siOrderedStruct):
-        res.addField(si, name = "bytes"):
-          res.add(ssoBytesLit(m, s, s.len))
-        res.addField(si, name = "more"):
-          res.add(ssoMoreLit(m, s))
-  else:
-    # Long: cache the LongString block to emit it only once per module per string.
-    # Always generate a fresh SmallString pointing at the (possibly cached) block.
-    let id = nodeTableTestOrSet(m.dataCache, n, m.labels)
-    var dataName: string
-    if id == m.labels:
-      dataName = getTempName(m)
-      res.addVarWithTypeAndInitializer(
-          if isConst: AlwaysConst else: Global,
-          name = dataName):
-        res.addSimpleStruct(m, name = "", baseType = ""):
-          res.addField(name = "rc", typ = NimInt)
-          res.addField(name = "fullLen", typ = NimInt)
-          res.addField(name = "capImpl", typ = NimInt)
-          res.addArrayField(name = "data", elementType = NimChar, len = s.len + 1)
-      do:
-        var di: StructInitializer
-        res.addStructInitializer(di, kind = siOrderedStruct):
-          res.addField(di, name = "fullLen"):
-            res.addIntValue(s.len)
-          res.addField(di, name = "rc"):
-            res.addIntValue(1)
-          res.addField(di, name = "capImpl"):
-            res.addIntValue(0)  # bit 0 = 0: static, never freed
-          res.addField(di, name = "data"):
-            res.add(makeCString(s))
-    else:
-      dataName = m.tmpBase & $id
-    # slen = StaticSlen (254): marks this as a static (never-freed) long string.
-    res.addVarWithInitializer(
-        if isConst: AlwaysConst else: Global,
-        name = tmp, typ = "SmallString"):
-      var si: StructInitializer
-      res.addStructInitializer(si, kind = siOrderedStruct):
-        res.addField(si, name = "bytes"):
-          res.add(ssoBytesLit(m, s, 254))
-        res.addField(si, name = "more"):
-          res.add(cCast(ptrType("LongString"), cAddr(dataName)))
-  m.s[cfsStrData].add(extract(res))
+  result.addf "{$1, (NimStrPayload*)&$2}", [rope(n.strVal.len), pureLit]

 # ------ Version selector ---------------------------------------------------

@@ -328,18 +104,15 @@ proc genStringLiteralDataOnly(m: BModule; s: string; info: TLineInfo;
    let tmp = getTempName(m)
    genStringLiteralDataOnlyV2(m, s, tmp, isConst)
    result.add tmp
-  of 3:
-    localError(m.config, info, "genStringLiteralDataOnly not supported for SmallString (nimsso)")
  else:
    localError(m.config, info, "cannot determine how to produce code for string literal")

-proc genNilStringLiteral(m: BModule; info: TLineInfo; result: var Builder) =
-  result.add(cCast(ptrType(cgsymValue(m, "NimStringDesc")), NimNil))
+proc genNilStringLiteral(m: BModule; info: TLineInfo; result: var Rope) =
+  appcg(m, result, "((#NimStringDesc*) NIM_NIL)", [])

-proc genStringLiteral(m: BModule; n: PNode; result: var Builder) =
+proc genStringLiteral(m: BModule; n: PNode; result: var Rope) =
  case detectStrVersion(m)
  of 0, 1: genStringLiteralV1(m, n, result)
  of 2: genStringLiteralV2(m, n, isConst = true, result)
-  of 3: genStringLiteralV3(m, n, isConst = true, result)
  else:
    localError(m.config, n.info, "cannot determine how to produce code for string literal")
--- a/compiler/ccgreset.nim
+++ b/compiler/ccgreset.nim
@@ -24,31 +24,28 @@ proc specializeResetN(p: BProc, accessor: Rope, n: PNode;
  of nkRecCase:
    if (n[0].kind != nkSym): internalError(p.config, n.info, "specializeResetN")
    let disc = n[0].sym
-    if disc.loc.snippet == "": fillObjectFields(p.module, typ)
+    if disc.loc.r == "": fillObjectFields(p.module, typ)
    if disc.loc.t == nil:
      internalError(p.config, n.info, "specializeResetN()")
-    let discField = dotField(accessor, disc.loc.snippet)
-    p.s(cpsStmts).addSwitchStmt(discField):
-      for i in 1..<n.len:
-        let branch = n[i]
-        assert branch.kind in {nkOfBranch, nkElse}
-        var caseBuilder: SwitchCaseBuilder
-        p.s(cpsStmts).addSwitchCase(caseBuilder):
-          if branch.kind == nkOfBranch:
-            genCaseRange(p, branch, caseBuilder)
-          else:
-            p.s(cpsStmts).addCaseElse(caseBuilder)
-        do:
-          specializeResetN(p, accessor, lastSon(branch), typ)
-          p.s(cpsStmts).addBreak()
-    specializeResetT(p, discField, disc.loc.t)
+    lineF(p, cpsStmts, "switch ($1.$2) {$n", [accessor, disc.loc.r])
+    for i in 1..<n.len:
+      let branch = n[i]
+      assert branch.kind in {nkOfBranch, nkElse}
+      if branch.kind == nkOfBranch:
+        genCaseRange(p, branch)
+      else:
+        lineF(p, cpsStmts, "default:$n", [])
+      specializeResetN(p, accessor, lastSon(branch), typ)
+      lineF(p, cpsStmts, "break;$n", [])
+    lineF(p, cpsStmts, "} $n", [])
+    specializeResetT(p, "$1.$2" % [accessor, disc.loc.r], disc.loc.t)
  of nkSym:
    let field = n.sym
    if field.typ.kind == tyVoid: return
-    if field.loc.snippet == "": fillObjectFields(p.module, typ)
+    if field.loc.r == "": fillObjectFields(p.module, typ)
    if field.loc.t == nil:
      internalError(p.config, n.info, "specializeResetN()")
-    specializeResetT(p, dotField(accessor, field.loc.snippet), field.loc.t)
+    specializeResetT(p, "$1.$2" % [accessor, field.loc.r], field.loc.t)
  else: internalError(p.config, n.info, "specializeResetN()")

 proc specializeResetT(p: BProc, accessor: Rope, typ: PType) =
@@ -57,60 +54,50 @@ proc specializeResetT(p: BProc, accessor: Rope, typ: PType) =
  case typ.kind
  of tyGenericInst, tyGenericBody, tyTypeDesc, tyAlias, tyDistinct, tyInferred,
     tySink, tyOwned:
-    specializeResetT(p, accessor, skipModifier(typ))
+    specializeResetT(p, accessor, lastSon(typ))
  of tyArray:
-    let arraySize = lengthOrd(p.config, typ.indexType)
+    let arraySize = lengthOrd(p.config, typ[0])
    var i: TLoc = getTemp(p, getSysType(p.module.g.graph, unknownLineInfo, tyInt))
-    p.s(cpsStmts).addForRangeExclusive(i.snippet, cIntValue(0), cIntValue(arraySize)):
-      specializeResetT(p, subscript(accessor, i.snippet), typ.elementType)
+    linefmt(p, cpsStmts, "for ($1 = 0; $1 < $2; $1++) {$n",
+            [i.r, arraySize])
+    specializeResetT(p, ropecg(p.module, "$1[$2]", [accessor, i.r]), typ[1])
+    lineF(p, cpsStmts, "}$n", [])
  of tyObject:
-    var x = typ.baseClass
-    if x != nil: x = x.skipTypes(skipPtrs)
-    specializeResetT(p, accessor.parentObj(p.module), x)
-    if typ.n != nil:
-      if typ.sym != nil and sfImportc in typ.sym.flags:
-        # imported C struct, nimZeroMem
-        p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimZeroMem"),
-          cCast(ptrType(CPointer), cAddr(accessor)),
-          cSizeof(getTypeDesc(p.module, typ)))
-      else:
-        specializeResetN(p, accessor, typ.n, typ)
+    for i in 0..<typ.len:
+      var x = typ[i]
+      if x != nil: x = x.skipTypes(skipPtrs)
+      specializeResetT(p, accessor.parentObj(p.module), x)
+    if typ.n != nil: specializeResetN(p, accessor, typ.n, typ)
  of tyTuple:
    let typ = getUniqueType(typ)
-    for i, a in typ.ikids:
-      specializeResetT(p, dotField(accessor, "Field" & $i), a)
+    for i in 0..<typ.len:
+      specializeResetT(p, ropecg(p.module, "$1.Field$2", [accessor, i]), typ[i])

  of tyString, tyRef, tySequence:
-    p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "unsureAsgnRef"),
-      cCast(ptrType(CPointer), cAddr(accessor)),
-      NimNil)
+    lineCg(p, cpsStmts, "#unsureAsgnRef((void**)&$1, NIM_NIL);$n", [accessor])

  of tyProc:
    if typ.callConv == ccClosure:
-      p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "unsureAsgnRef"),
-        cCast(ptrType(CPointer), cAddr(dotField(accessor, "ClE_0"))),
-        NimNil)
-      p.s(cpsStmts).addFieldAssignment(accessor, "ClP_0", NimNil)
+      lineCg(p, cpsStmts, "#unsureAsgnRef((void**)&$1.ClE_0, NIM_NIL);$n", [accessor])
+      lineCg(p, cpsStmts, "$1.ClP_0 = NIM_NIL;$n", [accessor])
    else:
-      p.s(cpsStmts).addAssignment(accessor, NimNil)
-  of tyChar, tyBool, tyEnum, tyRange, tyInt..tyUInt64:
-    p.s(cpsStmts).addAssignment(accessor, cIntValue(0))
+      lineCg(p, cpsStmts, "$1 = NIM_NIL;$n", [accessor])
+  of tyChar, tyBool, tyEnum, tyInt..tyUInt64:
+    lineCg(p, cpsStmts, "$1 = 0;$n", [accessor])
  of tyCstring, tyPointer, tyPtr, tyVar, tyLent:
-    p.s(cpsStmts).addAssignment(accessor, NimNil)
+    lineCg(p, cpsStmts, "$1 = NIM_NIL;$n", [accessor])
  of tySet:
    case mapSetType(p.config, typ)
    of ctArray:
-      let t = getTypeDesc(p.module, typ)
-      p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimZeroMem"),
-        accessor,
-        cSizeof(t))
+      lineCg(p, cpsStmts, "#nimZeroMem($1, sizeof($2));$n",
+          [accessor, getTypeDesc(p.module, typ)])
    of ctInt8, ctInt16, ctInt32, ctInt64:
-      p.s(cpsStmts).addAssignment(accessor, cIntValue(0))
+      lineCg(p, cpsStmts, "$1 = 0;$n", [accessor])
    else:
      raiseAssert "unexpected set type kind"
  of tyNone, tyEmpty, tyNil, tyUntyped, tyTyped, tyGenericInvocation,
-      tyGenericParam, tyOrdinal, tyOpenArray, tyForward, tyVarargs,
-      tyUncheckedArray, tyError, tyBuiltInTypeClass, tyUserTypeClass,
+      tyGenericParam, tyOrdinal, tyRange, tyOpenArray, tyForward, tyVarargs,
+      tyUncheckedArray, tyProxy, tyBuiltInTypeClass, tyUserTypeClass,
      tyUserTypeClassInst, tyCompositeTypeClass, tyAnd, tyOr, tyNot,
      tyAnything, tyStatic, tyFromExpr, tyConcept, tyVoid, tyIterable:
    discard
--- a/compiler/ccgstmts.nim
+++ b/compiler/ccgstmts.nim
--- a/compiler/ccgthreadvars.nim
+++ b/compiler/ccgthreadvars.nim
@@ -19,12 +19,9 @@ proc accessThreadLocalVar(p: BProc, s: PSym) =
  if emulatedThreadVars(p.config) and threadVarAccessed notin p.flags:
    p.flags.incl threadVarAccessed
    incl p.module.flags, usesThreadVars
-    p.procSec(cpsLocals).addVar(kind = Local,
-      name = "NimTV_",
-      typ = ptrType("NimThreadVars"))
-    p.procSec(cpsInit).addAssignment("NimTV_",
-      cCast(ptrType("NimThreadVars"),
-        cCall(cgsymValue(p.module, "GetThreadLocalVars"))))
+    p.procSec(cpsLocals).addf("\tNimThreadVars* NimTV_;$n", [])
+    p.procSec(cpsInit).add(
+      ropecg(p.module, "\tNimTV_ = (NimThreadVars*) #GetThreadLocalVars();$n", []))

 proc declareThreadVar(m: BModule, s: PSym, isExtern: bool) =
  if emulatedThreadVars(m.config):
@@ -33,51 +30,30 @@ proc declareThreadVar(m: BModule, s: PSym, isExtern: bool) =
    # allocator for it :-(
    if not containsOrIncl(m.g.nimtvDeclared, s.id):
      m.g.nimtvDeps.add(s.loc.t)
-      m.g.nimtv.addField(name = s.loc.snippet, typ = getTypeDesc(m, s.loc.t))
+      m.g.nimtv.addf("$1 $2;$n", [getTypeDesc(m, s.loc.t), s.loc.r])
  else:
-    let vis =
-      if isExtern: Extern
-      elif lfExportLib in s.loc.flags: ExportLibVar
-      else: Private
-    if m.config.cmd == cmdNifC and vis == Private and not isExtern:
-      # A `{.threadvar.}`/`{.global.}` thread-local declared inside a routine is
-      # emitted by every module that emit-everywhere's its enclosing routine
-      # (e.g. libp2p's `var keys {.global.}: HashSet`), so its content-addressed
-      # name collides at link. Same fix as a plain global (genGlobalVarDecl):
-      # `extern` declaration + a droppable `'d'` definition unit the merge stage
-      # assigns one owner. The thread-local storage class rides on both.
-      let cname = stripCnifMarks(s.loc.snippet)
-      let td = getTypeDesc(m, s.loc.t)
-      # `extern` declaration via the full `addVar` overload — it knows the
-      # thread-local storage class (`NIM_THREADVAR`); the simple `addVar`'s
-      # `addVarHeader` does not implement `Threadvar`.
-      m.s[cfsVars].addVar(m, s, name = s.loc.snippet, typ = td,
-                          kind = Threadvar, visibility = Extern)
-      m.s[cfsVars].add(cnifDefDirective(cname, "d", icNifName(m, s)))
-      m.s[cfsVars].addVar(m, s,
-        name = s.loc.snippet, typ = td, kind = Threadvar, visibility = vis)
-      m.s[cfsVars].add(cnifEndDefs())
-    else:
-      m.s[cfsVars].addVar(m, s,
-        name = s.loc.snippet,
-        typ = getTypeDesc(m, s.loc.t),
-        kind = Threadvar,
-        visibility = vis)
+    if isExtern: m.s[cfsVars].add("extern ")
+    elif lfExportLib in s.loc.flags: m.s[cfsVars].add("N_LIB_EXPORT_VAR ")
+    else: m.s[cfsVars].add("N_LIB_PRIVATE ")
+    if optThreads in m.config.globalOptions:
+      let sym = s.typ.sym
+      if sym != nil and sfCppNonPod in sym.flags:
+        m.s[cfsVars].add("NIM_THREAD_LOCAL ")
+      else: m.s[cfsVars].add("NIM_THREADVAR ")
+    m.s[cfsVars].add(getTypeDesc(m, s.loc.t))
+    m.s[cfsVars].addf(" $1;$n", [s.loc.r])

 proc generateThreadLocalStorage(m: BModule) =
-  if m.g.nimtv.buf.len != 0 and (usesThreadVars in m.flags or sfMainModule in m.module.flags):
+  if m.g.nimtv != "" and (usesThreadVars in m.flags or sfMainModule in m.module.flags):
    for t in items(m.g.nimtvDeps): discard getTypeDesc(m, t)
    finishTypeDescriptions(m)
-    m.s[cfsSeqTypes].addTypedef(name = "NimThreadVars"):
-      m.s[cfsSeqTypes].addSimpleStruct(m, name = "", baseType = ""):
-        m.s[cfsSeqTypes].add(extract(m.g.nimtv))
+    m.s[cfsSeqTypes].addf("typedef struct {$1} NimThreadVars;$n", [m.g.nimtv])

 proc generateThreadVarsSize(m: BModule) =
-  if m.g.nimtv.buf.len != 0:
+  if m.g.nimtv != "":
    let externc = if m.config.backend == backendCpp or
-                       sfCompileToCpp in m.module.flags: ExternC
-                  else: None
-    m.s[cfsProcs].addDeclWithVisibility(externc):
-      m.s[cfsProcs].addProcHeader("NimThreadVarsSize", NimInt, cProcParams())
-      m.s[cfsProcs].finishProcHeaderWithBody():
-        m.s[cfsProcs].addReturn(cCast(NimInt, cSizeof("NimThreadVars")))
+                       sfCompileToCpp in m.module.flags: "extern \"C\" "
+                  else: ""
+    m.s[cfsProcs].addf(
+      "$#NI NimThreadVarsSize(){return (NI)sizeof(NimThreadVars);}$n",
+      [externc.rope])
--- a/compiler/ccgtrav.nim
+++ b/compiler/ccgtrav.nim
@@ -16,16 +16,13 @@ type
    p: BProc
    visitorFrmt: string

+const
+  visitorFrmt = "#nimGCvisit((void*)$1, $2);$n"

 proc genTraverseProc(c: TTraversalClosure, accessor: Rope, typ: PType)
-proc genCaseRange(p: BProc, branch: PNode, info: var SwitchCaseBuilder)
+proc genCaseRange(p: BProc, branch: PNode)
 proc getTemp(p: BProc, t: PType, needsInit=false): TLoc

-proc visit(p: BProc, data, visitor: Snippet) =
-  p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimGCvisit"),
-    cCast(CPointer, data),
-    visitor)
-
 proc genTraverseProc(c: TTraversalClosure, accessor: Rope, n: PNode;
                     typ: PType) =
  if n == nil: return
@@ -37,35 +34,32 @@ proc genTraverseProc(c: TTraversalClosure, accessor: Rope, n: PNode;
    if (n[0].kind != nkSym): internalError(c.p.config, n.info, "genTraverseProc")
    var p = c.p
    let disc = n[0].sym
-    if disc.loc.snippet == "": fillObjectFields(c.p.module, typ)
+    if disc.loc.r == "": fillObjectFields(c.p.module, typ)
    if disc.loc.t == nil:
      internalError(c.p.config, n.info, "genTraverseProc()")
-    let discField = dotField(accessor, disc.loc.snippet)
-    p.s(cpsStmts).addSwitchStmt(discField):
-      for i in 1..<n.len:
-        let branch = n[i]
-        assert branch.kind in {nkOfBranch, nkElse}
-        var caseBuilder: SwitchCaseBuilder
-        p.s(cpsStmts).addSwitchCase(caseBuilder):
-          if branch.kind == nkOfBranch:
-            genCaseRange(c.p, branch, caseBuilder)
-          else:
-            p.s(cpsStmts).addCaseElse(caseBuilder)
-        do:
-          genTraverseProc(c, accessor, lastSon(branch), typ)
-          p.s(cpsStmts).addBreak()
+    lineF(p, cpsStmts, "switch ($1.$2) {$n", [accessor, disc.loc.r])
+    for i in 1..<n.len:
+      let branch = n[i]
+      assert branch.kind in {nkOfBranch, nkElse}
+      if branch.kind == nkOfBranch:
+        genCaseRange(c.p, branch)
+      else:
+        lineF(p, cpsStmts, "default:$n", [])
+      genTraverseProc(c, accessor, lastSon(branch), typ)
+      lineF(p, cpsStmts, "break;$n", [])
+    lineF(p, cpsStmts, "} $n", [])
  of nkSym:
    let field = n.sym
    if field.typ.kind == tyVoid: return
-    if field.loc.snippet == "": fillObjectFields(c.p.module, typ)
+    if field.loc.r == "": fillObjectFields(c.p.module, typ)
    if field.loc.t == nil:
      internalError(c.p.config, n.info, "genTraverseProc()")
-    genTraverseProc(c, dotField(accessor, field.loc.snippet), field.loc.t)
+    genTraverseProc(c, "$1.$2" % [accessor, field.loc.r], field.loc.t)
  else: internalError(c.p.config, n.info, "genTraverseProc()")

 proc parentObj(accessor: Rope; m: BModule): Rope {.inline.} =
  if not m.compileToCpp:
-    result = dotField(accessor, "Sup")
+    result = "$1.Sup" % [accessor]
  else:
    result = accessor

@@ -77,156 +71,125 @@ proc genTraverseProc(c: TTraversalClosure, accessor: Rope, typ: PType) =
  case typ.kind
  of tyGenericInst, tyGenericBody, tyTypeDesc, tyAlias, tyDistinct, tyInferred,
     tySink, tyOwned:
-    genTraverseProc(c, accessor, skipModifier(typ))
+    genTraverseProc(c, accessor, lastSon(typ))
  of tyArray:
-    let arraySize = lengthOrd(c.p.config, typ.indexType)
+    let arraySize = lengthOrd(c.p.config, typ[0])
    var i: TLoc = getTemp(p, getSysType(c.p.module.g.graph, unknownLineInfo, tyInt))
    var oldCode = p.s(cpsStmts)
-    var oldLen, newLen: int
-    p.s(cpsStmts).addForRangeExclusive(i.snippet, cIntValue(0), cIntValue(arraySize)):
-      oldLen = p.s(cpsStmts).buf.len
-      genTraverseProc(c, subscript(accessor, i.snippet), typ.elementType)
-      newLen = p.s(cpsStmts).buf.len
-    if oldLen == newLen:
+    freeze oldCode
+    linefmt(p, cpsStmts, "for ($1 = 0; $1 < $2; $1++) {$n",
+            [i.r, arraySize])
+    let oldLen = p.s(cpsStmts).len
+    genTraverseProc(c, ropecg(c.p.module, "$1[$2]", [accessor, i.r]), typ[1])
+    if p.s(cpsStmts).len == oldLen:
      # do not emit dummy long loops for faster debug builds:
      p.s(cpsStmts) = oldCode
+    else:
+      lineF(p, cpsStmts, "}$n", [])
  of tyObject:
-    var x = typ.baseClass
-    if x != nil: x = x.skipTypes(skipPtrs)
-    genTraverseProc(c, accessor.parentObj(c.p.module), x)
+    for i in 0..<typ.len:
+      var x = typ[i]
+      if x != nil: x = x.skipTypes(skipPtrs)
+      genTraverseProc(c, accessor.parentObj(c.p.module), x)
    if typ.n != nil: genTraverseProc(c, accessor, typ.n, typ)
  of tyTuple:
    let typ = getUniqueType(typ)
-    for i, a in typ.ikids:
-      genTraverseProc(c, dotField(accessor, "Field" & $i), a)
+    for i in 0..<typ.len:
+      genTraverseProc(c, ropecg(c.p.module, "$1.Field$2", [accessor, i]), typ[i])
  of tyRef:
-    visit(p, accessor, c.visitorFrmt)
+    lineCg(p, cpsStmts, visitorFrmt, [accessor, c.visitorFrmt])
  of tySequence:
    if optSeqDestructors notin c.p.module.config.globalOptions:
-      visit(p, accessor, c.visitorFrmt)
-    elif containsGarbageCollectedRef(typ.elementType):
+      lineCg(p, cpsStmts, visitorFrmt, [accessor, c.visitorFrmt])
+    elif containsGarbageCollectedRef(typ.lastSon):
      # destructor based seqs are themselves not traced but their data is, if
      # they contain a GC'ed type:
-      p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimGCvisitSeq"),
-        cCast(CPointer, accessor),
-        c.visitorFrmt)
+      lineCg(p, cpsStmts, "#nimGCvisitSeq((void*)$1, $2);$n", [accessor, c.visitorFrmt])
      #genTraverseProcSeq(c, accessor, typ)
  of tyString:
    if tfHasAsgn notin typ.flags:
-      visit(p, accessor, c.visitorFrmt)
+      lineCg(p, cpsStmts, visitorFrmt, [accessor, c.visitorFrmt])
  of tyProc:
    if typ.callConv == ccClosure:
-      visit(p, dotField(accessor, "ClE_0"), c.visitorFrmt)
+      lineCg(p, cpsStmts, visitorFrmt, [ropecg(c.p.module, "$1.ClE_0", [accessor]), c.visitorFrmt])
  else:
    discard

 proc genTraverseProcSeq(c: TTraversalClosure, accessor: Rope, typ: PType) =
  var p = c.p
  assert typ.kind == tySequence
-  var i = getTemp(p, getSysType(c.p.module.g.graph, unknownLineInfo, tyInt))
+  var i: TLoc = getTemp(p, getSysType(c.p.module.g.graph, unknownLineInfo, tyInt))
  var oldCode = p.s(cpsStmts)
-  var oldLen, newLen: int
-  var a = TLoc(snippet: accessor)
-  let le = lenExpr(c.p, a)
+  freeze oldCode
+  var a: TLoc = TLoc(r: accessor)

-  p.s(cpsStmts).addForRangeExclusive(i.snippet, cIntValue(0), le):
-    oldLen = p.s(cpsStmts).buf.len
-    genTraverseProc(c, subscript(dataField(c.p, accessor), i.snippet), typ.elementType)
-    newLen = p.s(cpsStmts).buf.len
-  if newLen == oldLen:
+  lineF(p, cpsStmts, "for ($1 = 0; $1 < $2; $1++) {$n",
+      [i.r, lenExpr(c.p, a)])
+  let oldLen = p.s(cpsStmts).len
+  genTraverseProc(c, "$1$3[$2]" % [accessor, i.r, dataField(c.p)], typ[0])
+  if p.s(cpsStmts).len == oldLen:
    # do not emit dummy long loops for faster debug builds:
    p.s(cpsStmts) = oldCode
+  else:
+    lineF(p, cpsStmts, "}$n", [])

 proc genTraverseProc(m: BModule, origTyp: PType; sig: SigHash): Rope =
+  var c: TTraversalClosure
  var p = newProc(nil, m)
  result = "Marker_" & getTypeName(m, origTyp, sig)
  let
    hcrOn = m.hcrOn
    typ = origTyp.skipTypes(abstractInstOwned)
    markerName = if hcrOn: result & "_actual" else: result
+    header = "static N_NIMCALL(void, $1)(void* p, NI op)" % [markerName]
    t = getTypeDesc(m, typ)

-  p.s(cpsLocals).addVar(kind = Local, name = "a", typ = t)
-  p.s(cpsInit).addAssignment("a", cCast(t, "p"))
+  lineF(p, cpsLocals, "$1 a;$n", [t])
+  lineF(p, cpsInit, "a = ($1)p;$n", [t])

-  var c = TTraversalClosure(p: p,
-    visitorFrmt: "op" # "#nimGCvisit((void*)$1, op);$n"
-    )
+  c.p = p
+  c.visitorFrmt = "op" # "#nimGCvisit((void*)$1, op);$n"

  assert typ.kind != tyTypeDesc
  if typ.kind == tySequence:
    genTraverseProcSeq(c, "a".rope, typ)
  else:
-    if skipTypes(typ.elementType, typedescInst+{tyOwned}).kind == tyArray:
+    if skipTypes(typ[0], typedescInst+{tyOwned}).kind == tyArray:
      # C's arrays are broken beyond repair:
-      genTraverseProc(c, "a".rope, typ.elementType)
+      genTraverseProc(c, "a".rope, typ[0])
    else:
-      genTraverseProc(c, cDeref("a"), typ.elementType)
+      genTraverseProc(c, "(*a)".rope, typ[0])

-  var headerBuilder = newBuilder("")
-  headerBuilder.addProcHeaderWithParams(ccNimCall, markerName, CVoid):
-    var paramBuilder: ProcParamBuilder
-    headerBuilder.addProcParams(paramBuilder):
-      headerBuilder.addParam(paramBuilder, name = "p", typ = CPointer)
-      headerBuilder.addParam(paramBuilder, name = "op", typ = NimInt)
-  let header = extract(headerBuilder)
+  let generatedProc = "$1 {$n$2$3$4}\n" %
+        [header, p.s(cpsLocals), p.s(cpsInit), p.s(cpsStmts)]

-  m.s[cfsProcHeaders].addDeclWithVisibility(StaticProc):
-    m.s[cfsProcHeaders].add(header)
-    m.s[cfsProcHeaders].finishProcHeaderAsProto()
-  m.s[cfsProcs].addDeclWithVisibility(StaticProc):
-    m.s[cfsProcs].add(header)
-    m.s[cfsProcs].finishProcHeaderWithBody():
-      m.s[cfsProcs].add(extract(p.s(cpsLocals)))
-      m.s[cfsProcs].add(extract(p.s(cpsInit)))
-      m.s[cfsProcs].add(extract(p.s(cpsStmts)))
+  m.s[cfsProcHeaders].addf("$1;\n", [header])
+  m.s[cfsProcs].add(generatedProc)

  if hcrOn:
-    var desc = newBuilder("")
-    var unnamedParamBuilder: ProcParamBuilder
-    desc.addProcParams(unnamedParamBuilder):
-      desc.addUnnamedParam(unnamedParamBuilder, CPointer)
-      desc.addUnnamedParam(unnamedParamBuilder, NimInt)
-    let unnamedParams = extract(desc)
-    m.s[cfsProcHeaders].addProcVar(ccNimCall, result, unnamedParams, CVoid)
-    m.s[cfsDynLibInit].addAssignmentWithValue(result):
-      m.s[cfsDynLibInit].addCast(procPtrTypeUnnamed(ccNimCall, CVoid, unnamedParams)):
-        m.s[cfsDynLibInit].addCall("hcrRegisterProc",
-          getModuleDllPath(m),
-          '"' & result & '"',
-          cCast(CPointer, markerName))
+    m.s[cfsProcHeaders].addf("N_NIMCALL_PTR(void, $1)(void*, NI);\n", [result])
+    m.s[cfsDynLibInit].addf("\t$1 = (N_NIMCALL_PTR(void, )(void*, NI)) hcrRegisterProc($3, \"$1\", (void*)$2);\n",
+         [result, markerName, getModuleDllPath(m)])

 proc genTraverseProcForGlobal(m: BModule, s: PSym; info: TLineInfo): Rope =
  discard genTypeInfoV1(m, s.loc.t, info)

+  var c: TTraversalClosure
  var p = newProc(nil, m)
  var sLoc = rdLoc(s.loc)
  result = getTempName(m)

  if sfThread in s.flags and emulatedThreadVars(m.config):
    accessThreadLocalVar(p, s)
-    sLoc = derefField("NimTV_", sLoc)
-
-  var c = TTraversalClosure(p: p,
-    visitorFrmt: cIntValue(0) # "#nimGCvisit((void*)$1, 0);$n"
-  )
+    sLoc = "NimTV_->" & sLoc

+  c.visitorFrmt = "0" # "#nimGCvisit((void*)$1, 0);$n"
+  c.p = p
+  let header = "static N_NIMCALL(void, $1)(void)" % [result]
  genTraverseProc(c, sLoc, s.loc.t)

-  var headerBuilder = newBuilder("")
-  headerBuilder.addProcHeaderWithParams(ccNimCall, result, CVoid):
-    var paramBuilder: ProcParamBuilder
-    headerBuilder.addProcParams(paramBuilder):
-      # (void)
-      discard
-  let header = extract(headerBuilder)
+  let generatedProc = "$1 {$n$2$3$4}$n" %
+        [header, p.s(cpsLocals), p.s(cpsInit), p.s(cpsStmts)]

-  m.s[cfsProcHeaders].addDeclWithVisibility(StaticProc):
-    m.s[cfsProcHeaders].add(header)
-    m.s[cfsProcHeaders].finishProcHeaderAsProto()
-  m.s[cfsProcs].addDeclWithVisibility(StaticProc):
-    m.s[cfsProcs].add(header)
-    m.s[cfsProcs].finishProcHeaderWithBody():
-      m.s[cfsProcs].add(extract(p.s(cpsLocals)))
-      m.s[cfsProcs].add(extract(p.s(cpsInit)))
-      m.s[cfsProcs].add(extract(p.s(cpsStmts)))
+  m.s[cfsProcHeaders].addf("$1;$n", [header])
+  m.s[cfsProcs].add(generatedProc)
--- a/compiler/ccgtypes.nim
+++ b/compiler/ccgtypes.nim
--- a/compiler/ccgutils.nim
+++ b/compiler/ccgutils.nim
@@ -10,10 +10,8 @@
 # This module declares some helpers for the C code generator.

 import
-  ast, types, msgs, wordrecg,
-  platform, trees, options, cgendata, mangleutils, renderer, modulegraphs
-
-import std/[hashes, strutils, formatfloat]
+  ast, types, hashes, strutils, msgs, wordrecg,
+  platform, trees, options, cgendata

 when defined(nimPreviewSlimSystem):
  import std/assertions
@@ -68,6 +66,53 @@ proc makeSingleLineCString*(s: string): string =
    c.toCChar(result)
  result.add('\"')

+proc mangle*(name: string): string =
+  result = newStringOfCap(name.len)
+  var start = 0
+  if name[0] in Digits:
+    result.add("X" & name[0])
+    start = 1
+  var requiresUnderscore = false
+  template special(x) =
+    result.add x
+    requiresUnderscore = true
+  for i in start..<name.len:
+    let c = name[i]
+    case c
+    of 'a'..'z', '0'..'9', 'A'..'Z':
+      result.add(c)
+    of '_':
+      # we generate names like 'foo_9' for scope disambiguations and so
+      # disallow this here:
+      if i > 0 and i < name.len-1 and name[i+1] in Digits:
+        discard
+      else:
+        result.add(c)
+    of '$': special "dollar"
+    of '%': special "percent"
+    of '&': special "amp"
+    of '^': special "roof"
+    of '!': special "emark"
+    of '?': special "qmark"
+    of '*': special "star"
+    of '+': special "plus"
+    of '-': special "minus"
+    of '/': special "slash"
+    of '\\': special "backslash"
+    of '=': special "eq"
+    of '<': special "lt"
+    of '>': special "gt"
+    of '~': special "tilde"
+    of ':': special "colon"
+    of '.': special "dot"
+    of '@': special "at"
+    of '|': special "bar"
+    else:
+      result.add("X" & toHex(ord(c), 2))
+      requiresUnderscore = true
+  if requiresUnderscore:
+    result.add "_"
+
 proc mapSetType(conf: ConfigRef; typ: PType): TCTypeKind =
  case int(getSize(conf, typ))
  of 1: result = ctInt8
@@ -79,10 +124,10 @@ proc mapSetType(conf: ConfigRef; typ: PType): TCTypeKind =
 proc ccgIntroducedPtr*(conf: ConfigRef; s: PSym, retType: PType): bool =
  var pt = skipTypes(s.typ, typedescInst)
  assert skResult != s.kind
-
+  
  #note precedence: params override types
  if optByRef in s.options: return true
-  elif sfByCopy in s.flags: return false
+  elif sfByCopy in s.flags: return false 
  elif tfByRef in pt.flags: return true
  elif tfByCopy in pt.flags: return false
  case pt.kind
@@ -106,91 +151,3 @@ proc ccgIntroducedPtr*(conf: ConfigRef; s: PSym, retType: PType): bool =
    result = not (pt.kind in {tyVar, tyArray, tyOpenArray, tyVarargs, tyRef, tyPtr, tyPointer} or
      pt.kind == tySet and mapSetType(conf, pt) == ctArray)

-proc encodeName*(name: string): string =
-  result = mangle(name)
-  result = $result.len & result
-
-proc makeUnique(m: BModule; s: PSym, name: string = ""): string =
-  result = if name == "": s.name.s else: name
-  # keep backend-minted ids out of the `_u` namespace; their item counter
-  # restarts at 0 and would collide with loaded symbols' ids
-  if s.itemId.isBackendMinted:
-    result.add "_c"
-    if (s.disamb and HookDisambBit) != 0'i32:
-      # A backend-minted sym whose `disamb` is content-derived (setHookDisamb gave
-      # it HookDisambBit) — e.g. the `rttiDestroy` wrapper. Its `itemId.item` is a
-      # PER-PROCESS backend counter, so using it makes the C name diverge across
-      # the emit-everywhere processes: the type's RTTI table (emit-everywhere,
-      # merge-deduped) ends up referencing one process's `_c<item>` while the
-      # wrapper is defined with another's -> undefined at link (`rttiDestroy_c23`).
-      # The content-derived disamb is stable across processes, so use it.
-      result.add $s.disamb
-    else:
-      result.add $s.itemId.item
-  else:
-    result.add "_u"
-    # Mirror `mangleProcNameExt`: use the per-(module,name) `disamb`, NOT
-    # `itemId.item`. Under the per-module IC backend the same symbol is loaded
-    # from a NIF in many processes and `itemId.item` is a fresh, load-order
-    # dependent counter — so a method base would mangle to `_u1` in one module,
-    # `_u3` in another and clean at its owner, none of which link. `disamb` is
-    # assigned deterministically per (module, name) and is serialized, so every
-    # process that touches the symbol derives the identical C name.
-    result.add $s.disamb
-  # module suffix LAST (a strippable trailing token; see `mangleProcNameExt`)
-  result.add "__"
-  result.add m.g.graph.ifaces[s.itemId.module].uniqueName
-
-proc encodeSym*(m: BModule; s: PSym; makeUnique: bool = false; extra: string = ""): string =
-  #Module::Type
-  var name = s.name.s & extra
-  if makeUnique:
-    name = makeUnique(m, s, name)
-  "N" & encodeName(s.skipGenericOwner.name.s) & encodeName(name) & "E"
-
-proc encodeType*(m: BModule; t: PType; staticLists: var string): string =
-  result = ""
-  var kindName = ($t.kind)[2..^1]
-  kindName[0] = toLower($kindName[0])[0]
-  case t.kind
-  of tyObject, tyEnum, tyDistinct, tyUserTypeClass, tyGenericParam:
-    result = encodeSym(m, t.sym)
-  of tyGenericInst, tyUserTypeClassInst, tyGenericBody:
-    result = encodeName(t[0].sym.name.s)
-    result.add "I"
-    for i in 1..<t.len - 1:
-      result.add encodeType(m, t[i], staticLists)
-    result.add "E"
-  of tySequence, tyOpenArray, tyArray, tyVarargs, tyTuple, tyProc, tySet, tyTypeDesc,
-    tyPtr, tyRef, tyVar, tyLent, tySink, tyUncheckedArray, tyOr, tyAnd, tyBuiltInTypeClass:
-    result =
-      case t.kind:
-      of tySequence: encodeName("seq")
-      else: encodeName(kindName)
-    result.add "I"
-    for i in 0..<t.len:
-      let s = t[i]
-      if s.isNil: continue
-      result.add encodeType(m, s, staticLists)
-    result.add "E"
-  of tyStatic:
-    if t.n != nil:
-      staticLists.add "_s" & renderTree(t.n)
-    else:
-      raiseAssert "unreachable"
-  of tyRange:
-    var val = "range_"
-    if t.n[0].typ.kind in {tyFloat..tyFloat128}:
-      val.addFloat t.n[0].floatVal
-      val.add "_"
-      val.addFloat t.n[1].floatVal
-    else:
-      val.add $t.n[0].intVal & "_" & $t.n[1].intVal
-    result = encodeName(val)
-  of tyString..tyUInt64, tyPointer, tyBool, tyChar, tyVoid, tyAnything, tyNil, tyEmpty:
-    result = encodeName(kindName)
-  of tyAlias, tyInferred, tyOwned:
-    result = encodeType(m, t.elementType, staticLists)
-  else:
-    assert false, "encodeType " & $t.kind
-
--- a/compiler/cgen.nim
+++ b/compiler/cgen.nim
--- a/compiler/cgendata.nim
+++ b/compiler/cgendata.nim
@@ -10,10 +10,8 @@
 ## This module contains the data structures for the C code generation phase.

 import
-  ast, ropes, options,
-  lineinfos, pathutils, modulegraphs, cbuilderbase
-
-import std/[intsets, tables, sets]
+  ast, ropes, options, intsets,
+  tables, ndi, lineinfos, pathutils, modulegraphs, sets

 type
  TLabel* = Rope              # for the C generator a label is just a rope
@@ -43,12 +41,12 @@ type
    ctUInt, ctUInt8, ctUInt16, ctUInt32, ctUInt64,
    ctArray, ctPtrToArray, ctStruct, ctPtr, ctNimStr, ctNimSeq, ctProc,
    ctCString
-  TCFileSections* = array[TCFileSection, Builder] # represents a generated C file
+  TCFileSections* = array[TCFileSection, Rope] # represents a generated C file
  TCProcSection* = enum       # the sections a generated C proc consists of
    cpsLocals,                # section of local variables for C proc
    cpsInit,                  # section for init of variables for C proc
    cpsStmts                  # section of local statements for C proc
-  TCProcSections* = array[TCProcSection, Builder] # represents a generated C proc
+  TCProcSections* = array[TCProcSection, Rope] # represents a generated C proc
  BModule* = ref TCGen
  BProc* = ref TCProc
  TBlock* = object
@@ -75,13 +73,10 @@ type
    flags*: set[TCProcFlag]
    lastLineInfo*: TLineInfo  # to avoid generating excessive 'nimln' statements
    currLineInfo*: TLineInfo  # AST codegen will make this superfluous
-    nestedTryStmts*: seq[tuple[fin: PNode, inExcept: bool, isHidden: bool, label: Natural]]
+    nestedTryStmts*: seq[tuple[fin: PNode, inExcept: bool, label: Natural]]
                              # in how many nested try statements we are
                              # (the vars must be volatile then)
-                              # `inExcept` is true when we are in the except part of a try block.
-                              # `isHidden` is true for compiler-injected `nkHiddenTryStmt` wrappers
-                              # (e.g. ARC's destructor try/finally around `except T as e:` bodies);
-                              # finallyActions walks past such wrappers to reach the user's try.
+                              # bool is true when are in the except part of a try block
    finallySafePoints*: seq[Rope]  # For correctly cleaning up exceptions when
                                   # using return in finally statements
    labels*: Natural          # for generating unique labels in the C proc
@@ -91,7 +86,7 @@ type
    options*: TOptions        # options that should be used for code
                              # generation; this is the same as prc.options
                              # unless prc == nil
-    optionsStack*: seq[(TOptions, TNoteKinds)]
+    optionsStack*: seq[TOptions]
    module*: BModule          # used to prevent excessive parameter passing
    withinLoop*: int          # > 0 if we are within a loop
    splitDecls*: int          # > 0 if we are in some context for C++ that
@@ -118,11 +113,11 @@ type
                        # computing alive data on our own.

  BModuleList* = ref object of RootObj
-    mainModProcs*, mainModInit*, otherModsInit*, mainDatInit*: Builder
+    mainModProcs*, mainModInit*, otherModsInit*, mainDatInit*: Rope
    mapping*: Rope             # the generated mapping file (if requested)
-    mods*: seq[BModule]     # list of all compiled modules
+    modules*: seq[BModule]     # list of all compiled modules
    modulesClosed*: seq[BModule] # list of the same compiled modules, but in the order they were closed
-    forwardedProcs*: seq[PSym] # procs that did not yet have a body
+    forwardedProcs*: seq[PSym] # proc:s that did not yet have a body
    generatedHeader*: BModule
    typeInfoMarker*: TypeCacheWithOwner
    typeInfoMarkerV2*: TypeCacheWithOwner
@@ -130,7 +125,7 @@ type
    graph*: ModuleGraph
    strVersion*, seqVersion*: int # version of the string/seq implementation to use

-    nimtv*: Builder         # Nim thread vars; the struct body
+    nimtv*: Rope            # Nim thread vars; the struct body
    nimtvDeps*: seq[PType]  # type deps: every module needs whole struct
    nimtvDeclared*: IntSet  # so that every var/field exists only once
                            # in the struct
@@ -140,7 +135,6 @@ type
                            # unconditionally...
                            # nimtvDeps is VERY hard to cache because it's
                            # not a list of IDs nor can it be made to be one.
-    mangledPrcs*: HashSet[string]

  TCGen = object of PPassContext # represents a C source file
    s*: TCFileSections        # sections of the C file
@@ -154,70 +148,49 @@ type
    typeABICache*: HashSet[SigHash] # cache for ABI checks; reusing typeCache
                              # would be ideal but for some reason enums
                              # don't seem to get cached so it'd generate
-                              # 1 ABI check per occurrence in code
+                              # 1 ABI check per occurence in code
    forwTypeCache*: TypeCache # cache for forward declarations of types
    declaredThings*: IntSet   # things we have declared in this .c file
    declaredProtos*: IntSet   # prototypes we have declared in this .c file
-    emittedContentDefs*: HashSet[string]
-      # cmdNifC per-module backend: content-addressed C names (generic
-      # instances and synthesized hooks) whose body this TU already emitted.
-      # Distinct symbols (minted in different source modules) can share one
-      # `_i<disamb>` name; `declaredThings` keys on symbol id and lets the
-      # second one through, so we dedup the body by name here instead.
-    queue*: seq[PSym]         # queue of procs to generate
    alive*: IntSet            # symbol IDs of alive data as computed by `dce.nim`
    headerFiles*: seq[string] # needed headers to include
    typeInfoMarker*: TypeCache # needed for generating type information
    typeInfoMarkerV2*: TypeCache
    initProc*: BProc          # code for init procedure
    preInitProc*: BProc       # code executed before the init proc
-    hcrCreateTypeInfosProc*: Builder # type info globals are in here when HCR=on
+    hcrCreateTypeInfosProc*: Rope # type info globals are in here when HCR=on
    inHcrInitGuard*: bool     # We are currently within a HCR reloading guard.
-    hcrInitGuard*: IfBuilder
    typeStack*: TTypeSeq      # used for type generation
    dataCache*: TNodeTable
    typeNodes*, nimTypes*: int # used for type info generation
    typeNodesName*, nimTypesName*: Rope # used for type info generation
    labels*: Natural          # for generating unique module-scope names
-    extensionLoaders*: array['0'..'9', Builder] # special procs for the
+    extensionLoaders*: array['0'..'9', Rope] # special procs for the
                                             # OpenGL wrapper
    sigConflicts*: CountTable[SigHash]
-    icImplMods*: IntSet       # module ids whose routine BODIES this TU
-                              # embeds (redirected defs, shared instances,
-                              # hooks); recorded as the artifact's cdeps so
-                              # the reuse gate can check their impl cookies
-    icDataDefs*: seq[tuple[cname, nifname: string]]
-                              # C names of data definitions (consts, globals,
-                              # RTTI) this TU embeds plus their NIF symbol
-                              # names (empty for RTTI, which has no symbol);
-                              # recorded in the cnif artifact so a later run
-                              # can reuse the TU and re-demand definitions
-                              # that cached TUs still reference
    g*: BModuleList
+    ndi*: NdiFile

 template config*(m: BModule): ConfigRef = m.g.config
 template config*(p: BProc): ConfigRef = p.module.g.config
 template vccAndC*(p: BProc): bool = p.module.config.cCompiler == ccVcc and p.module.config.backend == backendC

-proc delayedCodegen*(m: BModule): bool {.inline.} =
-  useAliveDataFromDce in m.flags or m.config.globalOptions.contains(optCompress)
-
 proc includeHeader*(this: BModule; header: string) =
  if not this.headerFiles.contains header:
    this.headerFiles.add header

-proc s*(p: BProc, s: TCProcSection): var Builder {.inline.} =
+proc s*(p: BProc, s: TCProcSection): var Rope {.inline.} =
  # section in the current block
  result = p.blocks[^1].sections[s]

-proc procSec*(p: BProc, s: TCProcSection): var Builder {.inline.} =
+proc procSec*(p: BProc, s: TCProcSection): var Rope {.inline.} =
  # top level proc sections
  result = p.blocks[0].sections[s]

 proc initBlock*(): TBlock =
  result = TBlock()
  for i in low(result.sections)..high(result.sections):
-    result.sections[i] = newBuilder("")
+    result.sections[i] = newRopeAppender()

 proc newProc*(prc: PSym, module: BModule): BProc =
  result = BProc(
--- a/compiler/cgmeth.nim
+++ b/compiler/cgmeth.nim
@@ -10,15 +10,12 @@
 ## This module implements code generation for methods.

 import
-  options, ast, msgs, idents, renderer, types, magicsys,
-  sempass2, modulegraphs, lineinfos, astalgo
-
-import std/intsets
+  intsets, options, ast, msgs, idents, renderer, types, magicsys,
+  sempass2, modulegraphs, lineinfos

 when defined(nimPreviewSlimSystem):
  import std/assertions

-import std/[tables]

 proc genConv(n: PNode, d: PType, downcast: bool; conf: ConfigRef): PNode =
  var dest = skipTypes(d, abstractPtrs)
@@ -69,23 +66,21 @@ type
 proc sameMethodBucket(a, b: PSym; multiMethods: bool): MethodResult =
  result = No
  if a.name.id != b.name.id: return
-  if a.typ.signatureLen != b.typ.signatureLen:
+  if a.typ.len != b.typ.len:
    return

-  var i = 0
-  for x, y in paramTypePairs(a.typ, b.typ):
-    inc i
-    var aa = x
-    var bb = y
+  for i in 1..<a.typ.len:
+    var aa = a.typ[i]
+    var bb = b.typ[i]
    while true:
      aa = skipTypes(aa, {tyGenericInst, tyAlias})
      bb = skipTypes(bb, {tyGenericInst, tyAlias})
      if aa.kind == bb.kind and aa.kind in {tyVar, tyPtr, tyRef, tyLent, tySink}:
-        aa = aa.elementType
-        bb = bb.elementType
+        aa = aa.lastSon
+        bb = bb.lastSon
      else:
        break
-    if sameType(x, y):
+    if sameType(a.typ[i], b.typ[i]):
      if aa.kind == tyObject and result != Invalid:
        result = Yes
    elif aa.kind == tyObject and bb.kind == tyObject and (i == 1 or multiMethods):
@@ -103,11 +98,10 @@ proc sameMethodBucket(a, b: PSym; multiMethods: bool): MethodResult =
      return No
  if result == Yes:
    # check for return type:
-    # ignore flags of return types; # bug #22673
-    if not sameTypeOrNil(a.typ.returnType, b.typ.returnType, {IgnoreFlags}):
-      if b.typ.returnType != nil and b.typ.returnType.kind == tyUntyped:
+    if not sameTypeOrNil(a.typ[0], b.typ[0]):
+      if b.typ[0] != nil and b.typ[0].kind == tyUntyped:
        # infer 'auto' from the base to make it consistent:
-        b.typ.setReturnType a.typ.returnType
+        b.typ[0] = a.typ[0]
      else:
        return No

@@ -123,18 +117,18 @@ proc attachDispatcher(s: PSym, dispatcher: PNode) =

 proc createDispatcher(s: PSym; g: ModuleGraph; idgen: IdGenerator): PSym =
  var disp = copySym(s, idgen)
-  incl(disp, sfDispatcher)
-  excl(disp, sfExported)
+  incl(disp.flags, sfDispatcher)
+  excl(disp.flags, sfExported)
  let old = disp.typ
-  disp.typ = copyType(disp.typ, idgen, disp.typ.owner)
+  disp.typ = copyType(disp.typ, nextTypeId(idgen), disp.typ.owner)
  copyTypeProps(g, idgen.module, disp.typ, old)

  # we can't inline the dispatcher itself (for now):
  if disp.typ.callConv == ccInline: disp.typ.callConv = ccNimCall
  disp.ast = copyTree(s.ast)
  disp.ast[bodyPos] = newNodeI(nkEmpty, s.info)
-  disp.locImpl.snippet = ""
-  if s.typ.returnType != nil:
+  disp.loc.r = ""
+  if s.typ[0] != nil:
    if disp.ast.len > resultPos:
      disp.ast[resultPos].sym = copySym(s.ast[resultPos].sym, idgen)
    else:
@@ -159,24 +153,6 @@ proc fixupDispatcher(meth, disp: PSym; conf: ConfigRef) =

 proc methodDef*(g: ModuleGraph; idgen: IdGenerator; s: PSym) =
  var witness: PSym = nil
-  if s.typ.firstParamType.owner.getModule != s.getModule and vtables in g.config.features and not
-      g.config.isDefined("nimInternalNonVtablesTesting") and sfFromGeneric notin s.flags:
-    # `sfFromGeneric` excepted: this is the same-module restriction for vtable
-    # slot placement, and it must be judged on the GENERIC method, not on an
-    # instance. The generic `method skip[T](x: Input[T])` never reaches here
-    # (`semMethodPrototype` registers generic methods via `addMethodToGeneric`,
-    # bypassing `methodDef`); only its instance `skip[string]` does, and that
-    # instance's first-param type `Input[string]` is owned by whichever module
-    # first instantiated it (`tparsecombnum`, which `import parsecomb`s and uses
-    # it), NOT by `Input[T]`'s defining module — so the comparison spuriously
-    # fails for a method that is perfectly legal at the generic level. (Concrete
-    # methods, `sfFromGeneric notin flags`, are still checked.)
-    localError(g.config, s.info, errGenerated, "method `" & s.name.s &
-          "` can be defined only in the same module with its type (" & s.typ.firstParamType.typeToString() & ")")
-  if sfImportc in s.flags:
-    localError(g.config, s.info, errGenerated, "method `" & s.name.s &
-          "` is not allowed to have 'importc' pragmas")
-
  for i in 0..<g.methods.len:
    let disp = g.methods[i].dispatcher
    case sameMethodBucket(disp, s, multimethods = optMultiMethods in g.config.globalOptions)
@@ -190,19 +166,12 @@ proc methodDef*(g: ModuleGraph; idgen: IdGenerator; s: PSym) =
           g.methods[i].methods[0] != s:
        # already exists due to forwarding definition?
        localError(g.config, s.info, "method is not a base")
-      logMethodDef(g, s)
      return
    of No: discard
    of Invalid:
      if witness.isNil: witness = g.methods[i].methods[0]
  # create a new dispatcher:
-  # stores the id and the position
-  if s.typ.firstParamType.skipTypes(skipPtrs).itemId notin g.bucketTable:
-    g.bucketTable[s.typ.firstParamType.skipTypes(skipPtrs).itemId] = 1
-  else:
-    g.bucketTable.inc(s.typ.firstParamType.skipTypes(skipPtrs).itemId)
  g.methods.add((methods: @[s], dispatcher: createDispatcher(s, g, idgen)))
-  logMethodDef(g, s)
  #echo "adding ", s.info
  if witness != nil:
    localError(g.config, s.info, "invalid declaration order; cannot attach '" & s.name.s &
@@ -210,7 +179,7 @@ proc methodDef*(g: ModuleGraph; idgen: IdGenerator; s: PSym) =
  elif sfBase notin s.flags:
    message(g.config, s.info, warnUseBase)

-proc relevantCol*(methods: seq[PSym], col: int): bool =
+proc relevantCol(methods: seq[PSym], col: int): bool =
  # returns true iff the position is relevant
  result = false
  var t = methods[0].typ[col].skipTypes(skipPtrs)
@@ -222,7 +191,7 @@ proc relevantCol*(methods: seq[PSym], col: int): bool =

 proc cmpSignatures(a, b: PSym, relevantCols: IntSet): int =
  result = 0
-  for col in FirstParamAt..<a.typ.signatureLen:
+  for col in 1..<a.typ.len:
    if contains(relevantCols, col):
      var aa = skipTypes(a.typ[col], skipPtrs)
      var bb = skipTypes(b.typ[col], skipPtrs)
@@ -230,7 +199,7 @@ proc cmpSignatures(a, b: PSym, relevantCols: IntSet): int =
      if (d != high(int)) and d != 0:
        return d

-proc sortBucket*(a: var seq[PSym], relevantCols: IntSet) =
+proc sortBucket(a: var seq[PSym], relevantCols: IntSet) =
  # we use shellsort here; fast and simple
  var n = a.len
  var h = 1
@@ -249,16 +218,16 @@ proc sortBucket*(a: var seq[PSym], relevantCols: IntSet) =
      a[j] = v
    if h == 1: break

-proc genIfDispatcher*(g: ModuleGraph; methods: seq[PSym], relevantCols: IntSet; idgen: IdGenerator): PSym =
+proc genDispatcher(g: ModuleGraph; methods: seq[PSym], relevantCols: IntSet; idgen: IdGenerator): PSym =
  var base = methods[0].ast[dispatcherPos].sym
  result = base
-  var paramLen = base.typ.signatureLen
+  var paramLen = base.typ.len
  var nilchecks = newNodeI(nkStmtList, base.info)
  var disp = newNodeI(nkIfStmt, base.info)
  var ands = getSysMagic(g, unknownLineInfo, "and", mAnd)
  var iss = getSysMagic(g, unknownLineInfo, "of", mOf)
  let boolType = getSysType(g, unknownLineInfo, tyBool)
-  for col in FirstParamAt..<paramLen:
+  for col in 1..<paramLen:
    if contains(relevantCols, col):
      let param = base.typ.n[col].sym
      if param.typ.skipTypes(abstractInst).kind in {tyRef, tyPtr}:
@@ -267,7 +236,7 @@ proc genIfDispatcher*(g: ModuleGraph; methods: seq[PSym], relevantCols: IntSet;
  for meth in 0..high(methods):
    var curr = methods[meth]      # generate condition:
    var cond: PNode = nil
-    for col in FirstParamAt..<paramLen:
+    for col in 1..<paramLen:
      if contains(relevantCols, col):
        var isn = newNodeIT(nkCall, base.info, boolType)
        isn.add newSymNode(iss)
@@ -282,7 +251,7 @@ proc genIfDispatcher*(g: ModuleGraph; methods: seq[PSym], relevantCols: IntSet;
          cond = a
        else:
          cond = isn
-    let retTyp = base.typ.returnType
+    let retTyp = base.typ[0]
    let call = newNodeIT(nkCall, base.info, retTyp)
    call.add newSymNode(curr)
    for col in 1..<paramLen:
@@ -308,13 +277,14 @@ proc genIfDispatcher*(g: ModuleGraph; methods: seq[PSym], relevantCols: IntSet;
  nilchecks.flags.incl nfTransf # should not be further transformed
  result.ast[bodyPos] = nilchecks

-proc generateIfMethodDispatchers*(g: ModuleGraph, idgen: IdGenerator) =
+proc generateMethodDispatchers*(g: ModuleGraph, idgen: IdGenerator): PNode =
+  result = newNode(nkStmtList)
  for bucket in 0..<g.methods.len:
    var relevantCols = initIntSet()
-    for col in FirstParamAt..<g.methods[bucket].methods[0].typ.signatureLen:
+    for col in 1..<g.methods[bucket].methods[0].typ.len:
      if relevantCol(g.methods[bucket].methods, col): incl(relevantCols, col)
      if optMultiMethods notin g.config.globalOptions:
        # if multi-methods are not enabled, we are interested only in the first field
        break
    sortBucket(g.methods[bucket].methods, relevantCols)
-    g.addDispatchers genIfDispatcher(g, g.methods[bucket].methods, relevantCols, idgen)
+    result.add newSymNode(genDispatcher(g, g.methods[bucket].methods, relevantCols, idgen))
--- a/compiler/closureiters.nim
+++ b/compiler/closureiters.nim
--- a/compiler/cmdlinehelper.nim
+++ b/compiler/cmdlinehelper.nim
@@ -11,9 +11,7 @@

 import
  options, idents, nimconf, extccomp, commands, msgs,
-  lineinfos, modulegraphs, condsyms, pathutils
-
-import std/[os, parseopt]
+  lineinfos, modulegraphs, condsyms, os, pathutils, parseopt

 proc prependCurDir*(f: AbsoluteFile): AbsoluteFile =
  when defined(unix):
@@ -53,16 +51,10 @@ proc processCmdLineAndProjectPath*(self: NimProg, conf: ConfigRef) =
 proc loadConfigsAndProcessCmdLine*(self: NimProg, cache: IdentCache; conf: ConfigRef;
                                   graph: ModuleGraph): bool =
  if self.suggestMode:
-    conf.setCmd cmdCheck
-    conf.ideActive = true
+    conf.setCmd cmdIdeTools
  if conf.cmd == cmdNimscript:
    incl(conf.globalOptions, optWasNimscript)
  loadConfigs(DefaultConfig, cache, conf, graph.idgen) # load all config files
-  # restores `conf.notes` after loading config files
-  # because it has overwrites the notes when compiling the system module which
-  # is a foreign module compared to the project
-  if conf.cmd in cmdBackends:
-    conf.notes = conf.mainPackageNotes

  if not self.suggestMode:
    let scriptFile = conf.projectFull.changeFileExt("nims")
--- a/compiler/cnif.nim
+++ b/compiler/cnif.nim
@@ -1,726 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2026 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-## The "cnif" artifact: the C code generator's output as a NIF file.
-##
-## This is deliberately *not* NIFC: the C text is kept verbatim (Nim's
-## C-level machinery — exception handling in particular — is more refined
-## than what NIFC models today; the gap can be closed incrementally later).
-## The only structure the artifact adds is the part dead code elimination
-## and generic-instance merging need:
-##
-## - raw C text as string literals
-## - every *global* entity's C name as a `Symbol` token
-## - every emitted proc definition as a `(cdef SymbolDef flags ...)` group
-##
-## The C generator marks names with control characters at the single place
-## a global's C name is minted (`fillBackendName`) and emits a definition
-## directive at the single place finished procs are appended; the marks then
-## ride through all of the snippet composition untouched. This module turns
-## the final marked module text into the `.c.nif` artifact and strips the
-## marks for the actual `.c` output. Rendering C from the artifact is a
-## plain token walk: string literals verbatim, symbols by name — which is
-## also where a later merge step redirects losing generic instances.
-##
-## Marker scheme (cannot collide: C string literals escape control chars,
-## and `\1`/`\31`/`\23` of cgen's postprocess directives are distinct):
-##   \2 name \3                       a global's C name
-##   \4 name \31 flags \31 nif \5     start of the definition of `name`;
-##                                    `nif` is the defining symbol's NIF name
-##                                    (empty for backend-minted symbols) so a
-##                                    later run can re-demand the definition
-##   \4 \5                            end of the definitions section
-
-import std / [tables, sets, os, assertions, syncio, algorithm]
-import "../dist/nimony/src/lib" / [nifbuilder, nifcoreparse]
-
-const
-  CnifSymStart* = '\2'
-  CnifSymEnd* = '\3'
-  CnifDefStart* = '\4'
-  CnifDefSep* = '\31'   # same separator char as cgen's postprocess directives
-  CnifDefEnd* = '\5'
-
-proc markCName*(name: string): string {.inline.} =
-  CnifSymStart & name & CnifSymEnd
-
-proc hasCnifMarks*(s: string): bool =
-  for c in s:
-    if c in {CnifSymStart, CnifSymEnd, CnifDefStart}: return true
-  false
-
-proc stripCnifMarks*(s: string): string =
-  ## Removes the symbol marks (keeping the names) and the definition
-  ## directives (entirely) so the result is plain C.
-  if not hasCnifMarks(s): return s
-  result = newStringOfCap(s.len)
-  var i = 0
-  while i < s.len:
-    case s[i]
-    of CnifSymStart, CnifSymEnd:
-      inc i
-    of CnifDefStart:
-      while i < s.len and s[i] != CnifDefEnd: inc i
-      inc i # skip CnifDefEnd
-    else:
-      result.add s[i]
-      inc i
-
-const
-  CnifVersion* = "4"
-    ## Artifact format version, stored in the meta head. Artifacts written
-    ## by an older compiler lack the NIF names and the cref group the
-    ## def-retention check needs (v2), the cdeps group the fine-grained
-    ## reuse gate needs (v3), or the type NIF names and cnif-marked extern
-    ## RTTI references the typeinfo flavor of the def-retention check
-    ## needs (v4); `readCnifHeads` reports them as invalid so their TUs
-    ## simply regenerate once.
-
-proc cnifDefDirective*(name, flags, nifName: string): string =
-  CnifDefStart & name & CnifDefSep & flags & CnifDefSep & nifName & CnifDefEnd
-
-proc cnifEndDefs*(): string =
-  CnifDefStart & CnifDefEnd
-
-proc writeCnifArtifact*(code: string; outfile: string;
-                        initRequired = false; datInitRequired = false;
-                        dataDefs: openArray[tuple[cname, nifname: string]] = [];
-                        semmedNif = ""; moduleBase = "";
-                        implDeps: openArray[string] = []) =
-  ## Splits the marked module text into the `.c.nif` artifact.
-  ## The artifact starts with a `(meta <flags> "semmedNif" "moduleBase"
-  ## "version")` head — whether the module has an init/datInit proc
-  ## ('i'/'d'), which semmed NIF it was generated from and the module's
-  ## mangled base name (what `registerModuleToMain` and the reuse decision
-  ## need when the TU is reused in a later run, possibly without the module
-  ## ever being loaded again) — a `(cdata (SymbolDef StrLit)*)` group naming
-  ## the data definitions (consts, globals, RTTI) the TU embeds together
-  ## with their NIF names, a `(cref Ident*)` group naming every C name
-  ## the TU references but does not define itself (what the def-retention
-  ## check consults when some *other* TU regenerates), and a
-  ## `(cdeps Ident*)` group naming the modules whose routine *bodies* this
-  ## TU embeds (redirected defs, shared instances, hooks): the fine-grained
-  ## reuse gate checks their `.impl.nif` cookies on top of the direct
-  ## imports' `.iface.nif` cookies.
-  # pre-pass: every marked name is a use, every definition directive (and
-  # every data def) is a definition; external references = uses - defs
-  var uses = initHashSet[string]()
-  var defs = initHashSet[string]()
-  block prePass:
-    var i = 0
-    while i < code.len:
-      case code[i]
-      of CnifSymStart:
-        inc i
-        var name = ""
-        while i < code.len and code[i] != CnifSymEnd:
-          name.add code[i]
-          inc i
-        inc i
-        uses.incl name
-      of CnifDefStart:
-        inc i
-        var payload = ""
-        while i < code.len and code[i] != CnifDefEnd:
-          payload.add code[i]
-          inc i
-        inc i
-        let sep = find(payload, CnifDefSep)
-        if sep > 0: defs.incl payload[0..<sep]
-        elif payload.len > 0: defs.incl payload
-      else:
-        inc i
-  for d in dataDefs: defs.incl d.cname
-  var crefs: seq[string] = @[]
-  for u in uses:
-    if u notin defs: crefs.add u
-  sort crefs
-
-  var b = nifbuilder.open(outfile)
-  b.withTree "stmts":
-    b.withTree "meta":
-      var metaFlags = ""
-      if initRequired: metaFlags.add 'i'
-      if datInitRequired: metaFlags.add 'd'
-      if metaFlags.len > 0: b.addIdent metaFlags
-      else: b.addEmpty
-      b.addStrLit semmedNif
-      b.addStrLit moduleBase
-      b.addStrLit CnifVersion
-    b.withTree "cdata":
-      for d in dataDefs:
-        b.addSymbolDef d.cname
-        b.addStrLit d.nifname
-    b.withTree "cref":
-      for r in crefs:
-        b.addIdent r
-    b.withTree "cdeps":
-      for s in implDeps:
-        b.addIdent s
-    var raw = ""
-    var inDef = false
-    template flushRaw() =
-      if raw.len > 0:
-        b.addStrLit raw
-        raw.setLen 0
-    var i = 0
-    while i < code.len:
-      case code[i]
-      of CnifSymStart:
-        flushRaw()
-        inc i
-        var name = ""
-        while i < code.len and code[i] != CnifSymEnd:
-          name.add code[i]
-          inc i
-        inc i # skip CnifSymEnd
-        b.addSymbol name, ""
-      of CnifDefStart:
-        flushRaw()
-        inc i
-        var payload = ""
-        while i < code.len and code[i] != CnifDefEnd:
-          payload.add code[i]
-          inc i
-        inc i # skip CnifDefEnd
-        if inDef:
-          b.endTree()
-          inDef = false
-        if payload.len > 0:
-          let sep = find(payload, CnifDefSep)
-          let name = if sep >= 0: payload[0..<sep] else: payload
-          var flags = if sep >= 0: payload[sep+1..^1] else: ""
-          var nifName = ""
-          let sep2 = find(flags, CnifDefSep)
-          if sep2 >= 0:
-            nifName = flags[sep2+1..^1]
-            flags = flags[0..<sep2]
-          b.addTree "cdef"
-          b.addSymbolDef name
-          if flags.len > 0: b.addIdent flags
-          else: b.addEmpty
-          b.addStrLit nifName
-          inDef = true
-      else:
-        raw.add code[i]
-        inc i
-    flushRaw()
-    if inDef:
-      b.endTree()
-  b.close()
-
-proc renderMarkedC*(code: string; live: HashSet[string]; dropped: var int): string =
-  ## Renders the final C text from the marked module text: symbol marks are
-  ## removed (keeping the names — a later merge step substitutes them here),
-  ## and definitions whose name is not in `live` are dropped entirely. Each
-  ## definition is self-delimiting (genProcAux emits an end directive right
-  ## after the proc's text), so text written by other emitters is never part
-  ## of a definition's span and survives unconditionally.
-  result = newStringOfCap(code.len)
-  var i = 0
-  while i < code.len:
-    case code[i]
-    of CnifSymStart, CnifSymEnd:
-      inc i
-    of CnifDefStart:
-      var payload = ""
-      inc i
-      while i < code.len and code[i] != CnifDefEnd:
-        payload.add code[i]
-        inc i
-      inc i # skip CnifDefEnd
-      if payload.len > 0:
-        let sep = find(payload, CnifDefSep)
-        let name = if sep >= 0: payload[0..<sep] else: payload
-        if name notin live:
-          inc dropped
-          # drop the definition's text: everything up to its end directive
-          while i < code.len and code[i] != CnifDefStart: inc i
-    else:
-      result.add code[i]
-      inc i
-
-# ---- Liveness over the artifact -------------------------------------------
-
-proc symOrIdentName(c: Cursor): string {.inline.} =
-  if c.kind == Ident: strVal(c) else: symName(c)
-
-type
-  CnifHeads* = object
-    ## The cheap-to-parse part of an artifact that a later run needs in
-    ## order to reuse the TU without regenerating it.
-    valid*: bool             ## file parsed, carries the meta head and has
-                             ## the current format version
-    initRequired*: bool
-    datInitRequired*: bool
-    semmedNif*: string       ## the semmed NIF this TU was generated from
-    moduleBase*: string      ## the module's mangled base name
-    cdefs*: seq[tuple[cname, nifname: string]] ## the proc definitions
-    cdata*: seq[tuple[cname, nifname: string]] ## the data definitions
-    crefs*: seq[string]      ## C names referenced but not defined here
-    cdeps*: seq[string]      ## module suffixes whose routine bodies this
-                             ## TU embeds (impl-cookie gated on reuse)
-
-proc readCnifHeads*(f: string): CnifHeads =
-  ## Reads `(meta ...)`, `(cdata ...)`, `(cref ...)` and the `(cdef ...)`
-  ## head names from an artifact. Artifacts written by an older compiler
-  ## (no meta head or a different format version) report `valid=false`.
-  result = CnifHeads()
-  if not fileExists(f): return
-  var pool = newPool()
-  var tags = newTagPool()
-  let stmtsTag = tags.registerTag("stmts")
-  let cdefTag = tags.registerTag("cdef")
-  let cdataTag = tags.registerTag("cdata")
-  let crefTag = tags.registerTag("cref")
-  let cdepsTag = tags.registerTag("cdeps")
-  let metaTag = tags.registerTag("meta")
-  var buf = parseFromFile(f, 1000, pool, tags)
-  var c = beginRead(buf)
-  if c.kind != TagLit or c.cursorTagId != stmtsTag:
-    endRead(c)
-    return
-  var version = ""
-  var sawMeta = false
-  c.loopInto:
-    if c.kind == TagLit:
-      if c.cursorTagId == metaTag:
-        sawMeta = true
-        var strIdx = 0
-        c.loopInto:
-          if c.kind == Ident:
-            for ch in strVal(c):
-              if ch == 'i': result.initRequired = true
-              elif ch == 'd': result.datInitRequired = true
-            inc c
-          elif c.kind == StrLit:
-            if strIdx == 0: result.semmedNif = strVal(c)
-            elif strIdx == 1: result.moduleBase = strVal(c)
-            elif strIdx == 2: version = strVal(c)
-            inc strIdx
-            inc c
-          else:
-            skip c
-      elif c.cursorTagId == cdataTag:
-        c.loopInto:
-          if c.kind == SymbolDef:
-            result.cdata.add (symName(c), "")
-            inc c
-          elif c.kind == StrLit:
-            if result.cdata.len > 0:
-              result.cdata[^1].nifname = strVal(c)
-            inc c
-          else:
-            skip c
-      elif c.cursorTagId == crefTag:
-        c.loopInto:
-          if c.kind in {Ident, Symbol, SymbolDef}:
-            result.crefs.add symOrIdentName(c)
-            inc c
-          else:
-            skip c
-      elif c.cursorTagId == cdepsTag:
-        c.loopInto:
-          if c.kind in {Ident, Symbol, SymbolDef}:
-            result.cdeps.add symOrIdentName(c)
-            inc c
-          else:
-            skip c
-      elif c.cursorTagId == cdefTag:
-        # fixed head: SymbolDef, flags (Ident or empty), NIF name StrLit;
-        # everything after that is the definition's body text
-        var state = 0
-        c.loopInto:
-          if c.kind == SymbolDef:
-            result.cdefs.add (symName(c), "")
-            state = 1
-            inc c
-          elif state == 1: # the flags field
-            state = 2
-            skip c
-          elif state == 2: # the NIF name
-            if c.kind == StrLit and result.cdefs.len > 0:
-              result.cdefs[^1].nifname = strVal(c)
-            state = 3
-            skip c
-          else:
-            skip c
-      else:
-        skip c
-    else:
-      skip c
-  endRead(c)
-  result.valid = sawMeta and version == CnifVersion
-
-type
-  CnifLiveness* = object
-    defs*: int      ## proc definitions emitted across all modules
-    liveDefs*: int  ## of those, reachable from the roots
-    live*: HashSet[string] ## live C names
-    broken*: bool
-
-proc computeLiveFromCArtifacts*(files: openArray[string]): CnifLiveness =
-  ## dce1-style mark&sweep over the C-shaped artifacts: a `(cdef ...)`
-  ## group is a definition (flags 'x'/'c'/'m' — exportc, compilerproc,
-  ## method/dispatcher — make it a root), names at the top level (data,
-  ## globals, init code) are roots, names inside a group are its uses.
-  ## Because the artifact is *fully lowered* output, no conservative
-  ## modelling is needed: every call the C code contains is a token here.
-  ##
-  ## NB: mangled C names contain no dots, so NIF's text reader classifies
-  ## them as `Ident` rather than `Symbol`; the dialect therefore treats
-  ## Ident tokens as name uses. Inside a `(cdef ...)` the flags ident is
-  ## the one immediately following the SymbolDef; everything after is a use.
-  result = CnifLiveness(live: initHashSet[string]())
-  var pool = newPool()
-  var tags = newTagPool()
-  let stmtsTag = tags.registerTag("stmts")
-  let cdefTag = tags.registerTag("cdef")
-  let cdataTag = tags.registerTag("cdata")
-  let crefTag = tags.registerTag("cref")
-  let cdepsTag = tags.registerTag("cdeps")
-  let metaTag = tags.registerTag("meta")
-  var uses = initTable[string, HashSet[string]]()
-  var roots = initHashSet[string]()
-  var defs = initHashSet[string]()
-  for f in files:
-    if not fileExists(f):
-      result.broken = true
-      return
-    var buf = parseFromFile(f, 1000, pool, tags)
-    var c = beginRead(buf)
-    if c.kind != TagLit or c.cursorTagId != stmtsTag:
-      result.broken = true
-      endRead(c)
-      return
-    c.loopInto:
-      case c.kind
-      of Symbol, Ident:
-        roots.incl symOrIdentName(c)
-        inc c
-      of TagLit:
-        if c.cursorTagId == metaTag or c.cursorTagId == cdataTag or
-            c.cursorTagId == crefTag or c.cursorTagId == cdepsTag:
-          # bookkeeping for TU reuse, irrelevant for liveness
-          skip c
-        elif c.cursorTagId == cdefTag:
-          var owner = ""
-          var flagsSeen = false
-          c.loopInto:
-            case c.kind
-            of SymbolDef:
-              owner = symName(c)
-              defs.incl owner
-              flagsSeen = false
-              inc c
-            of Symbol, Ident:
-              let name = symOrIdentName(c)
-              if not flagsSeen:
-                # the flags field right after the SymbolDef
-                flagsSeen = true
-                for ch in name:
-                  # 'd' marks a data definition (const/RTTI): never DCE'd, so it
-                  # is a root whose body keeps its referenced procs live
-                  if ch in {'x', 'c', 'm', 'd'}:
-                    roots.incl owner
-                    break
-              else:
-                uses.mgetOrPut(owner, initHashSet[string]()).incl name
-              inc c
-            of DotToken:
-              flagsSeen = true # empty flags field
-              inc c
-            else:
-              skip c
-        else:
-          c.loopInto:
-            if c.kind in {Symbol, Ident}:
-              roots.incl symOrIdentName(c)
-              inc c
-            else:
-              skip c
-      else:
-        skip c
-    endRead(c)
-  # mark & sweep
-  var work = newSeqOfCap[string](roots.len)
-  for r in roots: work.add r
-  while work.len > 0:
-    let s = work.pop()
-    if not result.live.containsOrIncl(s):
-      if uses.hasKey(s):
-        for dep in uses[s]:
-          if dep notin result.live:
-            work.add dep
-  result.defs = defs.len
-  for d in defs:
-    if d in result.live: inc result.liveDefs
-
-# ---- The merge stage: liveness + owner assignment -------------------------
-
-type
-  MergeDecision* = object
-    ## What the per-module backend's `merge` stage computes from every
-    ## module's `.c.nif` and what its `emit` stage consumes to render the
-    ## final `.c` of one module.
-    live*: HashSet[string]        ## globally reachable C names (dead cdefs
-                                  ## are dropped from every module)
-    owners*: Table[string, string] ## for each `'u'`-flagged (unique,
-                                  ## externally-linked) definition, the single
-                                  ## artifact base name allowed to embed its
-                                  ## body; every other module prototypes it
-    broken*: bool                 ## an artifact was missing or unparsable —
-                                  ## the caller should fall back / regenerate
-    defs*, liveDefs*: int
-
-proc computeMergeDecision*(files: openArray[string]): MergeDecision =
-  ## One pass over every `.c.nif`: the same mark&sweep as
-  ## `computeLiveFromCArtifacts` plus, per definition, owner assignment.
-  ##
-  ## Each `cg` process emits the body of every definition it demands
-  ## (emit-everywhere), so the same externally-linked definition appears in
-  ## several artifacts. A `'u'` flag on the `(cdef ...)` marks those that need
-  ## exactly one owner, assigned here across processes: the owner is the
-  ## lexicographically smallest artifact that emits it — a pure function of the
-  ## claimant set, hence stable across rebuilds. Definitions without `'u'`
-  ## (inline procs, dispatchers) are `static`/main-only and emitted into every
-  ## using TU, so they get no owner entry and are never deduplicated.
-  result = MergeDecision(live: initHashSet[string](),
-                         owners: initTable[string, string]())
-  var pool = newPool()
-  var tags = newTagPool()
-  let stmtsTag = tags.registerTag("stmts")
-  let cdefTag = tags.registerTag("cdef")
-  let cdataTag = tags.registerTag("cdata")
-  let crefTag = tags.registerTag("cref")
-  let cdepsTag = tags.registerTag("cdeps")
-  let metaTag = tags.registerTag("meta")
-  var uses = initTable[string, HashSet[string]]()
-  var roots = initHashSet[string]()
-  var defs = initHashSet[string]()
-  for f in files:
-    if not fileExists(f):
-      result.broken = true
-      return
-    let owner = extractFilename(f)
-    var buf = parseFromFile(f, 1000, pool, tags)
-    var c = beginRead(buf)
-    if c.kind != TagLit or c.cursorTagId != stmtsTag:
-      result.broken = true
-      endRead(c)
-      return
-    c.loopInto:
-      case c.kind
-      of Symbol, Ident:
-        roots.incl symOrIdentName(c)
-        inc c
-      of TagLit:
-        if c.cursorTagId == metaTag or c.cursorTagId == cdataTag or
-            c.cursorTagId == crefTag or c.cursorTagId == cdepsTag:
-          skip c
-        elif c.cursorTagId == cdefTag:
-          var ownerName = ""
-          var flagsSeen = false
-          var needsOwner = false
-          c.loopInto:
-            case c.kind
-            of SymbolDef:
-              ownerName = symName(c)
-              defs.incl ownerName
-              flagsSeen = false
-              inc c
-            of Symbol, Ident:
-              let name = symOrIdentName(c)
-              if not flagsSeen:
-                flagsSeen = true
-                for ch in name:
-                  if ch in {'x', 'c', 'm'}: roots.incl ownerName
-                  # 'u' = unique proc (DCE'd), 'd' = data (never DCE'd, hence a
-                  # root); both need a single owner across the emit-everywhere
-                  # processes
-                  elif ch == 'u': needsOwner = true
-                  elif ch == 'd':
-                    needsOwner = true
-                    roots.incl ownerName
-              else:
-                uses.mgetOrPut(ownerName, initHashSet[string]()).incl name
-              inc c
-            of DotToken:
-              flagsSeen = true # empty flags field
-              inc c
-            else:
-              skip c
-          if needsOwner and ownerName.len > 0:
-            # smallest claimant wins; ties impossible (one entry per name)
-            let prev = result.owners.getOrDefault(ownerName, "")
-            if prev.len == 0 or owner < prev:
-              result.owners[ownerName] = owner
-        else:
-          c.loopInto:
-            if c.kind in {Symbol, Ident}:
-              roots.incl symOrIdentName(c)
-              inc c
-            else:
-              skip c
-      else:
-        skip c
-    endRead(c)
-  var work = newSeqOfCap[string](roots.len)
-  for r in roots: work.add r
-  while work.len > 0:
-    let s = work.pop()
-    if not result.live.containsOrIncl(s):
-      if uses.hasKey(s):
-        for dep in uses[s]:
-          if dep notin result.live:
-            work.add dep
-  result.defs = defs.len
-  for d in defs:
-    if d in result.live: inc result.liveDefs
-
-const MergeDecisionFile* = "ic.backend.merge.nif"
-  ## Fixed name of the merge stage's output in the nimcache, read by `emit`.
-
-proc writeMergeDecision*(outfile: string; d: MergeDecision) =
-  ## Serializes the merge decision: `(merge (live Symbol*) (owners (own
-  ## Symbol StrLit)*))`. C names are mangled (no dots) so they serialize as
-  ## symbols; owner artifact base names go in string literals.
-  var live: seq[string] = @[]
-  for n in d.live: live.add n
-  sort live
-  var keys: seq[string] = @[]
-  for k in d.owners.keys: keys.add k
-  sort keys
-  var b = nifbuilder.open(outfile)
-  b.withTree "merge":
-    b.withTree "live":
-      for n in live: b.addSymbol n, ""
-    b.withTree "owners":
-      for k in keys:
-        b.withTree "own":
-          b.addSymbol k, ""
-          b.addStrLit d.owners[k]
-  b.close()
-
-proc readMergeDecision*(f: string): MergeDecision =
-  ## Reads back a `writeMergeDecision` file; `broken=true` if absent/unparsable.
-  result = MergeDecision(live: initHashSet[string](),
-                         owners: initTable[string, string]())
-  if not fileExists(f):
-    result.broken = true
-    return
-  var pool = newPool()
-  var tags = newTagPool()
-  let mergeTag = tags.registerTag("merge")
-  let liveTag = tags.registerTag("live")
-  let ownersTag = tags.registerTag("owners")
-  let ownTag = tags.registerTag("own")
-  var buf = parseFromFile(f, 1000, pool, tags)
-  var c = beginRead(buf)
-  if c.kind != TagLit or c.cursorTagId != mergeTag:
-    result.broken = true
-    endRead(c)
-    return
-  c.loopInto:
-    if c.kind == TagLit and c.cursorTagId == liveTag:
-      c.loopInto:
-        if c.kind in {Symbol, Ident}:
-          result.live.incl symOrIdentName(c)
-          inc c
-        else:
-          skip c
-    elif c.kind == TagLit and c.cursorTagId == ownersTag:
-      c.loopInto:
-        if c.kind == TagLit and c.cursorTagId == ownTag:
-          var key = ""
-          c.loopInto:
-            if c.kind in {Symbol, Ident}:
-              key = symOrIdentName(c)
-              inc c
-            elif c.kind == StrLit:
-              if key.len > 0: result.owners[key] = strVal(c)
-              inc c
-            else:
-              skip c
-        else:
-          skip c
-    else:
-      skip c
-  endRead(c)
-
-proc renderCFromArtifact*(artifact: string; d: MergeDecision; ownerId: string;
-                          dropped: var int): string =
-  ## The per-module backend's `emit` stage: render one module's final `.c` from
-  ## its `.c.nif` and the merge decision. String literals are emitted verbatim,
-  ## symbols by name; a `(cdef ...)` body is dropped when the name is dead, or
-  ## when it is a `'u'` unique definition this module does not own. The body's
-  ## prototype lives in the surrounding raw text (cgen emits a forward
-  ## declaration for every *used* proc, independent of where the body lands), so
-  ## a dropped body still leaves a valid declaration — no synthesis needed. The
-  ## head groups (meta/cdata/cref/cdeps) carry no C text.
-  result = ""
-  if not fileExists(artifact): return
-  var pool = newPool()
-  var tags = newTagPool()
-  let stmtsTag = tags.registerTag("stmts")
-  let cdefTag = tags.registerTag("cdef")
-  var buf = parseFromFile(artifact, 1000, pool, tags)
-  var c = beginRead(buf)
-  if c.kind != TagLit or c.cursorTagId != stmtsTag:
-    endRead(c)
-    return
-  c.loopInto:
-    case c.kind
-    of StrLit:
-      result.add strVal(c)
-      inc c
-    of Symbol, Ident:
-      result.add symOrIdentName(c)
-      inc c
-    of TagLit:
-      if c.cursorTagId == cdefTag:
-        # fixed head: SymbolDef, flags (Ident or empty), nifname StrLit; the
-        # rest is the definition's body text. `state` counts past the head.
-        var name = ""
-        var isUnique = false
-        var isData = false
-        var keep = true
-        var state = 0
-        c.loopInto:
-          if state == 0 and c.kind == SymbolDef:
-            name = symName(c)
-            state = 1
-            inc c
-          elif state == 1: # the flags field (one token: Ident/Symbol or empty)
-            if c.kind in {Ident, Symbol}:
-              for ch in symOrIdentName(c):
-                if ch == 'u': isUnique = true
-                elif ch == 'd': isData = true
-            state = 2
-            inc c
-          elif state == 2: # the NIF name (one StrLit) — decide keep here
-            let owned = d.owners.getOrDefault(name, ownerId) == ownerId
-            keep =
-              if isData: owned                      # data: kept by its owner only
-              elif isUnique: (name in d.live) and owned
-              else: name in d.live                  # inline/dispatcher: per-TU
-            if not keep: inc dropped
-            state = 3
-            inc c
-          else: # body tokens
-            if keep:
-              if c.kind == StrLit: result.add strVal(c)
-              elif c.kind in {Symbol, Ident}: result.add symOrIdentName(c)
-            inc c
-      else:
-        # head groups (meta/cdata/cref/cdeps) carry no C text
-        skip c
-    else:
-      inc c
-  endRead(c)
--- a/compiler/commands.nim
+++ b/compiler/commands.nim
@@ -24,12 +24,10 @@ bootSwitch(usedMarkAndSweep, defined(gcmarkandsweep), "--gc:markAndSweep")
 bootSwitch(usedGoGC, defined(gogc), "--gc:go")
 bootSwitch(usedNoGC, defined(nogc), "--gc:none")

-import std/[setutils, sets, os, strutils, parseutils, parseopt, sequtils, strtabs, enumutils]
+import std/[setutils, os, strutils, parseutils, parseopt, sequtils, strtabs]
 import
  msgs, options, nversion, condsyms, extccomp, platform,
-  wordrecg, nimblecmd, lineinfos, pathutils
-
-import std/pathnorm
+  wordrecg, nimblecmd, lineinfos, pathutils, pathnorm

 from ast import setUseIc, eqTypeFlags, tfGcSafe, tfNoSideEffect

@@ -118,7 +116,7 @@ const
  errInvalidCmdLineOption = "invalid command line option: '$1'"
  errOnOrOffExpectedButXFound = "'on' or 'off' expected, but '$1' found"
  errOnOffOrListExpectedButXFound = "'on', 'off' or 'list' expected, but '$1' found"
-  errOffHintsError = "'off', 'hint', 'warning', 'error' or 'usages' expected, but '$1' found"
+  errOffHintsError = "'off', 'hint', 'error' or 'usages' expected, but '$1' found"

 proc invalidCmdLineOption(conf: ConfigRef; pass: TCmdLinePass, switch: string, info: TLineInfo) =
  if switch == " ": localError(conf, info, errInvalidCmdLineOption % "-")
@@ -203,16 +201,11 @@ proc processSpecificNote*(arg: string, state: TSpecialWord, pass: TCmdLinePass,
  else: invalidCmdLineOption(conf, pass, orig, info)

  let isSomeHint = state in {wHint, wHintAsError}
-  let isSomeWarning = state in {wWarning, wWarningAsError}
  template findNote(noteMin, noteMax, name) =
    # unfortunately, hintUser and warningUser clash, otherwise implementation would simplify a bit
    let x = findStr(noteMin, noteMax, id, errUnknown)
    if x != errUnknown: notes = {TNoteKind(x)}
-    else:
-      if isSomeHint or isSomeWarning:
-        message(conf, info, warnUnknownNotes, "unknown $#: $#" % [name, id])
-      else:
-        localError(conf, info, "unknown $#: $#" % [name, id])
+    else: localError(conf, info, "unknown $#: $#" % [name, id])
  case id.normalize
  of "all": # other note groups would be easy to support via additional cases
    notes = if isSomeHint: {hintMin..hintMax} else: {warnMin..warnMax}
@@ -245,12 +238,10 @@ proc processCompile(conf: ConfigRef; filename: string) =
  extccomp.addExternalFileToCompile(conf, found)

 const
-  errNoneBoehmRefcExpectedButXFound = "'arc', 'orc', 'yrc', 'atomicArc', 'markAndSweep', 'boehm', 'go', 'none', 'regions', or 'refc' expected, but '$1' found"
+  errNoneBoehmRefcExpectedButXFound = "'arc', 'orc', 'atomicArc', 'markAndSweep', 'boehm', 'go', 'none', 'regions', or 'refc' expected, but '$1' found"
  errNoneSpeedOrSizeExpectedButXFound = "'none', 'speed' or 'size' expected, but '$1' found"
  errGuiConsoleOrLibExpectedButXFound = "'gui', 'console', 'lib' or 'staticlib' expected, but '$1' found"
  errInvalidExceptionSystem = "'goto', 'setjmp', 'cpp' or 'quirky' expected, but '$1' found"
-  errInvalidFeatureButXFound = Feature.toSeq.map(proc(val:Feature): string = "'$1'" % $val).join(", ") & " expected, but '$1' found"
-  errDefaultOrSsoExpectedButXFound = "'default' or 'sso' expected, but '$1' found"

 template warningOptionNoop(switch: string) =
  warningDeprecated(conf, info, "'$#' is deprecated, now a noop" % switch)
@@ -267,7 +258,6 @@ proc testCompileOptionArg*(conf: ConfigRef; switch, arg: string, info: TLineInfo
    of "markandsweep": result = conf.selectedGC == gcMarkAndSweep
    of "destructors", "arc": result = conf.selectedGC == gcArc
    of "orc": result = conf.selectedGC == gcOrc
-    of "yrc": result = conf.selectedGC == gcYrc
    of "hooks": result = conf.selectedGC == gcHooks
    of "go": result = conf.selectedGC == gcGo
    of "none": result = conf.selectedGC == gcNone
@@ -307,19 +297,6 @@ proc testCompileOptionArg*(conf: ConfigRef; switch, arg: string, info: TLineInfo
    else:
      result = false
      localError(conf, info, errInvalidExceptionSystem % arg)
-  of "strings":
-    case arg.normalize
-    of "default": result = conf.selectedStrings == stringDefault
-    of "sso": result = conf.selectedStrings == stringSso
-    else:
-      result = false
-      localError(conf, info, errDefaultOrSsoExpectedButXFound % arg)
-  of "experimental":
-    try:
-      result = conf.features.contains parseEnum[Feature](arg)
-    except ValueError:
-      result = false
-      localError(conf, info, errInvalidFeatureButXFound % arg)
  else:
    result = false
    invalidCmdLineOption(conf, passCmd1, switch, info)
@@ -373,7 +350,6 @@ proc testCompileOption*(conf: ConfigRef; switch: string, info: TLineInfo): bool
    result = false
  of "panics": result = contains(conf.globalOptions, optPanics)
  of "jsbigint64": result = contains(conf.globalOptions, optJsBigInt64)
-  of "mangle": result = contains(conf.globalOptions, optItaniumMangle)
  else:
    result = false
    invalidCmdLineOption(conf, passCmd1, switch, info)
@@ -469,7 +445,7 @@ template handleStdinOrCmdInput =
    conf.outDir = getNimcacheDir(conf)

 proc handleStdinInput*(conf: ConfigRef) =
-  conf.projectName = conf.stdinFile.string
+  conf.projectName = "stdinfile"
  conf.projectIsStdin = true
  handleStdinOrCmdInput()

@@ -483,9 +459,7 @@ proc parseCommand*(command: string): Command =
  of "cpp", "compiletocpp": cmdCompileToCpp
  of "objc", "compiletooc": cmdCompileToOC
  of "js", "compiletojs": cmdCompileToJS
-  of "nif": cmdCompileToNif
  of "r": cmdCrun
-  of "m": cmdM
  of "run": cmdTcc
  of "check": cmdCheck
  of "e": cmdNimscript
@@ -503,13 +477,10 @@ proc parseCommand*(command: string): Command =
  of "gendepend": cmdGendepend
  of "dump": cmdDump
  of "parse": cmdParse
+  of "rod": cmdRod
  of "secret": cmdInteractive
  of "nop", "help": cmdNop
  of "jsonscript": cmdJsonscript
-  of "nifc": cmdNifC  # generate C from NIF files
-  of "ic": cmdIc  # generate .build.nif for nifmake
-  of "icconfig": cmdIcConfig  # produce the precompiled config artifact
-  of "track": cmdTrack  # IDE goto-def / find-usages over `nim ic`'s NIF output
  else: cmdUnknown

 proc setCmd*(conf: ConfigRef, cmd: Command) =
@@ -521,12 +492,6 @@ proc setCmd*(conf: ConfigRef, cmd: Command) =
  of cmdCompileToCpp: conf.backend = backendCpp
  of cmdCompileToOC: conf.backend = backendObjc
  of cmdCompileToJS: conf.backend = backendJs
-  of cmdCompileToNif: conf.backend = backendNif
-  of cmdNifC:
-    conf.backend = backendC  # NIF to C compilation
-  of cmdM:
-    # cmdM requires optCompress for proper IC handling (include files, etc.)
-    conf.globalOptions.incl optCompress
  else: discard

 proc setCommandEarly*(conf: ConfigRef, command: string) =
@@ -581,7 +546,6 @@ proc unregisterArcOrc*(conf: ConfigRef) =
  undefSymbol(conf.symbols, "gcdestructors")
  undefSymbol(conf.symbols, "gcarc")
  undefSymbol(conf.symbols, "gcorc")
-  undefSymbol(conf.symbols, "gcyrc")
  undefSymbol(conf.symbols, "gcatomicarc")
  undefSymbol(conf.symbols, "nimSeqsV2")
  undefSymbol(conf.symbols, "nimV2")
@@ -615,10 +579,6 @@ proc processMemoryManagementOption(switch, arg: string, pass: TCmdLinePass,
      conf.selectedGC = gcOrc
      defineSymbol(conf.symbols, "gcorc")
      registerArcOrc(pass, conf)
-    of "yrc":
-      conf.selectedGC = gcYrc
-      defineSymbol(conf.symbols, "gcyrc")
-      registerArcOrc(pass, conf)
    of "atomicarc":
      conf.selectedGC = gcAtomicArc
      defineSymbol(conf.symbols, "gcatomicarc")
@@ -644,29 +604,10 @@ proc processMemoryManagementOption(switch, arg: string, pass: TCmdLinePass,
      defineSymbol(conf.symbols, "gcregions")
    else: localError(conf, info, errNoneBoehmRefcExpectedButXFound % arg)

-proc pathRelativeToConfig(arg: string, pass: TCmdLinePass, conf: ConfigRef): string =
-  if pass == passPP and not isAbsolute(arg):
-    assert isAbsolute(conf.currentConfigDir), "something is wrong with currentConfigDir"
-    result = conf.currentConfigDir / arg
-  else:
-    result = arg
-
 proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
                    conf: ConfigRef) =
  var key = ""
  var val = ""
-  # Record config-file switches so the `nim ic` driver can serialise them into a
-  # precompiled-config artifact and have its per-module child processes replay
-  # them instead of re-parsing the `nim.cfg` chain (and re-running `config.nims`
-  # in the VM) on every invocation. Only `passPP` (config-file) switches are
-  # captured; command-line switches are forwarded by the build graph as usual.
-  # Path-search switches are skipped: their net effect already lives in the
-  # resolved `searchPaths` the driver forwards as `--path`, and replaying their
-  # raw (often relative-to-config-dir) arguments here would misresolve.
-  if pass == passPP and switch.normalize notin
-      ["path", "p", "nimblepath", "lazypath", "excludepath",
-       "nonimblepath", "clearnimblepath", "nimcache"]:
-    conf.icConfigSwitches.add (switch, arg)
  case switch.normalize
  of "eval":
    expectArg(conf, switch, arg, pass, info)
@@ -708,7 +649,7 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
    # refs bug #18674, otherwise `--os:windows` messes up with `--nimcache` set
    # in config nims files, e.g. via: `import os; switch("nimcache", "/tmp/somedir")`
    if conf.target.targetOS == osWindows and DirSep == '/': arg = arg.replace('\\', '/')
-    conf.nimcacheDir = processPath(conf, pathRelativeToConfig(arg, pass, conf), info, notRelativeToProj=true)
+    conf.nimcacheDir = processPath(conf, arg, info, notRelativeToProj=true)
  of "out", "o":
    expectArg(conf, switch, arg, pass, info)
    let f = splitFile(processPath(conf, arg, info, notRelativeToProj=true).string)
@@ -719,14 +660,6 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
    conf.outDir = processPath(conf, arg, info, notRelativeToProj=true)
  of "usenimcache":
    processOnOffSwitchG(conf, {optUseNimcache}, arg, pass, info)
-  of "ideimports":
-    # nimsuggest: where the import closure comes from. IC is opt-in.
-    #   nif|on               load unchanged imports from precompiled NIF (cmdM)
-    #   source|off (default) recompile the whole closure from source (cmdCheck)
-    case arg.normalize
-    of "nif", "on", "": conf.ideImportsFromNif = true
-    of "source", "off": conf.ideImportsFromNif = false
-    else: localError(conf, info, "'--ideImports' expects 'nif' or 'source', got: '$1'" % arg)
  of "docseesrcurl":
    expectArg(conf, switch, arg, pass, info)
    conf.docSeeSrcUrl = arg
@@ -780,17 +713,6 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
    processMemoryManagementOption(switch, arg, pass, info, conf)
  of "mm":
    processMemoryManagementOption(switch, arg, pass, info, conf)
-  of "strings":
-    expectArg(conf, switch, arg, pass, info)
-    if pass in {passCmd2, passPP}:
-      case arg.normalize
-      of "default":
-        conf.selectedStrings = stringDefault
-      of "sso":
-        conf.selectedStrings = stringSso
-        defineSymbol(conf.symbols, "nimsso")
-      else:
-        localError(conf, info, errDefaultOrSsoExpectedButXFound % arg)
  of "warnings", "w":
    if processOnOffSwitchOrList(conf, {optWarns}, arg, pass, info): listWarnings(conf)
  of "warning": processSpecificNote(arg, wWarning, pass, info, switch, conf)
@@ -816,18 +738,6 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
      conf.globalOptions.excl optCDebug
    else:
      localError(conf, info, "expected native|gdb|on|off but found " & arg)
-  of "mangle":
-    case arg.normalize
-    of "nim":
-      conf.globalOptions.excl optItaniumMangle
-    of "cpp":
-      conf.globalOptions.incl optItaniumMangle
-    else:
-      localError(conf, info, "expected nim|cpp but found " & arg)
-  of "compress":
-    conf.globalOptions.incl optCompress
-  of "genbif":
-    processOnOffSwitchG(conf, {optGenBif}, arg, pass, info)
  of "g": # alias for --debugger:native
    conf.globalOptions.incl optCDebug
    conf.options.incl optLineDir
@@ -873,7 +783,7 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
    if conf.backend == backendJs or conf.cmd == cmdNimscript: discard
    else: processOnOffSwitchG(conf, {optThreads}, arg, pass, info)
    #if optThreads in conf.globalOptions: conf.setNote(warnGcUnsafe)
-  of "tlsemulation":
+  of "tlsemulation": 
    processOnOffSwitchG(conf, {optTlsEmulation}, arg, pass, info)
    if optTlsEmulation in conf.globalOptions:
      conf.legacyFeatures.incl emitGenerics
@@ -947,65 +857,14 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
    else: localError(conf, info, errOnOrOffExpectedButXFound % arg)
  of "noimportdoc":
    processOnOffSwitchG(conf, {optNoImportdoc}, arg, pass, info)
-  of "ismainmodule":
-    # `nim m` (IC) only: marks the single module being checked as the program's
-    # real entry point so that `isMainModule` and `when isMainModule:` resolve
-    # correctly even though every module is compiled with `sfMainModule` set.
-    conf.isMainModule = switchOn(arg)
-  of "icgroup":
-    # `nim m` only: register a module that belongs to the current strongly-
-    # connected import group, so it is compiled from source (not loaded from a
-    # precompiled NIF) and gets its own NIF written. `deps.nim` emits one
-    # `--icGroup:<path>` per member of a dependency cycle. The argument is an
-    # absolute .nim path produced by the dependency scanner.
-    expectArg(conf, switch, arg, pass, info)
-    if pass in {passCmd2, passPP}:
-      conf.icGroup.incl(canonicalizePath(conf, AbsoluteFile arg).string)
-  of "icproject":
-    # `nim m`/`nim nifc` only: the ORIGINAL project file (see options.icProject)
-    expectArg(conf, switch, arg, pass, info)
-    if pass in {passCmd2, passPP}:
-      conf.icProject = canonicalizePath(conf, AbsoluteFile arg).string
-  of "icpreparsedconfig":
-    # `nim m`/`nim nifc` only: path of the precompiled-config artifact (see
-    # options.icPreparsedConfig). Read in `passCmd1`, before `loadConfigs`, so
-    # config loading can replay it instead of re-parsing the `nim.cfg` chain.
-    expectArg(conf, switch, arg, pass, info)
-    conf.icPreparsedConfig = arg
-  of "icconfigout":
-    # `nim icconfig` only: where to write the precompiled config artifact (see
-    # options.icConfigOut). The `nim ic` driver spawns the producer with this.
-    expectArg(conf, switch, arg, pass, info)
-    conf.icConfigOut = arg
-  of "icbackendstage":
-    # `nim nifc` only: per-module backend stage, one of cg|merge|emit (see
-    # options.icBackendStage). Empty (switch unused) keeps the whole-program
-    # backend. Emitted by `deps.nim`'s backend build file.
-    expectArg(conf, switch, arg, pass, info)
-    if pass in {passCmd2, passPP}:
-      conf.icBackendStage = arg
-  of "icbackendmodule":
-    # `nim nifc` only: the NIF module suffix the cg/emit stage operates on (see
-    # options.icBackendModule).
-    expectArg(conf, switch, arg, pass, info)
-    if pass in {passCmd2, passPP}:
-      conf.icBackendModule = arg
  of "import":
    expectArg(conf, switch, arg, pass, info)
    if pass in {passCmd2, passPP}:
-      let m = findModule(conf, arg, toFullPath(conf, info)).string
-      if m.len == 0:
-        localError(conf, info, "Cannot resolve filename: " & arg)
-      else:
-        conf.implicitImports.add(if arg.startsWith(stdPrefix): arg else: m)
+      conf.implicitImports.add findModule(conf, arg, toFullPath(conf, info)).string
  of "include":
    expectArg(conf, switch, arg, pass, info)
    if pass in {passCmd2, passPP}:
-      let m = findModule(conf, arg, toFullPath(conf, info)).string
-      if m.len == 0:
-        localError(conf, info, "Cannot resolve filename: " & arg)
-      else:
-        conf.implicitIncludes.add m
+      conf.implicitIncludes.add findModule(conf, arg, toFullPath(conf, info)).string
  of "listcmd":
    processOnOffSwitchG(conf, {optListCmd}, arg, pass, info)
  of "asm":
@@ -1037,14 +896,8 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
    expectArg(conf, switch, arg, pass, info)
    var value: int = 10_000_000
    discard parseSaturatedNatural(arg, value)
-    if value <= 0: localError(conf, info, "maxLoopIterationsVM must be a positive integer greater than zero")
+    if not value > 0: localError(conf, info, "maxLoopIterationsVM must be a positive integer greater than zero")
    conf.maxLoopIterationsVM = value
-  of "maxcalldepthvm":
-    expectArg(conf, switch, arg, pass, info)
-    var value: int = 2_000
-    discard parseSaturatedNatural(arg, value)
-    if value <= 0: localError(conf, info, "maxCallDepthVM must be a positive integer greater than zero")
-    conf.maxCallDepthVM = value
  of "errormax":
    expectArg(conf, switch, arg, pass, info)
    # Note: `nim check` (etc) can overwrite this.
@@ -1054,10 +907,6 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
    var value: int = 0
    discard parseSaturatedNatural(arg, value)
    conf.errorMax = if value == 0: high(int) else: value
-  of "stdinfile":
-    expectArg(conf, switch, arg, pass, info)
-    conf.stdinFile = if os.isAbsolute(arg): AbsoluteFile(arg)
-                     else: AbsoluteFile(getCurrentDir() / arg)
  of "verbosity":
    expectArg(conf, switch, arg, pass, info)
    let verbosity = parseInt(arg)
@@ -1091,8 +940,7 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
      # xxx maybe also ic, since not in help?
    if pass in {passCmd2, passPP}:
      case arg.normalize
-      of "on": conf.ic = true
-      of "legacy": conf.symbolFiles = v2Sf
+      of "on": conf.symbolFiles = v2Sf
      of "off": conf.symbolFiles = disabledSf
      of "writeonly": conf.symbolFiles = writeOnlySf
      of "readonly": conf.symbolFiles = readOnlySf
@@ -1200,9 +1048,6 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
  of "shownonexports":
    expectNoArg(conf, switch, arg, pass, info)
    showNonExportedFields(conf)
-  of "raw":
-    expectNoArg(conf, switch, arg, pass, info)
-    docRawOutput(conf)
  of "exceptions":
    case arg.normalize
    of "cpp": conf.exc = excCpp
@@ -1234,10 +1079,9 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
      defineSymbol(conf.symbols, "nimSeqsV2")
  of "stylecheck":
    case arg.normalize
-    of "off": conf.globalOptions = conf.globalOptions - {optStyleHint, optStyleError, optStyleWarning}
-    of "hint": conf.globalOptions = conf.globalOptions + {optStyleHint} - {optStyleError, optStyleWarning}
-    of "warning": conf.globalOptions = conf.globalOptions + {optStyleWarning} - {optStyleHint, optStyleError}
-    of "error": conf.globalOptions = conf.globalOptions + {optStyleError} - {optStyleHint, optStyleWarning}
+    of "off": conf.globalOptions = conf.globalOptions - {optStyleHint, optStyleError}
+    of "hint": conf.globalOptions = conf.globalOptions + {optStyleHint} - {optStyleError}
+    of "error": conf.globalOptions = conf.globalOptions + {optStyleError}
    of "usages": conf.globalOptions.incl optStyleUsages
    else: localError(conf, info, errOffHintsError % arg)
  of "showallmismatches":
@@ -1327,16 +1171,8 @@ proc processArgument*(pass: TCmdLinePass; p: OptParser;
      # support UNIX style filenames everywhere for portable build scripts:
      if config.projectName.len == 0:
        config.projectName = unixToNativePath(p.key)
-      if config.cmd == cmdTrack:
-        # `nim track PROJ --def:...`: unlike a normal command (where everything
-        # after the project file is passed to the compiled program), `track`
-        # accepts its IDE-query switches AFTER the project — the natural,
-        # nimsuggest-like invocation form. So don't swallow the rest of the line
-        # into `arguments`; keep parsing the remaining tokens as switches.
-        result = false
-      else:
-        config.arguments = cmdLineRest(p)
-        result = true
+      config.arguments = cmdLineRest(p)
+      result = true
    else:
      result = false
  inc argsCount
--- a/compiler/concepts.nim
+++ b/compiler/concepts.nim
@@ -11,15 +11,13 @@
 ## for details. Note this is a first implementation and only the "Concept matching"
 ## section has been implemented.

-import ast, semdata, lookups, lineinfos, idents, msgs, renderer, types, layeredtable
-
-import std/sets
+import ast, astalgo, semdata, lookups, lineinfos, idents, msgs, renderer, types, intsets

 when defined(nimPreviewSlimSystem):
  import std/assertions

 const
-  logBindings = when defined(debugConcepts): true else: false
+  logBindings = false

 ## Code dealing with Concept declarations
 ## --------------------------------------
@@ -28,9 +26,9 @@ proc declareSelf(c: PContext; info: TLineInfo) =
  ## Adds the magical 'Self' symbols to the current scope.
  let ow = getCurrOwner(c)
  let s = newSym(skType, getIdent(c.cache, "Self"), c.idgen, ow, info)
-  s.typ = newType(tyTypeDesc, c.idgen, ow)
-  s.typ.incl {tfUnresolved, tfPacked}
-  s.typ.add newType(tyEmpty, c.idgen, ow)
+  s.typ = newType(tyTypeDesc, nextTypeId(c.idgen), ow)
+  s.typ.flags.incl {tfUnresolved, tfPacked}
+  s.typ.add newType(tyEmpty, nextTypeId(c.idgen), ow)
  addDecl(c, s, info)

 proc semConceptDecl(c: PContext; n: PNode): PNode =
@@ -70,418 +68,157 @@ proc semConceptDeclaration*(c: PContext; n: PNode): PNode =
 ## ----------------

 type
-  MatchFlags* = enum
-    mfDontBind  # Do not bind generic parameters
-    mfCheckGeneric  # formal <- formal comparison as opposed to formal <- operand
-
-  ConceptTypePair = tuple[conceptId, typeId: ItemId]
-    ## Pair of (concept type id, implementation type id) used for cycle detection
-
  MatchCon = object ## Context we pass around during concept matching.
-    bindings: LayeredIdTable
-    marker: HashSet[ConceptTypePair] ## Tracks (concept, type) pairs being checked to detect cycles.
+    inferred: seq[(PType, PType)] ## we need a seq here so that we can easily undo inferences \
+      ## that turned out to be wrong.
+    marker: IntSet ## Some protection against wild runaway recursions.
    potentialImplementation: PType ## the concrete type that might match the concept we try to match.
    magic: TMagic  ## mArrGet and mArrPut is wrong in system.nim and
                   ## cannot be fixed that easily.
                   ## Thus we special case it here.
-    concpt: PType  ## current concept being evaluated
-    flags: set[MatchFlags]
-
-  MatchKind = enum
-    mkNoMatch, mkSubset, mkSame
-
-const
-  asymmetricConceptParamMods = {tyVar, tySink, tyLent, tyOwned, tyAlias, tyInferred} # param modifiers that to not have to match implementation -> concept
-  bindableTypes = {tyGenericParam, tyOr, tyTypeDesc}
-
-proc conceptMatchNode(c: PContext; n: PNode; m: var MatchCon): bool
-
-proc matchType(c: PContext; fo, ao: PType; m: var MatchCon): bool
-
-proc matchReturnType(c: PContext; f, a: PType; m: var MatchCon): bool
-
-proc processConcept(c: PContext; concpt, invocation: PType, bindings: var LayeredIdTable; m: var MatchCon): bool

 proc existingBinding(m: MatchCon; key: PType): PType =
  ## checks if we bound the type variable 'key' already to some
  ## concrete type.
-  result = m.bindings.lookup(key)
-  if result == nil:
-    result = key
+  for i in 0..<m.inferred.len:
+    if m.inferred[i][0] == key: return m.inferred[i][1]
+  return nil

-const
-    ignorableForArgType = {tyVar, tySink, tyLent, tyOwned, tyAlias, tyInferred}
+proc conceptMatchNode(c: PContext; n: PNode; m: var MatchCon): bool

-proc unrollGenericParam(param: PType): PType =
-  result = param.skipTypes(ignorableForArgType)
-  while result.kind in {tyGenericParam, tyTypeDesc} and result.hasElementType and result.elementType.kind != tyNone:
-    result = result.elementType
-
-proc bindParam(c: PContext, m: var MatchCon; key, v: PType): bool {. discardable .} =
-  if v.kind == tyTypeDesc:
-    return false
-  var value = unrollGenericParam(v)
-  if value.kind == tyGenericParam:
-    value = existingBinding(m, value)
-    if value.kind == tyGenericParam:
-      if value.hasElementType:
-        value = value.elementType
-      else:
-        return true
-  if value.kind == tyStatic:
-    return false
-
-  if m.magic in {mArrPut, mArrGet} and value.kind in arrPutGetMagicApplies:
-    value = value.last
-  
-  let old = existingBinding(m, key)
-  if old != key:
-    # check previously bound value
-    if not matchType(c, old, value, m):
-      return false
-  elif key.hasElementType and not key.elementType.isNil and key.elementType.kind != tyNone:
-    # check constaint
-    if matchType(c, unrollGenericParam(key), value, m) == false:
-      return false
-  
-  when logBindings: echo "bind table adding '", key, "', ", value
-  assert value != nil
-  assert value.kind != tyVoid
-  m.bindings.put(key, value)
-  return true
-
-proc defSignatureType(n: PNode): PType = n[0].sym.typ
-
-proc conceptBody*(n: PType): PNode = n.n.lastSon
-
-proc acceptsAllTypes(t: PType): bool=
-  result = false
-  if t.kind == tyAnything:
-    result = true
-  elif t.kind == tyGenericParam:
-    if tfImplicitTypeParam in t.flags:
-      result = true
-    if not t.hasElementType or t.elementType.kind == tyNone:
-      result = true
-
-proc procDefSignature(s: PSym): PNode {. deprecated .} = 
-  var nc = s.ast.copyNode()
-  for i in 0 .. 5:
-    nc.add s.ast[i]
-  nc
-
-proc matchKids(c: PContext; f, a: PType; m: var MatchCon, start=0): bool=
-  result = true
-  for i in start ..< f.kidsLen - ord(f.kind in {tyGenericInst, tyGenericInvocation}):
-    if not matchType(c, f[i], a[i], m): return false
-
-iterator traverseTyOr(t: PType): PType {. closure .}=
-  for i in t.kids:
-    case i.kind:
-    of tyGenericParam:
-      if i.hasElementType:
-        for s in traverseTyOr(i.elementType):
-          yield s
-      else:
-        yield i
-    else:
-      yield i
-
-proc matchConceptToImpl(c: PContext, f, potentialImpl: PType; m: var MatchCon): bool =
-  assert not(potentialImpl.reduceToBase.kind == tyConcept)
-  let concpt = f.reduceToBase
-
-  # Handle self-referential concepts: when a concept references itself in its body
-  # (e.g., `A = concept; proc test(x: Self, y: A)`), the inner type A has n=nil.
-  # We detect this by checking if the concept has the same symbol name as the
-  # one we're currently matching and has no body (n=nil).
-  if concpt.n.isNil:
-    if concpt.sym != nil and m.concpt.sym != nil and
-       concpt.sym == m.concpt.sym:
-      # Self-reference: check if potentialImpl matches what we're already checking
-      return potentialImpl.id == m.potentialImplementation.id
-    # Concept without body that's not a self-reference - cannot match
-    return false
-
-  # Cycle detection: track (concept, type) pairs to prevent infinite recursion.
-  # Returns true on cycle (coinductive semantics) to support co-dependent concepts.
-  let pair: ConceptTypePair = (concpt.itemId, potentialImpl.itemId)
-  if pair in m.marker:
-    return true
-  m.marker.incl pair
-
-  var efPot = potentialImpl
-  if potentialImpl.isSelf:
-    if m.concpt.n == concpt.n:
-      m.marker.excl pair
-      return true
-    efPot = m.potentialImplementation
-
-  var oldBindings = m.bindings
-  m.bindings = newTypeMapLayer(m.bindings)
-  let oldPotentialImplementation = m.potentialImplementation
-  m.potentialImplementation = efPot
-  let oldConcept = m.concpt
-  m.concpt = concpt
-
-  var invocation: PType = nil
-  if f.kind in {tyGenericInvocation, tyGenericInst}:
-    invocation = f
-  result = processConcept(c, concpt, invocation, oldBindings, m)
-  m.potentialImplementation = oldPotentialImplementation
-  m.concpt = oldConcept
-  m.bindings = oldBindings
-  m.marker.excl pair
-
-proc cmpConceptDefs(c: PContext, fn, an: PNode, m: var MatchCon): bool=
-  if fn.kind != an.kind:
-    return false
-  if fn[namePos].sym.name != an[namePos].sym.name:
-    return false
-  let
-    ft = fn.defSignatureType
-    at = an.defSignatureType
-  if ft.len != at.len:
-    return false
-  
-  for i in 1 ..< ft.n.len:
-    m.bindings = m.bindings.newTypeMapLayer()
-    
-    let aType = at.n[i].typ
-    let fType = ft.n[i].typ
-    
-    if aType.isSelf and fType.isSelf:
-      continue
-    
-    if not matchType(c, fType, aType, m):
-      m.bindings.setToPreviousLayer()
-      return false
-  result = true
-  if not matchReturnType(c, ft.returnType, at.returnType, m):
-    m.bindings.setToPreviousLayer()
-    result = false
-
-proc conceptsMatch(c: PContext, fc, ac: PType; m: var MatchCon): MatchKind =
-  # XXX: In the future this may need extra parameters to carry info for container types
-  if fc.n == ac.n:
-    # This will have to take generic parameters into account at some point
-    return mkSame
-  let
-    fn = fc.conceptBody
-    an = ac.conceptBody
-    sameLen = fc.len == ac.len
-  var match = false
-  for fdef in fn:
-    var cmpResult = false
-    for ia, ndef in an:
-      match = cmpConceptDefs(c, fdef, ndef, m)
-      if match:
-        break
-    if not match:
-      return mkNoMatch
-  return mkSubset
-
-proc isObjectSubtype(f, a: PType): bool =
-  var t = a
-  result = false
-  while t != nil:
-    t = t.baseClass
-    if t == nil:
-      break
-    t = t.skipTypes({tyPtr,tyRef})
-    if t == nil:
-      break
-    if t.kind != tyObject:
-      break
-    if sameObjectTypes(f, t):
-      result = true
-      break
-
-proc matchType(c: PContext; fo, ao: PType; m: var MatchCon): bool =
+proc matchType(c: PContext; f, a: PType; m: var MatchCon): bool =
  ## The heart of the concept matching process. 'f' is the formal parameter of some
  ## routine inside the concept that we're looking for. 'a' is the formal parameter
  ## of a routine that might match.
-  
-  var
-    a = ao
-    f = fo
-  if a.isSelf:
-    if m.magic in {mArrPut, mArrGet}:
-      return false
-    a = m.potentialImplementation
-  if a.kind in bindableTypes:
-    a = existingBinding(m, ao)
-    if a == ao and a.kind == tyGenericParam and a.hasElementType and a.elementType.kind != tyNone:
-      a = a.elementType
-  
-  if f.isConcept:
-    if a.acceptsAllTypes:
-      return false
-    if a.skipTypes(ignorableForArgType).isConcept:
-      # if f is a subset of a then any match to a will also match f. Not the other way around
-      return conceptsMatch(c, a.reduceToBase, f.reduceToBase, m) >= mkSubset
-    else:
-      return matchConceptToImpl(c, f, a, m)
-  
-  result = false
-
+  const
+    ignorableForArgType = {tyVar, tySink, tyLent, tyOwned, tyGenericInst, tyAlias, tyInferred}
  case f.kind
  of tyAlias:
-    result = matchType(c, f.skipModifier, a, m)
+    result = matchType(c, f.lastSon, a, m)
  of tyTypeDesc:
    if isSelf(f):
-      let ua = a.skipTypes(asymmetricConceptParamMods)
-      if m.magic in {mArrPut, mArrGet}:
-        if m.potentialImplementation.reduceToBase.kind in arrPutGetMagicApplies:
-          bindParam(c, m, a, last m.potentialImplementation)
-          result = true
-      #elif ua.isConcept:
-      #  result = matchType(c, m.concpt, ua, m)
-      else:
-        result = matchType(c, a.skipTypes(ignorableForArgType), m.potentialImplementation, m)
+      #let oldLen = m.inferred.len
+      result = matchType(c, a, m.potentialImplementation, m)
+      #echo "self is? ", result, " ", a.kind, " ", a, " ", m.potentialImplementation, " ", m.potentialImplementation.kind
+      #m.inferred.setLen oldLen
+      #echo "A for ", result, " to ", typeToString(a), " to ", typeToString(m.potentialImplementation)
    else:
-      if a.kind == tyTypeDesc:
-        if not(a.hasElementType) or a.elementType.kind == tyNone:
+      if a.kind == tyTypeDesc and f.len == a.len:
+        for i in 0..<a.len:
+          if not matchType(c, f[i], a[i], m): return false
+        return true
+      else:
+        result = false
+
+  of tyGenericInvocation:
+    result = false
+    if a.kind == tyGenericInst and a[0].kind == tyGenericBody:
+      if sameType(f[0], a[0]) and f.len == a.len-1:
+        for i in 1 ..< f.len:
+          if not matchType(c, f[i], a[i], m): return false
+        return true
+  of tyGenericParam:
+    let ak = a.skipTypes({tyVar, tySink, tyLent, tyOwned})
+    if ak.kind in {tyTypeDesc, tyStatic} and not isSelf(ak):
+      result = false
+    else:
+      let old = existingBinding(m, f)
+      if old == nil:
+        if f.len > 0 and f[0].kind != tyNone:
+          # also check the generic's constraints:
+          let oldLen = m.inferred.len
+          result = matchType(c, f[0], a, m)
+          m.inferred.setLen oldLen
+          if result:
+            when logBindings: echo "A adding ", f, " ", ak
+            m.inferred.add((f, ak))
+        elif m.magic == mArrGet and ak.kind in {tyArray, tyOpenArray, tySequence, tyVarargs, tyCstring, tyString}:
+          when logBindings: echo "B adding ", f, " ", lastSon ak
+          m.inferred.add((f, lastSon ak))
          result = true
-        elif f.hasElementType:
-          result = matchType(c, f.elementType, a.elementType, m)
+        else:
+          when logBindings: echo "C adding ", f, " ", ak
+          m.inferred.add((f, ak))
+          #echo "binding ", typeToString(ak), " to ", typeToString(f)
+          result = true
+      elif not m.marker.containsOrIncl(old.id):
+        result = matchType(c, old, ak, m)
+        if m.magic == mArrPut and ak.kind == tyGenericParam:
+          result = true
+      else:
+        result = false
+    #echo "B for ", result, " to ", typeToString(a), " to ", typeToString(m.potentialImplementation)
+
  of tyVar, tySink, tyLent, tyOwned:
    # modifiers in the concept must be there in the actual implementation
    # too but not vice versa.
    if a.kind == f.kind:
-      result = matchType(c, f.elementType, a.elementType, m)
+      result = matchType(c, f[0], a[0], m)
    elif m.magic == mArrPut:
-      result = matchType(c, f.elementType, a, m)
-  of tyEnum, tyObject, tyDistinct:
-    if a.kind in ignorableForArgType:
-      result = matchType(c, f, a.skipTypes(ignorableForArgType), m)
+      result = matchType(c, f[0], a, m)
    else:
-      if a.kind == tyGenericInst:
-        # tyOr does this to generic typeclasses
-        result = a.base.sym == f.sym
-      else:
-        result = sameType(f, a)
-      if not result and f.kind == tyObject and a.kind == tyObject:
-        result = isObjectSubtype(f, a)
+      result = false
+  of tyEnum, tyObject, tyDistinct:
+    result = sameType(f, a)
  of tyEmpty, tyString, tyCstring, tyPointer, tyNil, tyUntyped, tyTyped, tyVoid:
    result = a.skipTypes(ignorableForArgType).kind == f.kind
  of tyBool, tyChar, tyInt..tyUInt64:
    let ak = a.skipTypes(ignorableForArgType)
    result = ak.kind == f.kind or ak.kind == tyOrdinal or
-      (ak.kind == tyGenericParam and ak.hasElementType and ak.elementType.kind == tyOrdinal)
-  of tyArray, tyTuple, tyVarargs, tyOpenArray, tyRange, tySequence, tyRef, tyPtr:
-    if f.kind == tyArray and f.kidsLen == 3 and a.kind == tyArray:
-      # XXX: this is a work-around!
-      # system.nim creates these for the magic array typeclass
-      result = true
-    else:
-      let ak = a.skipTypes(ignorableForArgType - {f.kind})
-      if ak.kind == f.kind:
-        if f.base.kind == tyNone:
-          result = true
-        elif f.kidsLen == ak.kidsLen:
-          result = matchKids(c, f, ak, m)
-  of tyGenericInvocation, tyGenericInst:
+       (ak.kind == tyGenericParam and ak.len > 0 and ak[0].kind == tyOrdinal)
+  of tyConcept:
+    let oldLen = m.inferred.len
+    let oldPotentialImplementation = m.potentialImplementation
+    m.potentialImplementation = a
+    result = conceptMatchNode(c, f.n.lastSon, m)
+    m.potentialImplementation = oldPotentialImplementation
+    if not result:
+      m.inferred.setLen oldLen
+  of tyArray, tyTuple, tyVarargs, tyOpenArray, tyRange, tySequence, tyRef, tyPtr,
+     tyGenericInst:
    result = false
-    let ea = a.skipTypes(ignorableForArgType)
-    if ea.kind in {tyGenericInst, tyGenericInvocation}:
-      var
-        k1 = f.kidsLen - ord(f.kind == tyGenericInst)
-        k2 = ea.kidsLen - ord(ea.kind == tyGenericInst)
-      if sameType(f.genericHead, ea.genericHead) and k1 == k2:
-        result = true
-        for i in 1 ..< k2:
-          if not matchType(c, f[i], ea[i], m):
-            result = false
-            break
-    elif f.kind == tyGenericInvocation:
-      # bind potential generic constraints into body
-      let body = f.base
-      for i in 1 ..< len(f):
-        bindParam(c,m,body[i-1], f[i])
-      result = matchType(c, body, a, m)
-    else: # tyGenericInst
-      result = matchType(c, f.last, a, m)
-  of tyOrdinal:
-    result = isOrdinalType(a, allowEnumWithHoles = false) or a.kind == tyGenericParam
-  of tyStatic:
-    var scomp = f.base
-    if scomp.kind == tyGenericParam:
-      if f.base.kidsLen > 0:
-        scomp = scomp.base
-    if a.kind == tyStatic:
-      result = matchType(c, scomp, a.base, m)
-    else:
-      result = matchType(c, scomp, a, m)
-  of tyGenericParam:
-    if a.acceptsAllTypes:
-      discard bindParam(c, m, f, a)
-      result = f.acceptsAllTypes
-    else:
-      result = bindParam(c, m, f, a)
-  of tyAnything:
-    result = true
-  of tyNot:
-    if a.kind == tyNot:
-      result = matchType(c, f.elementType, a.elementType, m)
-    else:
-      m.bindings = m.bindings.newTypeMapLayer()
-      result = not matchType(c, f.elementType, a, m)
-      m.bindings.setToPreviousLayer()
-  of tyAnd:
-    m.bindings = m.bindings.newTypeMapLayer()
-    result = true
-    for ff in traverseTyOr(f):
-      let r = matchType(c, ff, a, m)
-      if not r:
-        m.bindings.setToPreviousLayer()
-        result = false
-        break
-  of tyGenericBody:
-    var ak = a
-    if a.kind == tyGenericBody:
-      ak = last(a)
-    result = matchType(c, last(f), ak, m)
-  of tyCompositeTypeClass:
-    if a.kind == tyCompositeTypeClass:
-      result = matchKids(c, f, a, m)
-    else:
-      result = matchType(c, last(f), a, m)
-  of tyBuiltInTypeClass:
-    let target = f.genericHead.kind
-    result = a.skipTypes(ignorableForArgType).reduceToBase.kind == target
+    let ak = a.skipTypes(ignorableForArgType - {f.kind})
+    if ak.kind == f.kind and f.len == ak.len:
+      for i in 0..<ak.len:
+        if not matchType(c, f[i], ak[i], m): return false
+      return true
  of tyOr:
+    let oldLen = m.inferred.len
    if a.kind == tyOr:
+      # say the concept requires 'int|float|string' if the potentialImplementation
+      # says 'int|string' that is good enough.
      var covered = 0
-      for ff in traverseTyOr(f):
-        for aa in traverseTyOr(a):
-          m.bindings = m.bindings.newTypeMapLayer()
-          let r = matchType(c, ff, aa, m)
+      for i in 0..<f.len:
+        for j in 0..<a.len:
+          let oldLenB = m.inferred.len
+          let r = matchType(c, f[i], a[j], m)
          if r:
            inc covered
            break
-          m.bindings.setToPreviousLayer()
+          m.inferred.setLen oldLenB

-      result = covered >= a.kidsLen
+      result = covered >= a.len
+      if not result:
+        m.inferred.setLen oldLen
    else:
-      for ff in f.kids:
-        m.bindings = m.bindings.newTypeMapLayer()
-        result = matchType(c, ff, a, m)
+      result = false
+      for i in 0..<f.len:
+        result = matchType(c, f[i], a, m)
        if result: break # and remember the binding!
-        m.bindings.setToPreviousLayer()
-  of tySet:
-    result = false
-    if a.kind == tySet:
-      result = matchType(c, f.elementType, a.elementType, m)
+        m.inferred.setLen oldLen
+  of tyNot:
+    if a.kind == tyNot:
+      result = matchType(c, f[0], a[0], m)
+    else:
+      let oldLen = m.inferred.len
+      result = not matchType(c, f[0], a, m)
+      m.inferred.setLen oldLen
+  of tyAnything:
+    result = true
+  of tyOrdinal:
+    result = isOrdinalType(a, allowEnumWithHoles = false) or a.kind == tyGenericParam
  else:
    result = false
-  if result and ao.kind == tyGenericParam:
-    let bf = if f.isSelf: m.potentialImplementation else: f
-    if bindParam(c, m, ao, bf):
-      when logBindings: echo " ^ reverse binding"
-
-proc checkConstraint(c: PContext; f, a: PType; m: var MatchCon): bool =
-  result = matchType(c, f, a, m) or matchType(c, a, f, m)

 proc matchReturnType(c: PContext; f, a: PType; m: var MatchCon): bool =
  ## Like 'matchType' but with extra logic dealing with proc return types
@@ -491,38 +228,30 @@ proc matchReturnType(c: PContext; f, a: PType; m: var MatchCon): bool =
  elif a == nil:
    result = false
  else:
-    result = checkConstraint(c, f, a, m)
+    result = matchType(c, f, a, m)

 proc matchSym(c: PContext; candidate: PSym, n: PNode; m: var MatchCon): bool =
  ## Checks if 'candidate' matches 'n' from the concept body. 'n' is a nkProcDef
  ## or similar.

  # watch out: only add bindings after a completely successful match.
-  m.bindings = m.bindings.newTypeMapLayer()
+  let oldLen = m.inferred.len

  let can = candidate.typ.n
-  let con = defSignatureType(n).n
+  let con = n[0].sym.typ.n
+
  if can.len < con.len:
    # too few arguments, cannot be a match:
    return false
-  
-  if can.len > con.len:
-    # too many arguments (not optional)
-    for i in con.len ..< can.len:
-      if can[i].sym.ast == nil:
-        return false
-  
-  when defined(debugConcepts):
-    echo "considering: ", renderTree(candidate.procDefSignature), " ", candidate.magic
-  
+
  let common = min(can.len, con.len)
  for i in 1 ..< common:
-    if not checkConstraint(c, con[i].typ, can[i].typ, m):
-      m.bindings.setToPreviousLayer()
+    if not matchType(c, con[i].typ, can[i].typ, m):
+      m.inferred.setLen oldLen
      return false
-  
-  if not matchReturnType(c, n.defSignatureType.returnType, candidate.typ.returnType, m):
-    m.bindings.setToPreviousLayer()
+
+  if not matchReturnType(c, n[0].sym.typ[0], candidate.typ[0], m):
+    m.inferred.setLen oldLen
    return false

  # all other parameters have to be optional parameters:
@@ -530,7 +259,7 @@ proc matchSym(c: PContext; candidate: PSym, n: PNode; m: var MatchCon): bool =
    assert can[i].kind == nkSym
    if can[i].sym.ast == nil:
      # has too many arguments one of which is not optional:
-      m.bindings.setToPreviousLayer()
+      m.inferred.setLen oldLen
      return false

  return true
@@ -538,14 +267,12 @@ proc matchSym(c: PContext; candidate: PSym, n: PNode; m: var MatchCon): bool =
 proc matchSyms(c: PContext, n: PNode; kinds: set[TSymKind]; m: var MatchCon): bool =
  ## Walk the current scope, extract candidates which the same name as 'n[namePos]',
  ## 'n' is the nkProcDef or similar from the concept that we try to match.
-  result = false
-  var candidates = searchScopes(c, n[namePos].sym.name, kinds)
-  searchImportsAll(c, n[namePos].sym.name, kinds, candidates)
+  let candidates = searchInScopesAllCandidatesFilterBy(c, n[namePos].sym.name, kinds)
  for candidate in candidates:
+    #echo "considering ", typeToString(candidate.typ), " ", candidate.magic
    m.magic = candidate.magic
-    if matchSym(c, candidate, n, m):
-      result = true
-      break
+    if matchSym(c, candidate, n, m): return true
+  result = false

 proc conceptMatchNode(c: PContext; n: PNode; m: var MatchCon): bool =
  ## Traverse the concept's AST ('n') and see if every declaration inside 'n'
@@ -578,66 +305,35 @@ proc conceptMatchNode(c: PContext; n: PNode; m: var MatchCon): bool =
    # error was reported earlier.
    result = false

-proc fixBindings(bindings: var LayeredIdTable; concpt: PType; invocation: PType; m: var MatchCon) =
-  # invocation != nil means we have a non-atomic concept:
-  if invocation != nil and invocation.kind == tyGenericInvocation:
-    assert concpt.sym.typ.kind == tyGenericBody
-    
-    for i in 0 .. concpt.sym.typ.len - 1:
-      let thisSym = concpt.sym.typ[i]
-      if lookup(bindings, thisSym) != nil:
-        # dont trust the bindings over existing ones
-        continue
-      let found = m.bindings.lookup(thisSym)
-      if found != nil:
-        when logBindings: echo "Invocation bind: ", thisSym, " ", found
-        bindings.put(thisSym, found)
-    
-    # bind even more generic parameters
-    let genBody = invocation.base
-    assert genBody.kind == tyGenericBody
-    for i in FirstGenericParamAt ..< invocation.kidsLen:
-      let bpram = genBody[i - 1]
-      if lookup(bindings, invocation[i]) != nil:
-        # dont trust the bindings over existing ones
-        continue
-      let boundV = lookup(bindings, bpram)
-      when logBindings: echo "generic body bind: '", invocation[i], "' '", boundV, "'"
-      if boundV != nil:
-        bindings.put(invocation[i], boundV)
-  bindings.put(concpt, m.potentialImplementation)
-
-proc processConcept(c: PContext; concpt, invocation: PType, bindings: var LayeredIdTable; m: var MatchCon): bool =
-  m.bindings = m.bindings.newTypeMapLayer()
-  if invocation != nil and invocation.kind == tyGenericInst:
-    let genericBody = invocation.base
-    for i in 1..<invocation.kidsLen-1:
-      # instGenericContainer can bind `tyVoid`
-      if invocation[i].kind != tyVoid:
-        bindParam(c, m, genericBody[i-1], invocation[i])
-  result = conceptMatchNode(c, concpt.conceptBody, m)
-  if result and mfDontBind notin m.flags:
-    fixBindings(bindings, concpt, invocation, m)
-
-proc conceptMatch*(c: PContext; concpt, arg: PType; bindings: var LayeredIdTable; invocation: PType, flags: set[MatchFlags] = {}): bool =
+proc conceptMatch*(c: PContext; concpt, arg: PType; bindings: var TIdTable; invocation: PType): bool =
  ## Entry point from sigmatch. 'concpt' is the concept we try to match (here still a PType but
-  ## we extract its AST via 'concpt.n.lastSon'). 'arg' is the type that might fulfill the
+  ## we extract its AST via 'concpt.n.lastSon'). 'arg' is the type that might fullfill the
  ## concept's requirements. If so, we return true and fill the 'bindings' with pairs of
  ## (typeVar, instance) pairs. ('typeVar' is usually simply written as a generic 'T'.)
  ## 'invocation' can be nil for atomic concepts. For non-atomic concepts, it contains the
  ## `C[S, T]` parent type that we look for. We need this because we need to store bindings
  ## for 'S' and 'T' inside 'bindings' on a successful match. It is very important that
  ## we do not add any bindings at all on an unsuccessful match!
-  var m = MatchCon(bindings: bindings, potentialImplementation: arg, concpt: concpt, flags: flags, marker: initHashSet[ConceptTypePair]())
-  if arg.isConcept:
-    result = conceptsMatch(c, concpt.reduceToBase, arg.reduceToBase, m) >= mkSubset
-  elif arg.acceptsAllTypes:
-    # XXX: I think this is wrong, or at least partially wrong. Can still test ambiguous types
-    result = false
-  elif mfCheckGeneric in m.flags:
-    # prioritize concepts the least. Specifically if the arg is not a catch all as per above
-    result = true
-  else:
-    result = processConcept(c, concpt, invocation, bindings, m)
-
-  
+  var m = MatchCon(inferred: @[], potentialImplementation: arg)
+  result = conceptMatchNode(c, concpt.n.lastSon, m)
+  if result:
+    for (a, b) in m.inferred:
+      if b.kind == tyGenericParam:
+        var dest = b
+        while true:
+          dest = existingBinding(m, dest)
+          if dest == nil or dest.kind != tyGenericParam: break
+        if dest != nil:
+          bindings.idTablePut(a, dest)
+          when logBindings: echo "A bind ", a, " ", dest
+      else:
+        bindings.idTablePut(a, b)
+        when logBindings: echo "B bind ", a, " ", b
+    # we have a match, so bind 'arg' itself to 'concpt':
+    bindings.idTablePut(concpt, arg)
+    # invocation != nil means we have a non-atomic concept:
+    if invocation != nil and arg.kind == tyGenericInst and invocation.len == arg.len-1:
+      # bind even more generic parameters
+      assert invocation.kind == tyGenericInvocation
+      for i in 1 ..< invocation.len:
+        bindings.idTablePut(invocation[i], arg[i])
--- a/compiler/condsyms.nim
+++ b/compiler/condsyms.nim
@@ -10,7 +10,7 @@
 # This module handles the conditional symbols.

 import
-  std/strtabs
+  strtabs

 from options import Feature
 from lineinfos import hintMin, hintMax, warnMin, warnMax
@@ -143,6 +143,7 @@ proc initDefines*(symbols: StringTableRef) =
  defineSymbol("nimHasTemplateRedefinitionPragma")
  defineSymbol("nimHasCstringCase")
  defineSymbol("nimHasCallsitePragma")
+  defineSymbol("nimHasAmbiguousEnumHint")

  defineSymbol("nimHasWarnCastSizes") # deadcode
  defineSymbol("nimHasOutParams")
@@ -157,23 +158,6 @@ proc initDefines*(symbols: StringTableRef) =
  defineSymbol("nimAllowNonVarDestructor")
  defineSymbol("nimHasQuirky")
  defineSymbol("nimHasEnsureMove")
-  defineSymbol("nimHasNoReturnError")

-  defineSymbol("nimUseStrictDefs") # deadcode
+  defineSymbol("nimUseStrictDefs")
  defineSymbol("nimHasNolineTooLong")
-
-  defineSymbol("nimHasCastExtendedVm")
-  defineSymbol("nimHasWarnStdPrefix")
-
-  defineSymbol("nimHasVtables")
-  defineSymbol("nimHasGenericsOpenSym2")
-  defineSymbol("nimHasGenericsOpenSym3")
-  defineSymbol("nimHasJsNoLambdaLifting")
-  defineSymbol("nimHasDefaultFloatRoundtrip")
-  defineSymbol("nimHasXorSet")
-
-  defineSymbol("nimHasSetLengthSeqUninitMagic")
-  defineSymbol("nimHasPreviewDuplicateModuleError")
-
-  defineSymbol("nimHasImplicitRangeConversion")
-
--- a/compiler/depends.nim
+++ b/compiler/depends.nim
@@ -14,7 +14,7 @@ import options, ast, ropes, pathutils, msgs, lineinfos
 import modulegraphs

 import std/[os, parseutils]
-import std/strutils except addf
+import strutils except addf
 import std/private/globs

 when defined(nimPreviewSlimSystem):
--- a/compiler/deps.nim
+++ b/compiler/deps.nim
--- a/compiler/dfa.nim
+++ b/compiler/dfa.nim
@@ -22,9 +22,8 @@
 ## "A Graph–Free Approach to Data–Flow Analysis" by Markus Mohnen.
 ## https://link.springer.com/content/pdf/10.1007/3-540-45937-5_6.pdf

-import ast, lineinfos, renderer, aliasanalysis
+import ast, intsets, lineinfos, renderer, aliasanalysis
 import std/private/asciitables
-import std/intsets

 when defined(nimPreviewSlimSystem):
  import std/assertions
@@ -46,10 +45,10 @@ type
    case isTryBlock: bool
    of false:
      label: PSym
-      breakFixups: seq[(TPosition, seq[PNode])] # Contains the gotos for the breaks along with their pending finales
+      breakFixups: seq[(TPosition, seq[PNode])] #Contains the gotos for the breaks along with their pending finales
    of true:
      finale: PNode
-      raiseFixups: seq[TPosition] # Contains the gotos for the raises
+      raiseFixups: seq[TPosition] #Contains the gotos for the raises

  Con = object
    code: ControlFlowGraph
@@ -181,6 +180,14 @@ proc genIf(c: var Con, n: PNode) =
    goto Lend3
  L3:
    D
+    goto Lend3 # not eliminated to simplify the join generation
+  Lend3:
+    join F3
+  Lend2:
+    join F2
+  Lend:
+    join F1
+
  ]#
  var endings: seq[TPosition] = @[]
  let oldInteresting = c.interestingInstructions
@@ -205,6 +212,7 @@ proc genAndOr(c: var Con; n: PNode) =
  #   fork lab1
  #   asgn dest, b
  # lab1:
+  #   join F1
  c.gen(n[1])
  forkT:
    c.gen(n[2])
@@ -315,7 +323,7 @@ proc genRaise(c: var Con; n: PNode) =
      if c.blocks[i].isTryBlock:
        genBreakOrRaiseAux(c, i, n)
        return
-    assert false # Unreachable
+    assert false #Unreachable
  else:
    genNoReturn(c)

@@ -371,7 +379,7 @@ proc genCall(c: var Con; n: PNode) =
  if t != nil: t = t.skipTypes(abstractInst)
  for i in 1..<n.len:
    gen(c, n[i])
-    if t != nil and i < t.signatureLen and isOutParam(t[i]):
+    if t != nil and i < t.len and isOutParam(t[i]):
      # Pass by 'out' is a 'must def'. Good enough for a move optimizer.
      genDef(c, n[i])
  # every call can potentially raise:
@@ -381,6 +389,7 @@ proc genCall(c: var Con; n: PNode) =
    # fork lab1
    # goto exceptionHandler (except or finally)
    # lab1:
+    # join F1
    forkT:
      for i in countdown(c.blocks.high, 0):
        if c.blocks[i].isTryBlock:
@@ -439,8 +448,8 @@ proc gen(c: var Con; n: PNode) =
    genUse(c, n)
  of nkIfStmt, nkIfExpr: genIf(c, n)
  of nkWhenStmt:
-    # This is "when nimvm" node. Chose the second branch.
-    gen(c, n[1][0])
+    # This is "when nimvm" node. Chose the first branch.
+    gen(c, n[0][1])
  of nkCaseStmt: genCase(c, n)
  of nkWhileStmt: genWhile(c, n)
  of nkBlockExpr, nkBlockStmt: genBlock(c, n)
@@ -483,7 +492,7 @@ proc constructCfg*(s: PSym; body: PNode; root: PSym): ControlFlowGraph =
    gen(c, body)
    if root.kind == skResult:
      genImplicitReturn(c)
-  when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc) or defined(gcYrc):
+  when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc):
    result = c.code # will move
  else:
    shallowCopy(result, c.code)
--- a/compiler/docgen.nim
+++ b/compiler/docgen.nim
@@ -15,16 +15,15 @@
 ## For corresponding users' documentation see [Nim DocGen Tools Guide].

 import
-  ast, options, msgs, idents,
+  ast, strutils, strtabs, algorithm, sequtils, options, msgs, os, idents,
  wordrecg, syntaxes, renderer, lexer,
  packages/docutils/[rst, rstidx, rstgen, dochelpers],
-  trees, types,
-  typesrenderer, lineinfos,
-  pathutils, nimpaths, renderverbatim, packages
+  json, xmltree, trees, types,
+  typesrenderer, astalgo, lineinfos, intsets,
+  pathutils, tables, nimpaths, renderverbatim, osproc, packages
 import packages/docutils/rstast except FileIndex, TLineInfo

-import std/[os, strutils, strtabs, algorithm, json, osproc, tables, intsets, xmltree, sequtils]
-from std/uri import encodeUrl
+from uri import encodeUrl
 from nodejs import findNodeJs

 when defined(nimPreviewSlimSystem):
@@ -115,7 +114,7 @@ proc add(dest: var ItemPre, str: string) = dest.add ItemFragment(isRst: false, s

 proc addRstFileIndex(d: PDoc, fileIndex: lineinfos.FileIndex): rstast.FileIndex =
  let invalid = rstast.FileIndex(-1)
-  result = d.nimToRstFid.getOrDefault(fileIndex, invalid)
+  result = d.nimToRstFid.getOrDefault(fileIndex, default = invalid)
  if result == invalid:
    let fname = toFullPath(d.conf, fileIndex)
    result = addFilename(d.sharedState, fname)
@@ -148,7 +147,7 @@ proc cmpDecimalsIgnoreCase(a, b: string): int =
        limitB = iB
      while limitA < aLen and isDigit(a[limitA]): inc limitA
      while limitB < bLen and isDigit(b[limitB]): inc limitB
-      var pos = max(limitA-iA, limitB-iB)
+      var pos = max(limitA-iA, limitB-iA)
      while pos > 0:
        if limitA-pos < iA:  # digit in `a` is 0 effectively
          result = ord('0') - ord(b[limitB-pos])
@@ -289,7 +288,7 @@ template declareClosures(currentFilename: AbsoluteFile, destFile: string) =
    let outDirPath: RelativeFile =
        presentationPath(conf, AbsoluteFile(basedir / targetRelPath))
          # use presentationPath because `..` path can be be mangled to `_._`
-    result = (string(conf.outDir / outDirPath), "")
+    result.targetPath = string(conf.outDir / outDirPath)
    if not fileExists(result.targetPath):
      # this can happen if targetRelPath goes to parent directory `OUTDIR/..`.
      # Trying it, this may cause ambiguities, but allows us to insert
@@ -433,9 +432,6 @@ proc getVarIdx(varnames: openArray[string], id: string): int =

 proc genComment(d: PDoc, n: PNode): PRstNode =
  if n.comment.len > 0:
-    if optDocRaw in d.conf.globalOptions:
-      return newRstLeaf(n.comment)
-
    d.sharedState.currFileIdx = addRstFileIndex(d, n.info)
    try:
      result = parseRst(n.comment,
@@ -540,11 +536,10 @@ proc nodeToHighlightedHtml(d: PDoc; n: PNode; result: var string;
      elif s != nil and s.kind in {skType, skVar, skLet, skConst} and
           sfExported in s.flags and s.owner != nil and
           belongsToProjectPackage(d.conf, s.owner) and d.target == outHtml:
-        let href = (if d.module == s.owner: ""
-            else: externalDep(d, s.owner).changeFileExt("html")
-          ) & "#" & literal
-        result.addf "<a href=\"$1\"><span class=\"Identifier\">$2</span></a>",
-            [href, escLit]
+        let external = externalDep(d, s.owner)
+        result.addf "<a href=\"$1#$2\"><span class=\"Identifier\">$3</span></a>",
+          [changeFileExt(external, "html"), literal,
+           escLit]
      else:
        dispA(d.conf, result, "<span class=\"Identifier\">$1</span>",
              "\\spanIdentifier{$1}", [escLit])
@@ -834,8 +829,8 @@ proc getName(n: PNode): string =
  of nkAccQuoted:
    result = "`"
    for i in 0..<n.len: result.add(getName(n[i]))
-    result.add('`')
-  of nkOpenSymChoice, nkClosedSymChoice, nkOpenSym:
+    result = "`"
+  of nkOpenSymChoice, nkClosedSymChoice:
    result = getName(n[0])
  else:
    result = ""
@@ -853,7 +848,7 @@ proc getNameIdent(cache: IdentCache; n: PNode): PIdent =
    var r = ""
    for i in 0..<n.len: r.add(getNameIdent(cache, n[i]).s)
    result = getIdent(cache, r)
-  of nkOpenSymChoice, nkClosedSymChoice, nkOpenSym:
+  of nkOpenSymChoice, nkClosedSymChoice:
    result = getNameIdent(cache, n[0])
  else:
    result = nil
@@ -867,7 +862,7 @@ proc getRstName(n: PNode): PRstNode =
  of nkAccQuoted:
    result = getRstName(n[0])
    for i in 1..<n.len: result.text.add(getRstName(n[i]).text)
-  of nkOpenSymChoice, nkClosedSymChoice, nkOpenSym:
+  of nkOpenSymChoice, nkClosedSymChoice:
    result = getRstName(n[0])
  else:
    result = nil
@@ -1004,9 +999,8 @@ proc getTypeKind(n: PNode): string =
 proc toLangSymbol(k: TSymKind, n: PNode, baseName: string): LangSymbol =
  ## Converts symbol info (names/types/parameters) in `n` into format
  ## `LangSymbol` convenient for ``rst.nim``/``dochelpers.nim``.
-  result = LangSymbol(name: baseName.nimIdentNormalize,
-      symKind: k.toHumanStr
-  )
+  result.name = baseName.nimIdentNormalize
+  result.symKind = k.toHumanStr
  if k in routineKinds:
    var
      paramTypes: seq[string] = @[]
@@ -1035,7 +1029,7 @@ proc toLangSymbol(k: TSymKind, n: PNode, baseName: string): LangSymbol =
    if genNode != nil:
      var literal = ""
      var r: TSrcGen = initTokRender(genNode, {renderNoBody, renderNoComments,
-        renderNoPragmas, renderNoProcDefs, renderExpandUsing, renderNoPostfix})
+        renderNoPragmas, renderNoProcDefs, renderExpandUsing})
      var kind = tkEof
      while true:
        getNextTok(r, kind, literal)
@@ -1063,7 +1057,7 @@ proc genItem(d: PDoc, n, nameNode: PNode, k: TSymKind, docFlags: DocFlags, nonEx

  # Obtain the plain rendered string for hyperlink titles.
  var r: TSrcGen = initTokRender(n, {renderNoBody, renderNoComments, renderDocComments,
-    renderNoPragmas, renderNoProcDefs, renderExpandUsing, renderNoPostfix})
+    renderNoPragmas, renderNoProcDefs, renderExpandUsing})
  while true:
    getNextTok(r, kind, literal)
    if kind == tkEof:
@@ -1090,9 +1084,6 @@ proc genItem(d: PDoc, n, nameNode: PNode, k: TSymKind, docFlags: DocFlags, nonEx
    symbolOrIdEnc = encodeUrl(symbolOrId, usePlus = false)
    deprecationMsg = genDeprecationMsg(d, pragmaNode)
    rstLangSymbol = toLangSymbol(k, n, cleanPlainSymbol)
-    symNameNode =
-      if nameNode.kind == nkPostfix: nameNode[1]
-      else: nameNode

  # we generate anchors automatically for subsequent use in doc comments
  let lineinfo = rstast.TLineInfo(
@@ -1103,10 +1094,10 @@ proc genItem(d: PDoc, n, nameNode: PNode, k: TSymKind, docFlags: DocFlags, nonEx
               priority = symbolPriority(k), info = lineinfo,
               module = addRstFileIndex(d, FileIndex d.module.position))

-  var renderFlags = {renderNoBody, renderNoComments, renderDocComments,
-    renderSyms, renderExpandUsing, renderNoPostfix}
-  if nonExports:
-    renderFlags.incl renderNonExportedFields
+  let renderFlags =
+    if nonExports: {renderNoBody, renderNoComments, renderDocComments, renderSyms,
+      renderExpandUsing, renderNonExportedFields}
+    else: {renderNoBody, renderNoComments, renderDocComments, renderSyms, renderExpandUsing}
  nodeToHighlightedHtml(d, n, result, renderFlags, symbolOrIdEnc)

  let seeSrc = genSeeSrc(d, toFullPath(d.conf, n.info), n.info.line.int)
@@ -1129,19 +1120,18 @@ proc genItem(d: PDoc, n, nameNode: PNode, k: TSymKind, docFlags: DocFlags, nonEx
  let external = d.destFile.AbsoluteFile.relativeTo(d.conf.outDir, '/').changeFileExt(HtmlExt).string

  var attype = ""
-  if k in routineKinds and symNameNode.kind == nkSym:
+  if k in routineKinds and nameNode.kind == nkSym:
    let att = attachToType(d, nameNode.sym)
    if att != nil:
      attype = esc(d.target, att.name.s)
-  elif k == skType and symNameNode.kind == nkSym and
-      symNameNode.sym.typ.kind in {tyEnum, tyBool}:
-    let etyp = symNameNode.sym.typ
+  elif k == skType and nameNode.kind == nkSym and nameNode.sym.typ.kind in {tyEnum, tyBool}:
+    let etyp = nameNode.sym.typ
    for e in etyp.n:
      if e.sym.kind != skEnumField: continue
      let plain = renderPlainSymbolName(e)
      let symbolOrId = d.newUniquePlainSymbol(plain)
      setIndexTerm(d[], ieNim, htmlFile = external, id = symbolOrId,
-                   term = plain, linkTitle = symNameNode.sym.name.s & '.' & plain,
+                   term = plain, linkTitle = nameNode.sym.name.s & '.' & plain,
                   linkDesc = xmltree.escape(getPlainDocstring(e).docstringSummary),
                   line = n.info.line.int)

@@ -1162,8 +1152,8 @@ proc genItem(d: PDoc, n, nameNode: PNode, k: TSymKind, docFlags: DocFlags, nonEx
               linkTitle = detailedName,
               linkDesc = xmltree.escape(plainDocstring.docstringSummary),
               line = n.info.line.int)
-  if k == skType and symNameNode.kind == nkSym:
-    d.types.strTableAdd symNameNode.sym
+  if k == skType and nameNode.kind == nkSym:
+    d.types.strTableAdd nameNode.sym

 proc genJsonItem(d: PDoc, n, nameNode: PNode, k: TSymKind, nonExports = false): JsonItem =
  if not isVisible(d, nameNode): return
@@ -1171,21 +1161,15 @@ proc genJsonItem(d: PDoc, n, nameNode: PNode, k: TSymKind, nonExports = false):
    name = getNameEsc(d, nameNode)
    comm = genRecComment(d, n)
    r: TSrcGen
-    renderFlags = {renderNoBody, renderNoComments, renderDocComments,
-      renderExpandUsing, renderNoPostfix}
+    renderFlags = {renderNoBody, renderNoComments, renderDocComments, renderExpandUsing}
  if nonExports:
    renderFlags.incl renderNonExportedFields
  r = initTokRender(n, renderFlags)
-  result = JsonItem(json: %{ "name": %name, "type": %($k), "line": %n.info.line.int,
+  result.json = %{ "name": %name, "type": %($k), "line": %n.info.line.int,
                   "col": %n.info.col}
-  )
  if comm != nil:
-    if optDocRaw in d.conf.globalOptions:
-      result.json["description"] = %comm.text
-    else:
-      result.rst = comm
-      result.rstField = "description"
-
+    result.rst = comm
+    result.rstField = "description"
  if r.buf.len > 0:
    result.json["code"] = %r.buf
  if k in routineKinds:
@@ -1214,7 +1198,8 @@ proc genJsonItem(d: PDoc, n, nameNode: PNode, k: TSymKind, nonExports = false):
        var param = %{"name": %($genericParam)}
        if genericParam.sym.typ.len > 0:
          param["types"] = newJArray()
-          param["types"] = %($genericParam.sym.typ.elementType)
+        for kind in genericParam.sym.typ:
+          param["types"].add %($kind)
        result.json["signature"]["genericParams"].add param
  if optGenIndex in d.conf.globalOptions:
    genItem(d, n, nameNode, k, kForceExport)
@@ -1415,18 +1400,14 @@ proc generateDoc*(d: PDoc, n, orig: PNode, config: ConfigRef, docFlags: DocFlags
  of nkExportStmt:
    for it in n:
      if it.kind == nkSym:
-        if d.module != nil and d.module == it.sym.owner:  # in current module
-          # bug #23051; don't generate documentation for exported symbols again
-          if sfExported notin it.sym.flags:
-            generateDoc(d, it.sym.ast, orig, config, kForceExport)
-          # else it's to be handled in `of XxxSection` branch
+        if d.module != nil and d.module == it.sym.owner:
+          generateDoc(d, it.sym.ast, orig, config, kForceExport)
        elif it.sym.ast != nil:
-          # only export symbols in imported modules, not in current module
          exportSym(d, it.sym)
  of nkExportExceptStmt: discard "transformed into nkExportStmt by semExportExcept"
  of nkFromStmt, nkImportExceptStmt: traceDeps(d, n[0])
  of nkCallKinds:
-    var comm = default(ItemPre)
+    var comm: ItemPre = default(ItemPre)
    getAllRunnableExamples(d, n, comm)
    if comm.len != 0: d.modDescPre.add(comm)
  else: discard
@@ -1824,7 +1805,7 @@ proc writeOutputJson*(d: PDoc, useWarning = false) =
    "moduleDescription": modDesc,
    "entries": d.jEntriesFinal}
  if optStdout in d.conf.globalOptions:
-    writeLine(stdout, $content)
+    write(stdout, $content)
  else:
    let dir = d.destFile.splitFile.dir
    createDir(dir)
@@ -1900,9 +1881,6 @@ proc commandJson*(cache: IdentCache, conf: ConfigRef) =
  else:
    #echo getOutFile(gProjectFull, JsonExt)
    let filename = getOutFile(conf, RelativeFile conf.projectName, JsonExt)
-    conf.outFile = filename.relativeTo(conf.outDir)
-    let dir = filename.splitFile.dir
-    createDir(dir)
    try:
      writeFile(filename, content)
    except IOError:
@@ -1923,10 +1901,8 @@ proc commandTags*(cache: IdentCache, conf: ConfigRef) =
  if optStdout in d.conf.globalOptions:
    write(stdout, content)
  else:
+    #echo getOutFile(gProjectFull, TagsExt)
    let filename = getOutFile(conf, RelativeFile conf.projectName, TagsExt)
-    conf.outFile = filename.relativeTo(conf.outDir)
-    let dir = filename.splitFile.dir
-    createDir(dir)
    try:
      writeFile(filename, content)
    except IOError:
--- a/compiler/enumtostr.nim
+++ b/compiler/enumtostr.nim
@@ -14,7 +14,7 @@ proc genEnumToStrProc*(t: PType; info: TLineInfo; g: ModuleGraph; idgen: IdGener
  let res = newSym(skResult, getIdent(g.cache, "result"), idgen, result, info)
  res.typ = getSysType(g, info, tyString)

-  result.typ = newType(tyProc, idgen, t.owner)
+  result.typ = newType(tyProc, nextTypeId idgen, t.owner)
  result.typ.n = newNodeI(nkFormalParams, info)
  rawAddSon(result.typ, res.typ)
  result.typ.n.add newNodeI(nkEffectList, info)
@@ -33,10 +33,6 @@ proc genEnumToStrProc*(t: PType; info: TLineInfo; g: ModuleGraph; idgen: IdGener
    caseStmt.add newTree(nkOfBranch, newIntTypeNode(field.position, t),
      newTree(nkStmtList, newTree(nkFastAsgn, newSymNode(res), newStrNode(val, info))))
    #newIntTypeNode(nkIntLit, field.position, t)
-  # safety branch for invalid data:
-  caseStmt.add newTree(nkElse,
-    newTree(nkStmtList, newTree(nkFastAsgn, newSymNode(res),
-      newStrNode("", info))))

  body.add(caseStmt)

@@ -47,8 +43,8 @@ proc genEnumToStrProc*(t: PType; info: TLineInfo; g: ModuleGraph; idgen: IdGener
  n[bodyPos] = body
  n[resultPos] = newSymNode(res)
  result.ast = n
-  incl result.flagsImpl, {sfFromGeneric, sfNeverRaises}
-  setHookDisamb(g, result, "$enumtostr", t)
+  incl result.flags, sfFromGeneric
+  incl result.flags, sfNeverRaises

 proc searchObjCaseImpl(obj: PNode; field: PSym): PNode =
  case obj.kind
@@ -67,8 +63,8 @@ proc searchObjCaseImpl(obj: PNode; field: PSym): PNode =

 proc searchObjCase(t: PType; field: PSym): PNode =
  result = searchObjCaseImpl(t.n, field)
-  if result == nil and t.baseClass != nil:
-    result = searchObjCase(t.baseClass.skipTypes({tyAlias, tyGenericInst, tyRef, tyPtr}), field)
+  if result == nil and t.len > 0:
+    result = searchObjCase(t[0].skipTypes({tyAlias, tyGenericInst, tyRef, tyPtr}), field)
  doAssert result != nil

 proc genCaseObjDiscMapping*(t: PType; field: PSym; info: TLineInfo; g: ModuleGraph; idgen: IdGenerator): PSym =
@@ -80,7 +76,7 @@ proc genCaseObjDiscMapping*(t: PType; field: PSym; info: TLineInfo; g: ModuleGra
  let res = newSym(skResult, getIdent(g.cache, "result"), idgen, result, info)
  res.typ = getSysType(g, info, tyUInt8)

-  result.typ = newType(tyProc, idgen, t.owner)
+  result.typ = newType(tyProc, nextTypeId idgen, t.owner)
  result.typ.n = newNodeI(nkFormalParams, info)
  rawAddSon(result.typ, res.typ)
  result.typ.n.add newNodeI(nkEffectList, info)
@@ -110,4 +106,5 @@ proc genCaseObjDiscMapping*(t: PType; field: PSym; info: TLineInfo; g: ModuleGra
  n[bodyPos] = body
  n[resultPos] = newSymNode(res)
  result.ast = n
-  incl result.flagsImpl, {sfFromGeneric, sfNeverRaises}
+  incl result.flags, sfFromGeneric
+  incl result.flags, sfNeverRaises
--- a/compiler/errorhandling.nim
+++ b/compiler/errorhandling.nim
@@ -10,8 +10,7 @@
 ## This module contains support code for new-styled error
 ## handling via an `nkError` node kind.

-import ast, renderer, options, types
-import std/strutils
+import ast, renderer, options, strutils, types

 when defined(nimPreviewSlimSystem):
  import std/assertions
@@ -41,8 +40,7 @@ proc newError*(wrongNode: PNode; k: ErrorKind; args: varargs[PNode]): PNode =
  let innerError = errorSubNode(wrongNode)
  if innerError != nil:
    return innerError
-  var idgen = idGeneratorForPackage(-1'i32)
-  result = newNodeIT(nkError, wrongNode.info, newType(tyError, idgen, nil))
+  result = newNodeIT(nkError, wrongNode.info, newType(tyError, ItemId(module: -1, item: -1), nil))
  result.add wrongNode
  result.add newIntNode(nkIntLit, ord(k))
  for a in args: result.add a
@@ -52,8 +50,7 @@ proc newError*(wrongNode: PNode; msg: string): PNode =
  let innerError = errorSubNode(wrongNode)
  if innerError != nil:
    return innerError
-  var idgen = idGeneratorForPackage(-1'i32)
-  result = newNodeIT(nkError, wrongNode.info, newType(tyError, idgen, nil))
+  result = newNodeIT(nkError, wrongNode.info, newType(tyError, ItemId(module: -1, item: -1), nil))
  result.add wrongNode
  result.add newIntNode(nkIntLit, ord(CustomError))
  result.add newStrNode(msg, wrongNode.info)
--- a/compiler/evalffi.nim
+++ b/compiler/evalffi.nim
@@ -9,12 +9,10 @@

 ## This file implements the FFI part of the evaluator for Nim code.

-import ast, types, options, msgs, lineinfos
-from std/os import getAppFilename
+import ast, types, options, tables, dynlib, msgs, lineinfos
+from os import getAppFilename
 import libffi/libffi

-import std/[tables, dynlib]
-
 when defined(windows):
  const libcDll = "msvcrt.dll"
 elif defined(linux):
@@ -99,7 +97,7 @@ proc mapType(conf: ConfigRef, t: ast.PType): ptr libffi.Type =
     tyTyped, tyTypeDesc, tyProc, tyArray, tyStatic, tyNil:
    result = addr libffi.type_pointer
  of tyDistinct, tyAlias, tySink:
-    result = mapType(conf, t.skipModifier)
+    result = mapType(conf, t[0])
  else:
    result = nil
  # too risky:
@@ -126,16 +124,16 @@ proc packSize(conf: ConfigRef, v: PNode, typ: PType): int =
    if v.kind in {nkNilLit, nkPtrLit}:
      result = sizeof(pointer)
    else:
-      result = sizeof(pointer) + packSize(conf, v[0], typ.elementType)
+      result = sizeof(pointer) + packSize(conf, v[0], typ.lastSon)
  of tyDistinct, tyGenericInst, tyAlias, tySink:
-    result = packSize(conf, v, typ.skipModifier)
+    result = packSize(conf, v, typ[0])
  of tyArray:
    # consider: ptr array[0..1000_000, int] which is common for interfacing;
    # we use the real length here instead
    if v.kind in {nkNilLit, nkPtrLit}:
      result = sizeof(pointer)
    elif v.len != 0:
-      result = v.len * packSize(conf, v[0], typ.elementType)
+      result = v.len * packSize(conf, v[0], typ[1])
    else:
      result = 0
  else:
@@ -234,19 +232,19 @@ proc pack(conf: ConfigRef, v: PNode, typ: PType, res: pointer) =
        packRecCheck = 0
        globalError(conf, v.info, "cannot map value to FFI " & typeToString(v.typ))
      inc packRecCheck
-      pack(conf, v[0], typ.elementType, res +! sizeof(pointer))
+      pack(conf, v[0], typ.lastSon, res +! sizeof(pointer))
      dec packRecCheck
      awr(pointer, res +! sizeof(pointer))
  of tyArray:
-    let baseSize = getSize(conf, typ.elementType)
+    let baseSize = getSize(conf, typ[1])
    for i in 0..<v.len:
-      pack(conf, v[i], typ.elementType, res +! i * baseSize)
+      pack(conf, v[i], typ[1], res +! i * baseSize)
  of tyObject, tyTuple:
    packObject(conf, v, typ, res)
  of tyNil:
    discard
  of tyDistinct, tyGenericInst, tyAlias, tySink:
-    pack(conf, v, typ.skipModifier, res)
+    pack(conf, v, typ[0], res)
  else:
    globalError(conf, v.info, "cannot map value to FFI " & typeToString(v.typ))

@@ -304,9 +302,9 @@ proc unpackArray(conf: ConfigRef, x: pointer, typ: PType, n: PNode): PNode =
    result = n
    if result.kind != nkBracket:
      globalError(conf, n.info, "cannot map value from FFI")
-  let baseSize = getSize(conf, typ.elementType)
+  let baseSize = getSize(conf, typ[1])
  for i in 0..<result.len:
-    result[i] = unpack(conf, x +! i * baseSize, typ.elementType, result[i])
+    result[i] = unpack(conf, x +! i * baseSize, typ[1], result[i])

 proc canonNodeKind(k: TNodeKind): TNodeKind =
  case k
@@ -387,7 +385,7 @@ proc unpack(conf: ConfigRef, x: pointer, typ: PType, n: PNode): PNode =
      awi(nkPtrLit, cast[int](p))
    elif n != nil and n.len == 1:
      internalAssert(conf, n.kind == nkRefTy)
-      n[0] = unpack(conf, p, typ.elementType, n[0])
+      n[0] = unpack(conf, p, typ.lastSon, n[0])
      result = n
    else:
      result = nil
@@ -405,7 +403,7 @@ proc unpack(conf: ConfigRef, x: pointer, typ: PType, n: PNode): PNode =
  of tyNil:
    setNil()
  of tyDistinct, tyGenericInst, tyAlias, tySink:
-    result = unpack(conf, x, typ.skipModifier, n)
+    result = unpack(conf, x, typ.lastSon, n)
  else:
    # XXX what to do with 'array' here?
    result = nil
@@ -434,7 +432,7 @@ proc fficast*(conf: ConfigRef, x: PNode, destTyp: PType): PNode =
 proc callForeignFunction*(conf: ConfigRef, call: PNode): PNode =
  internalAssert conf, call[0].kind == nkPtrLit

-  var cif: TCif = default(TCif)
+  var cif: TCif
  var sig: ParamList = default(ParamList)
  # use the arguments' types for varargs support:
  for i in 1..<call.len:
@@ -444,7 +442,7 @@ proc callForeignFunction*(conf: ConfigRef, call: PNode): PNode =

  let typ = call[0].typ
  if prep_cif(cif, mapCallConv(conf, typ.callConv, call.info), cuint(call.len-1),
-              mapType(conf, typ.returnType), sig) != OK:
+              mapType(conf, typ[0]), sig) != OK:
    globalError(conf, call.info, "error in FFI call")

  var args: ArgList = default(ArgList)
@@ -453,15 +451,15 @@ proc callForeignFunction*(conf: ConfigRef, call: PNode): PNode =
    var t = call[i].typ
    args[i-1] = alloc0(packSize(conf, call[i], t))
    pack(conf, call[i], t, args[i-1])
-  let retVal = if isEmptyType(typ.returnType): pointer(nil)
-               else: alloc(getSize(conf, typ.returnType).int)
+  let retVal = if isEmptyType(typ[0]): pointer(nil)
+               else: alloc(getSize(conf, typ[0]).int)

  libffi.call(cif, fn, retVal, args)

  if retVal.isNil:
    result = newNode(nkEmpty)
  else:
-    result = unpack(conf, retVal, typ.returnType, nil)
+    result = unpack(conf, retVal, typ[0], nil)
    result.info = call.info

  if retVal != nil: dealloc retVal
@@ -474,7 +472,7 @@ proc callForeignFunction*(conf: ConfigRef, fn: PNode, fntyp: PType,
                          info: TLineInfo): PNode =
  internalAssert conf, fn.kind == nkPtrLit

-  var cif: TCif = default(TCif)
+  var cif: TCif
  var sig: ParamList = default(ParamList)
  for i in 0..len-1:
    var aTyp = args[i+start].typ
--- a/compiler/evaltempl.nim
+++ b/compiler/evaltempl.nim
@@ -9,16 +9,16 @@

 ## Template evaluation engine. Now hygienic.

-import options, ast, astalgo, msgs, renderer, lineinfos, idents, trees
-import std/strutils
+import
+  strutils, options, ast, astalgo, msgs, renderer, lineinfos, idents, trees

 type
  TemplCtx = object
    owner, genSymOwner: PSym
    instLines: bool   # use the instantiation lines numbers
    isDeclarative: bool
-    mapping: SymMapping # every gensym'ed symbol needs to be mapped to some
-                        # new symbol
+    mapping: TIdTable # every gensym'ed symbol needs to be mapped to some
+                      # new symbol
    config: ConfigRef
    ic: IdentCache
    instID: int
@@ -33,19 +33,6 @@ proc evalTemplateAux(templ, actual: PNode, c: var TemplCtx, result: PNode) =
    let x = param
    if x.kind == nkArgList:
      for y in items(x): result.add(y)
-    elif nfDefaultRefsParam in x.flags:
-      # value of default param needs to be evaluated like template body
-      # if it contains other template params
-      var res: PNode
-      if isAtom(x):
-        res = newNodeI(nkPar, x.info)
-        evalTemplateAux(x, actual, c, res)
-        if res.len == 1: res = res[0]
-      else:
-        res = copyNode(x)
-        for i in 0..<x.safeLen:
-          evalTemplateAux(x[i], actual, c, res)
-      result.add res
    else:
      result.add copyTree(x)

@@ -57,19 +44,18 @@ proc evalTemplateAux(templ, actual: PNode, c: var TemplCtx, result: PNode) =
        handleParam actual[s.position]
      elif (s.owner != nil) and (s.kind == skGenericParam or
           s.kind == skType and s.typ != nil and s.typ.kind == tyGenericParam):
-        handleParam actual[s.owner.typ.signatureLen + s.position - 1]
+        handleParam actual[s.owner.typ.len + s.position - 1]
      else:
        internalAssert c.config, sfGenSym in s.flags or s.kind == skType
-        var x = idTableGet(c.mapping, s)
+        var x = PSym(idTableGet(c.mapping, s))
        if x == nil:
          x = copySym(s, c.idgen)
          # sem'check needs to set the owner properly later, see bug #9476
-          setOwner(x, nil) # c.genSymOwner
+          x.owner = nil # c.genSymOwner
          #if x.kind == skParam and x.owner.kind == skModule:
          #  internalAssert c.config, false
          idTablePut(c.mapping, s, x)
        if sfGenSym in s.flags:
-          # TODO: getIdent(c.ic, "`" & x.name.s & "`gensym" & $c.instID)
          result.add newIdentNode(getIdent(c.ic, x.name.s & "`gensym" & $c.instID),
            if c.instLines: actual.info else: templ.info)
        else:
@@ -130,7 +116,7 @@ proc evalTemplateArgs(n: PNode, s: PSym; conf: ConfigRef; fromHlo: bool): PNode
    # now that we have working untyped parameters.
    genericParams = if fromHlo: 0
                    else: s.ast[genericParamsPos].len
-    expectedRegularParams = s.typ.paramsLen
+    expectedRegularParams = s.typ.len-1
    givenRegularParams = totalParams - genericParams
  if givenRegularParams < 0: givenRegularParams = 0

@@ -196,14 +182,14 @@ proc evalTemplate*(n: PNode, tmpl, genSymOwner: PSym;

  # replace each param by the corresponding node:
  var args = evalTemplateArgs(n, tmpl, conf, fromHlo)
-  var ctx = TemplCtx(owner: tmpl,
-    genSymOwner: genSymOwner,
-    config: conf,
-    ic: ic,
-    mapping: initSymMapping(),
-    instID: instID[],
-    idgen: idgen
-  )
+  var ctx: TemplCtx
+  ctx.owner = tmpl
+  ctx.genSymOwner = genSymOwner
+  ctx.config = conf
+  ctx.ic = ic
+  ctx.mapping = initIdTable()
+  ctx.instID = instID[]
+  ctx.idgen = idgen

  let body = tmpl.ast[bodyPos]
  #echo "instantion of ", renderTree(body, {renderIds})
--- a/compiler/expanddefaults.nim
+++ b/compiler/expanddefaults.nim
@@ -1,131 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2023 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-import lineinfos, ast, types
-
-proc caseObjDefaultBranch*(obj: PNode; branch: Int128): int =
-  result = 0
-  for i in 1 ..< obj.len:
-    for j in 0 .. obj[i].len - 2:
-      if obj[i][j].kind == nkRange:
-        let x = getOrdValue(obj[i][j][0])
-        let y = getOrdValue(obj[i][j][1])
-        if branch >= x and branch <= y:
-          return i
-      elif getOrdValue(obj[i][j]) == branch:
-        return i
-    if obj[i].len == 1:
-      # else branch
-      return i
-  return 1
-
-template newZero(t: PType; info: TLineInfo; k = nkIntLit): PNode = newNodeIT(k, info, t)
-
-proc expandDefault*(t: PType; info: TLineInfo): PNode
-
-proc expandField(s: PSym; info: TLineInfo): PNode =
-  result = newNodeIT(nkExprColonExpr, info, s.typ)
-  result.add newSymNode(s)
-  result.add expandDefault(s.typ, info)
-
-proc expandDefaultN(n: PNode; info: TLineInfo; res: PNode) =
-  case n.kind
-  of nkRecList:
-    for i in 0..<n.len:
-      expandDefaultN(n[i], info, res)
-  of nkRecCase:
-    res.add expandField(n[0].sym, info)
-    var branch = Zero
-    let constOrNil = n[0].sym.astdef
-    if constOrNil != nil:
-      branch = getOrdValue(constOrNil)
-
-    let selectedBranch = caseObjDefaultBranch(n, branch)
-    let b = lastSon(n[selectedBranch])
-    expandDefaultN b, info, res
-  of nkSym:
-    res.add expandField(n.sym, info)
-  else:
-    discard
-
-proc expandDefaultObj(t: PType; info: TLineInfo; res: PNode) =
-  if t.baseClass != nil:
-    expandDefaultObj(t.baseClass, info, res)
-  expandDefaultN(t.n, info, res)
-
-proc expandDefault(t: PType; info: TLineInfo): PNode =
-  case t.kind
-  of tyInt:     result = newZero(t, info, nkIntLit)
-  of tyInt8:    result = newZero(t, info, nkInt8Lit)
-  of tyInt16:   result = newZero(t, info, nkInt16Lit)
-  of tyInt32:   result = newZero(t, info, nkInt32Lit)
-  of tyInt64:   result = newZero(t, info, nkInt64Lit)
-  of tyUInt:    result = newZero(t, info, nkUIntLit)
-  of tyUInt8:   result = newZero(t, info, nkUInt8Lit)
-  of tyUInt16:  result = newZero(t, info, nkUInt16Lit)
-  of tyUInt32:  result = newZero(t, info, nkUInt32Lit)
-  of tyUInt64:  result = newZero(t, info, nkUInt64Lit)
-  of tyFloat:   result = newZero(t, info, nkFloatLit)
-  of tyFloat32: result = newZero(t, info, nkFloat32Lit)
-  of tyFloat64: result = newZero(t, info, nkFloat64Lit)
-  of tyFloat128: result = newZero(t, info, nkFloat64Lit)
-  of tyChar:    result = newZero(t, info, nkCharLit)
-  of tyBool:    result = newZero(t, info, nkIntLit)
-  of tyEnum:
-    # Could use low(T) here to finally fix old language quirks
-    result = newZero(t, info, nkIntLit)
-  of tyRange:
-    # Could use low(T) here to finally fix old language quirks
-    result = expandDefault(skipModifier t, info)
-  of tyVoid: result = newZero(t, info, nkEmpty)
-  of tySink, tyGenericInst, tyDistinct, tyAlias, tyOwned:
-    result = expandDefault(t.skipModifier, info)
-  of tyOrdinal, tyGenericBody, tyGenericParam, tyInferred, tyStatic:
-    if t.hasElementType:
-      result = expandDefault(t.skipModifier, info)
-    else:
-      result = newZero(t, info, nkEmpty)
-  of tyFromExpr:
-    if t.n != nil and t.n.typ != nil:
-      result = expandDefault(t.n.typ, info)
-    else:
-      result = newZero(t, info, nkEmpty)
-  of tyArray:
-    result = newZero(t, info, nkBracket)
-    let n = toInt64(lengthOrd(nil, t))
-    for i in 0..<n:
-      result.add expandDefault(t.elementType, info)
-  of tyPtr, tyRef, tyProc, tyPointer, tyCstring:
-    result = newZero(t, info, nkNilLit)
-  of tyVar, tyLent:
-    let e = t.elementType
-    if e.skipTypes(abstractInst).kind in {tyOpenArray, tyVarargs}:
-      # skip the modifier, `var openArray` is a (ptr, len) pair too:
-      result = expandDefault(e, info)
-    else:
-      result = newZero(e, info, nkNilLit)
-  of tySet:
-    result = newZero(t, info, nkCurly)
-  of tyObject:
-    result = newNodeIT(nkObjConstr, info, t)
-    result.add newNodeIT(nkType, info, t)
-    expandDefaultObj(t, info, result)
-  of tyTuple:
-    result = newZero(t, info, nkTupleConstr)
-    for it in t.kids:
-      result.add expandDefault(it, info)
-  of tyVarargs, tyOpenArray, tySequence, tyUncheckedArray:
-    result = newZero(t, info, nkBracket)
-  of tyString:
-    result = newZero(t, info, nkStrLit)
-  of tyNone, tyEmpty, tyUntyped, tyTyped, tyTypeDesc,
-     tyNil, tyGenericInvocation, tyError, tyBuiltInTypeClass,
-     tyUserTypeClass, tyUserTypeClassInst, tyCompositeTypeClass,
-     tyAnd, tyOr, tyNot, tyAnything, tyConcept, tyIterable, tyForward:
-    result = newZero(t, info, nkEmpty) # bug indicator
--- a/compiler/extccomp.nim
+++ b/compiler/extccomp.nim
@@ -19,7 +19,7 @@ import std/[os, osproc, streams, sequtils, times, strtabs, json, jsonutils, suga
 import std / strutils except addf

 when defined(nimPreviewSlimSystem):
-  import std/[syncio, assertions]
+  import std/syncio

 import ../dist/checksums/src/checksums/sha1

@@ -33,7 +33,6 @@ type
    hasGnuAsm,                # CC's asm uses the absurd GNU assembler syntax
    hasDeclspec,              # CC has __declspec(X)
    hasAttribute,             # CC has __attribute__((X))
-    hasBuiltinUnreachable     # CC has __builtin_unreachable
  TInfoCCProps* = set[TInfoCCProp]
  TInfoCC* = tuple[
    name: string,        # the short name of the compiler
@@ -63,7 +62,7 @@ type

 # Configuration settings for various compilers.
 # When adding new compilers, the cmake sources could be a good reference:
-# https://cmake.org/gitweb?p=cmake.git;a=tree;f=Modules/Platform;
+# http://cmake.org/gitweb?p=cmake.git;a=tree;f=Modules/Platform;

 template compiler(name, settings: untyped): untyped =
  proc name: TInfoCC {.compileTime.} = settings
@@ -96,7 +95,7 @@ compiler gcc:
    produceAsm: gnuAsmListing,
    cppXsupport: "-std=gnu++17 -funsigned-char",
    props: {hasSwitchRange, hasComputedGoto, hasCpp, hasGcGuard, hasGnuAsm,
-            hasAttribute, hasBuiltinUnreachable})
+            hasAttribute})

 # GNU C and C++ Compiler
 compiler nintendoSwitchGCC:
@@ -123,7 +122,7 @@ compiler nintendoSwitchGCC:
    produceAsm: gnuAsmListing,
    cppXsupport: "-std=gnu++17 -funsigned-char",
    props: {hasSwitchRange, hasComputedGoto, hasCpp, hasGcGuard, hasGnuAsm,
-            hasAttribute, hasBuiltinUnreachable})
+            hasAttribute})

 # LLVM Frontend for GCC/G++
 compiler llvmGcc:
@@ -162,11 +161,7 @@ compiler vcc:
    linkerExe: "cl",
    linkTmpl: "$builddll$vccplatform /Fe$exefile $objfiles $buildgui /nologo $options",
    includeCmd: " /I",
-    # HACK: we call `cl` so we have to pass `/link` for linker options,
-    # but users may still want to pass arguments to `cl` (see #14221)
-    # to deal with this, we add `/link` before each `/LIBPATH`,
-    # the linker ignores extra `/link`s since it's an unrecognized argument
-    linkDirCmd: " /link /LIBPATH:",
+    linkDirCmd: " /LIBPATH:",
    linkLibCmd: " $1.lib",
    debug: " /RTC1 /Z7 ",
    pic: "",
@@ -176,22 +171,6 @@ compiler vcc:
    cppXsupport: "",
    props: {hasCpp, hasAssume, hasDeclspec})

-# Nvidia CUDA NVCC Compiler
-compiler nvcc:
-  result = gcc()
-  result.name = "nvcc"
-  result.compilerExe = "nvcc"
-  result.cppCompiler = "nvcc"
-  result.compileTmpl = "-c -x cu -Xcompiler=\"$options\" $include -o $objfile $file"
-  result.linkTmpl = "$buildgui $builddll -o $exefile $objfiles -Xcompiler=\"$options\""
-
-# AMD HIPCC Compiler (rocm/cuda)
-compiler hipcc:
-  result = clang()
-  result.name = "hipcc"
-  result.compilerExe = "hipcc"
-  result.cppCompiler = "hipcc"
-
 compiler clangcl:
  result = vcc()
  result.name = "clang_cl"
@@ -257,8 +236,8 @@ compiler tcc:
    linkerExe: "tcc",
    linkTmpl: "-o $exefile $options $buildgui $builddll $objfiles",
    includeCmd: " -I",
-    linkDirCmd: " -L",
-    linkLibCmd: " -l$1",
+    linkDirCmd: "", # XXX: not supported yet
+    linkLibCmd: "", # XXX: not supported yet
    debug: " -g ",
    pic: "",
    asmStmtFrmt: "asm($1);$n",
@@ -305,9 +284,7 @@ const
    envcc(),
    icl(),
    icc(),
-    clangcl(),
-    hipcc(),
-    nvcc()]
+    clangcl()]

  hExt* = ".h"

@@ -341,7 +318,7 @@ proc getConfigVar(conf: ConfigRef; c: TSystemCC, suffix: string): string =
  var fullSuffix = suffix
  case conf.backend
  of backendCpp, backendJs, backendObjc: fullSuffix = "." & $conf.backend & suffix
-  of backendC, backendNif: discard
+  of backendC: discard
  of backendInvalid:
    # during parsing of cfg files; we don't know the backend yet, no point in
    # guessing wrong thing
@@ -474,11 +451,6 @@ proc noAbsolutePaths(conf: ConfigRef): bool {.inline.} =
 proc cFileSpecificOptions(conf: ConfigRef; nimname, fullNimFile: string): string =
  result = conf.compileOptions

-  if (conf.cCompiler == ccGcc or conf.cCompiler == ccCLang) and
-       conf.selectedGC == gcRefc:
-    # bug #10625
-    addOpt(result, "-fno-omit-frame-pointer")
-
  for option in conf.compileOptionsCmd:
    if strutils.find(result, option, 0) < 0:
      addOpt(result, option)
@@ -786,7 +758,7 @@ proc getLinkCmd(conf: ConfigRef; output: AbsoluteFile,
    # https://blog.molecular-matters.com/2017/05/09/deleting-pdb-files-locked-by-visual-studio/
    # and a bit about the .pdb format in case that is ever needed:
    # https://github.com/crosire/blink
-    # https://www.debuginfo.com/articles/debuginfomatch.html#pdbfiles
+    # http://www.debuginfo.com/articles/debuginfomatch.html#pdbfiles
    if conf.hcrOn and isVSCompatible(conf):
      let t = now()
      let pdb = output.string & "." & format(t, "MMMM-yyyy-HH-mm-") & $t.nanosecond & ".pdb"
@@ -810,59 +782,6 @@ template tryExceptOSErrorMessage(conf: ConfigRef; errorPrefix: string = "", body
        (ose.msg & " " & $ose.errorCode))
    raise

-proc createMacAppBundle(conf: ConfigRef; exefile: AbsoluteFile) =
-  let (dir, name, _) = splitFile(exefile.string)
-  let appBundleName = name & ".app"
-  let appBundlePath = dir / appBundleName
-  let contentsPath = appBundlePath / "Contents"
-  let macosPath = contentsPath / "MacOS"
-
-  createDir(macosPath)
-
-  let bundleExePath = macosPath / name
-  copyFileWithPermissions(exefile.string, bundleExePath)
-
-  let infoPlistPath = contentsPath / "Info.plist"
-
-  proc xmlEscape(s: string): string =
-    result = newStringOfCap(s.len)
-    for c in items(s):
-      case c:
-      of '<': result.add("&lt;")
-      of '>': result.add("&gt;")
-      of '&': result.add("&amp;")
-      of '"': result.add("&quot;")
-      of '\'': result.add("&apos;")
-      else:
-        if ord(c) < 32:
-          result.add("&#" & $ord(c) & ';')
-        else:
-          result.add(c)
-
-  let escapedName = xmlEscape(name)
-  let infoPlistContent = """<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
-<plist version="1.0">
-<dict>
-  <key>CFBundleExecutable</key>
-  <string>$1</string>
-  <key>CFBundleIdentifier</key>
-  <string>com.nim.$1</string>
-  <key>CFBundleName</key>
-  <string>$1</string>
-  <key>CFBundlePackageType</key>
-  <string>APPL</string>
-  <key>LSUIElement</key>
-  <string>1</string>
-</dict>
-</plist>""" % [escapedName]
-
-  writeFile(infoPlistPath, infoPlistContent)
-
-  removeFile(exefile.string)
-
-  rawMessage(conf, hintUserRaw, "Created Mac app bundle: " & appBundlePath)
-
 proc getExtraCmds(conf: ConfigRef; output: AbsoluteFile): seq[string] =
  result = @[]
  when defined(macosx):
@@ -1047,10 +966,6 @@ proc callCCompiler*(conf: ConfigRef) =
        preventLinkCmdMaxCmdLen(conf, linkCmd)
        for cmd in extraCmds:
          execExternalProgram(conf, cmd, hintExecuting)
-        # create Mac app bundle for GUI apps on macOS
-        when defined(macosx):
-          if conf.globalOptions * {optGenGuiApp, optGenDynLib, optGenStaticLib} == {optGenGuiApp}:
-            createMacAppBundle(conf, mainOutput)
  else:
    linkCmd = ""
  if optGenScript in conf.globalOptions:
@@ -1066,11 +981,10 @@ proc jsonBuildInstructionsFile*(conf: ConfigRef): AbsoluteFile =
  # works out of the box with `hashMainCompilationParams`.
  result = getNimcacheDir(conf) / conf.outFile.changeFileExt("json")

-const cacheVersion = "D20240927T193831" # update when `BuildCache` spec changes
+const cacheVersion = "D20210525T193831" # update when `BuildCache` spec changes
 type BuildCache = object
  cacheVersion: string
  outputFile: string
-  outputLastModificationTime: string
  compile: seq[(string, string)]
  link: seq[string]
  linkcmd: string
@@ -1084,7 +998,7 @@ type BuildCache = object
  depfiles: seq[(string, string)]
  nimexe: string

-proc writeJsonBuildInstructions*(conf: ConfigRef; deps: StringTableRef) =
+proc writeJsonBuildInstructions*(conf: ConfigRef) =
  var linkFiles = collect(for it in conf.externalToLink:
    var it = it
    if conf.noAbsolutePaths: it = it.extractFilename
@@ -1105,17 +1019,11 @@ proc writeJsonBuildInstructions*(conf: ConfigRef; deps: StringTableRef) =
    currentDir: getCurrentDir())
  if optRun in conf.globalOptions or isDefined(conf, "nimBetterRun"):
    bcache.cmdline = conf.commandLine
-    for it in conf.m.fileInfos:
+    bcache.depfiles = collect(for it in conf.m.fileInfos:
      let path = it.fullPath.string
      if isAbsolute(path): # TODO: else?
-        if path in deps:
-          bcache.depfiles.add (path, deps[path])
-        else: # backup for configs etc.
-          bcache.depfiles.add (path, $secureHashFile(path))
-
+        (path, $secureHashFile(path)))
    bcache.nimexe = hashNimExe()
-    if fileExists(bcache.outputFile):
-      bcache.outputLastModificationTime = $getLastModificationTime(bcache.outputFile)
  conf.jsonBuildFile = conf.jsonBuildInstructionsFile
  conf.jsonBuildFile.string.writeFile(bcache.toJson.pretty)

@@ -1136,8 +1044,6 @@ proc changeDetectedViaJsonBuildInstructions*(conf: ConfigRef; jsonFile: Absolute
    # xxx optimize by returning false if stdin input was the same
  for (file, hash) in bcache.depfiles:
    if $secureHashFile(file) != hash: return true
-  if bcache.outputLastModificationTime != $getLastModificationTime(bcache.outputFile):
-    return true

 proc runJsonBuildInstructions*(conf: ConfigRef; jsonFile: AbsoluteFile) =
  var bcache: BuildCache = default(BuildCache)
@@ -1154,7 +1060,7 @@ proc runJsonBuildInstructions*(conf: ConfigRef; jsonFile: AbsoluteFile) =
      "jsonscript command outputFile '$1' must match '$2' which was specified during --compileOnly, see \"outputFile\" entry in '$3' " %
      [outputCurrent, output, jsonFile.string])
  var cmds: TStringSeq = default(TStringSeq)
-  var prettyCmds: TStringSeq = default(TStringSeq)
+  var prettyCmds: TStringSeq= default(TStringSeq)
  let prettyCb = proc (idx: int) = writePrettyCmdsStderr(prettyCmds[idx])
  for (name, cmd) in bcache.compile:
    cmds.add cmd
--- a/compiler/filter_tmpl.nim
+++ b/compiler/filter_tmpl.nim
@@ -10,11 +10,9 @@
 # This module implements Nim's standard template filter.

 import
-  llstream, ast, msgs, options,
+  llstream, strutils, ast, msgs, options,
  filters, lineinfos, pathutils

-import std/strutils
-
 type
  TParseState = enum
    psDirective, psTempl
--- a/compiler/filters.nim
+++ b/compiler/filters.nim
@@ -10,11 +10,9 @@
 # This module implements Nim's simple filters and helpers for filters.

 import
-  llstream, idents, ast, msgs, options,
+  llstream, idents, strutils, ast, msgs, options,
  renderer, pathutils

-import std/strutils
-
 proc invalidPragma(conf: ConfigRef; n: PNode) =
  localError(conf, n.info,
      "'$1' not allowed here" % renderTree(n, {renderNoComments}))
--- a/compiler/gorgeimpl.nim
+++ b/compiler/gorgeimpl.nim
@@ -9,9 +9,8 @@

 ## Module that implements ``gorge`` for the compiler.

-import msgs, options, lineinfos, pathutils
-
-import std/[os, osproc, streams]
+import msgs, os, osproc, streams, options,
+  lineinfos, pathutils

 when defined(nimPreviewSlimSystem):
  import std/syncio
--- a/compiler/guards.nim
+++ b/compiler/guards.nim
@@ -46,7 +46,7 @@ proc isLocation(n: PNode): bool = not n.isValue

 proc isLet(n: PNode): bool =
  if n.kind == nkSym:
-    if n.sym.kind in {skLet, skConst, skTemp, skForVar}: # guard immutable variables
+    if n.sym.kind in {skLet, skTemp, skForVar}:
      result = true
    elif n.sym.kind == skParam and skipTypes(n.sym.typ,
                                             abstractInst).kind notin {tyVar}:
@@ -870,7 +870,7 @@ template isSub(x): untyped = x.getMagic in someSub
 template isVal(x): untyped = x.kind in {nkCharLit..nkUInt64Lit}
 template isIntVal(x, y): untyped = x.intVal == y

-import std/macros
+import macros

 macro `=~`(x: PNode, pat: untyped): bool =
  proc m(x, pat, conds: NimNode) =
@@ -1063,7 +1063,7 @@ proc pleViaModel(model: TModel; aa, bb: PNode): TImplication =
      let b = fact[2]
      if a.kind == nkSym: replacements.add((a,b))
      else: replacements.add((b,a))
-  var m = TModel()
+  var m: TModel
  var a = aa
  var b = bb
  if replacements.len > 0:
@@ -1098,8 +1098,8 @@ proc addFactLt*(m: var TModel; a, b: PNode) =
  addFactLe(m, a, bb)

 proc settype(n: PNode): PType =
-  var idgen = idGeneratorForPackage(-1'i32)
-  result = newType(tySet, idgen, n.typ.owner)
+  result = newType(tySet, ItemId(module: -1, item: -1), n.typ.owner)
+  var idgen: IdGenerator = nil
  addSonSkipIntLit(result, n.typ, idgen)

 proc buildOf(it, loc: PNode; o: Operators): PNode =
@@ -1165,12 +1165,8 @@ proc buildProperFieldCheck(access, check: PNode; o: Operators): PNode =
  if check[1].kind == nkCurly:
    result = copyTree(check)
    if access.kind == nkDotExpr:
-      # change the access to the discriminator field access
      var a = copyTree(access)
-      # set field name to discriminator field name
      a[1] = check[2]
-      # set discriminator field type: important for `neg`
-      a.typ = check[2].typ
      result[2] = a
      # 'access.kind != nkDotExpr' can happen for object constructors
      # which we don't check yet
--- a/compiler/hlo.nim
+++ b/compiler/hlo.nim
@@ -10,7 +10,7 @@
 # This include implements the high level optimization pass.
 # included from sem.nim

-proc hlo(c: PContext, n: PNode, loopDetector: int): PNode
+proc hlo(c: PContext, n: PNode): PNode

 proc evalPattern(c: PContext, n, orig: PNode): PNode =
  internalAssert c.config, n.kind == nkCall and n[0].kind == nkSym
@@ -61,11 +61,10 @@ proc applyPatterns(c: PContext, n: PNode): PNode =
        # activate this pattern again:
        c.patterns[i] = pattern

-proc hlo(c: PContext, n: PNode, loopDetector: int): PNode =
+proc hlo(c: PContext, n: PNode): PNode =
+  inc(c.hloLoopDetector)
  # simply stop and do not perform any further transformations:
-  if loopDetector > 300:
-    message(c.config, n.info, warnUser, "term rewrite macro instantiation too nested")
-    return n
+  if c.hloLoopDetector > 300: return n
  case n.kind
  of nkMacroDef, nkTemplateDef, procDefs:
    # already processed (special cases in semstmts.nim)
@@ -81,7 +80,7 @@ proc hlo(c: PContext, n: PNode, loopDetector: int): PNode =
      # no optimization applied, try subtrees:
      for i in 0..<result.safeLen:
        let a = result[i]
-        let h = hlo(c, a, loopDetector)
+        let h = hlo(c, a)
        if h != a: result[i] = h
    else:
      # perform type checking, so that the replacement still fits:
@@ -91,15 +90,17 @@ proc hlo(c: PContext, n: PNode, loopDetector: int): PNode =
        result = fitNode(c, n.typ, result, n.info)
      # optimization has been applied so check again:
      result = commonOptimizations(c.graph, c.idgen, c.module, result)
-      result = hlo(c, result, loopDetector + 1)
+      result = hlo(c, result)
      result = commonOptimizations(c.graph, c.idgen, c.module, result)

 proc hloBody(c: PContext, n: PNode): PNode =
  # fast exit:
  if c.patterns.len == 0 or optTrMacros notin c.config.options: return n
-  result = hlo(c, n, 0)
+  c.hloLoopDetector = 0
+  result = hlo(c, n)

 proc hloStmt(c: PContext, n: PNode): PNode =
  # fast exit:
  if c.patterns.len == 0 or optTrMacros notin c.config.options: return n
-  result = hlo(c, n, 0)
+  c.hloLoopDetector = 0
+  result = hlo(c, n)
--- a/compiler/ic/bitabs.nim
+++ b/compiler/ic/bitabs.nim
@@ -0,0 +1,173 @@
+## A BiTable is a table that can be seen as an optimized pair
+## of `(Table[LitId, Val], Table[Val, LitId])`.
+
+import hashes, rodfiles
+
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
+type
+  LitId* = distinct uint32
+
+  BiTable*[T] = object
+    vals: seq[T] # indexed by LitId
+    keys: seq[LitId]  # indexed by hash(val)
+
+proc initBiTable*[T](): BiTable[T] = BiTable[T](vals: @[], keys: @[])
+
+proc nextTry(h, maxHash: Hash): Hash {.inline.} =
+  result = (h + 1) and maxHash
+
+template maxHash(t): untyped = high(t.keys)
+template isFilled(x: LitId): bool = x.uint32 > 0'u32
+
+proc `$`*(x: LitId): string {.borrow.}
+proc `<`*(x, y: LitId): bool {.borrow.}
+proc `<=`*(x, y: LitId): bool {.borrow.}
+proc `==`*(x, y: LitId): bool {.borrow.}
+proc hash*(x: LitId): Hash {.borrow.}
+
+
+proc len*[T](t: BiTable[T]): int = t.vals.len
+
+proc mustRehash(length, counter: int): bool {.inline.} =
+  assert(length > counter)
+  result = (length * 2 < counter * 3) or (length - counter < 4)
+
+const
+  idStart = 256 ##
+  ## Ids do not start with 0 but with this value. The IR needs it.
+  ## TODO: explain why
+
+template idToIdx(x: LitId): int = x.int - idStart
+
+proc hasLitId*[T](t: BiTable[T]; x: LitId): bool =
+  let idx = idToIdx(x)
+  result = idx >= 0 and idx < t.vals.len
+
+proc enlarge[T](t: var BiTable[T]) =
+  var n: seq[LitId]
+  newSeq(n, len(t.keys) * 2)
+  swap(t.keys, n)
+  for i in 0..high(n):
+    let eh = n[i]
+    if isFilled(eh):
+      var j = hash(t.vals[idToIdx eh]) and maxHash(t)
+      while isFilled(t.keys[j]):
+        j = nextTry(j, maxHash(t))
+      t.keys[j] = move n[i]
+
+proc getKeyId*[T](t: BiTable[T]; v: T): LitId =
+  let origH = hash(v)
+  var h = origH and maxHash(t)
+  if t.keys.len != 0:
+    while true:
+      let litId = t.keys[h]
+      if not isFilled(litId): break
+      if t.vals[idToIdx t.keys[h]] == v: return litId
+      h = nextTry(h, maxHash(t))
+  return LitId(0)
+
+proc getOrIncl*[T](t: var BiTable[T]; v: T): LitId =
+  let origH = hash(v)
+  var h = origH and maxHash(t)
+  if t.keys.len != 0:
+    while true:
+      let litId = t.keys[h]
+      if not isFilled(litId): break
+      if t.vals[idToIdx t.keys[h]] == v: return litId
+      h = nextTry(h, maxHash(t))
+    # not found, we need to insert it:
+    if mustRehash(t.keys.len, t.vals.len):
+      enlarge(t)
+      # recompute where to insert:
+      h = origH and maxHash(t)
+      while true:
+        let litId = t.keys[h]
+        if not isFilled(litId): break
+        h = nextTry(h, maxHash(t))
+  else:
+    setLen(t.keys, 16)
+    h = origH and maxHash(t)
+
+  result = LitId(t.vals.len + idStart)
+  t.keys[h] = result
+  t.vals.add v
+
+
+proc `[]`*[T](t: var BiTable[T]; litId: LitId): var T {.inline.} =
+  let idx = idToIdx litId
+  assert idx < t.vals.len
+  result = t.vals[idx]
+
+proc `[]`*[T](t: BiTable[T]; litId: LitId): lent T {.inline.} =
+  let idx = idToIdx litId
+  assert idx < t.vals.len
+  result = t.vals[idx]
+
+proc hash*[T](t: BiTable[T]): Hash =
+  ## as the keys are hashes of the values, we simply use them instead
+  var h: Hash = 0
+  for i, n in pairs t.keys:
+    h = h !& hash((i, n))
+  result = !$h
+
+proc store*[T](f: var RodFile; t: BiTable[T]) =
+  storeSeq(f, t.vals)
+  storeSeq(f, t.keys)
+
+proc load*[T](f: var RodFile; t: var BiTable[T]) =
+  loadSeq(f, t.vals)
+  loadSeq(f, t.keys)
+
+when isMainModule:
+
+  var t: BiTable[string]
+
+  echo getOrIncl(t, "hello")
+
+  echo getOrIncl(t, "hello")
+  echo getOrIncl(t, "hello3")
+  echo getOrIncl(t, "hello4")
+  echo getOrIncl(t, "helloasfasdfdsa")
+  echo getOrIncl(t, "hello")
+  echo getKeyId(t, "hello")
+  echo getKeyId(t, "none")
+
+  for i in 0 ..< 100_000:
+    discard t.getOrIncl($i & "___" & $i)
+
+  for i in 0 ..< 100_000:
+    assert t.getOrIncl($i & "___" & $i).idToIdx == i + 4
+  echo "begin"
+  echo t.vals.len
+
+  echo t.vals[0]
+  echo t.vals[1004]
+
+  echo "middle"
+
+  var tf: BiTable[float]
+
+  discard tf.getOrIncl(0.4)
+  discard tf.getOrIncl(16.4)
+  discard tf.getOrIncl(32.4)
+  echo getKeyId(tf, 32.4)
+
+  var f2 = open("testblah.bin", fmWrite)
+  echo store(f2, tf)
+  f2.close
+
+  var f1 = open("testblah.bin", fmRead)
+
+  var t2: BiTable[float]
+
+  echo f1.load(t2)
+  echo t2.vals.len
+
+  echo getKeyId(t2, 32.4)
+
+  echo "end"
+
+
+  f1.close
--- a/compiler/ic/cbackend.nim
+++ b/compiler/ic/cbackend.nim
@@ -0,0 +1,181 @@
+#
+#
+#           The Nim Compiler
+#        (c) Copyright 2021 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## New entry point into our C/C++ code generator. Ideally
+## somebody would rewrite the old backend (which is 8000 lines of crufty Nim code)
+## to work on packed trees directly and produce the C code as an AST which can
+## then be rendered to text in a very simple manner. Unfortunately nobody wrote
+## this code. So instead we wrap the existing cgen.nim and its friends so that
+## we call directly into the existing code generation logic but avoiding the
+## naive, outdated `passes` design. Thus you will see some
+## `useAliveDataFromDce in flags` checks in the old code -- the old code is
+## also doing cross-module dependency tracking and DCE that we don't need
+## anymore. DCE is now done as prepass over the entire packed module graph.
+
+import std/packedsets, algorithm, tables
+
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
+import ".."/[ast, options, lineinfos, modulegraphs, cgendata, cgen,
+  pathutils, extccomp, msgs, modulepaths]
+
+import packed_ast, ic, dce, rodfiles
+
+proc unpackTree(g: ModuleGraph; thisModule: int;
+                tree: PackedTree; n: NodePos): PNode =
+  var decoder = initPackedDecoder(g.config, g.cache)
+  result = loadNodes(decoder, g.packed, thisModule, tree, n)
+
+proc setupBackendModule(g: ModuleGraph; m: var LoadedModule) =
+  if g.backend == nil:
+    g.backend = cgendata.newModuleList(g)
+  assert g.backend != nil
+  var bmod = cgen.newModule(BModuleList(g.backend), m.module, g.config)
+  bmod.idgen = idgenFromLoadedModule(m)
+
+proc generateCodeForModule(g: ModuleGraph; m: var LoadedModule; alive: var AliveSyms) =
+  var bmod = BModuleList(g.backend).modules[m.module.position]
+  assert bmod != nil
+  bmod.flags.incl useAliveDataFromDce
+  bmod.alive = move alive[m.module.position]
+
+  for p in allNodes(m.fromDisk.topLevel):
+    let n = unpackTree(g, m.module.position, m.fromDisk.topLevel, p)
+    cgen.genTopLevelStmt(bmod, n)
+
+  let disps = finalCodegenActions(g, bmod, newNodeI(nkStmtList, m.module.info))
+  if disps != nil:
+    for disp in disps:
+      genProcAux(bmod, disp.sym)
+  m.fromDisk.backendFlags = cgen.whichInitProcs(bmod)
+
+proc replayTypeInfo(g: ModuleGraph; m: var LoadedModule; origin: FileIndex) =
+  for x in mitems(m.fromDisk.emittedTypeInfo):
+    #echo "found type ", x, " for file ", int(origin)
+    g.emittedTypeInfo[x] = origin
+
+proc addFileToLink(config: ConfigRef; m: PSym) =
+  let filename = AbsoluteFile toFullPath(config, m.position.FileIndex)
+  let ext =
+      if config.backend == backendCpp: ".nim.cpp"
+      elif config.backend == backendObjc: ".nim.m"
+      else: ".nim.c"
+  let cfile = changeFileExt(completeCfilePath(config,
+                            mangleModuleName(config, filename).AbsoluteFile), ext)
+  let objFile = completeCfilePath(config, toObjFile(config, cfile))
+  if fileExists(objFile):
+    var cf = Cfile(nimname: m.name.s, cname: cfile,
+                   obj: objFile,
+                   flags: {CfileFlag.Cached})
+    addFileToCompile(config, cf)
+
+when defined(debugDce):
+  import os, std/packedsets
+
+proc storeAliveSymsImpl(asymFile: AbsoluteFile; s: seq[int32]) =
+  var f = rodfiles.create(asymFile.string)
+  f.storeHeader()
+  f.storeSection aliveSymsSection
+  f.storeSeq(s)
+  close f
+
+template prepare {.dirty.} =
+  let asymFile = toRodFile(config, AbsoluteFile toFullPath(config, position.FileIndex), ".alivesyms")
+  var s = newSeqOfCap[int32](alive[position].len)
+  for a in items(alive[position]): s.add int32(a)
+  sort(s)
+
+proc storeAliveSyms(config: ConfigRef; position: int; alive: AliveSyms) =
+  prepare()
+  storeAliveSymsImpl(asymFile, s)
+
+proc aliveSymsChanged(config: ConfigRef; position: int; alive: AliveSyms): bool =
+  prepare()
+  var f2 = rodfiles.open(asymFile.string)
+  f2.loadHeader()
+  f2.loadSection aliveSymsSection
+  var oldData: seq[int32] = @[]
+  f2.loadSeq(oldData)
+  f2.close
+  if f2.err == ok and oldData == s:
+    result = false
+  else:
+    when defined(debugDce):
+      let oldAsSet = toPackedSet[int32](oldData)
+      let newAsSet = toPackedSet[int32](s)
+      echo "set of live symbols changed ", asymFile.changeFileExt("rod"), " ", position, " ", f2.err
+      echo "in old but not in new ", oldAsSet.difference(newAsSet), " number of entries in old ", oldAsSet.len
+      echo "in new but not in old ", newAsSet.difference(oldAsSet), " number of entries in new ", newAsSet.len
+      #if execShellCmd(getAppFilename() & " rod " & quoteShell(asymFile.changeFileExt("rod"))) != 0:
+      #  echo "command failed"
+    result = true
+    storeAliveSymsImpl(asymFile, s)
+
+proc genPackedModule(g: ModuleGraph, i: int; alive: var AliveSyms) =
+  # case statement here to enforce exhaustive checks.
+  case g.packed[i].status
+  of undefined:
+    discard "nothing to do"
+  of loading, stored:
+    assert false
+  of storing, outdated:
+    storeAliveSyms(g.config, g.packed[i].module.position, alive)
+    generateCodeForModule(g, g.packed[i], alive)
+    closeRodFile(g, g.packed[i].module)
+  of loaded:
+    if g.packed[i].loadedButAliveSetChanged:
+      generateCodeForModule(g, g.packed[i], alive)
+    else:
+      addFileToLink(g.config, g.packed[i].module)
+      replayTypeInfo(g, g.packed[i], FileIndex(i))
+
+      if g.backend == nil:
+        g.backend = cgendata.newModuleList(g)
+      registerInitProcs(BModuleList(g.backend), g.packed[i].module, g.packed[i].fromDisk.backendFlags)
+
+proc generateCode*(g: ModuleGraph) =
+  ## The single entry point, generate C(++) code for the entire
+  ## Nim program aka `ModuleGraph`.
+  resetForBackend(g)
+  var alive = computeAliveSyms(g.packed, g.config)
+
+  when false:
+    for i in 0..high(g.packed):
+      echo i, " is of status ", g.packed[i].status, " ", toFullPath(g.config, FileIndex(i))
+
+  # First pass: Setup all the backend modules for all the modules that have
+  # changed:
+  for i in 0..high(g.packed):
+    # case statement here to enforce exhaustive checks.
+    case g.packed[i].status
+    of undefined:
+      discard "nothing to do"
+    of loading, stored:
+      assert false
+    of storing, outdated:
+      setupBackendModule(g, g.packed[i])
+    of loaded:
+      # Even though this module didn't change, DCE might trigger a change.
+      # Consider this case: Module A uses symbol S from B and B does not use
+      # S itself. A is then edited not to use S either. Thus we have to
+      # recompile B in order to remove S from the final result.
+      if aliveSymsChanged(g.config, g.packed[i].module.position, alive):
+        g.packed[i].loadedButAliveSetChanged = true
+        setupBackendModule(g, g.packed[i])
+
+  # Second pass: Code generation.
+  let mainModuleIdx = g.config.projectMainIdx2.int
+  # We need to generate the main module last, because only then
+  # all init procs have been registered:
+  for i in 0..high(g.packed):
+    if i != mainModuleIdx:
+      genPackedModule(g, i, alive)
+  if mainModuleIdx >= 0:
+    genPackedModule(g, mainModuleIdx, alive)
--- a/compiler/ic/dce.nim
+++ b/compiler/ic/dce.nim
@@ -0,0 +1,169 @@
+#
+#
+#           The Nim Compiler
+#        (c) Copyright 2021 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## Dead code elimination (=DCE) for IC.
+
+import std/[intsets, tables]
+
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
+import ".." / [ast, options, lineinfos, types]
+
+import packed_ast, ic, bitabs
+
+type
+  AliveSyms* = seq[IntSet]
+  AliveContext* = object ## Purpose is to fill the 'alive' field.
+    stack: seq[(int, TOptions, NodePos)] ## A stack for marking symbols as alive.
+    decoder: PackedDecoder ## We need a PackedDecoder for module ID address translations.
+    thisModule: int  ## The module we're currently analysing for DCE.
+    alive: AliveSyms ## The final result of our computation.
+    options: TOptions
+    compilerProcs: Table[string, (int, int32)]
+
+proc isExportedToC(c: var AliveContext; g: PackedModuleGraph; symId: int32): bool =
+  ## "Exported to C" procs are special (these are marked with '.exportc') because these
+  ## must not be optimized away!
+  let symPtr = unsafeAddr g[c.thisModule].fromDisk.syms[symId]
+  let flags = symPtr.flags
+  # due to a bug/limitation in the lambda lifting, unused inner procs
+  # are not transformed correctly; issue (#411). However, the whole purpose here
+  # is to eliminate unused procs. So there is no special logic required for this case.
+  if sfCompileTime notin flags:
+    if ({sfExportc, sfCompilerProc} * flags != {}) or
+        (symPtr.kind == skMethod):
+      result = true
+    else:
+      result = false
+      # XXX: This used to be a condition to:
+      #  (sfExportc in prc.flags and lfExportLib in prc.loc.flags) or
+    if sfCompilerProc in flags:
+      c.compilerProcs[g[c.thisModule].fromDisk.strings[symPtr.name]] = (c.thisModule, symId)
+  else:
+    result = false
+
+template isNotGeneric(n: NodePos): bool = ithSon(tree, n, genericParamsPos).kind == nkEmpty
+
+proc followLater(c: var AliveContext; g: PackedModuleGraph; module: int; item: int32) =
+  ## Marks a symbol 'item' as used and later in 'followNow' the symbol's body will
+  ## be analysed.
+  if not c.alive[module].containsOrIncl(item):
+    var body = g[module].fromDisk.syms[item].ast
+    if body != emptyNodeId:
+      let opt = g[module].fromDisk.syms[item].options
+      if g[module].fromDisk.syms[item].kind in routineKinds:
+        body = NodeId ithSon(g[module].fromDisk.bodies, NodePos body, bodyPos)
+      c.stack.add((module, opt, NodePos(body)))
+
+    when false:
+      let nid = g[module].fromDisk.syms[item].name
+      if nid != LitId(0):
+        let name = g[module].fromDisk.strings[nid]
+        if name in ["nimFrame", "callDepthLimitReached"]:
+          echo "I was called! ", name, " body exists: ", body != emptyNodeId, " ", module, " ", item
+
+proc requestCompilerProc(c: var AliveContext; g: PackedModuleGraph; name: string) =
+  let (module, item) = c.compilerProcs[name]
+  followLater(c, g, module, item)
+
+proc loadTypeKind(t: PackedItemId; c: AliveContext; g: PackedModuleGraph; toSkip: set[TTypeKind]): TTypeKind =
+  template kind(t: ItemId): TTypeKind = g[t.module].fromDisk.types[t.item].kind
+
+  var t2 = translateId(t, g, c.thisModule, c.decoder.config)
+  result = t2.kind
+  while result in toSkip:
+    t2 = translateId(g[t2.module].fromDisk.types[t2.item].types[^1], g, t2.module, c.decoder.config)
+    result = t2.kind
+
+proc rangeCheckAnalysis(c: var AliveContext; g: PackedModuleGraph; tree: PackedTree; n: NodePos) =
+  ## Replicates the logic of `ccgexprs.genRangeChck`.
+  ## XXX Refactor so that the duplicated logic is avoided. However, for now it's not clear
+  ## the approach has enough merit.
+  var dest = loadTypeKind(n.typ, c, g, abstractVar)
+  if optRangeCheck notin c.options or dest in {tyUInt..tyUInt64}:
+    discard "no need to generate a check because it was disabled"
+  else:
+    let n0t = loadTypeKind(n.firstSon.typ, c, g, {})
+    if n0t in {tyUInt, tyUInt64}:
+      c.requestCompilerProc(g, "raiseRangeErrorNoArgs")
+    else:
+      let raiser =
+        case loadTypeKind(n.typ, c, g, abstractVarRange)
+        of tyUInt..tyUInt64, tyChar: "raiseRangeErrorU"
+        of tyFloat..tyFloat128: "raiseRangeErrorF"
+        else: "raiseRangeErrorI"
+      c.requestCompilerProc(g, raiser)
+
+proc aliveCode(c: var AliveContext; g: PackedModuleGraph; tree: PackedTree; n: NodePos) =
+  ## Marks the symbols we encounter when we traverse the AST at `tree[n]` as alive, unless
+  ## it is purely in a declarative context (type section etc.).
+  case n.kind
+  of nkNone..pred(nkSym), succ(nkSym)..nkNilLit:
+    discard "ignore non-sym atoms"
+  of nkSym:
+    # This symbol is alive and everything its body references.
+    followLater(c, g, c.thisModule, n.operand)
+  of nkModuleRef:
+    let (n1, n2) = sons2(tree, n)
+    assert n1.kind == nkInt32Lit
+    assert n2.kind == nkInt32Lit
+    let m = n1.litId
+    let item = n2.operand
+    let otherModule = toFileIndexCached(c.decoder, g, c.thisModule, m).int
+    followLater(c, g, otherModule, item)
+  of nkMacroDef, nkTemplateDef, nkTypeSection, nkTypeOfExpr,
+     nkCommentStmt, nkIncludeStmt,
+     nkImportStmt, nkImportExceptStmt, nkExportStmt, nkExportExceptStmt,
+     nkFromStmt, nkStaticStmt:
+    discard
+  of nkVarSection, nkLetSection, nkConstSection:
+    # XXX ignore the defining local variable name?
+    for son in sonsReadonly(tree, n):
+      aliveCode(c, g, tree, son)
+  of nkChckRangeF, nkChckRange64, nkChckRange:
+    rangeCheckAnalysis(c, g, tree, n)
+  of nkProcDef, nkConverterDef, nkMethodDef, nkFuncDef, nkIteratorDef:
+    if n.firstSon.kind == nkSym and isNotGeneric(n):
+      let item = n.firstSon.operand
+      if isExportedToC(c, g, item):
+        # This symbol is alive and everything its body references.
+        followLater(c, g, c.thisModule, item)
+  else:
+    for son in sonsReadonly(tree, n):
+      aliveCode(c, g, tree, son)
+
+proc followNow(c: var AliveContext; g: PackedModuleGraph) =
+  ## Mark all entries in the stack. Marking can add more entries
+  ## to the stack but eventually we have looked at every alive symbol.
+  while c.stack.len > 0:
+    let (modId, opt, ast) = c.stack.pop()
+    c.thisModule = modId
+    c.options = opt
+    aliveCode(c, g, g[modId].fromDisk.bodies, ast)
+
+proc computeAliveSyms*(g: PackedModuleGraph; conf: ConfigRef): AliveSyms =
+  ## Entry point for our DCE algorithm.
+  var c = AliveContext(stack: @[], decoder: PackedDecoder(config: conf),
+                       thisModule: -1, alive: newSeq[IntSet](g.len),
+                       options: conf.options)
+  for i in countdown(high(g), 0):
+    if g[i].status != undefined:
+      c.thisModule = i
+      for p in allNodes(g[i].fromDisk.topLevel):
+        aliveCode(c, g, g[i].fromDisk.topLevel, p)
+
+  followNow(c, g)
+  result = move(c.alive)
+
+proc isAlive*(a: AliveSyms; module: int, item: int32): bool =
+  ## Backends use this to query if a symbol is `alive` which means
+  ## we need to produce (C/C++/etc) code for it.
+  result = a[module].contains(item)
+
--- a/compiler/ic/design.rst
+++ b/compiler/ic/design.rst
@@ -0,0 +1,56 @@
+====================================
+  Incremental Recompilations
+====================================
+
+We split the Nim compiler into a frontend and a backend.
+The frontend produces a set of `.rod` files. Every `.nim` module
+produces its own `.rod` file.
+
+- The IR must be a faithful representation of the AST in memory.
+- The backend can do its own caching but doesn't have to. In the
+  current implementation the backend also caches its results.
+
+Advantage of the "set of files" vs the previous global database:
+- By construction, we either read from the `.rod` file or from the
+  `.nim` file, there can be no inconsistency. There can also be no
+  partial updates.
+- No dependency to external packages (SQLite). SQLite simply is too
+  slow and the old way of serialization was too slow too. We use a
+  format designed for Nim and expect to base further tools on this
+  file format.
+
+References to external modules must be (moduleId, symId) pairs.
+The symbol IDs are module specific. This way no global ID increment
+mechanism needs to be implemented that we could get wrong. ModuleIds
+are rod-file specific too.
+
+
+
+Global state
+------------
+
+There is no global state.
+
+Rod File Format
+---------------
+
+It's a simple binary file format. `rodfiles.nim` contains some details.
+
+
+Backend
+-------
+
+Nim programmers have to come to enjoy whole-program dead code elimination,
+by default. Since this is a "whole program" optimization, it does break
+modularity. However, thanks to the packed AST representation we can perform
+this global analysis without having to unpack anything. This is basically
+a mark&sweep GC algorithm:
+
+- Start with the top level statements. Every symbol that is referenced
+  from a top level statement is not "dead" and needs to be compiled by
+  the backend.
+- Every symbol referenced from a referenced symbol also has to be
+  compiled.
+
+Caching logic: Only if the set of alive symbols is different from the
+last run, the module has to be regenerated.
--- a/compiler/ic/enum2nif.nim
+++ b/compiler/ic/enum2nif.nim
--- a/compiler/ic/ic.nim
+++ b/compiler/ic/ic.nim
--- a/compiler/ic/integrity.nim
+++ b/compiler/ic/integrity.nim
@@ -0,0 +1,153 @@
+#
+#
+#           The Nim Compiler
+#        (c) Copyright 2021 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## Integrity checking for a set of .rod files.
+## The set must cover a complete Nim project.
+
+import sets
+
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
+import ".." / [ast, modulegraphs]
+import packed_ast, bitabs, ic
+
+type
+  CheckedContext = object
+    g: ModuleGraph
+    thisModule: int32
+    checkedSyms: HashSet[ItemId]
+    checkedTypes: HashSet[ItemId]
+
+proc checkType(c: var CheckedContext; typeId: PackedItemId)
+proc checkForeignSym(c: var CheckedContext; symId: PackedItemId)
+proc checkNode(c: var CheckedContext; tree: PackedTree; n: NodePos)
+
+proc checkTypeObj(c: var CheckedContext; typ: PackedType) =
+  for child in typ.types:
+    checkType(c, child)
+  if typ.n != emptyNodeId:
+    checkNode(c, c.g.packed[c.thisModule].fromDisk.bodies, NodePos typ.n)
+  if typ.sym != nilItemId:
+    checkForeignSym(c, typ.sym)
+  if typ.owner != nilItemId:
+    checkForeignSym(c, typ.owner)
+  checkType(c, typ.typeInst)
+
+proc checkType(c: var CheckedContext; typeId: PackedItemId) =
+  if typeId == nilItemId: return
+  let itemId = translateId(typeId, c.g.packed, c.thisModule, c.g.config)
+  if not c.checkedTypes.containsOrIncl(itemId):
+    let oldThisModule = c.thisModule
+    c.thisModule = itemId.module
+    checkTypeObj c, c.g.packed[itemId.module].fromDisk.types[itemId.item]
+    c.thisModule = oldThisModule
+
+proc checkSym(c: var CheckedContext; s: PackedSym) =
+  if s.name != LitId(0):
+    assert c.g.packed[c.thisModule].fromDisk.strings.hasLitId s.name
+  checkType c, s.typ
+  if s.ast != emptyNodeId:
+    checkNode(c, c.g.packed[c.thisModule].fromDisk.bodies, NodePos s.ast)
+  if s.owner != nilItemId:
+    checkForeignSym(c, s.owner)
+
+proc checkLocalSym(c: var CheckedContext; item: int32) =
+  let itemId = ItemId(module: c.thisModule, item: item)
+  if not c.checkedSyms.containsOrIncl(itemId):
+    checkSym c, c.g.packed[c.thisModule].fromDisk.syms[item]
+
+proc checkForeignSym(c: var CheckedContext; symId: PackedItemId) =
+  let itemId = translateId(symId, c.g.packed, c.thisModule, c.g.config)
+  if not c.checkedSyms.containsOrIncl(itemId):
+    let oldThisModule = c.thisModule
+    c.thisModule = itemId.module
+    checkSym c, c.g.packed[itemId.module].fromDisk.syms[itemId.item]
+    c.thisModule = oldThisModule
+
+proc checkNode(c: var CheckedContext; tree: PackedTree; n: NodePos) =
+  if tree[n.int].typeId != nilItemId:
+    checkType(c, tree[n.int].typeId)
+  case n.kind
+  of nkEmpty, nkNilLit, nkType, nkNilRodNode:
+    discard
+  of nkIdent:
+    assert c.g.packed[c.thisModule].fromDisk.strings.hasLitId n.litId
+  of nkSym:
+    checkLocalSym(c, tree.nodes[n.int].operand)
+  of directIntLit:
+    discard
+  of externIntLit, nkFloatLit..nkFloat128Lit:
+    assert c.g.packed[c.thisModule].fromDisk.numbers.hasLitId n.litId
+  of nkStrLit..nkTripleStrLit:
+    assert c.g.packed[c.thisModule].fromDisk.strings.hasLitId n.litId
+  of nkModuleRef:
+    let (n1, n2) = sons2(tree, n)
+    assert n1.kind == nkInt32Lit
+    assert n2.kind == nkInt32Lit
+    checkForeignSym(c, PackedItemId(module: n1.litId, item: tree.nodes[n2.int].operand))
+  else:
+    for n0 in sonsReadonly(tree, n):
+      checkNode(c, tree, n0)
+
+proc checkTree(c: var CheckedContext; t: PackedTree) =
+  for p in allNodes(t): checkNode(c, t, p)
+
+proc checkLocalSymIds(c: var CheckedContext; m: PackedModule; symIds: seq[int32]) =
+  for symId in symIds:
+    assert symId >= 0 and symId < m.syms.len, $symId & " " & $m.syms.len
+
+proc checkModule(c: var CheckedContext; m: PackedModule) =
+  # We check that:
+  # - Every symbol references existing types and symbols.
+  # - Every tree node references existing types and symbols.
+  for i in 0..high(m.syms):
+    checkLocalSym c, int32(i)
+
+  checkTree c, m.toReplay
+  checkTree c, m.topLevel
+
+  for e in m.exports:
+    assert e[1] >= 0 and e[1] < m.syms.len
+    assert e[0] == m.syms[e[1]].name
+
+  for e in m.compilerProcs:
+    assert e[1] >= 0 and e[1] < m.syms.len
+    assert e[0] == m.syms[e[1]].name
+
+  checkLocalSymIds c, m, m.converters
+  checkLocalSymIds c, m, m.methods
+  checkLocalSymIds c, m, m.trmacros
+  checkLocalSymIds c, m, m.pureEnums
+  #[
+    To do: Check all these fields:
+
+    reexports*: seq[(LitId, PackedItemId)]
+    macroUsages*: seq[(PackedItemId, PackedLineInfo)]
+
+    typeInstCache*: seq[(PackedItemId, PackedItemId)]
+    procInstCache*: seq[PackedInstantiation]
+    attachedOps*: seq[(TTypeAttachedOp, PackedItemId, PackedItemId)]
+    methodsPerType*: seq[(PackedItemId, int, PackedItemId)]
+    enumToStringProcs*: seq[(PackedItemId, PackedItemId)]
+  ]#
+
+proc checkIntegrity*(g: ModuleGraph) =
+  var c = CheckedContext(g: g)
+  for i in 0..high(g.packed):
+    # case statement here to enforce exhaustive checks.
+    case g.packed[i].status
+    of undefined:
+      discard "nothing to do"
+    of loading:
+      assert false, "cannot check integrity: Module still loading"
+    of stored, storing, outdated, loaded:
+      c.thisModule = int32 i
+      checkModule(c, g.packed[i].fromDisk)
+
--- a/compiler/ic/navigator.nim
+++ b/compiler/ic/navigator.nim
@@ -0,0 +1,174 @@
+#
+#
+#           The Nim Compiler
+#        (c) Copyright 2021 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## Supports the "nim check --ic:on --defusages:FILE,LINE,COL"
+## IDE-like features. It uses the set of .rod files to accomplish
+## its task. The set must cover a complete Nim project.
+
+import sets
+
+from os import nil
+from std/private/miscdollars import toLocation
+
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
+import ".." / [ast, modulegraphs, msgs, options]
+import packed_ast, bitabs, ic
+
+type
+  NavContext = object
+    g: ModuleGraph
+    thisModule: int32
+    trackPos: PackedLineInfo
+    alreadyEmitted: HashSet[string]
+    outputSep: char # for easier testing, use short filenames and spaces instead of tabs.
+
+proc isTracked(current, trackPos: PackedLineInfo, tokenLen: int): bool =
+  if current.file == trackPos.file and current.line == trackPos.line:
+    let col = trackPos.col
+    if col >= current.col and col < current.col+tokenLen:
+      result = true
+    else:
+      result = false
+  else:
+    result = false
+
+proc searchLocalSym(c: var NavContext; s: PackedSym; info: PackedLineInfo): bool =
+  result = s.name != LitId(0) and
+    isTracked(info, c.trackPos, c.g.packed[c.thisModule].fromDisk.strings[s.name].len)
+
+proc searchForeignSym(c: var NavContext; s: ItemId; info: PackedLineInfo): bool =
+  let name = c.g.packed[s.module].fromDisk.syms[s.item].name
+  result = name != LitId(0) and
+    isTracked(info, c.trackPos, c.g.packed[s.module].fromDisk.strings[name].len)
+
+const
+  EmptyItemId = ItemId(module: -1'i32, item: -1'i32)
+
+proc search(c: var NavContext; tree: PackedTree): ItemId =
+  # We use the linear representation here directly:
+  for i in 0..high(tree.nodes):
+    case tree.nodes[i].kind
+    of nkSym:
+      let item = tree.nodes[i].operand
+      if searchLocalSym(c, c.g.packed[c.thisModule].fromDisk.syms[item], tree.nodes[i].info):
+        return ItemId(module: c.thisModule, item: item)
+    of nkModuleRef:
+      if tree.nodes[i].info.line == c.trackPos.line and tree.nodes[i].info.file == c.trackPos.file:
+        let (n1, n2) = sons2(tree, NodePos i)
+        assert n1.kind == nkInt32Lit
+        assert n2.kind == nkInt32Lit
+        let pId = PackedItemId(module: n1.litId, item: tree.nodes[n2.int].operand)
+        let itemId = translateId(pId, c.g.packed, c.thisModule, c.g.config)
+        if searchForeignSym(c, itemId, tree.nodes[i].info):
+          return itemId
+    else: discard
+  return EmptyItemId
+
+proc isDecl(tree: PackedTree; n: NodePos): bool =
+  # XXX This is not correct yet.
+  const declarativeNodes = procDefs + {nkMacroDef, nkTemplateDef,
+    nkLetSection, nkVarSection, nkUsingStmt, nkConstSection, nkTypeSection,
+    nkIdentDefs, nkEnumTy, nkVarTuple}
+  result = n.int >= 0 and tree[n.int].kind in declarativeNodes
+
+proc usage(c: var NavContext; info: PackedLineInfo; isDecl: bool) =
+  var m = ""
+  var file = c.g.packed[c.thisModule].fromDisk.strings[info.file]
+  if c.outputSep == ' ':
+    file = os.extractFilename file
+  toLocation(m, file, info.line.int, info.col.int + ColOffset)
+  if not c.alreadyEmitted.containsOrIncl(m):
+    msgWriteln c.g.config, (if isDecl: "def" else: "usage") & c.outputSep & m
+
+proc list(c: var NavContext; tree: PackedTree; sym: ItemId) =
+  for i in 0..high(tree.nodes):
+    case tree.nodes[i].kind
+    of nkSym:
+      let item = tree.nodes[i].operand
+      if sym.item == item and sym.module == c.thisModule:
+        usage(c, tree.nodes[i].info, isDecl(tree, parent(NodePos i)))
+    of nkModuleRef:
+      let (n1, n2) = sons2(tree, NodePos i)
+      assert n1.kind == nkInt32Lit
+      assert n2.kind == nkInt32Lit
+      let pId = PackedItemId(module: n1.litId, item: tree.nodes[n2.int].operand)
+      let itemId = translateId(pId, c.g.packed, c.thisModule, c.g.config)
+      if itemId.item == sym.item and sym.module == itemId.module:
+        usage(c, tree.nodes[i].info, isDecl(tree, parent(NodePos i)))
+    else: discard
+
+proc searchForIncludeFile(g: ModuleGraph; fullPath: string): int =
+  for i in 0..high(g.packed):
+    for k in 1..high(g.packed[i].fromDisk.includes):
+      # we start from 1 because the first "include" file is
+      # the module's filename.
+      if os.cmpPaths(g.packed[i].fromDisk.strings[g.packed[i].fromDisk.includes[k][0]], fullPath) == 0:
+        return i
+  return -1
+
+proc nav(g: ModuleGraph) =
+  # translate the track position to a packed position:
+  let unpacked = g.config.m.trackPos
+  var mid = unpacked.fileIndex.int
+
+  let fullPath = toFullPath(g.config, unpacked.fileIndex)
+
+  if g.packed[mid].status == undefined:
+    # check if 'mid' is an include file of some other module:
+    mid = searchForIncludeFile(g, fullPath)
+
+  if mid < 0:
+    localError(g.config, unpacked, "unknown file name: " & fullPath)
+    return
+
+  let fileId = g.packed[mid].fromDisk.strings.getKeyId(fullPath)
+
+  if fileId == LitId(0):
+    internalError(g.config, unpacked, "cannot find a valid file ID")
+    return
+
+  var c = NavContext(
+    g: g,
+    thisModule: int32 mid,
+    trackPos: PackedLineInfo(line: unpacked.line, col: unpacked.col, file: fileId),
+    outputSep: if isDefined(g.config, "nimIcNavigatorTests"): ' ' else: '\t'
+  )
+  var symId = search(c, g.packed[mid].fromDisk.topLevel)
+  if symId == EmptyItemId:
+    symId = search(c, g.packed[mid].fromDisk.bodies)
+
+  if symId == EmptyItemId:
+    localError(g.config, unpacked, "no symbol at this position")
+    return
+
+  for i in 0..high(g.packed):
+    # case statement here to enforce exhaustive checks.
+    case g.packed[i].status
+    of undefined:
+      discard "nothing to do"
+    of loading:
+      assert false, "cannot check integrity: Module still loading"
+    of stored, storing, outdated, loaded:
+      c.thisModule = int32 i
+      list(c, g.packed[i].fromDisk.topLevel, symId)
+      list(c, g.packed[i].fromDisk.bodies, symId)
+
+proc navDefinition*(g: ModuleGraph) = nav(g)
+proc navUsages*(g: ModuleGraph) = nav(g)
+proc navDefusages*(g: ModuleGraph) = nav(g)
+
+proc writeRodFiles*(g: ModuleGraph) =
+  for i in 0..high(g.packed):
+    case g.packed[i].status
+    of undefined, loading, stored, loaded:
+      discard "nothing to do"
+    of storing, outdated:
+      closeRodFile(g, g.packed[i].module)
--- a/compiler/ic/packed_ast.nim
+++ b/compiler/ic/packed_ast.nim
@@ -0,0 +1,422 @@
+#
+#
+#           The Nim Compiler
+#        (c) Copyright 2020 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## Packed AST representation, mostly based on a seq of nodes.
+## For IC support. Far future: Rewrite the compiler passes to
+## use this representation directly in all the transformations,
+## it is superior.
+
+import hashes, tables, strtabs
+import bitabs
+import ".." / [ast, options]
+
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
+type
+  SymId* = distinct int32
+  ModuleId* = distinct int32
+  NodePos* = distinct int
+
+  NodeId* = distinct int32
+
+  PackedItemId* = object
+    module*: LitId       # 0 if it's this module
+    item*: int32         # same as the in-memory representation
+
+const
+  nilItemId* = PackedItemId(module: LitId(0), item: -1.int32)
+
+const
+  emptyNodeId* = NodeId(-1)
+
+type
+  PackedLineInfo* = object
+    line*: uint16
+    col*: int16
+    file*: LitId
+
+  PackedLib* = object
+    kind*: TLibKind
+    generated*: bool
+    isOverridden*: bool
+    name*: LitId
+    path*: NodeId
+
+  PackedSym* = object
+    kind*: TSymKind
+    name*: LitId
+    typ*: PackedItemId
+    flags*: TSymFlags
+    magic*: TMagic
+    info*: PackedLineInfo
+    ast*: NodeId
+    owner*: PackedItemId
+    guard*: PackedItemId
+    bitsize*: int
+    alignment*: int # for alignment
+    options*: TOptions
+    position*: int
+    offset*: int32
+    disamb*: int32
+    externalName*: LitId # instead of TLoc
+    locFlags*: TLocFlags
+    annex*: PackedLib
+    when hasFFI:
+      cname*: LitId
+    constraint*: NodeId
+    instantiatedFrom*: PackedItemId
+
+  PackedType* = object
+    kind*: TTypeKind
+    callConv*: TCallingConvention
+    #nodekind*: TNodeKind
+    flags*: TTypeFlags
+    types*: seq[PackedItemId]
+    n*: NodeId
+    #nodeflags*: TNodeFlags
+    sym*: PackedItemId
+    owner*: PackedItemId
+    size*: BiggestInt
+    align*: int16
+    paddingAtEnd*: int16
+    # not serialized: loc*: TLoc because it is backend-specific
+    typeInst*: PackedItemId
+    nonUniqueId*: int32
+
+  PackedNode* = object     # 28 bytes
+    kind*: TNodeKind
+    flags*: TNodeFlags
+    operand*: int32  # for kind in {nkSym, nkSymDef}: SymId
+                     # for kind in {nkStrLit, nkIdent, nkNumberLit}: LitId
+                     # for kind in nkInt32Lit: direct value
+                     # for non-atom kinds: the number of nodes (for easy skipping)
+    typeId*: PackedItemId
+    info*: PackedLineInfo
+
+  PackedTree* = object ## usually represents a full Nim module
+    nodes*: seq[PackedNode]
+
+  PackedInstantiation* = object
+    key*, sym*: PackedItemId
+    concreteTypes*: seq[PackedItemId]
+
+proc `==`*(a, b: SymId): bool {.borrow.}
+proc hash*(a: SymId): Hash {.borrow.}
+
+proc `==`*(a, b: NodePos): bool {.borrow.}
+#proc `==`*(a, b: PackedItemId): bool {.borrow.}
+proc `==`*(a, b: NodeId): bool {.borrow.}
+
+proc newTreeFrom*(old: PackedTree): PackedTree =
+  result.nodes = @[]
+  when false: result.sh = old.sh
+
+when false:
+  proc declareSym*(tree: var PackedTree; kind: TSymKind;
+                  name: LitId; info: PackedLineInfo): SymId =
+    result = SymId(tree.sh.syms.len)
+    tree.sh.syms.add PackedSym(kind: kind, name: name, flags: {}, magic: mNone, info: info)
+
+  proc litIdFromName*(tree: PackedTree; name: string): LitId =
+    result = tree.sh.strings.getOrIncl(name)
+
+  proc add*(tree: var PackedTree; kind: TNodeKind; token: string; info: PackedLineInfo) =
+    tree.nodes.add PackedNode(kind: kind, info: info,
+                              operand: int32 getOrIncl(tree.sh.strings, token))
+
+  proc add*(tree: var PackedTree; kind: TNodeKind; info: PackedLineInfo) =
+    tree.nodes.add PackedNode(kind: kind, operand: 0, info: info)
+
+proc throwAwayLastNode*(tree: var PackedTree) =
+  tree.nodes.setLen(tree.nodes.len-1)
+
+proc addIdent*(tree: var PackedTree; s: LitId; info: PackedLineInfo) =
+  tree.nodes.add PackedNode(kind: nkIdent, operand: int32(s), info: info)
+
+proc addSym*(tree: var PackedTree; s: int32; info: PackedLineInfo) =
+  tree.nodes.add PackedNode(kind: nkSym, operand: s, info: info)
+
+proc addModuleId*(tree: var PackedTree; s: ModuleId; info: PackedLineInfo) =
+  tree.nodes.add PackedNode(kind: nkInt32Lit, operand: int32(s), info: info)
+
+proc addSymDef*(tree: var PackedTree; s: SymId; info: PackedLineInfo) =
+  tree.nodes.add PackedNode(kind: nkSym, operand: int32(s), info: info)
+
+proc isAtom*(tree: PackedTree; pos: int): bool {.inline.} = tree.nodes[pos].kind <= nkNilLit
+
+proc copyTree*(dest: var PackedTree; tree: PackedTree; n: NodePos) =
+  # and this is why the IR is superior. We can copy subtrees
+  # via a linear scan.
+  let pos = n.int
+  let L = if isAtom(tree, pos): 1 else: tree.nodes[pos].operand
+  let d = dest.nodes.len
+  dest.nodes.setLen(d + L)
+  for i in 0..<L:
+    dest.nodes[d+i] = tree.nodes[pos+i]
+
+when false:
+  proc copySym*(dest: var PackedTree; tree: PackedTree; s: SymId): SymId =
+    result = SymId(dest.sh.syms.len)
+    assert int(s) < tree.sh.syms.len
+    let oldSym = tree.sh.syms[s.int]
+    dest.sh.syms.add oldSym
+
+type
+  PatchPos = distinct int
+
+when false:
+  proc prepare*(tree: var PackedTree; kind: TNodeKind; info: PackedLineInfo): PatchPos =
+    result = PatchPos tree.nodes.len
+    tree.nodes.add PackedNode(kind: kind, operand: 0, info: info)
+
+proc prepare*(tree: var PackedTree; kind: TNodeKind; flags: TNodeFlags; typeId: PackedItemId; info: PackedLineInfo): PatchPos =
+  result = PatchPos tree.nodes.len
+  tree.nodes.add PackedNode(kind: kind, flags: flags, operand: 0, info: info,
+                            typeId: typeId)
+
+proc prepare*(dest: var PackedTree; source: PackedTree; sourcePos: NodePos): PatchPos =
+  result = PatchPos dest.nodes.len
+  dest.nodes.add source.nodes[sourcePos.int]
+
+proc patch*(tree: var PackedTree; pos: PatchPos) =
+  let pos = pos.int
+  assert tree.nodes[pos].kind > nkNilLit
+  let distance = int32(tree.nodes.len - pos)
+  tree.nodes[pos].operand = distance
+
+proc len*(tree: PackedTree): int {.inline.} = tree.nodes.len
+
+proc `[]`*(tree: PackedTree; i: int): lent PackedNode {.inline.} =
+  tree.nodes[i]
+
+proc nextChild(tree: PackedTree; pos: var int) {.inline.} =
+  if tree.nodes[pos].kind > nkNilLit:
+    assert tree.nodes[pos].operand > 0
+    inc pos, tree.nodes[pos].operand
+  else:
+    inc pos
+
+iterator sonsReadonly*(tree: PackedTree; n: NodePos): NodePos =
+  var pos = n.int
+  assert tree.nodes[pos].kind > nkNilLit
+  let last = pos + tree.nodes[pos].operand
+  inc pos
+  while pos < last:
+    yield NodePos pos
+    nextChild tree, pos
+
+iterator sons*(dest: var PackedTree; tree: PackedTree; n: NodePos): NodePos =
+  let patchPos = prepare(dest, tree, n)
+  for x in sonsReadonly(tree, n): yield x
+  patch dest, patchPos
+
+iterator isons*(dest: var PackedTree; tree: PackedTree;
+                n: NodePos): (int, NodePos) =
+  var i = 0
+  for ch0 in sons(dest, tree, n):
+    yield (i, ch0)
+    inc i
+
+iterator sonsFrom1*(tree: PackedTree; n: NodePos): NodePos =
+  var pos = n.int
+  assert tree.nodes[pos].kind > nkNilLit
+  let last = pos + tree.nodes[pos].operand
+  inc pos
+  if pos < last:
+    nextChild tree, pos
+  while pos < last:
+    yield NodePos pos
+    nextChild tree, pos
+
+iterator sonsWithoutLast2*(tree: PackedTree; n: NodePos): NodePos =
+  var count = 0
+  for child in sonsReadonly(tree, n):
+    inc count
+  var pos = n.int
+  assert tree.nodes[pos].kind > nkNilLit
+  let last = pos + tree.nodes[pos].operand
+  inc pos
+  while pos < last and count > 2:
+    yield NodePos pos
+    dec count
+    nextChild tree, pos
+
+proc parentImpl(tree: PackedTree; n: NodePos): NodePos =
+  # finding the parent of a node is rather easy:
+  var pos = n.int - 1
+  while pos >= 0 and (isAtom(tree, pos) or (pos + tree.nodes[pos].operand - 1 < n.int)):
+    dec pos
+  #assert pos >= 0, "node has no parent"
+  result = NodePos(pos)
+
+template parent*(n: NodePos): NodePos = parentImpl(tree, n)
+
+proc hasXsons*(tree: PackedTree; n: NodePos; x: int): bool =
+  var count = 0
+  if tree.nodes[n.int].kind > nkNilLit:
+    for child in sonsReadonly(tree, n): inc count
+  result = count == x
+
+proc hasAtLeastXsons*(tree: PackedTree; n: NodePos; x: int): bool =
+  if tree.nodes[n.int].kind > nkNilLit:
+    var count = 0
+    for child in sonsReadonly(tree, n):
+      inc count
+      if count >= x: return true
+  return false
+
+proc firstSon*(tree: PackedTree; n: NodePos): NodePos {.inline.} =
+  NodePos(n.int+1)
+proc kind*(tree: PackedTree; n: NodePos): TNodeKind {.inline.} =
+  tree.nodes[n.int].kind
+proc litId*(tree: PackedTree; n: NodePos): LitId {.inline.} =
+  LitId tree.nodes[n.int].operand
+proc info*(tree: PackedTree; n: NodePos): PackedLineInfo {.inline.} =
+  tree.nodes[n.int].info
+
+template typ*(n: NodePos): PackedItemId =
+  tree.nodes[n.int].typeId
+template flags*(n: NodePos): TNodeFlags =
+  tree.nodes[n.int].flags
+
+template operand*(n: NodePos): int32 =
+  tree.nodes[n.int].operand
+
+proc span*(tree: PackedTree; pos: int): int {.inline.} =
+  if isAtom(tree, pos): 1 else: tree.nodes[pos].operand
+
+proc sons2*(tree: PackedTree; n: NodePos): (NodePos, NodePos) =
+  assert(not isAtom(tree, n.int))
+  let a = n.int+1
+  let b = a + span(tree, a)
+  result = (NodePos a, NodePos b)
+
+proc sons3*(tree: PackedTree; n: NodePos): (NodePos, NodePos, NodePos) =
+  assert(not isAtom(tree, n.int))
+  let a = n.int+1
+  let b = a + span(tree, a)
+  let c = b + span(tree, b)
+  result = (NodePos a, NodePos b, NodePos c)
+
+proc ithSon*(tree: PackedTree; n: NodePos; i: int): NodePos =
+  result = default(NodePos)
+  if tree.nodes[n.int].kind > nkNilLit:
+    var count = 0
+    for child in sonsReadonly(tree, n):
+      if count == i: return child
+      inc count
+  assert false, "node has no i-th child"
+
+when false:
+  proc `@`*(tree: PackedTree; lit: LitId): lent string {.inline.} =
+    tree.sh.strings[lit]
+
+template kind*(n: NodePos): TNodeKind = tree.nodes[n.int].kind
+template info*(n: NodePos): PackedLineInfo = tree.nodes[n.int].info
+template litId*(n: NodePos): LitId = LitId tree.nodes[n.int].operand
+
+template symId*(n: NodePos): SymId = SymId tree.nodes[n.int].operand
+
+proc firstSon*(n: NodePos): NodePos {.inline.} = NodePos(n.int+1)
+
+when false:
+  # xxx `nkStrLit` or `nkStrLit..nkTripleStrLit:` below?
+  proc strLit*(tree: PackedTree; n: NodePos): lent string =
+    assert n.kind == nkStrLit
+    result = tree.sh.strings[LitId tree.nodes[n.int].operand]
+
+  proc strVal*(tree: PackedTree; n: NodePos): string =
+    assert n.kind == nkStrLit
+    result = tree.sh.strings[LitId tree.nodes[n.int].operand]
+    #result = cookedStrLit(raw)
+
+  proc filenameVal*(tree: PackedTree; n: NodePos): string =
+    case n.kind
+    of nkStrLit:
+      result = strVal(tree, n)
+    of nkIdent:
+      result = tree.sh.strings[n.litId]
+    of nkSym:
+      result = tree.sh.strings[tree.sh.syms[int n.symId].name]
+    else:
+      result = ""
+
+  proc identAsStr*(tree: PackedTree; n: NodePos): lent string =
+    assert n.kind == nkIdent
+    result = tree.sh.strings[LitId tree.nodes[n.int].operand]
+
+const
+  externIntLit* = {nkCharLit,
+    nkIntLit,
+    nkInt8Lit,
+    nkInt16Lit,
+    nkInt64Lit,
+    nkUIntLit,
+    nkUInt8Lit,
+    nkUInt16Lit,
+    nkUInt32Lit,
+    nkUInt64Lit} # nkInt32Lit is missing by design!
+
+  externSIntLit* = {nkIntLit, nkInt8Lit, nkInt16Lit, nkInt64Lit}
+  externUIntLit* = {nkUIntLit, nkUInt8Lit, nkUInt16Lit, nkUInt32Lit, nkUInt64Lit}
+  directIntLit* = nkInt32Lit
+
+when false:
+  proc identIdImpl(tree: PackedTree; n: NodePos): LitId =
+    if n.kind == nkIdent:
+      result = n.litId
+    elif n.kind == nkSym:
+      result = tree.sh.syms[int n.symId].name
+    else:
+      result = LitId(0)
+
+  template identId*(n: NodePos): LitId = identIdImpl(tree, n)
+
+template copyInto*(dest, n, body) =
+  let patchPos = prepare(dest, tree, n)
+  body
+  patch dest, patchPos
+
+template copyIntoKind*(dest, kind, info, body) =
+  let patchPos = prepare(dest, kind, info)
+  body
+  patch dest, patchPos
+
+when false:
+  proc hasPragma*(tree: PackedTree; n: NodePos; pragma: string): bool =
+    let litId = tree.sh.strings.getKeyId(pragma)
+    if litId == LitId(0):
+      return false
+    assert n.kind == nkPragma
+    for ch0 in sonsReadonly(tree, n):
+      if ch0.kind == nkExprColonExpr:
+        if ch0.firstSon.identId == litId:
+          return true
+      elif ch0.identId == litId:
+        return true
+
+proc getNodeId*(tree: PackedTree): NodeId {.inline.} = NodeId tree.nodes.len
+
+when false:
+  proc produceError*(dest: var PackedTree; tree: PackedTree; n: NodePos; msg: string) =
+    let patchPos = prepare(dest, nkError, n.info)
+    dest.add nkStrLit, msg, n.info
+    copyTree(dest, tree, n)
+    patch dest, patchPos
+
+iterator allNodes*(tree: PackedTree): NodePos =
+  var p = 0
+  while p < tree.len:
+    yield NodePos(p)
+    let s = span(tree, p)
+    inc p, s
+
+proc toPackedItemId*(item: int32): PackedItemId {.inline.} =
+  PackedItemId(module: LitId(0), item: item)
--- a/compiler/ic/replayer.nim
+++ b/compiler/ic/replayer.nim
@@ -14,16 +14,15 @@
 import ".." / [ast, modulegraphs, trees, extccomp, btrees,
  msgs, lineinfos, pathutils, options, cgmeth]

-import std/tables
+import tables

 when defined(nimPreviewSlimSystem):
  import std/assertions

-proc replayStateChanges*(module: PSym; g: ModuleGraph; list: PNode) =
-  ## `list` is an `nkStmtList` of `nkReplayAction` nodes (macro-cache puts/incs/
-  ## adds/incls and a few pragmas) recorded for `module`. Under the NIF backend a
-  ## loaded module's `ast` is never reconstructed, so the caller passes the replay
-  ## actions it parsed out of the module's NIF directly.
+import packed_ast, ic, bitabs
+
+proc replayStateChanges*(module: PSym; g: ModuleGraph) =
+  let list = module.ast
  assert list != nil
  assert list.kind == nkStmtList
  for n in list:
@@ -67,9 +66,8 @@ proc replayStateChanges*(module: PSym; g: ModuleGraph; list: PNode) =
          g.cacheTables[destKey] = initBTree[string, PNode]()
        if not contains(g.cacheTables[destKey], key):
          g.cacheTables[destKey].add(key, val)
-        # else: the same key was already replayed. Under IC the import closure is
-        # replayed (direct module + transitive deps), so the same registration can
-        # legitimately be reached twice; re-applying it is a no-op, not an error.
+        else:
+          internalError(g.config, n.info, "key already exists: " & key)
      of "incl":
        let destKey = n[1].strVal
        let val = n[2]
@@ -91,36 +89,72 @@ proc replayStateChanges*(module: PSym; g: ModuleGraph; list: PNode) =
      else:
        internalAssert g.config, false

-proc replayBackendActions*(g: ModuleGraph; module: PSym; list: PNode) =
-  ## Applies the backend-relevant replay actions (C compile/link directives)
-  ## found in a NIF-loaded module's top-level statement list. The `nifc`
-  ## backend loads modules without going through sem's `replayStateChanges`,
-  ## so e.g. math's `{.passL: "-lm".}` was lost and the final link failed
-  ## with undefined references. VM cache actions are deliberately NOT
-  ## replayed here — codegen does not run macros.
-  if list == nil: return
-  for n in list:
-    if n.kind == nkReplayAction and n.len >= 2 and
-        n[0].kind == nkStrLit and n[1].kind == nkStrLit:
-      case n[0].strVal
-      of "compile":
-        if n.len == 4 and n[2].kind == nkStrLit:
-          let cname = AbsoluteFile n[1].strVal
-          var cf = Cfile(nimname: splitFile(cname).name, cname: cname,
-                         obj: AbsoluteFile n[2].strVal,
-                         flags: {CfileFlag.External},
-                         customArgs: n[3].strVal)
-          extccomp.addExternalFileToCompile(g.config, cf)
-      of "link":
-        extccomp.addExternalFileToLink(g.config, AbsoluteFile n[1].strVal)
-      of "passl":
-        extccomp.addLinkOption(g.config, n[1].strVal)
-      of "passc":
-        extccomp.addCompileOption(g.config, n[1].strVal)
-      of "localpassc":
-        extccomp.addLocalCompileOption(g.config, n[1].strVal,
-          toFullPathConsiderDirty(g.config, module.info.fileIndex))
-      of "cppdefine":
-        options.cppDefine(g.config, n[1].strVal)
-      else:
-        discard
+proc replayBackendProcs*(g: ModuleGraph; module: int) =
+  for it in mitems(g.packed[module].fromDisk.attachedOps):
+    let key = translateId(it[0], g.packed, module, g.config)
+    let op = it[1]
+    let tmp = translateId(it[2], g.packed, module, g.config)
+    let symId = FullId(module: tmp.module, packed: it[2])
+    g.attachedOps[op][key] = LazySym(id: symId, sym: nil)
+
+  for it in mitems(g.packed[module].fromDisk.enumToStringProcs):
+    let key = translateId(it[0], g.packed, module, g.config)
+    let tmp = translateId(it[1], g.packed, module, g.config)
+    let symId = FullId(module: tmp.module, packed: it[1])
+    g.enumToStringProcs[key] = LazySym(id: symId, sym: nil)
+
+proc replayGenericCacheInformation*(g: ModuleGraph; module: int) =
+  ## We remember the generic instantiations a module performed
+  ## in order to to avoid the code bloat that generic code tends
+  ## to imply. This is cheaper than deduplication of identical
+  ## generic instantiations. However, deduplication is more
+  ## powerful and general and I hope to implement it soon too
+  ## (famous last words).
+  assert g.packed[module].status == loaded
+  for it in g.packed[module].fromDisk.typeInstCache:
+    let key = translateId(it[0], g.packed, module, g.config)
+    g.typeInstCache.mgetOrPut(key, @[]).add LazyType(id: FullId(module: module, packed: it[1]), typ: nil)
+
+  for it in mitems(g.packed[module].fromDisk.procInstCache):
+    let key = translateId(it.key, g.packed, module, g.config)
+    let sym = translateId(it.sym, g.packed, module, g.config)
+    var concreteTypes = newSeq[FullId](it.concreteTypes.len)
+    for i in 0..high(it.concreteTypes):
+      let tmp = translateId(it.concreteTypes[i], g.packed, module, g.config)
+      concreteTypes[i] = FullId(module: tmp.module, packed: it.concreteTypes[i])
+
+    g.procInstCache.mgetOrPut(key, @[]).add LazyInstantiation(
+      module: module, sym: FullId(module: sym.module, packed: it.sym),
+      concreteTypes: concreteTypes, inst: nil)
+
+  for it in mitems(g.packed[module].fromDisk.methodsPerType):
+    let key = translateId(it[0], g.packed, module, g.config)
+    let col = it[1]
+    let tmp = translateId(it[2], g.packed, module, g.config)
+    let symId = FullId(module: tmp.module, packed: it[2])
+    g.methodsPerType.mgetOrPut(key, @[]).add (col, LazySym(id: symId, sym: nil))
+
+  replayBackendProcs(g, module)
+
+  for it in mitems(g.packed[module].fromDisk.methods):
+    let sym = loadSymFromId(g.config, g.cache, g.packed, module,
+                            PackedItemId(module: LitId(0), item: it))
+    methodDef(g, g.idgen, sym)
+
+  when false:
+    # not used anymore:
+    for it in mitems(g.packed[module].fromDisk.compilerProcs):
+      let symId = FullId(module: module, packed: PackedItemId(module: LitId(0), item: it[1]))
+      g.lazyCompilerprocs[g.packed[module].fromDisk.sh.strings[it[0]]] = symId
+
+  for it in mitems(g.packed[module].fromDisk.converters):
+    let symId = FullId(module: module, packed: PackedItemId(module: LitId(0), item: it))
+    g.ifaces[module].converters.add LazySym(id: symId, sym: nil)
+
+  for it in mitems(g.packed[module].fromDisk.trmacros):
+    let symId = FullId(module: module, packed: PackedItemId(module: LitId(0), item: it))
+    g.ifaces[module].patterns.add LazySym(id: symId, sym: nil)
+
+  for it in mitems(g.packed[module].fromDisk.pureEnums):
+    let symId = FullId(module: module, packed: PackedItemId(module: LitId(0), item: it))
+    g.ifaces[module].pureEnums.add LazySym(id: symId, sym: nil)
--- a/compiler/ic/rodfiles.nim
+++ b/compiler/ic/rodfiles.nim
@@ -0,0 +1,251 @@
+#
+#
+#           The Nim Compiler
+#        (c) Copyright 2020 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## Low level binary format used by the compiler to store and load various AST
+## and related data.
+##
+## NB: this is incredibly low level and if you're interested in how the
+##     compiler works and less a storage format, you're probably looking for
+##     the `ic` or `packed_ast` modules to understand the logical format.
+
+from typetraits import supportsCopyMem
+
+when defined(nimPreviewSlimSystem):
+  import std/[syncio, assertions]
+
+## Overview
+## ========
+## `RodFile` represents a Rod File (versioned binary format), and the
+## associated data for common interactions such as IO and error tracking
+## (`RodFileError`). The file format broken up into sections (`RodSection`)
+## and preceded by a header (see: `cookie`). The precise layout, section
+## ordering and data following the section are determined by the user. See
+## `ic.loadRodFile`.
+##
+## A basic but "wrong" example of the lifecycle:
+## ---------------------------------------------
+## 1. `create` or `open`        - create a new one or open an existing
+## 2. `storeHeader`             - header info
+## 3. `storePrim` or `storeSeq` - save your stuff
+## 4. `close`                   - and we're done
+##
+## Now read the bits below to understand what's missing.
+##
+## ### Issues with the Example
+## Missing Sections:
+## This is a low level API, so headers and sections need to be stored and
+## loaded by the user, see `storeHeader` & `loadHeader` and `storeSection` &
+## `loadSection`, respectively.
+##
+## No Error Handling:
+## The API is centered around IO and prone to error, each operation checks or
+## sets the `RodFile.err` field. A user of this API needs to handle these
+## appropriately.
+##
+## API Notes
+## =========
+##
+## Valid inputs for Rod files
+## --------------------------
+## ASTs, hopes, dreams, and anything as long as it and any children it may have
+## support `copyMem`. This means anything that is not a pointer and that does not contain a pointer. At a glance these are:
+## * string
+## * objects & tuples (fields are recursed)
+## * sequences AKA `seq[T]`
+##
+## Note on error handling style
+## ----------------------------
+## A flag based approach is used where operations no-op in case of a
+## preexisting error and set the flag if they encounter one.
+##
+## Misc
+## ----
+## * 'Prim' is short for 'primitive', as in a non-sequence type
+
+type
+  RodSection* = enum
+    versionSection
+    configSection
+    stringsSection
+    checkSumsSection
+    depsSection
+    numbersSection
+    exportsSection
+    hiddenSection
+    reexportsSection
+    compilerProcsSection
+    trmacrosSection
+    convertersSection
+    methodsSection
+    pureEnumsSection
+    toReplaySection
+    topLevelSection
+    bodiesSection
+    symsSection
+    typesSection
+    typeInstCacheSection
+    procInstCacheSection
+    attachedOpsSection
+    methodsPerTypeSection
+    enumToStringProcsSection
+    typeInfoSection  # required by the backend
+    backendFlagsSection
+    aliveSymsSection # beware, this is stored in a `.alivesyms` file.
+
+  RodFileError* = enum
+    ok, tooBig, cannotOpen, ioFailure, wrongHeader, wrongSection, configMismatch,
+    includeFileChanged
+
+  RodFile* = object
+    f*: File
+    currentSection*: RodSection # for error checking
+    err*: RodFileError # little experiment to see if this works
+                       # better than exceptions.
+
+const
+  RodVersion = 1
+  cookie = [byte(0), byte('R'), byte('O'), byte('D'),
+            byte(sizeof(int)*8), byte(system.cpuEndian), byte(0), byte(RodVersion)]
+
+proc setError(f: var RodFile; err: RodFileError) {.inline.} =
+  f.err = err
+  #raise newException(IOError, "IO error")
+
+proc storePrim*(f: var RodFile; s: string) =
+  ## Stores a string.
+  ## The len is prefixed to allow for later retreival.
+  if f.err != ok: return
+  if s.len >= high(int32):
+    setError f, tooBig
+    return
+  var lenPrefix = int32(s.len)
+  if writeBuffer(f.f, addr lenPrefix, sizeof(lenPrefix)) != sizeof(lenPrefix):
+    setError f, ioFailure
+  else:
+    if s.len != 0:
+      if writeBuffer(f.f, unsafeAddr(s[0]), s.len) != s.len:
+        setError f, ioFailure
+
+proc storePrim*[T](f: var RodFile; x: T) =
+  ## Stores a non-sequence/string `T`.
+  ## If `T` doesn't support `copyMem` and is an object or tuple then the fields
+  ## are written -- the user from context will need to know which `T` to load.
+  if f.err != ok: return
+  when supportsCopyMem(T):
+    if writeBuffer(f.f, unsafeAddr(x), sizeof(x)) != sizeof(x):
+      setError f, ioFailure
+  elif T is tuple:
+    for y in fields(x):
+      storePrim(f, y)
+  elif T is object:
+    for y in fields(x):
+      when y is seq:
+        storeSeq(f, y)
+      else:
+        storePrim(f, y)
+  else:
+    {.error: "unsupported type for 'storePrim'".}
+
+proc storeSeq*[T](f: var RodFile; s: seq[T]) =
+  ## Stores a sequence of `T`s, with the len as a prefix for later retrieval.
+  if f.err != ok: return
+  if s.len >= high(int32):
+    setError f, tooBig
+    return
+  var lenPrefix = int32(s.len)
+  if writeBuffer(f.f, addr lenPrefix, sizeof(lenPrefix)) != sizeof(lenPrefix):
+    setError f, ioFailure
+  else:
+    for i in 0..<s.len:
+      storePrim(f, s[i])
+
+proc loadPrim*(f: var RodFile; s: var string) =
+  ## Read a string, the length was stored as a prefix
+  if f.err != ok: return
+  var lenPrefix = int32(0)
+  if readBuffer(f.f, addr lenPrefix, sizeof(lenPrefix)) != sizeof(lenPrefix):
+    setError f, ioFailure
+  else:
+    s = newString(lenPrefix)
+    if lenPrefix > 0:
+      if readBuffer(f.f, unsafeAddr(s[0]), s.len) != s.len:
+        setError f, ioFailure
+
+proc loadPrim*[T](f: var RodFile; x: var T) =
+  ## Load a non-sequence/string `T`.
+  if f.err != ok: return
+  when supportsCopyMem(T):
+    if readBuffer(f.f, unsafeAddr(x), sizeof(x)) != sizeof(x):
+      setError f, ioFailure
+  elif T is tuple:
+    for y in fields(x):
+      loadPrim(f, y)
+  elif T is object:
+    for y in fields(x):
+      when y is seq:
+        loadSeq(f, y)
+      else:
+        loadPrim(f, y)
+  else:
+    {.error: "unsupported type for 'loadPrim'".}
+
+proc loadSeq*[T](f: var RodFile; s: var seq[T]) =
+  ## `T` must be compatible with `copyMem`, see `loadPrim`
+  if f.err != ok: return
+  var lenPrefix = int32(0)
+  if readBuffer(f.f, addr lenPrefix, sizeof(lenPrefix)) != sizeof(lenPrefix):
+    setError f, ioFailure
+  else:
+    s = newSeq[T](lenPrefix)
+    for i in 0..<lenPrefix:
+      loadPrim(f, s[i])
+
+proc storeHeader*(f: var RodFile) =
+  ## stores the header which is described by `cookie`.
+  if f.err != ok: return
+  if f.f.writeBytes(cookie, 0, cookie.len) != cookie.len:
+    setError f, ioFailure
+
+proc loadHeader*(f: var RodFile) =
+  ## Loads the header which is described by `cookie`.
+  if f.err != ok: return
+  var thisCookie: array[cookie.len, byte] = default(array[cookie.len, byte])
+  if f.f.readBytes(thisCookie, 0, thisCookie.len) != thisCookie.len:
+    setError f, ioFailure
+  elif thisCookie != cookie:
+    setError f, wrongHeader
+
+proc storeSection*(f: var RodFile; s: RodSection) =
+  ## update `currentSection` and writes the bytes value of s.
+  if f.err != ok: return
+  assert f.currentSection < s
+  f.currentSection = s
+  storePrim(f, s)
+
+proc loadSection*(f: var RodFile; expected: RodSection) =
+  ## read the bytes value of s, sets and error if the section is incorrect.
+  if f.err != ok: return
+  var s: RodSection = default(RodSection)
+  loadPrim(f, s)
+  if expected != s and f.err == ok:
+    setError f, wrongSection
+
+proc create*(filename: string): RodFile =
+  ## create the file and open it for writing
+  result = default(RodFile)
+  if not open(result.f, filename, fmWrite):
+    setError result, cannotOpen
+
+proc close*(f: var RodFile) = close(f.f)
+
+proc open*(filename: string): RodFile =
+  ## open the file for reading
+  result = default(RodFile)
+  if not open(result.f, filename, fmRead):
+    setError result, cannotOpen
--- a/compiler/icconfig.nim
+++ b/compiler/icconfig.nim
@@ -1,292 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2026 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-## Precompiled config for the incremental compiler (`nim ic`).
-##
-## `nim ic` builds the program by spawning one `nim m` child per module (or
-## strongly-connected import group) plus a final `nim nifc`. Each child is a
-## full Nim process, so each would normally re-read the whole `nim.cfg` chain
-## *and* re-run `config.nims` through the VM — work that is identical for every
-## child and, because of the VM run, far from free. With ~85 modules in the
-## compiler itself that config work is paid ~85 times during `koch bootic`.
-##
-## The fix mirrors Nimony's `.cfg.nif`: the driver parses config once, records
-## the net effect, and the children replay it. Every config-file switch funnels
-## through `processSwitch(..., passPP, ...)` (`nimconf.parseAssignment` and the
-## `switch()` callback in `scriptconfig`), so the recorded sequence of those
-## switches, replayed in order, reproduces an identical `ConfigRef` without any
-## file read or VM run. The one config side effect that does not go through
-## `processSwitch` is `cppDefine` (it mutates `conf.cppDefines` directly), so the
-## resolved set is serialised alongside.
-##
-## Path-search switches are deliberately excluded from the recording (see
-## `commands.processSwitch`): their resolved result already lives in
-## `conf.searchPaths`, which the driver forwards to every child as absolute
-## `--path` arguments; replaying their raw, config-dir-relative arguments here
-## would misresolve.
-
-import options, commands, lineinfos, pathutils, msgs
-import std/[algorithm, os, sets, osproc, times, streams, syncio]
-import "../dist/nimony/src/lib" / [nifbuilder, nifcoreparse]
-
-const
-  IcConfigVersion* = "2"
-    ## Artifact format version. Bump on any layout change here so a child built
-    ## by an older compiler rejects a stale artifact and falls back to normal
-    ## config loading instead of replaying a format it cannot parse.
-
-proc writeIcConfig*(conf: ConfigRef; outfile: string) =
-  ## Serialise the resolved config (the config-file switches recorded during
-  ## `loadConfigs`, the resolved `cppDefines`/`searchPaths`, the nimcache dir, and
-  ## the list of config *source* files for staleness detection) into `outfile`.
-  ## `OnlyIfChanged`: when the content is byte-identical to what is already on
-  ## disk the file is left untouched so its mtime does not advance — otherwise
-  ## every `nim ic` run would re-fire the whole nifmake graph (see `nifler`'s
-  ## `produceConfig`, whose model this mirrors).
-  var b = nifbuilder.open(outfile, writeMode = OnlyIfChanged)
-  b.withTree "stmts":
-    b.withTree "meta":
-      b.addStrLit IcConfigVersion
-    b.withTree "sources":
-      # Every config file read while loading (nim.cfg chain + config.nims), so a
-      # later run can decide via mtimes whether this artifact is still current
-      # (see `sourcesChanged`).
-      for f in conf.configFiles:
-        b.addStrLit f.string
-    b.withTree "nimcache":
-      # Resolved build nimcache. Recorded (unlike the path-search switches) so the
-      # driver, which replays this artifact instead of parsing `nim.cfg`, still
-      # learns a `--nimcache:` set inside `nim.cfg` and builds in the right place.
-      b.addStrLit conf.nimcacheDir.string
-    b.withTree "cppdefines":
-      # HashSet iteration order is unspecified; sort so the artifact is
-      # byte-stable across runs (nifmake keys rebuilds off content changes).
-      var defs: seq[string] = @[]
-      for d in conf.cppDefines: defs.add d
-      sort defs
-      for d in defs: b.addStrLit d
-    b.withTree "searchpaths":
-      # The resolved (absolute) search paths. Path-search *switches* are skipped
-      # below because their raw arguments are config-dir-relative; the net effect
-      # lives here instead, so a replayer with no `--path` command-line arguments
-      # (the `nim ic` driver itself) still resolves imports. `nim m`/`nim nifc`
-      # children also receive these as forwarded `--path` args; the dedup on
-      # replay makes the overlap harmless.
-      for p in conf.searchPaths:
-        b.addStrLit p.string
-    b.withTree "switches":
-      for sw in conf.icConfigSwitches:
-        b.addTree "sw"
-        b.addStrLit sw.switch
-        b.addStrLit sw.arg
-        b.endTree()
-  b.close()
-
-proc applyIcConfig*(conf: ConfigRef; infile: string): bool =
-  ## Replay the precompiled config into `conf`. Returns false (and applies
-  ## nothing meaningful) when the artifact is missing or written by a compiler
-  ## with an incompatible format version, so the caller can fall back to reading
-  ## the config files normally.
-  if not fileExists(infile): return false
-  var pool = newPool()
-  var tags = newTagPool()
-  let
-    stmtsTag = tags.registerTag("stmts")
-    metaTag = tags.registerTag("meta")
-    sourcesTag = tags.registerTag("sources")
-    nimcacheTag = tags.registerTag("nimcache")
-    cppTag = tags.registerTag("cppdefines")
-    pathsTag = tags.registerTag("searchpaths")
-    switchesTag = tags.registerTag("switches")
-    swTag = tags.registerTag("sw")
-  var buf = parseFromFile(infile, 1000, pool, tags)
-  var c = beginRead(buf)
-  if c.kind != TagLit or c.cursorTagId != stmtsTag:
-    endRead(c)
-    return false
-  var version = ""
-  var sawMeta = false
-  let info = unknownLineInfo
-  c.loopInto:
-    if c.kind == TagLit:
-      if c.cursorTagId == metaTag:
-        sawMeta = true
-        c.loopInto:
-          if c.kind == StrLit:
-            version = strVal(c)
-            inc c
-          else:
-            skip c
-      elif c.cursorTagId == nimcacheTag:
-        c.loopInto:
-          if c.kind == StrLit:
-            let nc = strVal(c)
-            # Only when nimcache was not already pinned on the command line: a
-            # `--nimcache:` argument the driver/child was launched with must win
-            # over whatever `nim.cfg` recorded into the artifact.
-            if nc.len > 0 and conf.nimcacheDir.isEmpty:
-              conf.nimcacheDir = AbsoluteDir(nc)
-            inc c
-          else:
-            skip c
-      elif c.cursorTagId == sourcesTag:
-        # Replay does not need the source list; it exists only for
-        # `sourcesChanged`. Skip the whole section.
-        skip c
-      elif c.cursorTagId == cppTag:
-        c.loopInto:
-          if c.kind == StrLit:
-            cppDefine(conf, strVal(c))
-            inc c
-          else:
-            skip c
-      elif c.cursorTagId == pathsTag:
-        c.loopInto:
-          if c.kind == StrLit:
-            # Append preserving the serialised order (which already reflects the
-            # driver's addPath insert-at-front sequence), deduping against any
-            # path a child already received via a forwarded `--path` argument.
-            let d = AbsoluteDir(strVal(c))
-            if not conf.searchPaths.contains(d): conf.searchPaths.add d
-            inc c
-          else:
-            skip c
-      elif c.cursorTagId == switchesTag:
-        c.loopInto:
-          if c.kind == TagLit and c.cursorTagId == swTag:
-            var sw = ""
-            var arg = ""
-            var idx = 0
-            c.loopInto:
-              if c.kind == StrLit:
-                if idx == 0: sw = strVal(c)
-                else: arg = strVal(c)
-                inc idx
-                inc c
-              else:
-                skip c
-            processSwitch(sw, arg, passPP, info, conf)
-          else:
-            skip c
-      else:
-        skip c
-    else:
-      skip c
-  endRead(c)
-  result = sawMeta and version == IcConfigVersion
-
-proc sourcesChanged*(configFile: string): bool =
-  ## True when the precompiled config at `configFile` is missing, malformed,
-  ## written by an incompatible version, or any recorded config *source* file is
-  ## newer than it (or has vanished) — i.e. the artifact must be regenerated.
-  ## Mirrors nifler's `sourcesChanged`: the source list lives inside the artifact
-  ## so this needs no out-of-band knowledge of which `nim.cfg`s were read.
-  if not fileExists(configFile): return true
-  let modtime = getLastModificationTime(configFile)
-  var pool = newPool()
-  var tags = newTagPool()
-  let
-    stmtsTag = tags.registerTag("stmts")
-    metaTag = tags.registerTag("meta")
-    sourcesTag = tags.registerTag("sources")
-  var buf = parseFromFile(configFile, 1000, pool, tags)
-  var c = beginRead(buf)
-  if c.kind != TagLit or c.cursorTagId != stmtsTag:
-    endRead(c)
-    return true
-  var version = ""
-  var depsChanged = false
-  c.loopInto:
-    if c.kind == TagLit and c.cursorTagId == metaTag:
-      c.loopInto:
-        if c.kind == StrLit:
-          version = strVal(c)
-          inc c
-        else:
-          skip c
-    elif c.kind == TagLit and c.cursorTagId == sourcesTag:
-      c.loopInto:
-        if c.kind == StrLit:
-          let dep = strVal(c)
-          if not fileExists(dep) or getLastModificationTime(dep) >= modtime:
-            depsChanged = true
-          inc c
-        else:
-          skip c
-    else:
-      skip c
-  endRead(c)
-  result = depsChanged or version != IcConfigVersion
-
-proc produceIcConfig*(conf: ConfigRef) =
-  ## The `cmdIcConfig` command. By the time it runs, the normal pipeline has
-  ## already fully parsed the `nim.cfg` chain and run `config.nims`, so the
-  ## resolved config is sitting in `conf`; just serialise it to `--o`.
-  let outPath = conf.icConfigOut
-  if outPath.len == 0:
-    rawMessage(conf, errGenerated, "icconfig: missing output path (--icConfigOut)")
-    return
-  createDir(parentDir(outPath))
-  writeIcConfig(conf, outPath)
-
-proc ensureIcConfig*(conf: ConfigRef) =
-  ## Driver-side (`cmdIc`). Make sure an up-to-date precompiled config exists,
-  ## (re)producing it in a *separate* process when missing or stale, then point
-  ## `conf.icPreparsedConfig` at it so the driver replays the very same config its
-  ## `nim m`/`nim nifc` children will — perfect speed (config parsed at most once,
-  ## skipped entirely when nothing changed) and consistency (one producer, every
-  ## process replays its output). The artifact lives in the nimcache derived from
-  ## the command line (pre-config-parse), which is the one the children are told;
-  ## a `--nimcache:` set inside `nim.cfg` is recovered from the artifact itself.
-  let cacheDir = getNimcacheDir(conf).string
-  # Start from a clean cache when the on-disk NIF format stamp is absent or stale
-  # (see `icFormatVersion`). This must happen HERE, before the config artifact is
-  # produced — `commandIc` performs the same check later, but by then the artifact
-  # would already live in the cache and the wipe would delete it.
-  createDir(cacheDir)
-  let versionFile = cacheDir / "ic.version"
-  let stamp = if fileExists(versionFile): readFile(versionFile) else: ""
-  if stamp != icFormatVersion:
-    removeDir(cacheDir)
-    createDir(cacheDir)
-    writeFile(versionFile, icFormatVersion)
-  let outPath = cacheDir / "ic_config.cfg.nif"
-  if not fileExists(outPath) or sourcesChanged(outPath):
-    createDir(cacheDir)
-    # Re-invoke ourselves as the config producer: reuse this process's command
-    # line, dropping the command argument (`ic`/`track`) in favour of `icconfig`
-    # and the explicit output path. Every switch must land BEFORE the project
-    # file, because anything after the project is swallowed into
-    # `config.arguments` by `cmdLineRest` (and a non-empty `arguments` without
-    # `--run` is a hard error). Callers may legitimately put switches after the
-    # project — `nim track PROJ --def:...` — so we re-order rather than replay
-    # verbatim: all `-`-prefixed switches first (in encounter order), then the
-    # non-switch project token(s). The producer re-reads `nim.cfg` itself.
-    var pargs = @["icconfig", "--icConfigOut:" & outPath]
-    var rest: seq[string] = @[]
-    var droppedCmd = false
-    for a in commandLineParams():
-      if a.len == 0: continue
-      if a[0] == '-':
-        pargs.add a
-      elif not droppedCmd:
-        droppedCmd = true  # drop the original command token (`ic`/`track`)
-      else:
-        rest.add a  # project file (and any further non-switch tokens) go last
-    for a in rest: pargs.add a
-    let p = startProcess(getAppFilename(), args = pargs,
-                         options = {poStdErrToStdOut})
-    let outp = p.outputStream.readAll()
-    let code = p.waitForExit()
-    p.close()
-    if code != 0 or not fileExists(outPath):
-      rawMessage(conf, errGenerated,
-        "failed to produce precompiled config (exit code " & $code & "):\n" & outp)
-      return
-  conf.icPreparsedConfig = outPath
--- a/compiler/icmodnames.nim
+++ b/compiler/icmodnames.nim
@@ -1,55 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2026 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-## Nim's OWN module-suffix, replacing nimony's `gear2/modnames.moduleSuffix`.
-##
-## nimony's version hashes a path made RELATIVE to `getCurrentDir()` (or the
-## shortest search-path-relative form), so the produced suffix depends on the
-## current working directory AND the searchPath set. Under `nim ic` the
-## DISCOVERY pass (`deps.nim`, in the driver process) and the COMPILE pass
-## (`nifgen`/`typekeys`, in a child `nim m` process) can run with different CWDs
-## or `--path` sets, so the SAME file hashes to two different suffixes: e.g.
-## `std/staticos` became `sta5rk8sn1` at discovery but `sta4c0qxk` at compile, so
-## every importer waited forever for a `.s.bif` that was actually written under
-## the other name — a cold `nim ic` build (of anything pulling in `std/os`, whose
-## `oscommon` does `from std/staticos import PathComponent`) never converged.
-##
-## Hashing the CANONICAL ABSOLUTE path makes the suffix a pure function of the
-## file, identical across every process and call site. The base-name prefix +
-## base-36 `uhash` layout is kept byte-for-byte compatible with the old scheme so
-## nothing but the hashed string changes.
-
-import std/os
-import "../dist/nimony/src/lib" / tinyhashes
-
-const
-  PrefixLen = 3 # keep it short: the suffix ends up in every mangled C name
-  Base36 = "0123456789abcdefghijklmnopqrstuvwxyz"
-
-proc moduleSuffix*(path: string; searchPaths: openArray[string]): string =
-  ## `searchPaths` is accepted for signature-compatibility with the replaced
-  ## `modnames.moduleSuffix` but is deliberately IGNORED — the suffix must not
-  ## depend on the search-path set or the CWD (see the module doc).
-  # Absolute inputs (the norm at every call site: `toFullPath`/`projectFull`)
-  # pass straight through `normalizedPath` with no `getCurrentDir` involvement;
-  # a stray relative path is made absolute against the CWD only as a fallback.
-  var f = path
-  if not isAbsolute(f):
-    try: f = absolutePath(f)
-    except CatchableError: discard
-  f = normalizedPath(f)
-  let m = splitFile(f).name
-  var id = uhash(f)
-  result = newStringOfCap(10)
-  for i in 0 ..< min(m.len, PrefixLen):
-    result.add m[i]
-  # base-36 of the hash, low digit first (order is irrelevant for identity).
-  while id > 0'u32:
-    result.add Base36[int(id mod 36'u32)]
-    id = id div 36'u32
--- a/compiler/icnifcore.nim
+++ b/compiler/icnifcore.nim
@@ -1,252 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2026 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-## nifcore-based IC serialization helpers — Stage 1 of porting the IC backend
-## from the old `nifstreams`/`nifcursors` NIF stack to `nifcore` (see
-## `doc/ic_nifcore_port.md`).
-##
-## It hosts:
-## * the process-wide shared `Pool`/`TagPool` that stands in for the old global
-##   `nifstreams.pool`,
-## * `writeFileStable`, the content-stable file writer mirroring
-##   `nifcursors.writeFile(..., OnlyIfChanged)`,
-## * the first ported writer (`writeSemDeps`), used as the migration spike.
-##
-## No `nifstreams`/`nifcursors` types cross this module's boundary: callers pass
-## plain Nim values (config, ids, string lists), so it can coexist with the
-## still-old-API `ast2nif.nim` during the migration.
-
-import std / [syncio, algorithm]
-from std / os import removeFile, moveFile
-import options, pathutils, typekeys
-import "../dist/nimony/src/lib" / [nifcore, nifcoreparse, nifreader, bif]
-
-# One shared literals pool + tag pool for the whole process — the nifcore
-# analogue of the old global `nifstreams.pool`. A single shared pool keeps
-# string/symbol/file ids stable across every TokenBuf the IC backend builds,
-# preserving the old global-pool semantics during the migration. (Stage 6 may
-# move to fresh per-file pools for bif's fast path; see doc/ic_nifcore_port.md.)
-let icPool* = newPool()
-let icTags* = newTagPool()
-
-proc createIcBuf*(cap = 16): TokenBuf {.inline.} =
-  ## A `TokenBuf` bound to the shared IC pools.
-  createTokenBuf(cap, icPool, icTags)
-
-proc tagId*(s: string): TagId {.inline.} =
-  ## Intern a tag name in the shared tag pool.
-  icTags.registerTag(s)
-
-type
-  IcBuilder* = object
-    ## A thin nifcore `TokenBuf` builder whose surface is *primitive types only*
-    ## (strings/ints/floats). It lets the still-old-API `ast2nif.nim` drive a
-    ## nifcore buffer without any nifcore type crossing the module boundary —
-    ## the bridge that routes IC output onto the nifcore serializer (Stage 2).
-    buf*: TokenBuf
-
-proc newIcBuilder*(cap = 16): IcBuilder = IcBuilder(buf: createIcBuf(cap))
-
-proc openTag*(b: var IcBuilder; tag: string) {.inline.} = b.buf.openTag(tagId(tag))
-proc closeTag*(b: var IcBuilder) {.inline.} = b.buf.closeTag()
-proc addSymUse*(b: var IcBuilder; s: string) {.inline.} = b.buf.addSymUse(s)
-proc addSymDef*(b: var IcBuilder; s: string) {.inline.} = b.buf.addSymDef(s)
-proc addIdent*(b: var IcBuilder; s: string) {.inline.} = b.buf.addIdent(s)
-proc addStrLit*(b: var IcBuilder; s: string) {.inline.} = b.buf.addStrLit(s)
-proc addIntLit*(b: var IcBuilder; v: int64) {.inline.} = b.buf.addIntLit(v)
-proc addUIntLit*(b: var IcBuilder; v: uint64) {.inline.} = b.buf.addUIntLit(v)
-proc addFloatLit*(b: var IcBuilder; v: float64) {.inline.} = b.buf.addFloatLit(v)
-proc addCharLit*(b: var IcBuilder; c: char) {.inline.} = b.buf.addCharLit(c)
-proc addDotToken*(b: var IcBuilder) {.inline.} = b.buf.addDotToken()
-
-proc lineInfo*(b: var IcBuilder; file: string; line, col: int32; comment = "") =
-  ## Attach line info (+ optional `#comment#`) to the head just emitted. No-op
-  ## when `file` is empty (matches the old "emit only when info is valid").
-  ## Strings are interned in the shared pools; the file/comment ids reproduce
-  ## the old `pool.files`/`pool.strings` entries by string value.
-  if file.len == 0: return
-  let fid = icPool.filenames.getOrIncl(file)
-  let cid = if comment.len > 0: icPool.strings.getOrIncl(comment) else: StrId(0)
-  b.buf.appendLineInfo(fid, line, col, cid)
-
-proc writeFileStable*(b: var TokenBuf; path: string; onlyIfChanged = false) =
-  ## Serialize `b` to canonical module NIF text and write it. Mirrors
-  ## `nifcursors.writeFile`: the module suffix is derived from `path`
-  ## (`"." & extractModuleSuffix`), and `onlyIfChanged` skips the write when the
-  ## on-disk bytes already match — the content-stability nifmake's incremental
-  ## rebuild depends on.
-  let content = toModuleString(b, "." & extractModuleSuffix(path))
-  if onlyIfChanged:
-    let existing =
-      try: readFile(path)
-      except CatchableError: ""
-    if existing == content: return
-  writeFile(path, content)
-
-proc writeStable*(b: var IcBuilder; path: string; onlyIfChanged = false) {.inline.} =
-  writeFileStable(b.buf, path, onlyIfChanged)
-
-proc cursorPool*(c: Cursor): Pool {.inline.} = nifcore.pool(c)
-  ## The literals pool the cursor's buffer was built against. `ast2nif.nim`
-  ## imports `nifcore` with `except pool` (to keep nifstreams' global `pool`
-  ## var the writer uses), so the reader reaches a cursor's pool through here —
-  ## needed once `bif`-loaded buffers carry their OWN fresh pool rather than the
-  ## shared `icPool`.
-
-proc freshModuleCopy(b: var IcBuilder): TokenBuf =
-  ## Re-home `b.buf` into a PRIVATE, module-local pool via `addSubtree` (which
-  ## re-interns only the literals/tags this buffer actually uses). `b.buf` is bound
-  ## to the process-wide shared `icPool`/`icTags`; storing it directly would embed
-  ## the WHOLE shared pool (correct but huge — see `bif.storeToFile`). The copy's
-  ## fresh-pool reload reproduces ids verbatim (the bif fresh-pool INVARIANT).
-  result = createTokenBuf(b.buf.len, newPool(), newTagPool())
-  var c = b.buf.beginRead()
-  while c.hasMore:
-    addSubtree(result, c)
-    skip c
-
-proc storeBif*(b: var IcBuilder; path: string; dottedSuffix: string) =
-  ## Persist the buffer as a compact, self-contained binary NIF (`.bif`).
-  var fresh = freshModuleCopy(b)
-  bif.store(fresh, path, dottedSuffix)
-
-proc storeBifStable*(b: var IcBuilder; path: string; dottedSuffix: string) =
-  ## Content-stable `bif` write — the binary analogue of `writeFileStable`'s
-  ## `onlyIfChanged`: only replace `path` when the encoded bytes differ, so an
-  ## unchanged sidecar keeps its mtime and nifmake prunes the dependent rebuild
-  ## cascade. Used for the iface/impl cookies + dep sidecars whose byte-stability
-  ## gates incremental builds. (bif encoding is deterministic for a given buffer
-  ## under fresh pools, so equal content ⇒ equal bytes.)
-  var fresh = freshModuleCopy(b)
-  let tmp = path & ".tmp"
-  bif.store(fresh, tmp, dottedSuffix)
-  let newBytes = readFile(tmp)
-  let oldBytes =
-    try: readFile(path)
-    except CatchableError: ""
-  if newBytes == oldBytes:
-    removeFile(tmp)
-  else:
-    moveFile(tmp, path)
-
-# --- subtree splicing (shared pool, so a raw subtree copy is exact) ----------
-
-proc addAll*(dest: var IcBuilder; src: var IcBuilder) =
-  ## Append every top-level subtree of `src` into `dest` — the nifcore analogue
-  ## of the old `dest.add wholeBuffer` splice.
-  var c = src.buf.beginRead()
-  while c.hasMore:
-    addSubtree(dest.buf, c)
-    skip c
-
-proc addStmtsBody*(dest: var IcBuilder; src: var IcBuilder) =
-  ## Append the BODY of a `(stmts . . <body> )` builder into `dest`, dropping the
-  ## wrapper tag and its two leading dot slots (flags/type) — the nifcore
-  ## analogue of the old `for i in 3 ..< content.len-1: dest.add content[i]`.
-  var c = src.buf.beginRead()   # at (stmts
-  c.into:
-    skip c   # flags dot
-    skip c   # type dot
-    while c.hasMore:
-      addSubtree(dest.buf, c)
-      skip c
-
-# --- cookie input: a line-info-free logical token list of the module ---------
-# The cookie hashers (ast2nif) need a flat, ParRi-bearing, index-addressable
-# view of the serialized module. nifcore has no ParRi kind and variable-width
-# tokens, so we flatten the buffer here (in the clean nifcore world) into a
-# neutral `CookieTok` list — no nifcore type crosses into ast2nif.
-
-type
-  CookieKind* = enum
-    ckParLe, ckParRi, ckSym, ckSymDef, ckIdent, ckStr, ckInt, ckUInt, ckFloat, ckChar, ckDot
-  CookieTok* = object
-    kind*: CookieKind
-    tag*: string       # ckParLe
-    name*: string      # ckSym / ckSymDef
-    sym*: uint32       # ckSym / ckSymDef id (identity key)
-    str*: string       # ckIdent / ckStr
-    ival*: int64
-    uval*: uint64
-    fval*: float64
-    cval*: uint32
-
-proc flattenGo(c: var Cursor; b: TokenBuf; acc: var seq[CookieTok]) =
-  while c.hasMore:
-    case c.kind
-    of TagLit:
-      acc.add CookieTok(kind: ckParLe, tag: b.tags.tagName(c.cursorTagId))
-      c.into:
-        flattenGo(c, b, acc)
-      acc.add CookieTok(kind: ckParRi)
-    of Symbol:
-      acc.add CookieTok(kind: ckSym, name: symName(c, b.pool), sym: uint32(symId(c, b.pool)))
-      skip c
-    of SymbolDef:
-      acc.add CookieTok(kind: ckSymDef, name: symName(c, b.pool), sym: uint32(symId(c, b.pool)))
-      skip c
-    of Ident:
-      acc.add CookieTok(kind: ckIdent, str: strVal(c, b.pool)); skip c
-    of StrLit:
-      acc.add CookieTok(kind: ckStr, str: strVal(c, b.pool)); skip c
-    of IntLit:
-      acc.add CookieTok(kind: ckInt, ival: intVal(c)); skip c
-    of UIntLit:
-      acc.add CookieTok(kind: ckUInt, uval: uintVal(c)); skip c
-    of FloatLit:
-      acc.add CookieTok(kind: ckFloat, fval: floatVal(c)); skip c
-    of CharLit:
-      acc.add CookieTok(kind: ckChar, cval: uint32(ord(charLit(c)))); skip c
-    of DotToken:
-      acc.add CookieTok(kind: ckDot); skip c
-    else:
-      skip c   # LineInfoLit / ExtendedSuffix ride on heads, never standalone
-
-proc flattenForCookie*(b: var IcBuilder): seq[CookieTok] =
-  ## Flatten the nifcore module buffer to the cookie hashers' flat token list.
-  result = newSeqOfCap[CookieTok](b.buf.len)
-  var cur = b.buf.beginRead()
-  flattenGo(cur, b.buf, result)
-
-proc collectBifStrLits*(path: string): seq[string] =
-  ## Read a small `(tag "s" "s" …)` bif sidecar (`semdeps`/`edges`) and return every
-  ## string literal it holds, in order — the binary analogue of the old nifstreams
-  ## scan that collected `StrLit`s. Keeps nifcore types out of `deps.nim`, which
-  ## only needs the recorded string list.
-  ##
-  ## Uses `loadFromFile` (a full read into owned memory) rather than the mmap-backed
-  ## `bif.load`, then CLOSES the handle. `bif.load` intentionally leaves the mapping
-  ## resident for the process lifetime; for the `nim ic` driver that reads these
-  ## sidecars while `nim m` children rewrite them, a lingering read mapping is a
-  ## Windows sharing violation: the child's `open(path, fmWrite)` fails with
-  ## `IOError: cannot open`. These sidecars are tiny, so the zero-copy mmap buys
-  ## nothing here anyway.
-  result = @[]
-  var f = open(path, fmRead)
-  var m = bif.loadFromFile(f)
-  close(f)
-  var c = m.buf.beginRead()
-  while c.hasMore:
-    if c.kind == StrLit: result.add strVal(c)
-    inc c
-
-proc writeSemDeps*(config: ConfigRef; thisModule: int32; importPaths: seq[string]) =
-  ## Stage 1 spike: the nifcore port of `ast2nif.writeSemDeps`. Serializes the
-  ## module's resolved direct imports as `(semdeps "path" ...)`. Byte-identical
-  ## to the old writer (verified), so `nim ic` build graphs are unaffected.
-  let selfSuffix = modname(thisModule, config)
-  var paths = importPaths
-  sort paths
-  var dest = newIcBuilder(4 + 2*paths.len)
-  dest.openTag "semdeps"
-  for p in paths:
-    dest.addStrLit p
-  dest.closeTag()
-  let path = toGeneratedFile(config, AbsoluteFile(selfSuffix), ".s.deps.bif").string
-  storeBifStable(dest, path, "." & extractModuleSuffix(path))
--- a/compiler/idents.nim
+++ b/compiler/idents.nim
@@ -11,8 +11,8 @@
 # An identifier is a shared immutable string that can be compared by its
 # id. This module is essential for the compiler's performance.

-import wordrecg
-import std/hashes
+import
+  hashes, wordrecg

 when defined(nimPreviewSlimSystem):
  import std/assertions
--- a/compiler/idetools.nim
+++ b/compiler/idetools.nim
@@ -1,279 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2026 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-## NIF-based goto-definition / find-all-usages for `nim track`.
-##
-## This is the mainline-Nim port of nimony's `idetools.nim`. It answers a
-## `--def:FILE,LINE,COL` / `--usages:FILE,LINE,COL` query by *scanning the
-## `.s.bif` files* (binary NIF, see `dist/nimony/src/lib/bif.nim`) that the
-## preceding `nim ic` frontend (`nim track`) emitted into the nimcache directory
-## — NOT by re-running sem. NIF distinguishes a definition (`SymbolDef` token) from a use
-## (`Symbol` token) syntactically, so goto-def / find-uses become plain token
-## scans over type-checked NIF, which is more reliable than the classic PSym
-## engine because generics and macros are type-checked in the NIF too.
-##
-## Two passes (mirroring nimony's `usages`):
-##  1. Load the queried module's `.s.bif` and find the `Symbol`/`SymbolDef`
-##     token whose line info + identifier length contains `conf.m.trackPos`.
-##     That yields the mangled symbol NAME and whether it is global (>= 2 dots).
-##  2. `--usages`: emit every `Symbol` (use) token; `--def`: every `SymbolDef`.
-##     A global symbol is scanned across every module `.s.bif`; a local one only
-##     within the queried module.
-##
-## IMPORTANT porting note: `bif.load` mints FRESH per-file pools, so a `SymId`
-## from module A's buffer is meaningless in module B's. The cross-module match is
-## therefore by the mangled NAME string, never by `SymId` (nimony can compare ids
-## because it parses every text NIF into one shared global pool; we cannot).
-
-import std / [os, strutils, sets]
-import options, msgs, pathutils
-import lineinfos as astli
-import ast2nif   # toNifFilename
-from deps import includerSbifs   # deps-guided include-file lookup
-import "../dist/nimony/src/lib/nifcore"
-from "../dist/nimony/src/lib" / bif import load, BifModule, containsSym
-
-proc identLen(name: string): int =
-  ## Length of the displayed identifier: the run before the first `.` of a
-  ## mangled NIF name (`ident.disamb[.moduleSuffix]`). Bounds the column match.
-  let d = name.find('.')
-  result = if d < 0: name.len else: d
-
-proc isGlobalName(name: string): bool =
-  ## A global symbol carries `ident.disamb.moduleSuffix` (>= 2 dots); a local at
-  ## most `ident.disamb` (<= 1 dot). `moduleSuffix` is a dot-free hash, so a raw
-  ## dot count is equivalent to nifbuilder's suffix-compressed test for our use.
-  var dots = 0
-  for i in 1 ..< name.len:
-    if name[i] == '.': inc dots
-  result = dots >= 2
-
-proc posMatch(c: Cursor; conf: ConfigRef; target: TLineInfo; tokenLen: int): bool =
-  ## True when `target` (the queried position) falls within the identifier span
-  ## of the Symbol/SymbolDef token at `c`. Mirrors nimony's `lineInfoMatch`; the
-  ## filename is resolved through the loaded buffer's own pool (fresh per file),
-  ## then mapped to a `FileIndex` exactly like `ast2nif.oldLineInfo`.
-  let li = rawLineInfo(c)
-  if not li.isValid: return false
-  if li.line.int != target.line.int: return false
-  let f = fileInfoIdx(conf, AbsoluteFile lineInfoFile(c))
-  if f != target.fileIndex: return false
-  if target.col.int < li.col.int: return false
-  if target.col.int > li.col.int + tokenLen: return false
-  result = true
-
-const sep = '\t'
-
-proc formatSuggest(s: Suggest): string =
-  ## Reproduce `suggest.$Suggest` for the `ideDef`/`ideUse` sections without
-  ## importing `suggest` (which would create an import cycle). Layout:
-  ## `section⭾symkind⭾qualifiedPath⭾forth⭾filePath⭾line⭾column⭾⭾quality`.
-  ## symkind is always `skUnknown` here — the raw NIF scan has no PSym to give a
-  ## real kind (like nimony's `foundSymbol`, which leaves it empty).
-  result = $s.section
-  result.add sep
-  result.add "skUnknown"
-  result.add sep
-  if s.qualifiedPath.len != 0:
-    result.add s.qualifiedPath.join(".")
-  result.add sep
-  result.add s.forth
-  result.add sep
-  result.add s.filePath
-  result.add sep
-  result.add $s.line
-  result.add sep
-  result.add $s.column
-  result.add sep            # empty doc field (docgen is off outside nimsuggest)
-  if s.version == 0 or s.version == 3:
-    result.add sep
-    result.add $s.quality
-
-proc emit(conf: ConfigRef; c: Cursor; section: IdeCmd; name: string;
-          seen: var HashSet[string]) =
-  ## Report one hit as a nimsuggest-compatible result (routed through the
-  ## structured-output hook / `--stdout`). We only have the mangled name + line
-  ## info from the raw NIF, so symkind/type are left empty — like nimony's
-  ## `foundSymbol`. `seen` deduplicates: the same source location can back
-  ## several NIF `Symbol` tokens (e.g. a call argument re-emitted in a lowered
-  ## form), which must surface as one hit.
-  let li = rawLineInfo(c)
-  if not li.isValid: return
-  let key = $section.int & ":" & lineInfoFile(c) & ":" & $li.line.int & ":" & $li.col.int
-  if seen.containsOrIncl(key):
-    return  # already reported this location for this section
-  let s = Suggest(section: section,
-                  qualifiedPath: @[name[0 ..< identLen(name)]],
-                  filePath: lineInfoFile(c),
-                  line: li.line.int,
-                  column: li.col.int,
-                  tokenLen: identLen(name),
-                  forth: "",
-                  symkind: 0'u8,
-                  quality: 100,
-                  version: conf.suggestVersion)
-  if conf.suggestionResultHook != nil:
-    conf.suggestionResultHook(s)
-  else:
-    conf.suggestWriteln(formatSuggest(s))
-
-proc tokenSymId(c: Cursor): SymId {.inline.} =
-  ## SymId (in the cursor's own per-file pool) of a `Symbol`/`SymbolDef` token,
-  ## or `SymId(0)` for an inline-encoded one — which is never our search target:
-  ## a mangled name (`ident.disamb.suffix`) is always longer than
-  ## `StrInlineMaxLen`, so every occurrence of the symbol we look for is stored by
-  ## pool id, decoded here with a shift and no string materialization.
-  if isInlineLit(c): SymId(0) else: SymId(combinedPayload(c) shr 1)
-
-template symMatches(c: Cursor): bool =
-  ## True when the token at `c` is the searched symbol. The fast path is a pure
-  ## integer compare against `targetSym` (the symbol's id in THIS module's pool,
-  ## resolved once per file by the caller). `targetSym == 0` means the name is not
-  ## representable as a pool id (a rare <=3-byte local): fall back to a string
-  ## compare, correct for both inline and pooled encodings.
-  (if targetSym != SymId(0): tokenSymId(c) == targetSym else: symName(c) == targetName)
-
-proc scanUses(conf: ConfigRef; m: var BifModule; targetSym: SymId; targetName: string;
-              seen: var HashSet[string]) =
-  ## `--usages`: report every `Symbol` (use) occurrence with valid line info.
-  if m.buf.len == 0: return
-  var c = m.buf.beginRead()
-  while c.hasMore:
-    if c.kind == Symbol and symMatches(c) and rawLineInfo(c).isValid:
-      emit(conf, c, ideUse, targetName, seen)
-    inc c
-  c.endRead()
-
-proc scanDef(conf: ConfigRef; m: var BifModule; targetSym: SymId; targetName: string;
-             seen: var HashSet[string]) =
-  ## `--def`: report the declaration of the target symbol if this module owns it
-  ## (has its `SymbolDef`). The `SymbolDef` token itself carries no line info; the
-  ## declaration location lives on the *enclosing tag* (e.g. `(sd @file:line:col`,
-  ## like `bif.buildIndex`'s `mostRecentTagPos`). When that tag has no line info
-  ## either, fall back to the declaration-site `Symbol` occurrence — but only in
-  ## the owning module, so a plain user of the symbol is never reported as a def.
-  if m.buf.len == 0: return
-  var c = m.buf.beginRead()
-  var mostRecentTagPos = 0
-  var sawDef = false
-  var emitted = false
-  var fallbackPos = -1
-  while c.hasMore:
-    case c.kind
-    of TagLit:
-      mostRecentTagPos = cursorToPosition(m.buf, c)
-      inc c
-    of SymbolDef:
-      if symMatches(c):
-        sawDef = true
-        var tc = cursorAt(m.buf, mostRecentTagPos)
-        if rawLineInfo(tc).isValid:
-          emit(conf, tc, ideDef, targetName, seen)
-          emitted = true
-        tc.endRead()
-      inc c
-    of Symbol:
-      if fallbackPos < 0 and symMatches(c) and rawLineInfo(c).isValid:
-        fallbackPos = cursorToPosition(m.buf, c)
-      inc c
-    else:
-      inc c
-  c.endRead()
-  if sawDef and not emitted and fallbackPos >= 0:
-    var fc = cursorAt(m.buf, fallbackPos)
-    emit(conf, fc, ideDef, targetName, seen)
-    fc.endRead()
-
-proc scanBuf(conf: ConfigRef; m: var BifModule; section: IdeCmd;
-             targetSym: SymId; targetName: string; seen: var HashSet[string]) =
-  ## Emit hits for the target symbol in `m` per the query kind. `ideDus`
-  ## (`--defusages`) reports both the definition and every usage.
-  if section in {ideDef, ideDus}:
-    scanDef(conf, m, targetSym, targetName, seen)
-  if section in {ideUse, ideDus}:
-    scanUses(conf, m, targetSym, targetName, seen)
-
-proc findPos(conf: ConfigRef; m: var BifModule; target: TLineInfo;
-             foundName: var string): bool =
-  ## Scan `m` for the `Symbol`/`SymbolDef` token covering the queried position
-  ## `target` and set `foundName` to its mangled name. Returns true on a hit.
-  if m.buf.len == 0: return false
-  var c = m.buf.beginRead()
-  result = false
-  while c.hasMore:
-    let k = c.kind
-    if k == Symbol or k == SymbolDef:
-      let nm = symName(c)
-      if posMatch(c, conf, target, identLen(nm)):
-        foundName = nm
-        result = true
-        break
-    inc c
-  c.endRead()
-
-proc runIdeQuery*(conf: ConfigRef) =
-  ## Entry point: called from `main.nim` after `commandCheck` when a
-  ## `--def`/`--usages` query is active. Assumes the check just emitted the
-  ## project's `.s.bif` files into `getNimcacheDir(conf)`.
-  let section = conf.ideCmd
-  if section notin {ideDef, ideUse, ideDus}: return
-  let target = conf.m.trackPos
-  if target.fileIndex.int32 < 0: return
-
-  # Pass 1: position -> symbol. Try the queried file's own module bif first (the
-  # fast path when the position is inside a real module). An include file has no
-  # module bif of its own — its tokens live in the *including* module's bif with
-  # include-file line info — so when the direct lookup misses, consult the
-  # `.deps.nif` preludes (`includerSbifs`) to load only the module(s) that
-  # include the queried file (directly or transitively), never every bif in the
-  # nimcache. `ownerFile` is the bif that owns the hit.
-  let modFile = toNifFilename(conf, target.fileIndex)
-  var foundName = ""
-  var ownerFile = ""
-  if fileExists(modFile):
-    var qm = load(modFile)
-    if findPos(conf, qm, target, foundName):
-      ownerFile = modFile
-  if foundName.len == 0:
-    for cand in includerSbifs(conf, toFullPath(conf, target.fileIndex).AbsoluteFile):
-      if cand == modFile: continue
-      var m = load(cand)
-      if findPos(conf, m, target, foundName):
-        ownerFile = cand
-        break
-  if foundName.len == 0: return
-
-  # Pass 2: emit definition / usages. `seen` spans every module so a location is
-  # reported once even when scanned across the whole nimcache.
-  #
-  # Cross-file matching is by SymId, not by decoding every token's name. Two
-  # filters keep it cheap:
-  #   1. `bif.containsSym` — a sym-table-only probe that reads just the small
-  #      trailing pools, NOT the token block or any `BiTable`. A module that never
-  #      references the symbol is rejected here without a full `load` (no pools
-  #      built, no token block mapped) — so a query whose symbol lives in a few
-  #      modules no longer pays to load the whole nimcache.
-  #   2. For a module that does contain it, `bif.load` mints a fresh per-file pool,
-  #      so the name is resolved to THIS file's SymId once via `getKeyId`; the scan
-  #      then compares integer ids per token instead of materializing a string for
-  #      each (see `symMatches`).
-  var seen = initHashSet[string]()
-  if isGlobalName(foundName):
-    for f in walkFiles((getNimcacheDir(conf).string) / "*.s.bif"):
-      if not containsSym(f, foundName): continue
-      var m = load(f)
-      let tid = m.buf.pool.syms.getKeyId(foundName)
-      if tid != SymId(0):
-        scanBuf(conf, m, section, tid, foundName, seen)
-  else:
-    # Local symbol: its mangled name is not unique across modules, so restrict
-    # the scan to the module it lives in (the one that owns the queried position).
-    var qm = load(ownerFile)
-    let tid = qm.buf.pool.syms.getKeyId(foundName)
-    scanBuf(conf, qm, section, tid, foundName, seen)
--- a/compiler/importer.nim
+++ b/compiler/importer.nim
@@ -10,12 +10,10 @@
 ## This module implements the symbol importing mechanism.

 import
-  ast, msgs, options, idents, lookups,
-  semdata, modulepaths, sigmatch, lineinfos,
-  modulegraphs, wordrecg
-from std/strutils import `%`, startsWith, replace
-from std/sequtils import addUnique
-import std/[sets, tables, intsets]
+  intsets, ast, astalgo, msgs, options, idents, lookups,
+  semdata, modulepaths, sigmatch, lineinfos, sets,
+  modulegraphs, wordrecg, tables
+from strutils import `%`

 when defined(nimPreviewSlimSystem):
  import std/assertions
@@ -108,8 +106,8 @@ proc rawImportSymbol(c: PContext, s, origin: PSym; importSet: var IntSet) =
          else:
            importPureEnumField(c, e)
  else:
-    if s.kind == skConverter: addConverter(c, s)
-    if hasPattern(s): addPattern(c, s)
+    if s.kind == skConverter: addConverter(c, LazySym(sym: s))
+    if hasPattern(s): addPattern(c, LazySym(sym: s))
  if s.owner != origin:
    c.exportIndirections.incl((origin.id, s.id))

@@ -144,7 +142,7 @@ proc importSymbol(c: PContext, n: PNode, fromMod: PSym; importSet: var IntSet) =
    # for an enumeration we have to add all identifiers
    if multiImport:
      # for a overloadable syms add all overloaded routines
-      var it: ModuleIter = default(ModuleIter)
+      var it: ModuleIter
      var e = initModuleIter(it, c.graph, fromMod, s.name)
      while e != nil:
        if e.name.id != s.name.id: internalError(c.config, n.info, "importSymbol: 3")
@@ -190,19 +188,22 @@ proc addImport(c: PContext; im: sink ImportedModule) =
 template addUnnamedIt(c: PContext, fromMod: PSym; filter: untyped) {.dirty.} =
  for it in mitems c.graph.ifaces[fromMod.position].converters:
    if filter:
-      if sfExported in it.flags:
+      loadPackedSym(c.graph, it)
+      if sfExported in it.sym.flags:
        addConverter(c, it)
  for it in mitems c.graph.ifaces[fromMod.position].patterns:
    if filter:
-      if sfExported in it.flags:
+      loadPackedSym(c.graph, it)
+      if sfExported in it.sym.flags:
        addPattern(c, it)
  for it in mitems c.graph.ifaces[fromMod.position].pureEnums:
    if filter:
-      importPureEnumFields(c, it, it.typ)
+      loadPackedSym(c.graph, it)
+      importPureEnumFields(c, it.sym, it.sym.typ)

 proc importAllSymbolsExcept(c: PContext, fromMod: PSym, exceptSet: IntSet) =
  c.addImport ImportedModule(m: fromMod, mode: importExcept, exceptSet: exceptSet)
-  addUnnamedIt(c, fromMod, it.name.id notin exceptSet)
+  addUnnamedIt(c, fromMod, it.sym.name.id notin exceptSet)

 proc importAllSymbols*(c: PContext, fromMod: PSym) =
  c.addImport ImportedModule(m: fromMod, mode: importAll)
@@ -228,7 +229,12 @@ proc importForwarded(c: PContext, n: PNode, exceptSet: IntSet; fromMod: PSym; im
    for i in 0..n.safeLen-1:
      importForwarded(c, n[i], exceptSet, fromMod, importSet)

-proc importModuleAs(c: PContext; n: PNode, realModule: PSym, importHidden, trackUnusedImport: bool): PSym =
+proc addUnique[T](x: var seq[T], y: sink T) {.noSideEffect.} =
+  for i in 0..high(x):
+    if x[i] == y: return
+  x.add y
+    
+proc importModuleAs(c: PContext; n: PNode, realModule: PSym, importHidden: bool): PSym =
  result = realModule
  template createModuleAliasImpl(ident): untyped =
    createModuleAlias(realModule, c.idgen, ident, n.info, c.config.options)
@@ -242,18 +248,13 @@ proc importModuleAs(c: PContext; n: PNode, realModule: PSym, importHidden, track
    # avoids modifying `realModule`, see D20201209T194412 for `import {.all.}`
    result = createModuleAliasImpl(realModule.name)
  if importHidden:
-    ensureMutable result
-    result.optionsImpl.incl optImportHidden
-  let moduleIdent = if n.kind in {nkInfix, nkImportAs}: n[^1] else: n
-  result.info = moduleIdent.info
-  if trackUnusedImport:
-    c.unusedImports.add((result, result.info))
+    result.options.incl optImportHidden
+  c.unusedImports.add((result, n.info))
  c.importModuleMap[result.id] = realModule.id
  c.importModuleLookup.mgetOrPut(result.name.id, @[]).addUnique realModule.id

 proc transformImportAs(c: PContext; n: PNode): tuple[node: PNode, importHidden: bool] =
-  result = (nil, false)
-  var ret = default(typeof(result))
+  var ret: typeof(result)
  proc processPragma(n2: PNode): PNode =
    let (result2, kws) = splitPragmas(c, n2)
    result = result2
@@ -288,10 +289,10 @@ proc myImportModule(c: PContext, n: var PNode, importStmtResult: PNode): PSym =
                toFullPath(c.config, c.graph.importStack[i+1])
      c.recursiveDep = err

-    let trackUnusedImport = warnUnusedImportX in c.config.notes
+    var realModule: PSym
    discard pushOptionEntry(c)
-    let realModule = c.graph.importModuleCallback(c.graph, c.module, f)
-    result = importModuleAs(c, n, realModule, transf.importHidden, trackUnusedImport)
+    realModule = c.graph.importModuleCallback(c.graph, c.module, f)
+    result = importModuleAs(c, n, realModule, transf.importHidden)
    popOptionEntry(c)

    #echo "set back to ", L
@@ -304,26 +305,13 @@ proc myImportModule(c: PContext, n: var PNode, importStmtResult: PNode): PSym =
      var prefix = ""
      if realModule.constraint != nil: prefix = realModule.constraint.strVal & "; "
      message(c.config, n.info, warnDeprecated, prefix & realModule.name.s & " is deprecated")
-    let moduleNameNorm = getModuleName(c.config, n).replace("\\", "/")
-    if belongsToStdlib(c.graph, result) and not startsWith(moduleNameNorm, stdPrefix) and
-        not startsWith(moduleNameNorm, "system/") and not startsWith(moduleNameNorm, "packages/"):
-      message(c.config, n.info, warnStdPrefix, realModule.name.s)
-
-    proc suggestMod(n: PNode; s: PSym) =
-      if n.kind == nkImportAs:
-        suggestMod(n[0], realModule)
-      elif n.kind == nkInfix:
-        suggestMod(n[2], s)
-      else:
-        suggestSym(c.graph, n.info, s, c.graph.usageSym, false)
-    suggestMod(n, result)
+    suggestSym(c.graph, n.info, result, c.graph.usageSym, false)
    importStmtResult.add newSymNode(result, n.info)
    #newStrNode(toFullPath(c.config, f), n.info)
  else:
    result = nil

 proc afterImport(c: PContext, m: PSym) =
-  if isCachedModule(c.graph, m): return
  # fixes bug #17510, for re-exported symbols
  let realModuleId = c.importModuleMap[m.id]
  for s in allSyms(c.graph, m):
@@ -335,7 +323,7 @@ proc impMod(c: PContext; it: PNode; importStmtResult: PNode) =
  let m = myImportModule(c, it, importStmtResult)
  if m != nil:
    # ``addDecl`` needs to be done before ``importAllSymbols``!
-    addDecl(c, m) # add symbol to symbol table of module
+    addDecl(c, m, it.info) # add symbol to symbol table of module
    importAllSymbols(c, m)
    #importForwarded(c, m.ast, emptySet, m)
    afterImport(c, m)
@@ -372,7 +360,7 @@ proc evalFrom*(c: PContext, n: PNode): PNode =
  var m = myImportModule(c, n[0], result)
  if m != nil:
    n[0] = newSymNode(m)
-    addDecl(c, m)               # add symbol to symbol table of module
+    addDecl(c, m, n.info)               # add symbol to symbol table of module

    var im = ImportedModule(m: m, mode: importSet, imported: initIntSet())
    for i in 1..<n.len:
@@ -387,7 +375,7 @@ proc evalImportExcept*(c: PContext, n: PNode): PNode =
  var m = myImportModule(c, n[0], result)
  if m != nil:
    n[0] = newSymNode(m)
-    addDecl(c, m)               # add symbol to symbol table of module
+    addDecl(c, m, n.info)               # add symbol to symbol table of module
    importAllSymbolsExcept(c, m, readExceptSet(c, n))
    #importForwarded(c, m.ast, exceptSet, m)
    afterImport(c, m)
--- a/compiler/injectdestructors.nim
+++ b/compiler/injectdestructors.nim
@@ -14,17 +14,15 @@
 ## See doc/destructors.rst for a spec of the implemented rewrite rules

 import
-  ast, astalgo, msgs, renderer, magicsys, types, idents,
-  options, lowerings, modulegraphs,
+  intsets, strtabs, ast, astalgo, msgs, renderer, magicsys, types, idents,
+  strutils, options, lowerings, tables, modulegraphs,
  lineinfos, parampatterns, sighashes, liftdestructors, optimizer,
  varpartitions, aliasanalysis, dfa, wordrecg

-import std/[strtabs, tables, strutils, intsets]
-
 when defined(nimPreviewSlimSystem):
  import std/assertions

-from trees import exprStructuralEquivalent, getRoot, whichPragma, getPotentialWrites
+from trees import exprStructuralEquivalent, getRoot, whichPragma

 type
  Con = object
@@ -69,14 +67,12 @@ proc hasDestructor(c: Con; t: PType): bool {.inline.} =
  result = ast.hasDestructor(t)
  when toDebug.len > 0:
    # for more effective debugging
-    if not result and c.graph.config.selectedGC in {gcArc, gcOrc, gcYrc, gcAtomicArc}:
+    if not result and c.graph.config.selectedGC in {gcArc, gcOrc, gcAtomicArc}:
      assert(not containsGarbageCollectedRef(t))

-proc getTemp(c: var Con; s: var Scope; typ: PType; info: TLineInfo; needsInit: bool): PNode =
+proc getTemp(c: var Con; s: var Scope; typ: PType; info: TLineInfo): PNode =
  let sym = newSym(skTemp, getIdent(c.graph.cache, ":tmpD"), c.idgen, c.owner, info)
  sym.typ = typ
-  if not needsInit:
-    sym.incl sfNoInit
  s.vars.add(sym)
  result = newSymNode(sym)

@@ -102,7 +98,6 @@ when false:
 proc isLastReadImpl(n: PNode; c: var Con; scope: var Scope): bool =
  let root = parampatterns.exprRoot(n, allowCalls=false)
  if root == nil: return false
-  elif sfSingleUsedTemp in root.flags: return true

  var s = addr(scope)
  while s != nil:
@@ -165,16 +160,12 @@ proc isLastReadImpl(n: PNode; c: var Con; scope: var Scope): bool =
  else:
    result = false

-template hasDestructorOrAsgn(c: var Con, typ: PType): bool =
-  # bug #23354; an object type could have a non-trivial assignements when it is passed to a sink parameter
-  hasDestructor(c, typ) or (c.graph.config.selectedGC in {gcArc, gcOrc, gcYrc, gcAtomicArc} and
-        typ.kind == tyObject and not isTrivial(getAttachedOp(c.graph, typ, attachedAsgn)))
-
 proc isLastRead(n: PNode; c: var Con; s: var Scope): bool =
-  if not hasDestructorOrAsgn(c, n.typ): return true
+  if not hasDestructor(c, n.typ): return true

  let m = skipConvDfa(n)
-  result = isLastReadImpl(n, c, s)
+  result = (m.kind == nkSym and sfSingleUsedTemp in m.sym.flags) or
+      isLastReadImpl(n, c, s)

 proc isFirstWrite(n: PNode; c: var Con): bool =
  let m = skipConvDfa(n)
@@ -191,11 +182,10 @@ proc isCursor(n: PNode): bool =
  else:
    false

-template isFullyUnpackedTuple(n: PNode): bool =
+template isUnpackedTuple(n: PNode): bool =
  ## we move out all elements of unpacked tuples,
  ## hence unpacked tuples themselves don't need to be destroyed
  ## except it's already a cursor
-  ## restricted to `skTemp`, tuple temps where not every field is unpacked should not use `skTemp`
  (n.kind == nkSym and n.sym.kind == skTemp and
   n.sym.typ.kind == tyTuple and sfCursor notin n.sym.flags)

@@ -204,8 +194,7 @@ proc checkForErrorPragma(c: Con; t: PType; ri: PNode; opname: string; inferredFr
  if inferredFromCopy:
    m.add ", which is inferred from unavailable '=copy'"

-  if (opname == "=" or opname == "=copy" or opname == "=dup") and
-       ri != nil:
+  if (opname == "=" or opname == "=copy" or opname == "=dup") and ri != nil:
    m.add "; requires a copy because it's not the last read of '"
    m.add renderTree(ri)
    m.add '\''
@@ -220,17 +209,15 @@ proc checkForErrorPragma(c: Con; t: PType; ri: PNode; opname: string; inferredFr
      m.add " a 'sink' parameter"
  m.add "; routine: "
  m.add c.owner.name.s
-  #m.add "\n\n"
-  #m.add renderTree(c.body, {renderIds})
  localError(c.graph.config, ri.info, errGenerated, m)

 proc makePtrType(c: var Con, baseType: PType): PType =
-  result = newType(tyPtr, c.idgen, c.owner)
+  result = newType(tyPtr, nextTypeId c.idgen, c.owner)
  addSonSkipIntLit(result, baseType, c.idgen)

 proc genOp(c: var Con; op: PSym; dest: PNode): PNode =
  var addrExp: PNode
-  if op.typ != nil and op.typ.signatureLen > 1 and op.typ.firstParamType.kind != tyVar:
+  if op.typ != nil and op.typ.len > 1 and op.typ[1].kind != tyVar:
    addrExp = dest
  else:
    addrExp = newNodeIT(nkHiddenAddr, dest.info, makePtrType(c, dest.typ))
@@ -245,18 +232,6 @@ proc genOp(c: var Con; t: PType; kind: TTypeAttachedOp; dest, ri: PNode): PNode
    let canon = c.graph.canonTypes.getOrDefault(h)
    if canon != nil:
      op = getAttachedOp(c.graph, canon, kind)
-  if op == nil or op.ast.isGenericRoutine:
-    # IC: injectDestructorCalls is demand-driven and runs HERE (cg), not in the
-    # `lower` stage, so a structural, env-agnostic op the lower stage never had
-    # reason to serialize — most often a closure PROC type's `=destroy`/`=sink`
-    # (which act on the `(ClP_0, ClE_0)` tuple, NOT the concrete env) — must be
-    # lifted on demand, exactly as the lazy path's cg does. This is safe now:
-    # closure-env identity resolves via `attachedOps[itemId]`/env-erased typeKey,
-    # env objects load complete, and atomicRefOp's type-erased path covers any
-    # still-incomplete env (so the lift never walks a nil field).
-    excl t.flagsImpl, tfCheckedForDestructor
-    createTypeBoundOps(c.graph, nil, t, dest.info, c.idgen)
-    op = getAttachedOp(c.graph, t, kind)
  if op == nil:
    #echo dest.typ.id
    globalError(c.graph.config, dest.info, "internal error: '" & AttachedOpToStr[kind] &
@@ -267,12 +242,7 @@ proc genOp(c: var Con; t: PType; kind: TTypeAttachedOp; dest, ri: PNode): PNode
  dbg:
    if kind == attachedDestructor:
      echo "destructor is ", op.id, " ", op.ast
-  if sfError in op.flags:
-    if ri != nil:
-      checkForErrorPragma(c, t, ri, AttachedOpToStr[kind])
-    else:
-      # uses the lineinfos of `dest` is `ri` is not available
-      checkForErrorPragma(c, t, dest, AttachedOpToStr[kind])
+  if sfError in op.flags: checkForErrorPragma(c, t, ri, AttachedOpToStr[kind])
  c.genOp(op, dest)

 proc genDestroy(c: var Con; dest: PNode): PNode =
@@ -300,7 +270,7 @@ proc deepAliases(dest, ri: PNode): bool =
    return aliases(dest, ri) != no

 proc genSink(c: var Con; s: var Scope; dest, ri: PNode; flags: set[MoveOrCopyFlag] = {}): PNode =
-  if (c.inLoopCond == 0 and (isFullyUnpackedTuple(dest) or IsDecl in flags or
+  if (c.inLoopCond == 0 and (isUnpackedTuple(dest) or IsDecl in flags or
      (isAnalysableFieldAccess(dest, c.owner) and isFirstWrite(dest, c)))) or
      isNoInit(dest) or IsReturn in flags:
    # optimize sink call into a bitwise memcopy
@@ -316,7 +286,7 @@ proc genSink(c: var Con; s: var Scope; dest, ri: PNode; flags: set[MoveOrCopyFla
      if deepAliases(dest, ri):
        # consider: x = x + y, it is wrong to destroy the destination first!
        # tmp to support self assignments
-        let tmp = c.getTemp(s, dest.typ, dest.info, needsInit = false)
+        let tmp = c.getTemp(s, dest.typ, dest.info)
        result = newTree(nkStmtList, newTree(nkFastAsgn, tmp, dest), newTree(nkFastAsgn, dest, ri),
                         c.genDestroy(tmp))
      else:
@@ -325,7 +295,7 @@ proc genSink(c: var Con; s: var Scope; dest, ri: PNode; flags: set[MoveOrCopyFla
 proc isCriticalLink(dest: PNode): bool {.inline.} =
  #[
  Lins's idea that only "critical" links can introduce a cycle. This is
-  critical for the performance guarantees that we strive for: If you
+  critical for the performance gurantees that we strive for: If you
  traverse a data structure, no tracing will be performed at all.
  ORC is about this promise: The GC only touches the memory that the
  mutator touches too.
@@ -342,15 +312,14 @@ proc isCriticalLink(dest: PNode): bool {.inline.} =
  ]#
  result = dest.kind != nkSym

-proc finishCopy(c: var Con; result, dest: PNode; flags: set[MoveOrCopyFlag]; isFromSink: bool) =
-  if c.graph.config.selectedGC in {gcOrc, gcYrc} and IsExplicitSink notin flags:
-    # add cyclic flag, but not to sink calls, which IsExplicitSink generates
-    let t = dest.typ.skipTypes(tyUserTypeClasses + {tyGenericInst, tyAlias, tySink, tyDistinct})
+proc finishCopy(c: var Con; result, dest: PNode; isFromSink: bool) =
+  if c.graph.config.selectedGC == gcOrc:
+    let t = dest.typ.skipTypes({tyGenericInst, tyAlias, tySink, tyDistinct})
    if cyclicType(c.graph, t):
      result.add boolLit(c.graph, result.info, isFromSink or isCriticalLink(dest))

 proc genMarkCyclic(c: var Con; result, dest: PNode) =
-  if c.graph.config.selectedGC in {gcOrc, gcYrc}:
+  if c.graph.config.selectedGC == gcOrc:
    let t = dest.typ.skipTypes({tyGenericInst, tyAlias, tySink, tyDistinct})
    if cyclicType(c.graph, t):
      if t.kind == tyRef:
@@ -385,7 +354,7 @@ proc genDiscriminantAsgn(c: var Con; s: var Scope; n: PNode): PNode =
  # but fields within active case branch might need destruction

  # tmp to support self assignments
-  let tmp = c.getTemp(s, n[1].typ, n.info, needsInit = false)
+  let tmp = c.getTemp(s, n[1].typ, n.info)

  result = newTree(nkStmtList)
  result.add newTree(nkFastAsgn, tmp, p(n[1], c, s, consumed))
@@ -425,7 +394,7 @@ proc genWasMoved(c: var Con, n: PNode): PNode =
    result = genOp(c, op, n)
  else:
    result = newNodeI(nkCall, n.info)
-    result.add(newSymNode(createMagic(c.graph, c.idgen, "wasMoved", mWasMoved)))
+    result.add(newSymNode(createMagic(c.graph, c.idgen, "`=wasMoved`", mWasMoved)))
    result.add copyTree(n) #mWasMoved does not take the address
    #if n.kind != nkSym:
    #  message(c.graph.config, n.info, warnUser, "wasMoved(" & $n & ")")
@@ -438,10 +407,7 @@ proc genDefaultCall(t: PType; c: Con; info: TLineInfo): PNode =
 proc destructiveMoveVar(n: PNode; c: var Con; s: var Scope): PNode =
  # generate: (let tmp = v; reset(v); tmp)
  if (not hasDestructor(c, n.typ)) and c.inEnsureMove == 0:
-    assert n.kind != nkSym or not hasDestructor(c, n.sym.typ) or
-          (n.typ.kind == tyPtr and n.sym.typ.kind == tyRef)
-      # bug #23505; transformed by `transf`: addr (deref ref) -> ptr
-      # we know it's really a pointer; so here we assign it directly
+    assert n.kind != nkSym or not hasDestructor(c, n.sym.typ)
    result = copyTree(n)
  else:
    result = newNodeIT(nkStmtListExpr, n.info, n.typ)
@@ -471,64 +437,62 @@ proc isCapturedVar(n: PNode): bool =
  else: result = false

 proc passCopyToSink(n: PNode; c: var Con; s: var Scope): PNode =
-  let nTyp = n.typ.skipTypes(tyUserTypeClasses)
-  if not hasDestructorOrAsgn(c, nTyp):
-    # Non-managed (plain-old-data) type: no ownership transfer is needed.
-    # Return the expression directly — no temp required.
-    if c.graph.config.selectedGC in {gcArc, gcOrc, gcYrc, gcAtomicArc}:
-      assert(not containsManagedMemory(nTyp))
-    if nTyp.skipTypes(abstractInst).kind in {tyOpenArray, tyVarargs}:
-      localError(c.graph.config, n.info, "cannot create an implicit openArray copy to be passed to a sink parameter")
-    return p(n, c, s, normal)
  result = newNodeIT(nkStmtListExpr, n.info, n.typ)
-  let tmp = c.getTemp(s, nTyp, n.info, needsInit = false)
-  let typ = nTyp.skipTypes({tyGenericInst, tyAlias, tySink})
-  let op = getAttachedOp(c.graph, typ, attachedDup)
-  if op != nil and tfHasOwned notin typ.flags:
-    if sfError in op.flags:
-      c.checkForErrorPragma(nTyp, n, "=dup")
-    else:
-      let copyOp = getAttachedOp(c.graph, typ, attachedAsgn)
-      if copyOp != nil and sfError in copyOp.flags and
-         sfOverridden notin op.flags:
-        c.checkForErrorPragma(nTyp, n, "=dup", inferredFromCopy = true)
+  let tmp = c.getTemp(s, n.typ, n.info)
+  if hasDestructor(c, n.typ):
+    let typ = n.typ.skipTypes({tyGenericInst, tyAlias, tySink})
+    let op = getAttachedOp(c.graph, typ, attachedDup)
+    if op != nil and tfHasOwned notin typ.flags:
+      if sfError in op.flags:
+        c.checkForErrorPragma(n.typ, n, "=dup")
+      else:
+        let copyOp = getAttachedOp(c.graph, typ, attachedAsgn)
+        if copyOp != nil and sfError in copyOp.flags and
+           sfOverridden notin op.flags:
+          c.checkForErrorPragma(n.typ, n, "=dup", inferredFromCopy = true)

-    let src = p(n, c, s, normal)
-    var newCall = newTreeIT(nkCall, src.info, src.typ,
-          newSymNode(op),
-          src)
-    c.finishCopy(newCall, n, {}, isFromSink = true)
-    result.add newTreeI(nkFastAsgn,
-        src.info, tmp,
-        newCall
-    )
+      let src = p(n, c, s, normal)
+      var newCall = newTreeIT(nkCall, src.info, src.typ,
+            newSymNode(op),
+            src)
+      c.finishCopy(newCall, n, isFromSink = true)
+      result.add newTreeI(nkFastAsgn,
+          src.info, tmp,
+          newCall
+      )
+    else:
+      result.add c.genWasMoved(tmp)
+      var m = c.genCopy(tmp, n, {})
+      m.add p(n, c, s, normal)
+      c.finishCopy(m, n, isFromSink = true)
+      result.add m
+    if isLValue(n) and not isCapturedVar(n) and n.typ.skipTypes(abstractInst).kind != tyRef and c.inSpawn == 0:
+      message(c.graph.config, n.info, hintPerformance,
+        ("passing '$1' to a sink parameter introduces an implicit copy; " &
+        "if possible, rearrange your program's control flow to prevent it") % $n)
+    if c.inEnsureMove > 0:
+      localError(c.graph.config, n.info, errFailedMove,
+        ("cannot move '$1', passing '$1' to a sink parameter introduces an implicit copy") % $n)
  else:
-    result.add c.genWasMoved(tmp)
-    var m = c.genCopy(tmp, n, {})
-    m.add p(n, c, s, normal)
-    c.finishCopy(m, n, {}, isFromSink = true)
-    result.add m
-  if isLValue(n) and not isCapturedVar(n) and nTyp.skipTypes(abstractInst).kind != tyRef and c.inSpawn == 0:
-    message(c.graph.config, n.info, hintPerformance,
-      ("passing '$1' to a sink parameter introduces an implicit copy; " &
-      "if possible, rearrange your program's control flow to prevent it") % $n)
-  if c.inEnsureMove > 0:
-    localError(c.graph.config, n.info, errFailedMove,
-      ("cannot move '$1', passing '$1' to a sink parameter introduces an implicit copy") % $n)
+    if c.graph.config.selectedGC in {gcArc, gcOrc, gcAtomicArc}:
+      assert(not containsManagedMemory(n.typ))
+    if n.typ.skipTypes(abstractInst).kind in {tyOpenArray, tyVarargs}:
+      localError(c.graph.config, n.info, "cannot create an implicit openArray copy to be passed to a sink parameter")
+    result.add newTree(nkAsgn, tmp, p(n, c, s, normal))
  # Since we know somebody will take over the produced copy, there is
  # no need to destroy it.
  result.add tmp

 proc isDangerousSeq(t: PType): bool {.inline.} =
  let t = t.skipTypes(abstractInst)
-  result = t.kind == tySequence and tfHasOwned notin t.elementType.flags
+  result = t.kind == tySequence and tfHasOwned notin t[0].flags

 proc containsConstSeq(n: PNode): bool =
  if n.kind == nkBracket and n.len > 0 and n.typ != nil and isDangerousSeq(n.typ):
    return true
  result = false
  case n.kind
-  of nkExprEqExpr, nkExprColonExpr, nkHiddenStdConv, nkHiddenSubConv, nkCast:
+  of nkExprEqExpr, nkExprColonExpr, nkHiddenStdConv, nkHiddenSubConv:
    result = containsConstSeq(n[1])
  of nkObjConstr, nkClosure:
    for i in 1..<n.len:
@@ -545,7 +509,7 @@ proc ensureDestruction(arg, orig: PNode; c: var Con; s: var Scope): PNode =
    # produce temp creation for (fn, env). But we need to move 'env'?
    # This was already done in the sink parameter handling logic.
    result = newNodeIT(nkStmtListExpr, arg.info, arg.typ)
-    let tmp = c.getTemp(s, arg.typ, arg.info, true)
+    let tmp = c.getTemp(s, arg.typ, arg.info)
    result.add c.genSink(s, tmp, arg, {IsDecl})
    result.add tmp
    s.final.add c.genDestroy(tmp)
@@ -585,7 +549,7 @@ proc cycleCheck(n: PNode; c: var Con) =
 proc pVarTopLevel(v: PNode; c: var Con; s: var Scope; res: PNode) =
  # move the variable declaration to the top of the frame:
  s.vars.add v.sym
-  if isFullyUnpackedTuple(v):
+  if isUnpackedTuple(v):
    if c.inLoop > 0:
      # unpacked tuple needs reset at every loop iteration
      res.add newTree(nkFastAsgn, v, genDefaultCall(v.typ, c, v.info))
@@ -624,11 +588,9 @@ template processScopeExpr(c: var Con; s: var Scope; ret: PNode, processCall: unt
  # There is a possibility to do this check: s.wasMoved.len > 0 or s.final.len > 0
  # later and use it to eliminate the temporary when theres no need for it, but its
  # tricky because you would have to intercept moveOrCopy at a certain point
-  let tmp = c.getTemp(s.parent[], ret.typ, ret.info, needsInit = true)
+  let tmp = c.getTemp(s.parent[], ret.typ, ret.info)
  tmp.sym.flags = tmpFlags
-  let cpy = if hasDestructor(c, ret.typ) and
-                ret.typ.kind notin {tyOpenArray, tyVarargs}:
-                # bug #23247 we don't own the data, so it's harmful to destroy it
+  let cpy = if hasDestructor(c, ret.typ):
              s.parent[].final.add c.genDestroy(tmp)
              moveOrCopy(tmp, ret, c, s, {IsDecl})
            else:
@@ -680,7 +642,7 @@ template handleNestedTempl(n, processCall: untyped, willProduceStmt = false,
      for j in 0 ..< it.len-1:
        branch[j] = copyTree(it[j])
      var ofScope = nestedScope(s, it.lastSon)
-      branch[^1] = if n.typ.isEmptyType or it[^1].typ.isEmptyType or willProduceStmt:
+      branch[^1] = if it[^1].typ.isEmptyType or willProduceStmt:
                     processScope(c, ofScope, maybeVoid(it[^1], ofScope))
                   else:
                     processScopeExpr(c, ofScope, it[^1], processCall, tmpFlags)
@@ -728,7 +690,7 @@ template handleNestedTempl(n, processCall: untyped, willProduceStmt = false,
        #Condition needs to be destroyed outside of the condition/branch scope
        branch[0] = p(it[0], c, s, normal)

-      branch[^1] = if n.typ.isEmptyType or it[^1].typ.isEmptyType or willProduceStmt:
+      branch[^1] = if it[^1].typ.isEmptyType or willProduceStmt:
                     processScope(c, branchScope, maybeVoid(it[^1], branchScope))
                   else:
                     processScopeExpr(c, branchScope, it[^1], processCall, tmpFlags)
@@ -785,10 +747,10 @@ proc pRaiseStmt(n: PNode, c: var Con; s: var Scope): PNode =
      result = copyNode(n)
      result.add call
    else:
-      let tmp = c.getTemp(s, n[0].typ, n.info, needsInit = true)
+      let tmp = c.getTemp(s, n[0].typ, n.info)
      var m = c.genCopyNoCheck(tmp, n[0], attachedAsgn)
      m.add p(n[0], c, s, normal)
-      c.finishCopy(m, n[0], {}, isFromSink = false)
+      c.finishCopy(m, n[0], isFromSink = false)
      result = newTree(nkStmtList, c.genWasMoved(tmp), m)
      var toDisarm = n[0]
      if toDisarm.kind == nkStmtListExpr: toDisarm = toDisarm.lastSon
@@ -803,35 +765,6 @@ proc pRaiseStmt(n: PNode, c: var Con; s: var Scope): PNode =
      result.add copyNode(n[0])
  s.needsTry = true

-template isCustomDestructor(c: Con, t: PType): bool =
-  hasDestructor(c, t) and
-          getAttachedOp(c.graph, t, attachedDestructor) != nil and
-          sfOverridden in getAttachedOp(c.graph, t, attachedDestructor).flags
-
-proc hasCustomDestructor(c: Con, t: PType): bool =
-  result = isCustomDestructor(c, t)
-  var obj = t
-  while obj.baseClass != nil:
-    obj = skipTypes(obj.baseClass, abstractPtrs)
-    result = result or isCustomDestructor(c, obj)
-
-const
-  exprBranchKinds = {nkStmtListExpr, nkBlockExpr, nkIfExpr, nkCaseStmt,
-                     nkTryStmt, nkPragmaBlock}
-
-proc distributeAsgn(asgnKind: TNodeKind; dest, ri: PNode; c: var Con; s: var Scope): PNode =
-  ## Distributes an assignment ``dest = ri`` into the leaf expressions of
-  ## ``ri`` when ``ri`` is an expression-based control flow construct. This
-  ## avoids creating pointless intermediate temporaries (bug #25850). The
-  ## descent is recursive so that nestings like ``block: ...; if c: a else: b``
-  ## assign directly to ``dest`` instead of going through a temp per branch.
-  if ri.kind in exprBranchKinds:
-    template process(child, s): untyped =
-      distributeAsgn(asgnKind, dest, child, c, s)
-    handleNestedTempl(ri, process, willProduceStmt = true)
-  else:
-    result = newTree(asgnKind, dest, p(ri, c, s, consumed))
-
 proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSingleUsedTemp}; inReturn = false): PNode =
  if n.kind in {nkStmtList, nkStmtListExpr, nkBlockStmt, nkBlockExpr, nkIfStmt,
                nkIfExpr, nkCaseStmt, nkWhen, nkWhileStmt, nkParForStmt, nkTryStmt, nkPragmaBlock}:
@@ -845,7 +778,15 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing
      result = passCopyToSink(n, c, s)
    elif n.kind in {nkBracket, nkObjConstr, nkTupleConstr, nkClosure, nkNilLit} +
         nkCallKinds + nkLiterals:
-      result = p(n, c, s, consumed)
+      if n.kind in nkCallKinds and n[0].kind == nkSym:
+        if n[0].sym.magic == mEnsureMove:
+          inc c.inEnsureMove
+          result = p(n[1], c, s, sinkArg)
+          dec c.inEnsureMove
+        else:
+          result = p(n, c, s, consumed)
+      else:
+        result = p(n, c, s, consumed)
    elif ((n.kind == nkSym and isSinkParam(n.sym)) or isAnalysableFieldAccess(n, c.owner)) and
        isLastRead(n, c, s) and not (n.kind == nkSym and isCursor(n)):
      # Sinked params can be consumed only once. We need to reset the memory
@@ -865,9 +806,6 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing
    elif n.kind in {nkObjDownConv, nkObjUpConv}:
      result = copyTree(n)
      result[0] = p(n[0], c, s, sinkArg)
-    elif n.kind == nkCast and n.typ.skipTypes(abstractInst).kind in {tyString, tySequence}:
-      result = copyTree(n)
-      result[1] = p(n[1], c, s, sinkArg)
    elif n.typ == nil:
      # 'raise X' can be part of a 'case' expression. Deal with it here:
      result = p(n, c, s, normal)
@@ -911,25 +849,29 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing
      for i in 1..<n.len:
        if n[i].kind == nkExprColonExpr:
          let field = lookupFieldAgain(t, n[i][0].sym)
-          if field != nil and (sfCursor in field.flags or field.typ.kind in {tyOpenArray, tyVarargs}):
-            # don't sink fields with openarray types
+          if field != nil and sfCursor in field.flags:
            result[i][1] = p(n[i][1], c, s, normal)
          else:
            result[i][1] = p(n[i][1], c, s, m)
        else:
          result[i] = p(n[i], c, s, m)
-      if mode == normal and (isRefConstr or hasCustomDestructor(c, t)):
+      if mode == normal and isRefConstr:
        result = ensureDestruction(result, n, c, s)
    of nkCallKinds:
+      if n[0].kind == nkSym and n[0].sym.magic == mEnsureMove:
+        inc c.inEnsureMove
+        result = p(n[1], c, s, sinkArg)
+        dec c.inEnsureMove
+        return
+
      let inSpawn = c.inSpawn
      if n[0].kind == nkSym and n[0].sym.magic == mSpawn:
        c.inSpawn.inc
      elif c.inSpawn > 0:
        c.inSpawn.dec

-      # bug #23907; skips tyGenericInst for generic callbacks
-      let parameters = if n[0].typ != nil: n[0].typ.skipTypes(abstractInst) else: n[0].typ
-      let L = if parameters != nil: parameters.signatureLen else: 0
+      let parameters = n[0].typ
+      let L = if parameters != nil: parameters.len else: 0

      when false:
        var isDangerous = false
@@ -938,19 +880,13 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing
          isDangerous = true

      result = shallowCopy(n)
-
-      if n[0].kind == nkSym and n[0].sym.magic == mEnsureMove:
-        inc c.inEnsureMove
-        result[1] = p(n[1], c, s, sinkArg)
-        dec c.inEnsureMove
-      else:
-        for i in 1..<n.len:
-          if i < L and isCompileTimeOnly(parameters[i]):
-            result[i] = n[i]
-          elif i < L and (isSinkTypeForParam(parameters[i]) or inSpawn > 0):
-            result[i] = p(n[i], c, s, sinkArg)
-          else:
-            result[i] = p(n[i], c, s, normal)
+      for i in 1..<n.len:
+        if i < L and isCompileTimeOnly(parameters[i]):
+          result[i] = n[i]
+        elif i < L and (isSinkTypeForParam(parameters[i]) or inSpawn > 0):
+          result[i] = p(n[i], c, s, sinkArg)
+        else:
+          result[i] = p(n[i], c, s, normal)

      when false:
        if isDangerous:
@@ -958,17 +894,14 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing

      if n[0].kind == nkSym and n[0].sym.magic in {mNew, mNewFinalize}:
        result[0] = copyTree(n[0])
-        if c.graph.config.selectedGC in {gcHooks, gcArc, gcAtomicArc, gcOrc, gcYrc}:
+        if c.graph.config.selectedGC in {gcHooks, gcArc, gcAtomicArc, gcOrc}:
          let destroyOld = c.genDestroy(result[1])
          result = newTree(nkStmtList, destroyOld, result)
      else:
        result[0] = p(n[0], c, s, normal)
      if canRaise(n[0]): s.needsTry = true
      if mode == normal:
-        if result.typ != nil and result.typ.kind notin {tyOpenArray, tyVarargs}:
-          # Returns of openarray types shouldn't be destroyed
-          # bug #19435; # bug #23247
-          result = ensureDestruction(result, n, c, s)
+        result = ensureDestruction(result, n, c, s)
    of nkDiscardStmt: # Small optimization
      result = shallowCopy(n)
      if n[0].kind != nkEmpty:
@@ -978,9 +911,6 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing
    of nkVarSection, nkLetSection:
      # transform; var x = y to  var x; x op y  where op is a move or copy
      result = newNodeI(nkStmtList, n.info)
-
-      let isInProc = c.owner.kind in {skProc, skFunc, skMethod, skIterator, skConverter}
-
      for it in n:
        var ri = it[^1]
        if it.kind == nkVarTuple and hasDestructor(c, ri.typ):
@@ -996,15 +926,7 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing
              s.locals.add v.sym
              pVarTopLevel(v, c, s, result)
            if ri.kind != nkEmpty:
-              let isGlobalPragma = v.kind == nkSym and
-                      {sfPure, sfGlobal} <= v.sym.flags and
-                      isInProc
-
-              if isGlobalPragma:
-                c.graph.procGlobals.add newTree(nkFastAsgn, v, ri)
-              else:
-                let value = moveOrCopy(v, ri, c, s, if v.kind == nkSym: {IsDecl} else: {})
-                result.add value
+              result.add moveOrCopy(v, ri, c, s, if v.kind == nkSym: {IsDecl} else: {})
            elif ri.kind == nkEmpty and c.inLoop > 0:
              let skipInit = v.kind == nkDotExpr and # Closure var
                             sfNoInit in v[1].sym.flags
@@ -1033,11 +955,6 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing
        result = moveOrCopy(p(n[0], c, s, mode), n[1], c, s, flags)
      elif isDiscriminantField(n[0]):
        result = c.genDiscriminantAsgn(s, n)
-      elif n[1].kind in exprBranchKinds:
-        # Distribute the assignment into each branch to avoid
-        # creating pointless temporaries for expression-based control flow.
-        let dest = p(n[0], c, s, mode)
-        result = distributeAsgn(n.kind, dest, n[1], c, s)
      else:
        result = copyNode(n)
        result.add p(n[0], c, s, mode)
@@ -1181,25 +1098,6 @@ proc genFieldAccessSideEffects(c: var Con; s: var Scope; dest, ri: PNode; flags:
  var snk = c.genSink(s, dest, newAccess, flags)
  result = newTree(nkStmtList, v, snk, c.genWasMoved(newAccess))

-proc ownsData(c: var Con; s: var Scope; orig: PNode; flags: set[MoveOrCopyFlag]): PNode =
-  var n = orig
-  while true:
-    case n.kind
-    of nkDotExpr, nkCheckedFieldExpr, nkBracketExpr:
-      n = n[0]
-    else:
-      break
-  if n.kind in nkCallKinds and n.typ != nil and hasDestructor(c, n.typ):
-    result = newNodeIT(nkStmtListExpr, orig.info, orig.typ)
-    let tmp = c.getTemp(s, n.typ, n.info, needsInit = true)
-    tmp.sym.flagsImpl.incl sfSingleUsedTemp
-    result.add newTree(nkFastAsgn, tmp, copyTree(n))
-    s.final.add c.genDestroy(tmp)
-    n[] = tmp[]
-    result.add copyTree(orig)
-  else:
-    result = nil
-
 proc moveOrCopy(dest, ri: PNode; c: var Con; s: var Scope, flags: set[MoveOrCopyFlag] = {}): PNode =
  var ri = ri
  var isEnsureMove = 0
@@ -1226,7 +1124,7 @@ proc moveOrCopy(dest, ri: PNode; c: var Con; s: var Scope, flags: set[MoveOrCopy
    of nkCallKinds:
      result = c.genSink(s, dest, p(ri, c, s, consumed), flags)
    of nkBracketExpr:
-      if isFullyUnpackedTuple(ri[0]):
+      if isUnpackedTuple(ri[0]):
        # unpacking of tuple: take over the elements
        result = c.genSink(s, dest, p(ri, c, s, consumed), flags)
      elif isAnalysableFieldAccess(ri, c.owner) and isLastRead(ri, c, s):
@@ -1244,7 +1142,7 @@ proc moveOrCopy(dest, ri: PNode; c: var Con; s: var Scope, flags: set[MoveOrCopy
        result = c.genCopy(dest, ri, flags)
        dec c.inEnsureMove, isEnsureMove
        result.add p(ri, c, s, consumed)
-        c.finishCopy(result, dest, flags, isFromSink = false)
+        c.finishCopy(result, dest, isFromSink = false)
    of nkBracket:
      # array constructor
      if ri.len > 0 and isDangerousSeq(ri.typ):
@@ -1252,7 +1150,7 @@ proc moveOrCopy(dest, ri: PNode; c: var Con; s: var Scope, flags: set[MoveOrCopy
        result = c.genCopy(dest, ri, flags)
        dec c.inEnsureMove, isEnsureMove
        result.add p(ri, c, s, consumed)
-        c.finishCopy(result, dest, flags, isFromSink = false)
+        c.finishCopy(result, dest, isFromSink = false)
      else:
        result = c.genSink(s, dest, p(ri, c, s, consumed), flags)
    of nkObjConstr, nkTupleConstr, nkClosure, nkCharLit..nkNilLit:
@@ -1262,9 +1160,9 @@ proc moveOrCopy(dest, ri: PNode; c: var Con; s: var Scope, flags: set[MoveOrCopy
        # Rule 3: `=sink`(x, z); wasMoved(z)
        let snk = c.genSink(s, dest, ri, flags)
        result = newTree(nkStmtList, snk, c.genWasMoved(ri))
-      elif ri.sym.kind != skParam and
-          isAnalysableFieldAccess(ri, c.owner) and
-          isLastRead(ri, c, s) and canBeMoved(c, dest.typ):
+      elif ri.sym.kind != skParam and ri.sym.owner == c.owner and
+          isLastRead(ri, c, s) and canBeMoved(c, dest.typ) and not isCursor(ri) and
+          not ({sfGlobal, sfPure} <= ri.sym.flags):
        # Rule 3: `=sink`(x, z); wasMoved(z)
        let snk = c.genSink(s, dest, ri, flags)
        result = newTree(nkStmtList, snk, c.genWasMoved(ri))
@@ -1273,24 +1171,17 @@ proc moveOrCopy(dest, ri: PNode; c: var Con; s: var Scope, flags: set[MoveOrCopy
        result = c.genCopy(dest, ri, flags)
        dec c.inEnsureMove, isEnsureMove
        result.add p(ri, c, s, consumed)
-        c.finishCopy(result, dest, flags, isFromSink = false)
+        c.finishCopy(result, dest, isFromSink = false)
    of nkHiddenSubConv, nkHiddenStdConv, nkConv, nkObjDownConv, nkObjUpConv, nkCast:
-      if IsExplicitSink in flags:
-        result = c.genSink(s, dest, p(ri, c, s, consumed), flags)
-      else:
-        result = c.genSink(s, dest, p(ri, c, s, sinkArg), flags)
-    of nkStmtListExpr, nkBlockExpr, nkIfExpr, nkCaseStmt, nkTryStmt, nkPragmaBlock:
+      result = c.genSink(s, dest, p(ri, c, s, sinkArg), flags)
+    of nkStmtListExpr, nkBlockExpr, nkIfExpr, nkCaseStmt, nkTryStmt:
      template process(child, s): untyped = moveOrCopy(dest, child, c, s, flags)
      # We know the result will be a stmt so we use that fact to optimize
      handleNestedTempl(ri, process, willProduceStmt = true)
    of nkRaiseStmt:
      result = pRaiseStmt(ri, c, s)
    else:
-      let isOwnsData = ownsData(c, s, ri2, flags)
-
-      if isOwnsData != nil:
-        result = moveOrCopy(dest, isOwnsData, c, s, flags)
-      elif isAnalysableFieldAccess(ri, c.owner) and isLastRead(ri, c, s) and
+      if isAnalysableFieldAccess(ri, c.owner) and isLastRead(ri, c, s) and
          canBeMoved(c, dest.typ):
        # Rule 3: `=sink`(x, z); wasMoved(z)
        let snk = c.genSink(s, dest, ri, flags)
@@ -1300,7 +1191,7 @@ proc moveOrCopy(dest, ri: PNode; c: var Con; s: var Scope, flags: set[MoveOrCopy
        result = c.genCopy(dest, ri, flags)
        dec c.inEnsureMove, isEnsureMove
        result.add p(ri, c, s, consumed)
-        c.finishCopy(result, dest, flags, isFromSink = false)
+        c.finishCopy(result, dest, isFromSink = false)

 when false:
  proc computeUninit(c: var Con) =
@@ -1329,55 +1220,6 @@ when false:
      for i in 0..<n.safeLen:
        injectDefaultCalls(n[i], c)

-proc replaceSinkParam(n: PNode, mapping: Table[int, PSym]): PNode =
-  case n.kind
-  of nkSym:
-    if n.sym.id in mapping:
-      result = newSymNode(mapping[n.sym.id])
-    else:
-      result = n
-  of nkVarSection, nkLetSection:
-    result = copyNode(n)
-    newSons(result, n.len)
-    for i in 0..<n.len:
-      result[i] = copyNode(n[i])
-      for j in 0..<n[i].len-1:
-        result[i].add n[i][j]
-      result[i].add replaceSinkParam(n[i][^1], mapping)
-  of {nkNone..nkNilLit}-{nkSym}, nkTypeSection, nkProcDef, nkConverterDef,
-      nkMethodDef, nkIteratorDef, nkMacroDef, nkTemplateDef, nkLambda, nkDo,
-      nkFuncDef, nkConstSection, nkConstDef, nkIncludeStmt, nkImportStmt,
-      nkExportStmt, nkPragma, nkCommentStmt, nkBreakState,
-      nkTypeOfExpr, nkMixinStmt, nkBindStmt:
-    result = n
-  else:
-    result = copyNode(n)
-    for i in 0..<n.len:
-      result.add replaceSinkParam(n[i], mapping)
-
-proc addSinkCopy(c: var Con; s: var Scope; sinkParams: seq[PSym]; n: PNode): PNode =
-  result = newNodeI(nkStmtList, n.info)
-  var mapping = initTable[int, PSym]()
-
-  var mutated = newSeq[PNode]()
-  getPotentialWrites(n, false, mutated)
-  var mutatedSet = initIntSet()
-  for m in mutated:
-    mutatedSet.incl m.sym.id
-  for param in sinkParams:
-    if param.id in mutatedSet:
-      let newSym = newSym(skTemp, getIdent(c.graph.cache, "sinkCopy"), c.idgen, param.owner, n.info)
-      newSym.flagsImpl.incl sfFromGeneric
-      newSym.typ = param.typ.elementType
-      mapping[param.id] = newSym
-      let v = newNodeI(nkVarSection, n.info)
-      v.addVar(newSymNode(newSym), newSymNode(param))
-      result.add v
-  if mapping.len > 0:
-    result.add replaceSinkParam(n, mapping)
-  else:
-    result = n
-
 proc injectDestructorCalls*(g: ModuleGraph; idgen: IdGenerator; owner: PSym; n: PNode): PNode =
  when toDebug.len > 0:
    shouldDebug = toDebug == owner.name.s or toDebug == "always"
@@ -1391,24 +1233,15 @@ proc injectDestructorCalls*(g: ModuleGraph; idgen: IdGenerator; owner: PSym; n:
  var scope = Scope(body: n)
  let body = p(n, c, scope, normal)

-  var sinkParams = newSeq[PSym]()
-
  if owner.kind in {skProc, skFunc, skMethod, skIterator, skConverter}:
    let params = owner.typ.n
    for i in 1..<params.len:
      let t = params[i].sym.typ
-      if isSinkTypeForParam(t):
-        let baseType = t.skipTypes({tySink})
-        if baseType.kind in {tyString, tySequence, tyArray, tyTuple, tyObject}:
-          sinkParams.add params[i].sym
-        if hasDestructor(c, baseType):
-          scope.final.add c.genDestroy(params[i])
+      if isSinkTypeForParam(t) and hasDestructor(c, t.skipTypes({tySink})):
+        scope.final.add c.genDestroy(params[i])
  #if optNimV2 in c.graph.config.globalOptions:
  #  injectDefaultCalls(n, c)
  result = optimize processScope(c, scope, body)
-  if sinkParams.len > 0:
-    result = addSinkCopy(c, scope, sinkParams, result)
-
  dbg:
    echo ">---------transformed-to--------->"
    echo renderTree(result, {renderIds})
--- a/compiler/inliner.nim
+++ b/compiler/inliner.nim
@@ -1,122 +0,0 @@
-
-proc copySymdef(n: PNode; locals: var Table[int, PSym]; idgen: IdGenerator; owner: PSym): PNode =
-  case n.kind
-  of nkEmpty..pred(nkSym), succ(nkSym)..nkNilLit:
-    result = n
-  of nkSym:
-    let oldSym = n.sym
-    let newSym = copySym(oldSym, idgen)
-    setOwner(newSym, owner)
-    locals[oldSym.id] = newSym
-    result = newSymNode(newSym, oldSym.info)
-  else:
-    result = shallowCopy(n)
-    for i in 0..<n.len:
-      result[i] = copySymdef(n[i], locals, idgen, owner)
-
-proc copyInlineProcBody(n: PNode; locals: var Table[int, PSym]; idgen: IdGenerator; owner: PSym): PNode =
-  case n.kind
-  of nkEmpty..pred(nkSym), succ(nkSym)..nkNilLit:
-    result = n
-  of nkSym:
-    let sym = locals.getOrDefault(n.sym.id)
-    if sym != nil:
-      result = newSymNode(sym, n.info)
-    else:
-      result = n
-  of nkLetSection, nkVarSection:
-    result = shallowCopy(n)
-    for i in 0..<n.len:
-      let it = n[i]
-      if it.kind == nkCommentStmt:
-        result[i] = it
-      elif it.kind in {nkIdentDefs, nkConstDef}:
-        result[i] = shallowCopy(it)
-        for j in 0..<it.len-2:
-          result[i][j] = copySymdef(it[j], locals, idgen, owner)
-        for j in it.len-2..<it.len:
-          result[i][j] = copyInlineProcBody(it[j], locals, idgen, owner)
-      else:
-        assert it.kind == nkVarTuple
-        result[i] = shallowCopy(it)
-        for j in 0..<it.len-2:
-          assert it[j].kind == nkSym
-          let oldSym = it[j].sym
-          let newSym = copySym(oldSym, idgen)
-          setOwner(newSym, owner)
-          locals[oldSym.id] = newSym
-          result[i][j] = newSymNode(newSym, oldSym.info)
-        for j in it.len-2..<it.len:
-          result[i][j] = copyInlineProcBody(it[j], locals, idgen, owner)
-
-  of nkForStmt, nkParForStmt:
-    result = shallowCopy(n)
-    for i in 0..<n.len-2:
-      assert n[i].kind == nkSym
-      let oldSym = n[i].sym
-      let newSym = copySym(oldSym, idgen)
-      setOwner(newSym, owner)
-      locals[oldSym.id] = newSym
-      result[i] = newSymNode(newSym, oldSym.info)
-    result[n.len-2] = copyInlineProcBody(n[n.len-2], locals, idgen, owner)
-    result[n.len-1] = copyInlineProcBody(n[n.len-1], locals, idgen, owner)
-  of routineDefs, nkTypeSection, nkTypeOfExpr, nkMixinStmt, nkBindStmt, nkConstSection:
-    result = n
-  else:
-    result = shallowCopy(n)
-    for i in 0..<n.len:
-      result[i] = copyInlineProcBody(n[i], locals, idgen, owner)
-
-proc copyParams(n: PNode; locals: var Table[int, PSym]; idgen: IdGenerator; owner: PSym): PNode =
-  result = shallowCopy(n)
-  result[0] = n[0] # return type
-  for i in 1..<n.len:
-    let it = n[i]
-    assert it.kind == nkIdentDefs
-    result[i] = shallowCopy(it)
-    for j in 0..<it.len-2:
-      assert it[j].kind == nkSym
-      let oldSym = it[j].sym
-      let newSym = copySym(oldSym, idgen)
-      setOwner(newSym, owner)
-      locals[oldSym.id] = newSym
-      result[i][j] = newSymNode(newSym, oldSym.info)
-      owner.typ.addParam newSym
-    for j in it.len-2..<it.len:
-      result[i][j] = copyInlineProcBody(it[j], locals, idgen, owner)
-
-proc copyInlineProc(prc: PSym; idgen: IdGenerator): PSym =
-  result = copySym(prc, idgen)
-  var locals = initTable[int, PSym]()
-
-  var a = shallowCopy(prc.ast)
-  if resultPos < prc.ast.len and prc.ast[resultPos].kind == nkSym:
-    let oldRes = prc.ast[resultPos].sym
-    let newRes = copySym(oldRes, idgen)
-    setOwner(newRes, result)
-    locals[oldRes.id] = newRes
-    a[resultPos] = newSymNode(newRes, oldRes.info)
-
-  result.typ = copyType(prc.typ, idgen, result)
-  result.typ.n = newNodeI(prc.typ.n.kind, prc.typ.n.info)
-  if prc.typ.n.len > 0:
-    result.typ.n.add copyNode(prc.typ.n[0])
-    for i in 1..<prc.typ.n.len:
-      let it = prc.typ.n[i]
-      assert it.kind == nkSym
-      let oldSym = it.sym
-      let newSym = copySym(oldSym, idgen)
-      setOwner(newSym, result)
-      locals[oldSym.id] = newSym
-      result.typ.addParam newSym
-
-  for i in 0..<prc.ast.len:
-    if i == paramsPos:
-      a[i] = copyTree(prc.ast[i])
-    elif i == resultPos and prc.ast[i].kind == nkSym:
-      discard "handled above"
-    else:
-      a[i] = copyInlineProcBody(prc.ast[i], locals, idgen, result)
-  result.ast = a
-
-  #echo "Produced: ", renderTree(result.ast, {renderIds})
--- a/compiler/installer.ini
+++ b/compiler/installer.ini
@@ -6,11 +6,11 @@ Name: "Nim"
 Version: "$version"
 Platforms: """
  windows: i386;amd64
-  linux: i386;hppa;ia64;alpha;amd64;powerpc64;arm;sparc;sparc64;s390x;m68k;mips;mipsel;mips64;mips64el;powerpc;powerpc64el;arm64;riscv32;riscv64;loongarch64
+  linux: i386;hppa;ia64;alpha;amd64;powerpc64;arm;sparc;sparc64;m68k;mips;mipsel;mips64;mips64el;powerpc;powerpc64el;arm64;riscv32;riscv64
  macosx: i386;amd64;powerpc64;arm64
  solaris: i386;amd64;sparc;sparc64
  freebsd: i386;amd64;powerpc64;arm;arm64;riscv64;sparc64;mips;mipsel;mips64;mips64el;powerpc;powerpc64el
-  netbsd: i386;amd64;arm64
+  netbsd: i386;amd64
  openbsd: i386;amd64;arm;arm64
  dragonfly: i386;amd64
  crossos: amd64
@@ -71,7 +71,6 @@ Files: "testament"
 Files: "nimsuggest"
 Files: "nimsuggest/tests/*.nim"
 Files: "changelogs/*.md"
-Files: "ci/funs.sh"

 [Lib]
 Files: "lib"
@@ -80,7 +79,6 @@ Files: "lib"
 Files: "examples"
 Files: "dist/nimble"
 Files: "dist/checksums"
-Files: "dist/nimony"

 Files: "tests"

@@ -148,4 +146,4 @@ licenses: "bin/nim,MIT;lib/*,MIT;"

 [nimble]
 pkgName: "nim"
-pkgFiles: "compiler/*;doc/basicopt.txt;doc/advopt.txt;doc/nimdoc.css;doc/nimdoc.cls"
+pkgFiles: "compiler/*;doc/basicopt.txt;doc/advopt.txt;doc/nimdoc.css"
--- a/compiler/int128.nim
+++ b/compiler/int128.nim
@@ -3,7 +3,7 @@
 ## hold all from `low(BiggestInt)` to `high(BiggestUInt)`, This
 ## type is for that purpose.

-from std/math import trunc
+from math import trunc

 when defined(nimPreviewSlimSystem):
  import std/assertions
@@ -34,7 +34,6 @@ proc `$`*(a: Int128): string

 proc toInt128*[T: SomeInteger | bool](arg: T): Int128 =
  {.noSideEffect.}:
-    result = Zero
    when T is bool: result.sdata(0) = int32(arg)
    elif T is SomeUnsignedInt:
      when sizeof(arg) <= 4:
@@ -209,35 +208,30 @@ proc `==`*(a, b: Int128): bool =
  return true

 proc bitnot*(a: Int128): Int128 =
-  result = Zero
  result.udata[0] = not a.udata[0]
  result.udata[1] = not a.udata[1]
  result.udata[2] = not a.udata[2]
  result.udata[3] = not a.udata[3]

 proc bitand*(a, b: Int128): Int128 =
-  result = Zero
  result.udata[0] = a.udata[0] and b.udata[0]
  result.udata[1] = a.udata[1] and b.udata[1]
  result.udata[2] = a.udata[2] and b.udata[2]
  result.udata[3] = a.udata[3] and b.udata[3]

 proc bitor*(a, b: Int128): Int128 =
-  result = Zero
  result.udata[0] = a.udata[0] or b.udata[0]
  result.udata[1] = a.udata[1] or b.udata[1]
  result.udata[2] = a.udata[2] or b.udata[2]
  result.udata[3] = a.udata[3] or b.udata[3]

 proc bitxor*(a, b: Int128): Int128 =
-  result = Zero
  result.udata[0] = a.udata[0] xor b.udata[0]
  result.udata[1] = a.udata[1] xor b.udata[1]
  result.udata[2] = a.udata[2] xor b.udata[2]
  result.udata[3] = a.udata[3] xor b.udata[3]

 proc `shr`*(a: Int128, b: int): Int128 =
-  result = Zero
  let b = b and 127
  if b < 32:
    result.sdata(3) = a.sdata(3) shr b
@@ -264,7 +258,6 @@ proc `shr`*(a: Int128, b: int): Int128 =
    result.sdata(0) = a.sdata(3) shr (b and 31)

 proc `shl`*(a: Int128, b: int): Int128 =
-  result = Zero
  let b = b and 127
  if b < 32:
    result.udata[0] = a.udata[0] shl b
@@ -288,7 +281,6 @@ proc `shl`*(a: Int128, b: int): Int128 =
    result.udata[3] = a.udata[0] shl (b and 31)

 proc `+`*(a, b: Int128): Int128 =
-  result = Zero
  let tmp0 = uint64(a.udata[0]) + uint64(b.udata[0])
  result.udata[0] = cast[uint32](tmp0)
  let tmp1 = uint64(a.udata[1]) + uint64(b.udata[1]) + (tmp0 shr 32)
@@ -321,7 +313,6 @@ proc abs(a: int32): int =
  if a < 0: -a else: a

 proc `*`(a: Int128, b: uint32): Int128 =
-  result = Zero
  let tmp0 = uint64(a.udata[0]) * uint64(b)
  let tmp1 = uint64(a.udata[1]) * uint64(b)
  let tmp2 = uint64(a.udata[2]) * uint64(b)
@@ -344,7 +335,6 @@ proc `*=`(a: var Int128, b: int32) =
  a = a * b

 proc makeInt128(high, low: uint64): Int128 =
-  result = Zero
  result.udata[0] = cast[uint32](low)
  result.udata[1] = cast[uint32](low shr 32)
  result.udata[2] = cast[uint32](high)
@@ -368,7 +358,7 @@ proc `*`*(lhs, rhs: Int128): Int128 =
 proc `*=`*(a: var Int128, b: Int128) =
  a = a * b

-import std/bitops
+import bitops

 proc fastLog2*(a: Int128): int =
  result = 0
@@ -383,8 +373,6 @@ proc fastLog2*(a: Int128): int =

 proc divMod*(dividend, divisor: Int128): tuple[quotient, remainder: Int128] =
  assert(divisor != Zero)
-  result = (Zero, Zero)
-
  let isNegativeA = isNegative(dividend)
  let isNegativeB = isNegative(divisor)

@@ -460,9 +448,7 @@ proc addInt128*(result: var string; value: Int128) =
    var i = initialSize
    var j = high(result)
    while i < j:
-      let tmp = result[i]
-      result[i] = result[j]
-      result[j] = tmp
+      swap(result[i], result[j])
      i += 1
      j -= 1

@@ -553,28 +539,24 @@ proc toInt128*(arg: float64): Int128 =
    return res

 proc maskUInt64*(arg: Int128): Int128 {.noinit, inline.} =
-  result = Zero
  result.udata[0] = arg.udata[0]
  result.udata[1] = arg.udata[1]
  result.udata[2] = 0
  result.udata[3] = 0

 proc maskUInt32*(arg: Int128): Int128 {.noinit, inline.} =
-  result = Zero
  result.udata[0] = arg.udata[0]
  result.udata[1] = 0
  result.udata[2] = 0
  result.udata[3] = 0

 proc maskUInt16*(arg: Int128): Int128 {.noinit, inline.} =
-  result = Zero
  result.udata[0] = arg.udata[0] and 0xffff
  result.udata[1] = 0
  result.udata[2] = 0
  result.udata[3] = 0

 proc maskUInt8*(arg: Int128): Int128 {.noinit, inline.} =
-  result = Zero
  result.udata[0] = arg.udata[0] and 0xff
  result.udata[1] = 0
  result.udata[2] = 0
--- a/compiler/isolation_check.nim
+++ b/compiler/isolation_check.nim
@@ -11,9 +11,7 @@
 ## https://github.com/nim-lang/RFCs/issues/244 for more details.

 import
-  ast, types, renderer
-
-import std/intsets
+  ast, types, renderer, intsets

 when defined(nimPreviewSlimSystem):
  import std/assertions
@@ -54,18 +52,18 @@ proc canAlias(arg, ret: PType; marker: var IntSet): bool =
  of tyObject:
    if isFinal(ret):
      result = canAliasN(arg, ret.n, marker)
-      if not result and ret.baseClass != nil:
-        result = canAlias(arg, ret.baseClass, marker)
+      if not result and ret.len > 0 and ret[0] != nil:
+        result = canAlias(arg, ret[0], marker)
    else:
      result = true
  of tyTuple:
    result = false
-    for r in ret.kids:
-      result = canAlias(arg, r, marker)
+    for i in 0..<ret.len:
+      result = canAlias(arg, ret[i], marker)
      if result: break
  of tyArray, tySequence, tyDistinct, tyGenericInst,
     tyAlias, tyInferred, tySink, tyLent, tyOwned, tyRef:
-    result = canAlias(arg, ret.skipModifier, marker)
+    result = canAlias(arg, ret.lastSon, marker)
  of tyProc:
    result = ret.callConv == ccClosure
  else:
@@ -119,16 +117,14 @@ proc containsDangerousRefAux(t: PType; marker: var IntSet): SearchResult =
  if result != NotFound: return result
  case t.kind
  of tyObject:
-    if t.baseClass != nil:
-      result = containsDangerousRefAux(t.baseClass.skipTypes(skipPtrs), marker)
+    if t[0] != nil:
+      result = containsDangerousRefAux(t[0].skipTypes(skipPtrs), marker)
    if result == NotFound: result = containsDangerousRefAux(t.n, marker)
  of tyGenericInst, tyDistinct, tyAlias, tySink:
-    result = containsDangerousRefAux(skipModifier(t), marker)
-  of tyArray, tySet, tySequence:
-    result = containsDangerousRefAux(t.elementType, marker)
-  of tyTuple:
-    for a in t.kids:
-      result = containsDangerousRefAux(a, marker)
+    result = containsDangerousRefAux(lastSon(t), marker)
+  of tyArray, tySet, tyTuple, tySequence:
+    for i in 0..<t.len:
+      result = containsDangerousRefAux(t[i], marker)
      if result == Found: return result
  else:
    discard
@@ -166,7 +162,7 @@ proc containsVariable(n: PNode): bool =
 proc checkIsolate*(n: PNode): bool =
  if types.containsTyRef(n.typ):
    # XXX Maybe require that 'n.typ' is acyclic. This is not much
-    # worse than the already existing inheritance and closure restrictions.
+    # worse than the already exisiting inheritance and closure restrictions.
    case n.kind
    of nkCharLit..nkNilLit:
      result = true
--- a/compiler/itemids.nim
+++ b/compiler/itemids.nim
@@ -1,98 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2026 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-## `ItemId` is the identity of a symbol or type: a `(module, item)` pair.
-##
-## The fields are private on purpose: the module half reserves bit 30 as the
-## "backend minted" marker, so all construction and inspection has to go
-## through this module's API and the marker bit can never leak into module
-## indexing or arithmetic.
-##
-## Three id spaces coexist per module:
-## - Semantic-phase and NIF-loader ids: `itemId(module, item)` with `item > 0`.
-## - Backend-minted ids (IC codegen, `nim nifc`: transf labels and temps,
-##   lifted hooks): `backendItemId` sets `BackendModuleBit`, so these can
-##   never compare equal to a loader id even though both counters mint the
-##   same small `item` range in one process. They never cross a process
-##   boundary and must never be written to a NIF file.
-## - Derived env/tuple-field ids (`lowerings.addField`): the source local's
-##   id with `item` negated. `derivedFieldId` preserves the backend marker,
-##   keeping the derivation collision-free for both id spaces above.
-
-import std/hashes
-
-when defined(nimPreviewSlimSystem):
-  import std/assertions
-
-const
-  BackendModuleBit = 0x4000_0000'i32
-    # Bit 30 of the module field. Bit 31 stays clear so marked module values
-    # remain non-negative and cannot be mistaken for the special negative
-    # module ids like `PackageModuleId`.
-  PackageModuleId* = -3'i32
-
-type
-  ItemId* = object
-    moduleBits: int32
-    itemBits: int32
-
-proc itemId*(module, item: int32): ItemId {.inline.} =
-  assert module < 0 or (module and BackendModuleBit) == 0
-  ItemId(moduleBits: module, itemBits: item)
-
-proc backendItemId*(module, item: int32): ItemId {.inline.} =
-  ## An id minted during IC codegen; distinct from every `itemId` of the
-  ## same module so that the loader's stub counter and the backend's counter
-  ## cannot collide in id-keyed tables.
-  assert module >= 0 and (module and BackendModuleBit) == 0
-  ItemId(moduleBits: module or BackendModuleBit, itemBits: item)
-
-proc module*(x: ItemId): int32 {.inline.} =
-  if x.moduleBits >= 0: x.moduleBits and not BackendModuleBit
-  else: x.moduleBits
-
-proc item*(x: ItemId): int32 {.inline.} = x.itemBits
-
-proc isBackendMinted*(x: ItemId): bool {.inline.} =
-  x.moduleBits >= 0 and (x.moduleBits and BackendModuleBit) != 0
-
-proc derivedFieldId*(source: ItemId): ItemId {.inline.} =
-  ## The id of the env/tuple field that `lowerings.addField` derives for a
-  ## captured local: `item` negated, module bits (including the backend
-  ## marker) preserved.
-  ItemId(moduleBits: source.moduleBits, itemBits: -abs(source.itemBits))
-
-proc matchesDerivedFieldId*(field, source: ItemId): bool {.inline.} =
-  ## Does `field` carry the id `derivedFieldId` would derive for `source`?
-  ## `source` may itself already be the derived field id.
-  field.moduleBits == source.moduleBits and
-    field.itemBits == -abs(source.itemBits)
-
-proc `==`*(a, b: ItemId): bool {.inline.} =
-  # raw bit comparison: a backend-minted id never equals a loader id
-  a.itemBits == b.itemBits and a.moduleBits == b.moduleBits
-
-proc hash*(x: ItemId): Hash =
-  var h: Hash = hash(x.moduleBits)
-  h = h !& hash(x.itemBits)
-  result = !$h
-
-proc `$`*(x: ItemId): string =
-  result = "(module: " & $x.module & ", item: " & $x.itemBits
-  if x.isBackendMinted: result.add ", backend"
-  result.add ")"
-
-const
-  moduleShift = when defined(cpu32): 20 else: 24
-
-proc toId*(a: ItemId): int {.inline.} =
-  ## Packs an ItemId into a single int. Uses the raw module bits so the
-  ## backend marker keeps the two id spaces disjoint (bit 30 shifts to
-  ## bit 54; like the module/item split itself this needs a 64-bit int).
-  (a.moduleBits.int shl moduleShift) + a.itemBits.int
--- a/compiler/jsgen.nim
+++ b/compiler/jsgen.nim
--- a/compiler/jstypes.nim
+++ b/compiler/jstypes.nim
@@ -69,7 +69,7 @@ proc genObjectFields(p: PProc, typ: PType, n: PNode): Rope =
  else: internalError(p.config, n.info, "genObjectFields")

 proc objHasTypeField(t: PType): bool {.inline.} =
-  tfInheritable in t.flags or t.baseClass != nil
+  tfInheritable in t.flags or t[0] != nil

 proc genObjectInfo(p: PProc, typ: PType, name: Rope) =
  let kind = if objHasTypeField(typ): tyObject else: tyTuple
@@ -79,9 +79,9 @@ proc genObjectInfo(p: PProc, typ: PType, name: Rope) =
  p.g.typeInfo.addf("var NNI$1 = $2;$n",
       [rope(typ.id), genObjectFields(p, typ, typ.n)])
  p.g.typeInfo.addf("$1.node = NNI$2;$n", [name, rope(typ.id)])
-  if (typ.kind == tyObject) and (typ.baseClass != nil):
+  if (typ.kind == tyObject) and (typ[0] != nil):
    p.g.typeInfo.addf("$1.base = $2;$n",
-         [name, genTypeInfo(p, typ.baseClass.skipTypes(skipPtrs))])
+         [name, genTypeInfo(p, typ[0].skipTypes(skipPtrs))])

 proc genTupleFields(p: PProc, typ: PType): Rope =
  var s: Rope = ""
@@ -117,17 +117,17 @@ proc genEnumInfo(p: PProc, typ: PType, name: Rope) =
  prepend(p.g.typeInfo, s)
  p.g.typeInfo.add(n)
  p.g.typeInfo.addf("$1.node = NNI$2;$n", [name, rope(typ.id)])
-  if typ.baseClass != nil:
+  if typ[0] != nil:
    p.g.typeInfo.addf("$1.base = $2;$n",
-         [name, genTypeInfo(p, typ.baseClass)])
+         [name, genTypeInfo(p, typ[0])])

 proc genTypeInfo(p: PProc, typ: PType): Rope =
-  let t = typ.skipTypes({tyGenericInst, tyDistinct, tyAlias, tySink, tyOwned} + tyUserTypeClasses)
+  let t = typ.skipTypes({tyGenericInst, tyDistinct, tyAlias, tySink, tyOwned})
  result = "NTI$1" % [rope(t.id)]
  if containsOrIncl(p.g.typeInfoGenerated, t.id): return
  case t.kind
  of tyDistinct:
-    result = genTypeInfo(p, t.skipModifier)
+    result = genTypeInfo(p, t[0])
  of tyPointer, tyProc, tyBool, tyChar, tyCstring, tyString, tyInt..tyUInt64:
    var s =
      "var $1 = {size: 0,kind: $2,base: null,node: null,finalizer: null};$n" %
@@ -139,18 +139,18 @@ proc genTypeInfo(p: PProc, typ: PType): Rope =
              [result, rope(ord(t.kind))]
    prepend(p.g.typeInfo, s)
    p.g.typeInfo.addf("$1.base = $2;$n",
-         [result, genTypeInfo(p, t.elementType)])
+         [result, genTypeInfo(p, t.lastSon)])
  of tyArray:
    var s =
      "var $1 = {size: 0, kind: $2, base: null, node: null, finalizer: null};$n" %
              [result, rope(ord(t.kind))]
    prepend(p.g.typeInfo, s)
    p.g.typeInfo.addf("$1.base = $2;$n",
-         [result, genTypeInfo(p, t.elementType)])
+         [result, genTypeInfo(p, t[1])])
  of tyEnum: genEnumInfo(p, t, result)
  of tyObject: genObjectInfo(p, t, result)
  of tyTuple: genTupleInfo(p, t, result)
  of tyStatic:
-    if t.n != nil: result = genTypeInfo(p, skipModifier t)
+    if t.n != nil: result = genTypeInfo(p, lastSon t)
    else: internalError(p.config, "genTypeInfo(" & $t.kind & ')')
  else: internalError(p.config, "genTypeInfo(" & $t.kind & ')')
--- a/compiler/lambdalifting.nim
+++ b/compiler/lambdalifting.nim
@@ -10,12 +10,10 @@
 # This file implements lambda lifting for the transformator.

 import
-  options, ast, astalgo, msgs,
-  idents, renderer, types, magicsys, lowerings, modulegraphs, lineinfos,
+  intsets, strutils, options, ast, astalgo, msgs,
+  idents, renderer, types, magicsys, lowerings, tables, modulegraphs, lineinfos,
  transf, liftdestructors, typeallowed

-import std/[strutils, tables, intsets]
-
 when defined(nimPreviewSlimSystem):
  import std/assertions

@@ -135,24 +133,21 @@ proc createClosureIterStateType*(g: ModuleGraph; iter: PSym; idgen: IdGenerator)
  var n = newNodeI(nkRange, iter.info)
  n.add newIntNode(nkIntLit, -1)
  n.add newIntNode(nkIntLit, 0)
-  result = newType(tyRange, idgen, iter)
+  result = newType(tyRange, nextTypeId(idgen), iter)
  result.n = n
  var intType = nilOrSysInt(g)
-  if intType.isNil: intType = newType(tyInt, idgen, iter)
+  if intType.isNil: intType = newType(tyInt, nextTypeId(idgen), iter)
  rawAddSon(result, intType)

 proc createStateField(g: ModuleGraph; iter: PSym; idgen: IdGenerator): PSym =
  result = newSym(skField, getIdent(g.cache, ":state"), idgen, iter, iter.info)
  result.typ = createClosureIterStateType(g, iter, idgen)

-template isIterator*(owner: PSym): bool =
-  owner.kind == skIterator and owner.typ.callConv == ccClosure
-
 proc createEnvObj(g: ModuleGraph; idgen: IdGenerator; owner: PSym; info: TLineInfo): PType =
+  # YYY meh, just add the state field for every closure for now, it's too
+  # hard to figure out if it comes from a closure iterator:
  result = createObj(g, idgen, owner, info, final=false)
-  result.incl tfFinal
-  if owner.isIterator:
-    rawAddField(result, createStateField(g, owner, idgen))
+  rawAddField(result, createStateField(g, owner, idgen))

 proc getClosureIterResult*(g: ModuleGraph; iter: PSym; idgen: IdGenerator): PSym =
  if resultPos < iter.ast.len:
@@ -160,25 +155,13 @@ proc getClosureIterResult*(g: ModuleGraph; iter: PSym; idgen: IdGenerator): PSym
  else:
    # XXX a bit hacky:
    result = newSym(skResult, getIdent(g.cache, ":result"), idgen, iter, iter.info, {})
-    result.typ = iter.typ.returnType
-    incl(result.flagsImpl, sfUsed)
+    result.typ = iter.typ[0]
+    incl(result.flags, sfUsed)
    iter.ast.add newSymNode(result)

-proc closureParams(routine: PSym): PNode =
-  ## The formal parameters node lambda lifting reads and extends. In a
-  ## from-source compilation `routine.ast[paramsPos]` and `routine.typ.n` are the
-  ## very same node (see the `typ.n.len` based position math below). Under IC the
-  ## loaded proc AST omits the parameters (they are kept only in `typ.n`), so
-  ## restore the shared node here.
-  result = routine.ast[paramsPos]
-  if (result == nil or result.kind == nkEmpty) and routine.typ != nil and
-      routine.typ.n != nil and routine.ast.len > paramsPos:
-    result = routine.typ.n
-    routine.ast[paramsPos] = result
-
-proc addHiddenParam*(routine: PSym, param: PSym) =
+proc addHiddenParam(routine: PSym, param: PSym) =
  assert param.kind == skParam
-  var params = closureParams(routine)
+  var params = routine.ast[paramsPos]
  # -1 is correct here as param.position is 0 based but we have at position 0
  # some nkEffect node:
  param.position = routine.typ.n.len-1
@@ -187,24 +170,26 @@ proc addHiddenParam*(routine: PSym, param: PSym) =
  assert sfFromGeneric in param.flags
  #echo "produced environment: ", param.id, " for ", routine.id

-proc getEnvParam*(routine: PSym): PSym =
-  if routine.ast.isNil: return nil
-  let params = closureParams(routine)
-  if params == nil or params.len == 0: return nil
+proc getHiddenParam(g: ModuleGraph; routine: PSym): PSym =
+  let params = routine.ast[paramsPos]
  let hidden = lastSon(params)
  if hidden.kind == nkSym and hidden.sym.kind == skParam and hidden.sym.name.s == paramName:
    result = hidden.sym
    assert sfFromGeneric in result.flags
  else:
-    result = nil
-
-proc getHiddenParam(g: ModuleGraph; routine: PSym): PSym =
-  result = getEnvParam(routine)
-  if result.isNil:
    # writeStackTrace()
    localError(g.config, routine.info, "internal error: could not find env param for " & routine.name.s)
    result = routine

+proc getEnvParam*(routine: PSym): PSym =
+  let params = routine.ast[paramsPos]
+  let hidden = lastSon(params)
+  if hidden.kind == nkSym and hidden.sym.name.s == paramName:
+    result = hidden.sym
+    assert sfFromGeneric in result.flags
+  else:
+    result = nil
+
 proc interestingVar(s: PSym): bool {.inline.} =
  result = s.kind in {skVar, skLet, skTemp, skForVar, skParam, skResult} and
    sfGlobal notin s.flags and
@@ -213,7 +198,7 @@ proc interestingVar(s: PSym): bool {.inline.} =
 proc illegalCapture(s: PSym): bool {.inline.} =
  result = classifyViewType(s.typ) != noView or s.kind == skResult

-proc isInnerProc*(s: PSym): bool =
+proc isInnerProc(s: PSym): bool =
  if s.kind in {skProc, skFunc, skMethod, skConverter, skIterator} and s.magic == mNone:
    result = s.skipGenericOwner.kind in routineKinds
  else:
@@ -229,10 +214,6 @@ proc newAsgnStmt(le, ri: PNode, info: TLineInfo): PNode =
  result[0] = le
  result[1] = ri

-proc markInjectDestructors(s: PSym) {.inline.} =
-  backendEnsureMutable s
-  s.flagsImpl.incl sfInjectDestructors
-
 proc makeClosure*(g: ModuleGraph; idgen: IdGenerator; prc: PSym; env: PNode; info: TLineInfo): PNode =
  result = newNodeIT(nkClosure, info, prc.typ)
  result.add(newSymNode(prc))
@@ -245,19 +226,28 @@ proc makeClosure*(g: ModuleGraph; idgen: IdGenerator; prc: PSym; env: PNode; inf
  #if isClosureIterator(result.typ):
  createTypeBoundOps(g, nil, result.typ, info, idgen)
  if tfHasAsgn in result.typ.flags or optSeqDestructors in g.config.globalOptions:
-    markInjectDestructors(prc)
+    prc.flags.incl sfInjectDestructors

-template liftingHarmful(conf: ConfigRef; owner: PSym): bool =
+proc interestingIterVar(s: PSym): bool {.inline.} =
+  # XXX optimization: Only lift the variable if it lives across
+  # yield/return boundaries! This can potentially speed up
+  # closure iterators quite a bit.
+  result = s.kind in {skResult, skVar, skLet, skTemp, skForVar} and sfGlobal notin s.flags
+
+template isIterator*(owner: PSym): bool =
+  owner.kind == skIterator and owner.typ.callConv == ccClosure
+
+proc liftingHarmful(conf: ConfigRef; owner: PSym): bool {.inline.} =
  ## lambda lifting can be harmful for JS-like code generators.
  let isCompileTime = sfCompileTime in owner.flags or owner.kind == skMacro
-  jsNoLambdaLifting in conf.legacyFeatures and conf.backend == backendJs and not isCompileTime
+  result = conf.backend == backendJs and not isCompileTime

 proc createTypeBoundOpsLL(g: ModuleGraph; refType: PType; info: TLineInfo; idgen: IdGenerator; owner: PSym) =
  if owner.kind != skMacro:
-    createTypeBoundOps(g, nil, refType.elementType, info, idgen)
+    createTypeBoundOps(g, nil, refType.lastSon, info, idgen)
    createTypeBoundOps(g, nil, refType, info, idgen)
    if tfHasAsgn in refType.flags or optSeqDestructors in g.config.globalOptions:
-      markInjectDestructors(owner)
+      owner.flags.incl sfInjectDestructors

 proc genCreateEnv(env: PNode): PNode =
  var c = newNodeIT(nkObjConstr, env.info, env.typ)
@@ -272,7 +262,8 @@ proc liftIterSym*(g: ModuleGraph; n: PNode; idgen: IdGenerator; owner: PSym): PN
  let iter = n.sym
  assert iter.isIterator

-  result = newNodeIT(nkStmtListExpr, n.info, iter.typ)
+  result = newNodeIT(nkStmtListExpr, n.info, n.typ)
+
  let hp = getHiddenParam(g, iter)
  var env: PNode
  if owner.isIterator:
@@ -293,6 +284,15 @@ proc liftIterSym*(g: ModuleGraph; n: PNode; idgen: IdGenerator; owner: PSym): PN
  createTypeBoundOpsLL(g, env.typ, n.info, idgen, owner)
  result.add makeClosure(g, idgen, iter, env, n.info)

+proc freshVarForClosureIter*(g: ModuleGraph; s: PSym; idgen: IdGenerator; owner: PSym): PNode =
+  let envParam = getHiddenParam(g, owner)
+  let obj = envParam.typ.skipTypes({tyOwned, tyRef, tyPtr})
+  let field = addField(obj, s, g.cache, idgen)
+
+  var access = newSymNode(envParam)
+  assert obj.kind == tyObject
+  result = rawIndirectAccess(access, field, s.info)
+
 # ------------------ new stuff -------------------------------------------

 proc markAsClosure(g: ModuleGraph; owner: PSym; n: PNode) =
@@ -302,32 +302,12 @@ proc markAsClosure(g: ModuleGraph; owner: PSym; n: PNode) =
    localError(g.config, n.info,
      ("'$1' is of type <$2> which cannot be captured as it would violate memory" &
       " safety, declared here: $3; using '-d:nimNoLentIterators' helps in some cases." &
-       " Consider using a <ref T> which can be captured.") %
-      [s.name.s, typeToString(s.typ.skipTypes({tyVar})), g.config$s.info])
+       " Consider using a <ref $2> which can be captured.") %
+      [s.name.s, typeToString(s.typ), g.config$s.info])
  elif not (owner.typ.isClosure or owner.isNimcall and not owner.isExplicitCallConv or isEnv):
    localError(g.config, n.info, "illegal capture '$1' because '$2' has the calling convention: <$3>" %
      [s.name.s, owner.name.s, $owner.typ.callConv])
-  unsealForTransform(owner.typ)
-  incl(owner.typ, tfCapturesEnv)
-  # A closure proc type that captures an env owns a REF to it: copying the closure
-  # value must incref the env and destroying it must decref. That is exactly what
-  # `tfHasAsgn` signals to `injectDestructorCalls` (so a closure assignment becomes
-  # `=copy`, not a raw field store).
-  #
-  # Set it HERE (closure-type creation) so the flag is DETERMINISTIC and serializes
-  # with the type — but ONLY under `nim ic`. The per-module `lower` stage is a
-  # separate process that lowers routines in index order; if a consumer (e.g.
-  # `workNimAsyncContinue`) was lowered before the closure type's ops were lifted,
-  # its env store emitted a RAW assign with no incref → freed env → async
-  # "yielded `nil`". A normal single-process `nim c` build does NOT need this —
-  # `createTypeBoundOps` sets the flag lazily, in lift order, before it matters
-  # (the old `liftdestructors ~1498` "XXX Breaks IC!" side effect) — and setting it
-  # eagerly there REGRESSES codegen: a `=destroy` hook gets generated against the
-  # bare `void(*)(void)` proc representation but is then called with closure structs
-  # (`eqdestroy__u2__stdZtypedthreads` type mismatch — broke megatest). So gate on
-  # `cmdNifC`; normal builds keep the lazy (devel) behavior.
-  if g.config.cmd == cmdNifC:
-    incl(owner.typ, tfHasAsgn)
+  incl(owner.typ.flags, tfCapturesEnv)
  if not isEnv:
    owner.typ.callConv = ccClosure

@@ -360,20 +340,16 @@ proc getEnvTypeForOwner(c: var DetectionPass; owner: PSym;
                        info: TLineInfo): PType =
  result = c.ownerToType.getOrDefault(owner.id)
  if result.isNil:
-    let env = getEnvParam(owner)
-    if env.isNil or not owner.isIterator:
-      result = newType(tyRef, c.idgen, owner)
-      let obj = createEnvObj(c.graph, c.idgen, owner, info)
-      rawAddSon(result, obj)
-    else:
-      result = env.typ
+    result = newType(tyRef, nextTypeId(c.idgen), owner)
+    let obj = createEnvObj(c.graph, c.idgen, owner, info)
+    rawAddSon(result, obj)
    c.ownerToType[owner.id] = result

 proc asOwnedRef(c: var DetectionPass; t: PType): PType =
  if optOwnedRefs in c.graph.config.globalOptions:
    assert t.kind == tyRef
-    result = newType(tyOwned, c.idgen, t.owner)
-    result.incl tfHasOwned
+    result = newType(tyOwned, nextTypeId(c.idgen), t.owner)
+    result.flags.incl tfHasOwned
    result.rawAddSon t
  else:
    result = t
@@ -381,7 +357,7 @@ proc asOwnedRef(c: var DetectionPass; t: PType): PType =
 proc getEnvTypeForOwnerUp(c: var DetectionPass; owner: PSym;
                          info: TLineInfo): PType =
  var r = c.getEnvTypeForOwner(owner, info)
-  result = newType(tyPtr, c.idgen, owner)
+  result = newType(tyPtr, nextTypeId(c.idgen), owner)
  rawAddSon(result, r.skipTypes({tyOwned, tyRef, tyPtr}))

 proc createUpField(c: var DetectionPass; dest, dep: PSym; info: TLineInfo) =
@@ -445,37 +421,19 @@ Consider:
 proc isTypeOf(n: PNode): bool =
  n.kind == nkSym and n.sym.magic in {mTypeOf, mType}

-proc isEnvTypeForRoutine(envTyp: PType; routine: PSym): bool =
-  ## True if `envTyp` is (maybe wrapped) env object type owned by `routine`, as
-  ## created by `getEnvTypeForOwner` / `createEnvObj`.
-  let obj = envTyp.skipTypes({tyOwned, tyRef, tyPtr})
-  result = obj.kind == tyObject and obj.owner.id == routine.id
-
 proc addClosureParam(c: var DetectionPass; fn: PSym; info: TLineInfo) =
  var cp = getEnvParam(fn)
  let owner = if fn.kind == skIterator: fn else: fn.skipGenericOwner
  let t = c.getEnvTypeForOwner(owner, info)
  if cp == nil:
    cp = newSym(skParam, getIdent(c.graph.cache, paramName), c.idgen, fn, fn.info)
-    incl(cp.flagsImpl, sfFromGeneric)
+    incl(cp.flags, sfFromGeneric)
    cp.typ = t
    addHiddenParam(fn, cp)
  elif cp.typ != t and fn.kind != skIterator:
-    # Nested `liftLambdas` uses a fresh `DetectionPass`, so `getEnvTypeForOwner`
-    # can allocate another PType for the same logical env; the hidden param from
-    # the inner pass is authoritative (bug #21242).
-    if isEnvTypeForRoutine(cp.typ, owner) and isEnvTypeForRoutine(t, owner):
-      c.ownerToType[owner.id] = cp.typ
-    else:
-      localError(c.graph.config, fn.info, "internal error: inconsistent environment type")
+    localError(c.graph.config, fn.info, "internal error: inconsistent environment type")
  #echo "adding closure to ", fn.name.s

-proc iterEnvHasUpField(g: ModuleGraph, iter: PSym): bool =
-  let cp = getEnvParam(iter)
-  doAssert(cp != nil, "Env param not present in iter")
-  let upField = lookupInRecord(cp.typ.skipTypes({tyOwned, tyRef, tyPtr}).n, getIdent(g.cache, upName))
-  upField != nil
-
 proc detectCapturedVars(n: PNode; owner: PSym; c: var DetectionPass) =
  case n.kind
  of nkSym:
@@ -491,15 +449,25 @@ proc detectCapturedVars(n: PNode; owner: PSym; c: var DetectionPass) =
    if innerProc:
      if s.isIterator: c.somethingToDo = true
      if not c.processed.containsOrIncl(s.id):
-        let body = transformBody(c.graph, c.idgen, s, {useCache})
+        let body = transformBody(c.graph, c.idgen, s, useCache)
        detectCapturedVars(body, s, c)
    let ow = s.skipGenericOwner
-    let innerClosure = innerProc and s.typ.callConv == ccClosure and (not s.isIterator or iterEnvHasUpField(c.graph, s))
+    let innerClosure = innerProc and s.typ.callConv == ccClosure and not s.isIterator
    let interested = interestingVar(s)
    if ow == owner:
      if owner.isIterator:
        c.somethingToDo = true
        addClosureParam(c, owner, n.info)
+        if interestingIterVar(s):
+          if not c.capturedVars.contains(s.id):
+            if not c.inTypeOf: c.capturedVars.incl(s.id)
+            let obj = getHiddenParam(c.graph, owner).typ.skipTypes({tyOwned, tyRef, tyPtr})
+            #let obj = c.getEnvTypeForOwner(s.owner).skipTypes({tyOwned, tyRef, tyPtr})
+
+            if s.name.id == getIdent(c.graph.cache, ":state").id:
+              obj.n[0].sym.itemId = ItemId(module: s.itemId.module, item: -s.itemId.item)
+            else:
+              discard addField(obj, s, c.graph.cache, c.idgen)
    # direct or indirect dependency:
    elif innerClosure or interested:
      discard """
@@ -581,8 +549,8 @@ proc accessViaEnvParam(g: ModuleGraph; n: PNode; owner: PSym): PNode =
  let envParam = getHiddenParam(g, owner)
  if not envParam.isNil:
    var access = newSymNode(envParam)
-    var obj = access.typ.elementType
    while true:
+      let obj = access.typ[0]
      assert obj.kind == tyObject
      let field = getFieldFromObj(obj, s)
      if field != nil:
@@ -590,7 +558,6 @@ proc accessViaEnvParam(g: ModuleGraph; n: PNode; owner: PSym): PNode =
      let upField = lookupInRecord(obj.n, getIdent(g.cache, upName))
      if upField == nil: break
      access = rawIndirectAccess(access, upField, n.info)
-      obj = access.typ.baseClass
  localError(g.config, n.info, "internal error: environment misses: " & s.name.s)
  result = n

@@ -602,7 +569,7 @@ proc newEnvVar(cache: IdentCache; owner: PSym; typ: PType; info: TLineInfo; idge
  when false:
    if owner.kind == skIterator and owner.typ.callConv == ccClosure:
      let it = getHiddenParam(owner)
-      addUniqueField(it.typ.elementType, v)
+      addUniqueField(it.typ[0], v)
      result = indirectAccess(newSymNode(it), v, v.info)
    else:
      result = newSymNode(v)
@@ -673,7 +640,7 @@ proc rawClosureCreation(owner: PSym;
        if owner.kind != skMacro:
          createTypeBoundOps(d.graph, nil, fieldAccess.typ, env.info, d.idgen)
        if tfHasAsgn in fieldAccess.typ.flags or optSeqDestructors in d.graph.config.globalOptions:
-          markInjectDestructors(owner)
+          owner.flags.incl sfInjectDestructors

  let upField = lookupInRecord(env.typ.skipTypes({tyOwned, tyRef, tyPtr}).n, getIdent(d.graph.cache, upName))
  if upField != nil:
@@ -699,27 +666,16 @@ proc finishClosureCreation(owner: PSym; d: var DetectionPass; c: LiftingPass;
    res.add newAsgnStmt(unowned, nilLit, info)
    createTypeBoundOpsLL(d.graph, unowned.typ, info, d.idgen, owner)

-proc getUpForIter(g: ModuleGraph; owner, iterOwner: PSym, expectedUpTyp: PType): PNode =
-  var p = getHiddenParam(g, owner)
-  var res = p.newSymNode
-  while res.typ.skipTypes({tyOwned, tyRef, tyPtr}) != expectedUpTyp:
-    let upField = lookupInRecord(p.typ.skipTypes({tyOwned, tyRef, tyPtr}).n, getIdent(g.cache, upName))
-    if upField == nil:
-      return nil
-    p = upField
-    res = rawIndirectAccess(res, upField, p.info)
-  res
-
-proc closureCreationForIter(owner: PSym, iter: PNode;
+proc closureCreationForIter(iter: PNode;
                            d: var DetectionPass; c: var LiftingPass): PNode =
  result = newNodeIT(nkStmtListExpr, iter.info, iter.sym.typ)
-  let iterOwner = iter.sym.skipGenericOwner
-  var v = newSym(skVar, getIdent(d.graph.cache, envName), d.idgen, iterOwner, iter.info)
-  incl(v.flagsImpl, sfShadowed)
+  let owner = iter.sym.skipGenericOwner
+  var v = newSym(skVar, getIdent(d.graph.cache, envName), d.idgen, owner, iter.info)
+  incl(v.flags, sfShadowed)
  v.typ = asOwnedRef(d, getHiddenParam(d.graph, iter.sym).typ)
  var vnode: PNode
-  if iterOwner.isIterator:
-    let it = getHiddenParam(d.graph, iterOwner)
+  if owner.isIterator:
+    let it = getHiddenParam(d.graph, owner)
    addUniqueField(it.typ.skipTypes({tyOwned, tyRef, tyPtr}), v, d.graph.cache, d.idgen)
    vnode = indirectAccess(newSymNode(it), v, v.info)
  else:
@@ -728,14 +684,12 @@ proc closureCreationForIter(owner: PSym, iter: PNode;
    addVar(vs, vnode)
    result.add(vs)
  result.add genCreateEnv(vnode)
-  createTypeBoundOpsLL(d.graph, vnode.typ, iter.info, d.idgen, iterOwner)
+  createTypeBoundOpsLL(d.graph, vnode.typ, iter.info, d.idgen, owner)

  let upField = lookupInRecord(v.typ.skipTypes({tyOwned, tyRef, tyPtr}).n, getIdent(d.graph.cache, upName))
  if upField != nil:
-    let expectedUpTyp = upField.typ.skipTypes({tyOwned, tyRef, tyPtr})
-    let u = if iterOwner == owner: setupEnvVar(iterOwner, d, c, iter.info)
-            else: getUpForIter(d.graph, owner, iterOwner, expectedUpTyp)
-    if u != nil and u.typ.skipTypes({tyOwned, tyRef, tyPtr}) == expectedUpTyp:
+    let u = setupEnvVar(owner, d, c, iter.info)
+    if u.typ.skipTypes({tyOwned, tyRef, tyPtr}) == upField.typ.skipTypes({tyOwned, tyRef, tyPtr}):
      result.add(newAsgnStmt(rawIndirectAccess(vnode, upField, iter.info),
                 u, iter.info))
    else:
@@ -769,7 +723,7 @@ proc symToClosure(n: PNode; owner: PSym; d: var DetectionPass;
    let available = getHiddenParam(d.graph, owner)
    result = makeClosure(d.graph, d.idgen, s, available.newSymNode, n.info)
  elif s.isIterator:
-    result = closureCreationForIter(owner, n, d, c)
+    result = closureCreationForIter(n, d, c)
  elif s.skipGenericOwner == owner:
    # direct dependency, so use the outer's env variable:
    result = makeClosure(d.graph, d.idgen, s, setupEnvVar(owner, d, c, n.info), n.info)
@@ -801,7 +755,7 @@ proc liftCapturedVars(n: PNode; owner: PSym; d: var DetectionPass;
        #  echo renderTree(s.getBody, {renderIds})
        let oldInContainer = c.inContainer
        c.inContainer = 0
-        var body = transformBody(d.graph, d.idgen, s, {})
+        var body = transformBody(d.graph, d.idgen, s, dontUseCache)
        body = liftCapturedVars(body, s, d, c)
        if c.envVars.getOrDefault(s.id).isNil:
          s.transformedBody = body
@@ -816,6 +770,8 @@ proc liftCapturedVars(n: PNode; owner: PSym; d: var DetectionPass;
    elif s.id in d.capturedVars:
      if s.owner != owner:
        result = accessViaEnvParam(d.graph, n, owner)
+      elif owner.isIterator and interestingIterVar(s):
+        result = accessViaEnvParam(d.graph, n, owner)
      else:
        result = accessViaEnvVar(n, owner, d, c)
  of nkEmpty..pred(nkSym), succ(nkSym)..nkNilLit, nkComesFrom,
@@ -923,19 +879,20 @@ proc liftIterToProc*(g: ModuleGraph; fn: PSym; body: PNode; ptrType: PType;
  fn.typ.callConv = oldCC

 proc liftLambdas*(g: ModuleGraph; fn: PSym, body: PNode; tooEarly: var bool;
-                  idgen: IdGenerator; flags: TransformFlags): PNode =
+                  idgen: IdGenerator, force: bool): PNode =
+  # XXX backend == backendJs does not suffice! The compiletime stuff needs
+  # the transformation even when compiling to JS ...
+
+  # However we can do lifting for the stuff which is *only* compiletime.
  let isCompileTime = sfCompileTime in fn.flags or fn.kind == skMacro

-  if body.kind == nkEmpty or (jsNoLambdaLifting in g.config.legacyFeatures and
+  if body.kind == nkEmpty or (
      g.config.backend == backendJs and not isCompileTime) or
-      (fn.skipGenericOwner.kind != skModule and force notin flags):
+      (fn.skipGenericOwner.kind != skModule and not force):

    # ignore forward declaration:
    result = body
    tooEarly = true
-    if fn.isIterator:
-      var d = initDetectionPass(g, fn, idgen)
-      addClosureParam(d, fn, body.info)
  else:
    var d = initDetectionPass(g, fn, idgen)
    detectCapturedVars(body, fn, d)
@@ -1024,20 +981,6 @@ proc liftForLoop*(g: ModuleGraph; body: PNode; idgen: IdGenerator; owner: PSym):
      for i in 0..<op.len-1:
        result.add op[i]

-  elif op.kind != nkSym: # might have side effects
-    # bug #25046
-    # create a temp for the closure
-    # var :closureTemp
-    # :closureTemp = ...
-    let tempSym = newSym(skLet, getIdent(g.cache, ":closureTemp"), idgen, owner, body.info)
-    tempSym.typ = call[0].typ
-    let temp = newSymNode(tempSym)
-    var v = newNodeI(nkVarSection, body.info)
-    addVar(v, temp)
-    result.add(v)
-    result.add newAsgnStmt(temp, call[0], body.info)
-    call[0] = temp
-
  var loopBody = newNodeI(nkStmtList, body.info, 3)
  var whileLoop = newNodeI(nkWhileStmt, body.info, 2)
  whileLoop[0] = newIntTypeNode(1, getSysType(g, body.info, tyBool))
@@ -1048,15 +991,12 @@ proc liftForLoop*(g: ModuleGraph; body: PNode; idgen: IdGenerator; owner: PSym):
  # gather vars in a tuple:
  var v2 = newNodeI(nkLetSection, body.info)
  var vpart = newNodeI(if body.len == 3: nkIdentDefs else: nkVarTuple, body.info)
-  if body.len == 3 and body[0].kind == nkVarTuple:
-    vpart = body[0] # fixes for (i,j) in walk() # bug #15924
-  else:
-    for i in 0..<body.len-2:
-      if body[i].kind == nkSym:
-        body[i].sym.transitionToLet()
-      vpart.add body[i]
+  for i in 0..<body.len-2:
+    if body[i].kind == nkSym:
+      body[i].sym.transitionToLet()
+    vpart.add body[i]

-    vpart.add newNodeI(nkEmpty, body.info) # no explicit type
+  vpart.add newNodeI(nkEmpty, body.info) # no explicit type
  if not env.isNil:
    call[0] = makeClosure(g, idgen, call[0].sym, env.newSymNode, body.info)
  vpart.add call
--- a/compiler/layeredtable.nim
+++ b/compiler/layeredtable.nim
@@ -1,90 +0,0 @@
-import ast, astalgo
-
-type
-  LayeredIdTableObj* {.acyclic.} = object
-    ## stack of type binding contexts implemented as a linked list
-    topLayer*: TypeMapping
-      ## the mappings on the current layer
-    nextLayer*: ref LayeredIdTableObj
-      ## the parent type binding context, possibly `nil`
-    previousLen*: int
-      ## total length of the bindings up to the parent layer,
-      ## used to track if new bindings were added
-
-const useRef = not defined(gcDestructors)
-  # implementation detail, only arc/orc doesn't cause issues when
-  # using LayeredIdTable as an object and not a ref
-
-when useRef:
-  type LayeredIdTable* = ref LayeredIdTableObj
-else:
-  type LayeredIdTable* = LayeredIdTableObj
-
-proc initLayeredTypeMap*(pt: sink TypeMapping = initTypeMapping()): LayeredIdTable =
-  result = LayeredIdTable(topLayer: pt, nextLayer: nil)
-
-proc shallowCopy*(pt: LayeredIdTable): LayeredIdTable {.inline.} =
-  ## copies only the type bindings of the current layer, but not any parent layers,
-  ## useful for write-only bindings
-  result = LayeredIdTable(topLayer: pt.topLayer, nextLayer: pt.nextLayer, previousLen: pt.previousLen)
-  #copyIdTable(result.topLayer, pt.topLayer)
-
-proc currentLen*(pt: LayeredIdTable): int =
-  ## the sum of the cached total binding count of the parents and
-  ## the current binding count, just used to track if bindings were added
-  pt.previousLen + pt.topLayer.counter
-
-proc newTypeMapLayer*(pt: LayeredIdTable): LayeredIdTable =
-  result = LayeredIdTable(topLayer: initTypeMapping(), previousLen: pt.currentLen)
-  when useRef:
-    result.nextLayer = pt
-  else:
-    new(result.nextLayer)
-    result.nextLayer[] = pt
-
-proc setToPreviousLayer*(pt: var LayeredIdTable) {.inline.} =
-  when useRef:
-    pt = pt.nextLayer
-  else:
-    # Must read nextLayer into a temp before destroying pt:
-    # `pt = pt.nextLayer[]` would call eqcopy(&pt, &(*pt.nextLayer)) which
-    # decrements pt.nextLayer's rc (freeing it) before reading pt.nextLayer.nextLayer.
-    let tmp = pt.nextLayer[]
-    pt = tmp
-
-iterator pairs*(pt: LayeredIdTable): (ItemId, PType) =
-  var tm = pt
-  while true:
-    for (k, v) in idTablePairs(tm.topLayer):
-      yield (k, v)
-    if tm.nextLayer == nil:
-      break
-    tm.setToPreviousLayer
-
-proc lookup(typeMap: ref LayeredIdTableObj, key: ItemId): PType =
-  result = nil
-  var tm = typeMap
-  while tm != nil:
-    result = getOrDefault(tm.topLayer, key)
-    if result != nil: return
-    tm = tm.nextLayer
-
-template lookup*(typeMap: ref LayeredIdTableObj, key: PType): PType =
-  ## recursively looks up binding of `key` in all parent layers
-  lookup(typeMap, key.itemId)
-
-when not useRef:
-  proc lookup(typeMap: LayeredIdTableObj, key: ItemId): PType {.inline.} =
-    result = getOrDefault(typeMap.topLayer, key)
-    if result == nil and typeMap.nextLayer != nil:
-      result = lookup(typeMap.nextLayer, key)
-
-  template lookup*(typeMap: LayeredIdTableObj, key: PType): PType =
-    lookup(typeMap, key.itemId)
-
-proc put(typeMap: var LayeredIdTable, key: ItemId, value: PType) {.inline.} =
-  typeMap.topLayer[key] = value
-
-template put*(typeMap: var LayeredIdTable, key, value: PType) =
-  ## binds `key` to `value` only in current layer
-  put(typeMap, key.itemId, value)
--- a/compiler/layouter.nim
+++ b/compiler/layouter.nim
@@ -9,7 +9,7 @@

 ## Layouter for nimpretty.

-import idents, lexer, ast, lineinfos, llstream, options, msgs, strutils, pathutils
+import idents, lexer, lineinfos, llstream, options, msgs, strutils, pathutils

 const
  MinLineLen = 15
@@ -243,28 +243,23 @@ proc renderTokens*(em: var Emitter): string =

  return content

-type
-  FinalCheck = proc (content: string; origAst: PNode): bool {.nimcall.}
-
-proc writeOut*(em: Emitter; content: string; origAst: PNode; check: FinalCheck) =
+proc writeOut*(em: Emitter, content: string)  =
  ## Write to disk
  let outFile = em.config.absOutFile
  if fileExists(outFile) and readFile(outFile.string) == content:
    discard "do nothing, see #9499"
    return
+  var f = llStreamOpen(outFile, fmWrite)
+  if f == nil:
+    rawMessage(em.config, errGenerated, "cannot open file: " & outFile.string)
+    return
+  f.llStreamWrite content
+  llStreamClose(f)

-  if check(content, origAst):
-    var f = llStreamOpen(outFile, fmWrite)
-    if f == nil:
-      rawMessage(em.config, errGenerated, "cannot open file: " & outFile.string)
-      return
-    f.llStreamWrite content
-    llStreamClose(f)
-
-proc closeEmitter*(em: var Emitter; origAst: PNode; check: FinalCheck) =
+proc closeEmitter*(em: var Emitter) =
  ## Renders emitter tokens and write to a file
  let content = renderTokens(em)
-  em.writeOut(content, origAst, check)
+  em.writeOut(content)

 proc wr(em: var Emitter; x: string; lt: LayoutToken) =
  em.tokens.add x
--- a/compiler/lexer.nim
+++ b/compiler/lexer.nim
@@ -16,10 +16,8 @@
 # DOS or Macintosh text files, even when it is not the native format.

 import
-  options, msgs, platform, idents, nimlexbase, llstream,
-  wordrecg, lineinfos, pathutils
-
-import std/[hashes, parseutils, strutils]
+  hashes, options, msgs, strutils, platform, idents, nimlexbase, llstream,
+  wordrecg, lineinfos, pathutils, parseutils

 when defined(nimPreviewSlimSystem):
  import std/[assertions, formatfloat]
@@ -122,6 +120,7 @@ type
                              # this is needed because scanning comments
                              # needs so much look-ahead
    currLineIndent*: int
+    strongSpaces*, allowTabs*: bool
    errorHandler*: ErrorHandler
    cache*: IdentCache
    when defined(nimsuggest):
@@ -175,6 +174,32 @@ proc printTok*(conf: ConfigRef; tok: Token) =
  # xxx factor with toLocation
  msgWriteln(conf, $tok.line & ":" & $tok.col & "\t" & $tok.tokType & " " & $tok)

+proc initToken*(L: var Token) =
+  L.tokType = tkInvalid
+  L.iNumber = 0
+  L.indent = 0
+  L.spacing = {}
+  L.literal = ""
+  L.fNumber = 0.0
+  L.base = base10
+  L.ident = nil
+  when defined(nimpretty):
+    L.commentOffsetA = 0
+    L.commentOffsetB = 0
+
+proc fillToken(L: var Token) =
+  L.tokType = tkInvalid
+  L.iNumber = 0
+  L.indent = 0
+  L.spacing = {}
+  setLen(L.literal, 0)
+  L.fNumber = 0.0
+  L.base = base10
+  L.ident = nil
+  when defined(nimpretty):
+    L.commentOffsetA = 0
+    L.commentOffsetB = 0
+
 proc openLexer*(lex: var Lexer, fileIdx: FileIndex, inputstream: PLLStream;
                 cache: IdentCache; config: ConfigRef) =
  openBaseLexer(lex, inputstream)
@@ -300,7 +325,8 @@ proc getNumber(L: var Lexer, result: var Token) =
    # Used to get slightly human friendlier err messages.
    const literalishChars = {'A'..'Z', 'a'..'z', '0'..'9', '_', '.', '\''}
    var msgPos = L.bufpos
-    var t = Token(literal: "")
+    var t: Token
+    t.literal = ""
    L.bufpos = startpos # Use L.bufpos as pos because of matchChars
    matchChars(L, t, literalishChars)
    # We must verify +/- specifically so that we're not past the literal
@@ -316,28 +342,6 @@ proc getNumber(L: var Lexer, result: var Token) =
    L.bufpos = msgPos
    lexMessage(L, msgKind, msg % t.literal)

-  proc checkBitWidth(L: var Lexer, base: NumericalBase, tokType: TokType, 
-                     numDigits: int, startpos: int) =
-    # Check bit width for non-base-10 literals
-    # Warn if the digit count exceeds what can fit in the target type
-    let bitsPerDigit = case base
-      of base2: 1
-      of base8: 3
-      of base16: 4
-      else: raiseAssert "unreachable"
-    let bitWidth = case tokType
-      of tkInt8Lit, tkUInt8Lit: 8
-      of tkInt16Lit, tkUInt16Lit: 16
-      of tkInt32Lit, tkUInt32Lit: 32
-      of tkInt64Lit, tkUIntLit, tkIntLit, tkUInt64Lit: 64
-      else: raiseAssert "unreachable"
-    # Maximum digits = ceil(bitWidth / bitsPerDigit) = (bitWidth + bitsPerDigit - 1) div bitsPerDigit
-    let maxDigits = (bitWidth + bitsPerDigit - 1) div bitsPerDigit
-    if numDigits > maxDigits:
-      lexMessageLitNum(L,
-        "number has " & $numDigits & " digits but type only supports " &
-        $maxDigits & " digits: '$1'", startpos, warnLongLiterals)
-
  var
    xi: BiggestInt
    isBase10 = true
@@ -513,11 +517,6 @@ proc getNumber(L: var Lexer, result: var Token) =
          setNumber result.fNumber, (cast[ptr float64](addr(xi)))[]
        else: internalError(L.config, getLineInfo(L), "getNumber")

-        # Check bit width for non-base-10 literals
-        # Warn if the digit count exceeds what can fit in the target type
-        if result.base != base10 and result.tokType in {tkIntLit..tkUInt64Lit} and numDigits > 0:
-          checkBitWidth(L, result.base, result.tokType, numDigits, startpos)
-
        # Bounds checks. Non decimal literals are allowed to overflow the range of
        # the datatype as long as their pattern don't overflow _bitwise_, hence
        # below checks of signed sizes against uint*.high is deliberate:
@@ -797,7 +796,7 @@ proc getString(L: var Lexer, tok: var Token, mode: StringMode) =
    if mode != normal: tok.tokType = tkRStrLit
    else: tok.tokType = tkStrLit
    while true:
-      let c = L.buf[pos]
+      var c = L.buf[pos]
      if c == '\"':
        if mode != normal and L.buf[pos+1] == '\"':
          inc(pos, 2)
@@ -823,7 +822,7 @@ proc getCharacter(L: var Lexer; tok: var Token) =
  tokenBegin(tok, L.bufpos)
  let startPos = L.bufpos
  inc(L.bufpos)               # skip '
-  let c = L.buf[L.bufpos]
+  var c = L.buf[L.bufpos]
  case c
  of '\0'..pred(' '), '\'':
    lexMessage(L, errGenerated, "invalid character literal")
@@ -923,7 +922,7 @@ proc getSymbol(L: var Lexer, tok: var Token) =
    tok.tokType = tkSymbol
  else:
    tok.tokType = TokType(tok.ident.id + ord(tkSymbol))
-    if suspicious and {optStyleHint, optStyleError, optStyleWarning} * L.config.globalOptions != {}:
+    if suspicious and {optStyleHint, optStyleError} * L.config.globalOptions != {}:
      lintReport(L.config, getLineInfo(L), tok.ident.s.normalize, tok.ident.s)
  L.bufpos = pos

@@ -941,7 +940,7 @@ proc getOperator(L: var Lexer, tok: var Token) =
  tokenBegin(tok, pos)
  var h: Hash = 0
  while true:
-    let c = L.buf[pos]
+    var c = L.buf[pos]
    if c in OpChars:
      h = h !& ord(c)
      inc(pos)
@@ -1009,6 +1008,23 @@ proc getPrecedence*(tok: Token): int =
  of tkOr, tkXor, tkPtr, tkRef: result = 3
  else: return -10

+proc newlineFollows*(L: Lexer): bool =
+  result = false
+  var pos = L.bufpos
+  while true:
+    case L.buf[pos]
+    of ' ', '\t':
+      inc(pos)
+    of CR, LF:
+      result = true
+      break
+    of '#':
+      inc(pos)
+      if L.buf[pos] == '#': inc(pos)
+      if L.buf[pos] != '[': return true
+    else:
+      break
+
 proc skipMultiLineComment(L: var Lexer; tok: var Token; start: int;
                          isDoc: bool) =
  var pos = start
@@ -1100,7 +1116,9 @@ proc scanComment(L: var Lexer, tok: var Token) =
        toStrip = 0
      else:  # found first non-whitespace character
        stripInit = true
+    var lastBackslash = -1
    while L.buf[pos] notin {CR, LF, nimlexbase.EndOfFile}:
+      if L.buf[pos] == '\\': lastBackslash = pos+1
      tok.literal.add(L.buf[pos])
      inc(pos)
    tokenEndIgnore(tok, pos)
@@ -1143,7 +1161,7 @@ proc skip(L: var Lexer, tok: var Token) =
      inc(pos)
      tok.spacing.incl(tsLeading)
    of '\t':
-      lexMessagePos(L, errGenerated, pos, "tabs are not allowed, use spaces instead")
+      if not L.allowTabs: lexMessagePos(L, errGenerated, pos, "tabs are not allowed, use spaces instead")
      inc(pos)
    of CR, LF:
      tokenEndPrevious(tok, pos)
@@ -1211,7 +1229,7 @@ proc rawGetTok*(L: var Lexer, tok: var Token) =
        L.previousToken.line = tok.line.uint16
        L.previousToken.col = tok.col.int16

-  reset(tok)
+  fillToken(tok)
  if L.indentAhead >= 0:
    tok.indent = L.indentAhead
    L.currLineIndent = L.indentAhead
@@ -1223,7 +1241,7 @@ proc rawGetTok*(L: var Lexer, tok: var Token) =
    if tok.tokType == tkComment:
      L.indentAhead = L.currLineIndent
      return
-  let c = L.buf[L.bufpos]
+  var c = L.buf[L.bufpos]
  tok.line = L.lineNumber
  tok.col = getColNumber(L, L.bufpos)
  if c in SymStartChars - {'r', 'R'} - UnicodeOperatorStartChars:
@@ -1349,7 +1367,7 @@ proc rawGetTok*(L: var Lexer, tok: var Token) =
          lexMessage(L, errGenerated, "invalid token: no whitespace between number and identifier")
    of '-':
      if L.buf[L.bufpos+1] in {'0'..'9'} and
-          (L.bufpos == 0 or L.buf[L.bufpos-1] in UnaryMinusWhitelist):
+          (L.bufpos-1 == 0 or L.buf[L.bufpos-1] in UnaryMinusWhitelist):
        # x)-23 # binary minus
        # ,-23  # unary minus
        # \n-78 # unary minus? Yes.
@@ -1382,6 +1400,7 @@ proc getIndentWidth*(fileIdx: FileIndex, inputstream: PLLStream;
  result = 0
  var lex: Lexer = default(Lexer)
  var tok: Token = default(Token)
+  initToken(tok)
  openLexer(lex, fileIdx, inputstream, cache, config)
  var prevToken = tkEof
  while tok.tokType != tkEof:
@@ -1394,11 +1413,11 @@ proc getIndentWidth*(fileIdx: FileIndex, inputstream: PLLStream;

 proc getPrecedence*(ident: PIdent): int =
  ## assumes ident is binary operator already
-  let
-    tokType =
-      if ident.id in ord(tokKeywordLow) - ord(tkSymbol)..ord(tokKeywordHigh) - ord(tkSymbol):
-        TokType(ident.id + ord(tkSymbol))
-      else: tkOpr
-    tok = Token(ident: ident, tokType: tokType)
-
+  var tok: Token
+  initToken(tok)
+  tok.ident = ident
+  tok.tokType =
+    if tok.ident.id in ord(tokKeywordLow) - ord(tkSymbol)..ord(tokKeywordHigh) - ord(tkSymbol):
+      TokType(tok.ident.id + ord(tkSymbol))
+    else: tkOpr
  getPrecedence(tok)
--- a/compiler/liftdestructors.nim
+++ b/compiler/liftdestructors.nim
@@ -11,9 +11,8 @@
 ## (`=sink`, `=copy`, `=destroy`, `=deepCopy`, `=wasMoved`, `=dup`).

 import modulegraphs, lineinfos, idents, ast, renderer, semdata,
-  sighashes, lowerings, options, types, msgs, magicsys, ccgutils
+  sighashes, lowerings, options, types, msgs, magicsys, tables, ccgutils

-import std/tables
 from trees import isCaseObj

 when defined(nimPreviewSlimSystem):
@@ -56,10 +55,10 @@ proc destructorOverridden(g: ModuleGraph; t: PType): bool =
  op != nil and sfOverridden in op.flags

 proc fillBodyTup(c: var TLiftCtx; t: PType; body, x, y: PNode) =
-  for i, a in t.ikids:
+  for i in 0..<t.len:
    let lit = lowerings.newIntLit(c.g, x.info, i)
-    let b = if c.kind == attachedTrace: y else: y.at(lit, a)
-    fillBody(c, a, body, x.at(lit, a), b)
+    let b = if c.kind == attachedTrace: y else: y.at(lit, t[i])
+    fillBody(c, t[i], body, x.at(lit, t[i]), b)

 proc dotField(x: PNode, f: PSym): PNode =
  result = newNodeI(nkDotExpr, x.info, 2)
@@ -91,7 +90,7 @@ proc defaultOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    call.typ = t
    body.add newAsgnStmt(x, call)
  elif c.kind == attachedWasMoved:
-    body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+    body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)

 proc genAddr(c: var TLiftCtx; x: PNode): PNode =
  if x.kind == nkHiddenDeref:
@@ -139,36 +138,34 @@ proc genContainerOf(c: var TLiftCtx; objType: PType, field, x: PSym): PNode =
  result.add minusExpr

 proc destructorCall(c: var TLiftCtx; op: PSym; x: PNode): PNode =
-  var destroy = newNodeIT(nkCall, x.info, op.typ.returnType)
+  var destroy = newNodeIT(nkCall, x.info, op.typ[0])
  destroy.add(newSymNode(op))
-  if op.typ.firstParamType.kind != tyVar:
+  if op.typ[1].kind != tyVar:
    destroy.add x
  else:
    destroy.add genAddr(c, x)
  if sfNeverRaises notin op.flags:
    c.canRaise = true
  if c.addMemReset:
-    result = newTree(nkStmtList, destroy, genBuiltin(c, mWasMoved,  "wasMoved", x))
+    result = newTree(nkStmtList, destroy, genBuiltin(c, mWasMoved,  "`=wasMoved`", x))
  else:
    result = destroy

 proc genWasMovedCall(c: var TLiftCtx; op: PSym; x: PNode): PNode =
-  result = newNodeIT(nkCall, x.info, op.typ.returnType)
+  result = newNodeIT(nkCall, x.info, op.typ[0])
  result.add(newSymNode(op))
  result.add genAddr(c, x)

-proc fillBodyObj(c: var TLiftCtx; n, body, x, y: PNode; enforceDefaultOp: bool, enforceWasMoved = false) =
+proc fillBodyObj(c: var TLiftCtx; n, body, x, y: PNode; enforceDefaultOp: bool) =
  case n.kind
  of nkSym:
    if c.filterDiscriminator != nil: return
    let f = n.sym
    let b = if c.kind == attachedTrace: y else: y.dotField(f)
-    if (sfCursor in f.flags and c.g.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc, gcHooks}) or
+    if (sfCursor in f.flags and c.g.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcHooks}) or
        enforceDefaultOp:
      defaultOp(c, f.typ, body, x.dotField(f), b)
    else:
-      if enforceWasMoved:
-        body.add genBuiltin(c, mWasMoved, "wasMoved", x.dotField(f))
      fillBody(c, f.typ, body, x.dotField(f), b)
  of nkNilLit: discard
  of nkRecCase:
@@ -207,7 +204,7 @@ proc fillBodyObj(c: var TLiftCtx; n, body, x, y: PNode; enforceDefaultOp: bool,
      branch[^1] = newNodeI(nkStmtList, c.info)

      fillBodyObj(c, n[i].lastSon, branch[^1], x, y,
-                  enforceDefaultOp = localEnforceDefaultOp, enforceWasMoved = c.kind == attachedAsgn)
+                  enforceDefaultOp = localEnforceDefaultOp)
      if branch[^1].len == 0: inc emptyBranches
      caseStmt.add(branch)
    if emptyBranches != n.len-1:
@@ -218,44 +215,20 @@ proc fillBodyObj(c: var TLiftCtx; n, body, x, y: PNode; enforceDefaultOp: bool,
      fillBodyObj(c, n[0], body, x, y, enforceDefaultOp = false)
    c.filterDiscriminator = oldfilterDiscriminator
  of nkRecList:
-    # destroys in reverse order #24719
-    if c.kind == attachedDestructor:
-      for i in countdown(n.len-1, 0):
-        fillBodyObj(c, n[i], body, x, y, enforceDefaultOp, enforceWasMoved)
-    else:
-      for t in items(n): fillBodyObj(c, t, body, x, y, enforceDefaultOp, enforceWasMoved)
+    for t in items(n): fillBodyObj(c, t, body, x, y, enforceDefaultOp)
  else:
    illFormedAstLocal(n, c.g.config)

 proc fillBodyObjTImpl(c: var TLiftCtx; t: PType, body, x, y: PNode) =
-  template fillBase =
-    if t.baseClass != nil:
-      let dest = newNodeIT(nkHiddenSubConv, c.info, t.baseClass)
-      dest.add newNodeI(nkEmpty, c.info)
-      dest.add x
-      var src = y
-      if c.kind in {attachedAsgn, attachedDeepCopy, attachedSink}:
-        src = newNodeIT(nkHiddenSubConv, c.info, t.baseClass)
-        src.add newNodeI(nkEmpty, c.info)
-        src.add y
-
-      fillBody(c, skipTypes(t.baseClass, abstractPtrs), body, dest, src)
-  template fillFields =
-    fillBodyObj(c, t.n, body, x, y, enforceDefaultOp = false)
-
-  if c.kind == attachedDestructor:
-    # destroys in reverse order #24719
-    fillFields()
-    fillBase()
-  else:
-    fillBase()
-    fillFields()
+  if t.len > 0 and t[0] != nil:
+    fillBody(c, skipTypes(t[0], abstractPtrs), body, x, y)
+  fillBodyObj(c, t.n, body, x, y, enforceDefaultOp = false)

 proc fillBodyObjT(c: var TLiftCtx; t: PType, body, x, y: PNode) =
  var hasCase = isCaseObj(t.n)
  var obj = t
-  while obj.baseClass != nil:
-    obj = skipTypes(obj.baseClass, abstractPtrs)
+  while obj.len > 0 and obj[0] != nil:
+    obj = skipTypes(obj[0], abstractPtrs)
    hasCase = hasCase or isCaseObj(obj.n)

  if hasCase and c.kind in {attachedAsgn, attachedDeepCopy}:
@@ -284,7 +257,7 @@ proc fillBodyObjT(c: var TLiftCtx; t: PType, body, x, y: PNode) =
      body.add genIf(c, cond, newTreeI(nkReturnStmt, c.info, newNodeI(nkEmpty, c.info)))
    var temp = newSym(skTemp, getIdent(c.g.cache, lowerings.genPrefix), c.idgen, c.fn, c.info)
    temp.typ = x.typ
-    incl(temp, sfFromGeneric)
+    incl(temp.flags, sfFromGeneric)
    var v = newNodeI(nkVarSection, c.info)
    let blob = newSymNode(temp)
    v.addVar(blob, x)
@@ -292,8 +265,7 @@ proc fillBodyObjT(c: var TLiftCtx; t: PType, body, x, y: PNode) =
    #body.add newAsgnStmt(blob, x)

    var wasMovedCall = newNodeI(nkCall, c.info)
-    wasMovedCall.add(newSymNode(createMagic(c.g, c.idgen, "wasMoved", mWasMoved)))
-
+    wasMovedCall.add(newSymNode(createMagic(c.g, c.idgen, "`=wasMoved`", mWasMoved)))
    wasMovedCall.add x # mWasMoved does not take the address
    body.add wasMovedCall

@@ -306,7 +278,6 @@ proc fillBodyObjT(c: var TLiftCtx; t: PType, body, x, y: PNode) =
    c.kind = attachedDestructor
    fillBodyObjTImpl(c, t, body, blob, y)
    c.kind = prevKind
-
  else:
    fillBodyObjTImpl(c, t, body, x, y)

@@ -316,7 +287,7 @@ proc boolLit*(g: ModuleGraph; info: TLineInfo; value: bool): PNode =

 proc getCycleParam(c: TLiftCtx): PNode =
  assert c.kind in {attachedAsgn, attachedDup}
-  if c.fn.typ.len == 3 + ord(c.kind == attachedAsgn):
+  if c.fn.typ.len == 4:
    result = c.fn.typ.n.lastSon
    assert result.kind == nkSym
    assert result.sym.name.s == "cyclic"
@@ -330,35 +301,27 @@ proc newHookCall(c: var TLiftCtx; op: PSym; x, y: PNode): PNode =
  result.add newSymNode(op)
  if sfNeverRaises notin op.flags:
    c.canRaise = true
-  if op.typ.firstParamType.kind == tyVar:
+  if op.typ[1].kind == tyVar:
    result.add genAddr(c, x)
  else:
    result.add x
  if y != nil:
    result.add y
-  if op.typ.signatureLen == 4:
+  if op.typ.len == 4:
    assert y != nil
-    if c.fn.typ.signatureLen == 4:
+    if c.fn.typ.len == 4:
      result.add getCycleParam(c)
    else:
      # assume the worst: A cycle is created:
      result.add boolLit(c.g, y.info, true)

 proc newOpCall(c: var TLiftCtx; op: PSym; x: PNode): PNode =
-  result = newNodeIT(nkCall, x.info, op.typ.returnType)
+  result = newNodeIT(nkCall, x.info, op.typ[0])
  result.add(newSymNode(op))
  result.add x
  if sfNeverRaises notin op.flags:
    c.canRaise = true

-  if c.kind == attachedDup and op.typ.len == 3:
-    assert x != nil
-    if c.fn.typ.len == 3:
-      result.add getCycleParam(c)
-    else:
-      # assume the worst: A cycle is created:
-      result.add boolLit(c.g, x.info, true)
-
 proc newDeepCopyCall(c: var TLiftCtx; op: PSym; x, y: PNode): PNode =
  result = newAsgnStmt(x, newOpCall(c, op, y))

@@ -380,10 +343,6 @@ proc requiresDestructor(c: TLiftCtx; t: PType): bool {.inline.} =
 proc instantiateGeneric(c: var TLiftCtx; op: PSym; t, typeInst: PType): PSym =
  if c.c != nil and typeInst != nil:
    result = c.c.instTypeBoundOp(c.c, op, typeInst, c.info, attachedAsgn, 1)
-  elif typeInst != nil and getAttachedOp(c.g, typeInst, c.kind) != nil:
-    # c.c == nil in lambdalifting
-    # hooks are already insted
-    result = getAttachedOp(c.g, typeInst, c.kind)
  else:
    localError(c.g.config, c.info,
      "cannot generate destructor for generic type: " & typeToString(t))
@@ -397,8 +356,7 @@ proc considerAsgnOrSink(c: var TLiftCtx; t: PType; body, x, y: PNode;
    if op != nil and op != c.fn and
        (sfOverridden in op.flags or destructorOverridden):
      if sfError in op.flags:
-        ensureMutable c.fn
-        incl c.fn.flagsImpl, sfError
+        incl c.fn.flags, sfError
      #else:
      #  markUsed(c.g.config, c.info, op, c.g.usageSym)
      onUse(c.info, op)
@@ -424,8 +382,7 @@ proc considerAsgnOrSink(c: var TLiftCtx; t: PType; body, x, y: PNode;
      if op == nil:
        op = produceSym(c.g, c.c, t, c.kind, c.info, c.idgen)
    if sfError in op.flags:
-      ensureMutable c.fn
-      incl c.fn.flagsImpl, sfError
+      incl c.fn.flags, sfError
    #else:
    #  markUsed(c.g.config, c.info, op, c.g.usageSym)
    onUse(c.info, op)
@@ -541,7 +498,7 @@ proc considerUserDefinedOp(c: var TLiftCtx; t: PType; body, x, y: PNode): bool =
 proc declareCounter(c: var TLiftCtx; body: PNode; first: BiggestInt): PNode =
  var temp = newSym(skTemp, getIdent(c.g.cache, lowerings.genPrefix), c.idgen, c.fn, c.info)
  temp.typ = getSysType(c.g, body.info, tyInt)
-  incl(temp.flagsImpl, sfFromGeneric)
+  incl(temp.flags, sfFromGeneric)

  var v = newNodeI(nkVarSection, c.info)
  result = newSymNode(temp)
@@ -551,29 +508,13 @@ proc declareCounter(c: var TLiftCtx; body: PNode; first: BiggestInt): PNode =
 proc declareTempOf(c: var TLiftCtx; body: PNode; value: PNode): PNode =
  var temp = newSym(skTemp, getIdent(c.g.cache, lowerings.genPrefix), c.idgen, c.fn, c.info)
  temp.typ = value.typ
-  incl(temp.flagsImpl, sfFromGeneric)
+  incl(temp.flags, sfFromGeneric)

  var v = newNodeI(nkVarSection, c.info)
  result = newSymNode(temp)
  v.addVar(result, value)
  body.add v

-proc considerInferDupFromCopy(c: var TLiftCtx; t: PType; body, x, y: PNode): bool =
-  ## For `=dup`, if no explicit hook exists, try to infer from `=copy` hook
-  ## to maintain backward compatibility. Returns true if inference was applied.
-  if c.kind == attachedDup:
-    var op2 = getAttachedOp(c.g, t, attachedAsgn)
-    if op2 != nil and sfOverridden in op2.flags:
-      #markUsed(c.g.config, c.info, op, c.g.usageSym)
-      onUse(c.info, op2)
-      body.add genBuiltin(c, mWasMoved, "wasMoved", x)
-      body.add newHookCall(c, op2, x, y)
-      result = true
-    else:
-      result = false
-  else:
-    result = false
-
 proc addIncStmt(c: var TLiftCtx; body, i: PNode) =
  let incCall = genBuiltin(c, mInc, "inc", i)
  incCall.add lowerings.newIntLit(c.g, c.info, 1)
@@ -592,12 +533,10 @@ proc setLenStrCall(c: var TLiftCtx; x, y: PNode): PNode =
  result = genBuiltin(c, mSetLengthStr, "setLen", x) # genAddr(g, x))
  result.add lenCall

-proc setLenSeqCall(c: var TLiftCtx; t: PType; x, y: PNode; noinit = false): PNode =
+proc setLenSeqCall(c: var TLiftCtx; t: PType; x, y: PNode): PNode =
  let lenCall = genBuiltin(c, mLengthSeq, "len", y)
  lenCall.typ = getSysType(c.g, x.info, tyInt)
-  let name = if noinit: "setLenUninit" else: "setLen"
-  let magic = if noinit: mSetLengthSeqUninit else: mSetLengthSeq
-  var op = getSysMagic(c.g, x.info, name, magic)
+  var op = getSysMagic(c.g, x.info, "setLen", mSetLengthSeq)
  op = instantiateGeneric(c, op, t, t)
  result = newTree(nkCall, newSymNode(op, x.info), x, lenCall)

@@ -605,7 +544,7 @@ proc forallElements(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  let counterIdx = body.len
  let i = declareCounter(c, body, toInt64(firstOrd(c.g.config, t)))
  let whileLoop = genWhileLoop(c, i, x)
-  let elemType = t.elementType
+  let elemType = t.lastSon
  let b = if c.kind == attachedTrace: y else: y.at(i, elemType)
  fillBody(c, elemType, whileLoop[1], x.at(i, elemType), b)
  if whileLoop[1].len > 0:
@@ -622,35 +561,11 @@ proc checkSelfAssignment(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  cond.typ = getSysType(c.g, c.info, tyBool)
  body.add genIf(c, cond, newTreeI(nkReturnStmt, c.info, newNodeI(nkEmpty, c.info)))

-proc genBulkCopySeq(c: var TLiftCtx; t: PType; body, x, y: PNode) =
-  ## Generates a call to nimCopySeqPayload for bulk memcpy of seq data.
-  let elemType = t.elementType
-  let sym = magicsys.getCompilerProc(c.g, "nimCopySeqPayload")
-  if sym == nil:
-    localError(c.g.config, c.info, "system module needs: nimCopySeqPayload")
-    return
-  var sizeOf = genBuiltin(c, mSizeOf, "sizeof", newNodeIT(nkType, c.info, elemType))
-  sizeOf.typ = getSysType(c.g, c.info, tyInt)
-  var alignOf = genBuiltin(c, mAlignOf, "alignof", newNodeIT(nkType, c.info, elemType))
-  alignOf.typ = getSysType(c.g, c.info, tyInt)
-  let call = newNodeI(nkCall, c.info)
-  call.add newSymNode(sym)
-  call.add newTreeIT(nkAddr, c.info, makePtrType(c.fn, x.typ, c.idgen), x)
-  call.add newTreeIT(nkAddr, c.info, makePtrType(c.fn, y.typ, c.idgen), y)
-  call.add sizeOf
-  call.add alignOf
-  call.typ = sym.typ.returnType
-  body.add call
-
 proc fillSeqOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  case c.kind
  of attachedDup:
-    let bulkCopy = supportsCopyMem(t.elementType)
-    body.add setLenSeqCall(c, t, x, y, noinit = bulkCopy)
-    if bulkCopy:
-      genBulkCopySeq(c, t, body, x, y)
-    else:
-      forallElements(c, t, body, x, y)
+    body.add setLenSeqCall(c, t, x, y)
+    forallElements(c, t, body, x, y)
  of attachedAsgn, attachedDeepCopy:
    # we generate:
    # if x.p == y.p:
@@ -659,14 +574,9 @@ proc fillSeqOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    # var i = 0
    # while i < y.len: dest[i] = y[i]; inc(i)
    # This is usually more efficient than a destroy/create pair.
-    # For trivially copyable types, use bulk copyMem instead of element loop.
    checkSelfAssignment(c, t, body, x, y)
-    let bulkCopy = supportsCopyMem(t.elementType)
-    body.add setLenSeqCall(c, t, x, y, noinit = bulkCopy)
-    if bulkCopy:
-      genBulkCopySeq(c, t, body, x, y)
-    else:
-      forallElements(c, t, body, x, y)
+    body.add setLenSeqCall(c, t, x, y)
+    forallElements(c, t, body, x, y)
  of attachedSink:
    let moveCall = genBuiltin(c, mMove, "move", x)
    moveCall.add y
@@ -681,7 +591,7 @@ proc fillSeqOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    if canFormAcycle(c.g, t.elemType):
      # follow all elements:
      forallElements(c, t, body, x, y)
-  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)

 proc useSeqOrStrOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  createTypeBoundOps(c.g, c.c, t, body.info, c.idgen)
@@ -711,11 +621,6 @@ proc useSeqOrStrOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
      doAssert t.asink != nil
      body.add newHookCall(c, t.asink, x, y)
  of attachedDestructor:
-    when defined(icDbg):
-      if t.destructor == nil:
-        echo "MISSING destructor: ", typeToString(t), " kind=", t.kind,
-          " itemId=", t.itemId, " uniqueId=", t.uniqueId, " state=", t.state,
-          " owner=", (if t.owner != nil: t.owner.name.s else: "nil")
    doAssert t.destructor != nil
    body.add destructorCall(c, t.destructor, x)
  of attachedTrace:
@@ -724,7 +629,7 @@ proc useSeqOrStrOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
      if op == nil:
        return # protect from recursion
      body.add newHookCall(c, op, x, y)
-  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)
  of attachedDup:
    # XXX: replace these with assertions.
    let op = getAttachedOp(c.g, t, c.kind)
@@ -737,27 +642,20 @@ proc fillStrOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  of attachedAsgn, attachedDeepCopy, attachedDup:
    body.add callCodegenProc(c.g, "nimAsgnStrV2", c.info, genAddr(c, x), y)
  of attachedSink:
-    if c.g.config.usesSso():
-      # SmallString: destroy old dst, then bit-copy src (no rc increment — this is a move).
-      # No .p aliasing check needed; rc-based destroy handles COW sharing correctly.
-      doAssert t.destructor != nil
-      body.add destructorCall(c, t.destructor, x)
-      body.add newAsgnStmt(x, y)
-    else:
-      let moveCall = genBuiltin(c, mMove, "move", x)
-      moveCall.add y
-      doAssert t.destructor != nil
-      moveCall.add destructorCall(c, t.destructor, x)
-      body.add moveCall
+    let moveCall = genBuiltin(c, mMove, "move", x)
+    moveCall.add y
+    doAssert t.destructor != nil
+    moveCall.add destructorCall(c, t.destructor, x)
+    body.add moveCall
  of attachedDestructor:
    body.add genBuiltin(c, mDestroy, "destroy", x)
  of attachedTrace:
    discard "strings are atomic and have no inner elements that are to trace"
-  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)

 proc cyclicType*(g: ModuleGraph, t: PType): bool =
  case t.kind
-  of tyRef: result = types.canFormAcycle(g, t.elementType)
+  of tyRef: result = types.canFormAcycle(g, t.lastSon)
  of tyProc: result = t.callConv == ccClosure
  else: result = false

@@ -780,56 +678,25 @@ proc atomicRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    dest[] = source
    decRef tmp

-  For YRC the write barrier is more complicated still and must be:
-
-    let tmp = dest
-    # assignment must come first so that the collector sees the most-recent graph:
-    atomic: dest[] = source
-    # Then teach the cycle collector about the changes edge (these use locks, see yrc.nim):
-    incRef source
-    decRef tmp
-
-  This is implemented as a single runtime call (nimAsgnYrc / nimSinkYrc).
  ]#
  var actions = newNodeI(nkStmtList, c.info)
-  let elemType = t.elementType
+  let elemType = t.lastSon

  createTypeBoundOps(c.g, c.c, elemType, c.info, c.idgen)
+  let isCyclic = c.g.config.selectedGC == gcOrc and types.canFormAcycle(c.g, elemType)

-  # YRC uses dedicated runtime procs for the entire write barrier:
-  if c.g.config.selectedGC == gcYrc:
-    let desc =
-      if isFinal(elemType):
-        let ti = genBuiltin(c, mGetTypeInfoV2, "getTypeInfoV2", newNodeIT(nkType, x.info, elemType))
-        ti.typ = getSysType(c.g, c.info, tyPointer)
-        ti
-      else:
-        newNodeIT(nkNilLit, c.info, getSysType(c.g, c.info, tyPointer))
-    case c.kind
-    of attachedAsgn, attachedDup:
-      body.add callCodegenProc(c.g, "nimAsgnYrc", c.info, genAddr(c, x), y, desc)
-      return
-    of attachedSink:
-      body.add callCodegenProc(c.g, "nimSinkYrc", c.info, genAddr(c, x), y, desc)
-      return
-    else: discard # fall through for destructor, trace, wasMoved
-
-  let isCyclic = c.g.config.selectedGC in {gcOrc, gcYrc} and types.canFormAcycle(c.g, elemType)
-
-  let isInheritableAcyclicRef = c.g.config.selectedGC in {gcOrc, gcYrc} and
+  let isInheritableAcyclicRef = c.g.config.selectedGC == gcOrc and
                      (not isPureObject(elemType)) and
                      tfAcyclic in skipTypes(elemType, abstractInst+{tyOwned}-{tyTypeDesc}).flags
  # dynamic Acyclic refs need to use dyn decRef

-  let useStatic = isFinal(elemType)
-
  let tmp =
    if isCyclic and c.kind in {attachedAsgn, attachedSink, attachedDup}:
      declareTempOf(c, body, x)
    else:
      x

-  if useStatic:
+  if isFinal(elemType):
    addDestructorCall(c, elemType, actions, genDeref(tmp, nkDerefExpr))
    var alignOf = genBuiltin(c, mAlignOf, "alignof", newNodeIT(nkType, c.info, elemType))
    alignOf.typ = getSysType(c.g, c.info, tyInt)
@@ -840,7 +707,7 @@ proc atomicRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =

  var cond: PNode
  if isCyclic:
-    if useStatic:
+    if isFinal(elemType):
      let typInfo = genBuiltin(c, mGetTypeInfoV2, "getTypeInfoV2", newNodeIT(nkType, x.info, elemType))
      typInfo.typ = getSysType(c.g, c.info, tyPointer)
      cond = callCodegenProc(c.g, "nimDecRefIsLastCyclicStatic", c.info, tmp, typInfo)
@@ -875,7 +742,7 @@ proc atomicRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  of attachedDeepCopy: assert(false, "cannot happen")
  of attachedTrace:
    if isCyclic:
-      if useStatic:
+      if isFinal(elemType):
        let typInfo = genBuiltin(c, mGetTypeInfoV2, "getTypeInfoV2", newNodeIT(nkType, x.info, elemType))
        typInfo.typ = getSysType(c.g, c.info, tyPointer)
        body.add callCodegenProc(c.g, "nimTraceRef", c.info, genAddrOf(x, c.idgen), typInfo, y)
@@ -883,7 +750,7 @@ proc atomicRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
        # If the ref is polymorphic we have to account for this
        body.add callCodegenProc(c.g, "nimTraceRefDyn", c.info, genAddrOf(x, c.idgen), y)
      #echo "can follow ", elemType, " static ", isFinal(elemType)
-  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)
  of attachedDup:
    if isCyclic:
      body.add newAsgnStmt(x, y)
@@ -900,26 +767,7 @@ proc atomicClosureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  let xenv = genBuiltin(c, mAccessEnv, "accessEnv", x)
  xenv.typ = getSysType(c.g, c.info, tyPointer)

-  # Closures are (fnPtr, env) pairs. nimAsgnYrc/nimSinkYrc handle the env pointer
-  # (atomic store + buffered inc/dec). We also need newAsgnStmt to copy the fnPtr.
-  if c.g.config.selectedGC == gcYrc:
-    let nilDesc = newNodeIT(nkNilLit, c.info, getSysType(c.g, c.info, tyPointer))
-    let yenv = genBuiltin(c, mAccessEnv, "accessEnv", y)
-    yenv.typ = getSysType(c.g, c.info, tyPointer)
-    case c.kind
-    of attachedAsgn, attachedDup:
-      # nimAsgnYrc: save old env, atomic store new env, inc new env, dec old env
-      body.add callCodegenProc(c.g, "nimAsgnYrc", c.info, genAddr(c, xenv), yenv, nilDesc)
-      # Raw struct copy to also update the function pointer (env write is redundant but benign)
-      body.add newAsgnStmt(x, y)
-      return
-    of attachedSink:
-      body.add callCodegenProc(c.g, "nimSinkYrc", c.info, genAddr(c, xenv), yenv, nilDesc)
-      body.add newAsgnStmt(x, y)
-      return
-    else: discard # fall through for destructor, trace, wasMoved
-
-  let isCyclic = c.g.config.selectedGC in {gcOrc, gcYrc}
+  let isCyclic = c.g.config.selectedGC == gcOrc
  let tmp =
    if isCyclic and c.kind in {attachedAsgn, attachedSink, attachedDup}:
      declareTempOf(c, body, xenv)
@@ -952,6 +800,7 @@ proc atomicClosureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
      body.add genIf(c, cond, actions)
    else:
      body.add genIf(c, yenv, callCodegenProc(c.g, "nimIncRef", c.info, yenv))
+
      body.add genIf(c, cond, actions)
      body.add newAsgnStmt(x, y)
  of attachedDup:
@@ -968,7 +817,7 @@ proc atomicClosureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  of attachedDeepCopy: assert(false, "cannot happen")
  of attachedTrace:
    body.add callCodegenProc(c.g, "nimTraceRefDyn", c.info, genAddrOf(xenv, c.idgen), y)
-  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)

 proc weakrefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  case c.kind
@@ -996,12 +845,12 @@ proc weakrefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
      body.sons.insert(des, 0)
  of attachedDeepCopy: assert(false, "cannot happen")
  of attachedTrace: discard
-  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)

 proc ownedRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  var actions = newNodeI(nkStmtList, c.info)

-  let elemType = t.skipModifier
+  let elemType = t.lastSon
  #fillBody(c, elemType, actions, genDeref(x), genDeref(y))
  #var disposeCall = genBuiltin(c, mDispose, "dispose", x)

@@ -1024,7 +873,7 @@ proc ownedRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    body.add genIf(c, x, actions)
  of attachedDeepCopy: assert(false, "cannot happen")
  of attachedTrace: discard
-  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)

 proc closureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  if c.kind == attachedDeepCopy:
@@ -1036,7 +885,7 @@ proc closureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    call[1] = y
    body.add newAsgnStmt(x, call)
  elif (optOwnedRefs in c.g.config.globalOptions and
-      optRefCheck in c.g.config.options) or c.g.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc}:
+      optRefCheck in c.g.config.options) or c.g.config.selectedGC in {gcArc, gcAtomicArc, gcOrc}:
    let xx = genBuiltin(c, mAccessEnv, "accessEnv", x)
    xx.typ = getSysType(c.g, c.info, tyPointer)
    case c.kind
@@ -1064,7 +913,7 @@ proc closureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
        body.sons.insert(des, 0)
    of attachedDeepCopy: assert(false, "cannot happen")
    of attachedTrace: discard
-    of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+    of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)

 proc ownedClosureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  let xx = genBuiltin(c, mAccessEnv, "accessEnv", x)
@@ -1082,25 +931,16 @@ proc ownedClosureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    body.add genIf(c, xx, actions)
  of attachedDeepCopy: assert(false, "cannot happen")
  of attachedTrace: discard
-  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+  of attachedWasMoved: body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)

 proc fillBody(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  case t.kind
  of tyNone, tyEmpty, tyVoid: discard
-  of tyUncheckedArray:
-    # An UncheckedArray has no known length, so it cannot be copied, moved or
-    # destroyed as a value: it only ever lives behind a pointer and its bytes
-    # are managed manually (element ops for seqs/strings go through the
-    # seq/string hooks, which know the length). Emitting `x = y` for it (as the
-    # pointer-like group below does) produces an assignment of an unsized array,
-    # which the C backend cannot lower (genAssignment: tyUncheckedArray). So all
-    # value hooks for it are no-ops.
-    discard
  of tyPointer, tySet, tyBool, tyChar, tyEnum, tyInt..tyUInt64, tyCstring,
-      tyPtr, tyVar, tyLent:
+      tyPtr, tyUncheckedArray, tyVar, tyLent:
    defaultOp(c, t, body, x, y)
  of tyRef:
-    if c.g.config.selectedGC in {gcArc, gcOrc, gcYrc, gcAtomicArc}:
+    if c.g.config.selectedGC in {gcArc, gcOrc, gcAtomicArc}:
      atomicRefOp(c, t, body, x, y)
    elif (optOwnedRefs in c.g.config.globalOptions and
        optRefCheck in c.g.config.options):
@@ -1109,7 +949,7 @@ proc fillBody(c: var TLiftCtx; t: PType; body, x, y: PNode) =
      defaultOp(c, t, body, x, y)
  of tyProc:
    if t.callConv == ccClosure:
-      if c.g.config.selectedGC in {gcArc, gcOrc, gcYrc, gcAtomicArc}:
+      if c.g.config.selectedGC in {gcArc, gcOrc, gcAtomicArc}:
        atomicClosureOp(c, t, body, x, y)
      else:
        closureOp(c, t, body, x, y)
@@ -1141,13 +981,9 @@ proc fillBody(c: var TLiftCtx; t: PType; body, x, y: PNode) =
      # 'selectedGC' here to determine if we have the new runtime.
      discard considerUserDefinedOp(c, t, body, x, y)
    elif tfHasAsgn in t.flags:
-      # seqs with elements using custom hooks in refc
      if c.kind in {attachedAsgn, attachedSink, attachedDeepCopy}:
        body.add newSeqCall(c, x, y)
-      if c.kind == attachedWasMoved:
-        body.add genBuiltin(c, mWasMoved, "wasMoved", x)
-      else:
-        forallElements(c, t, body, x, y)
+      forallElements(c, t, body, x, y)
    else:
      defaultOp(c, t, body, x, y)
  of tyString:
@@ -1164,18 +1000,23 @@ proc fillBody(c: var TLiftCtx; t: PType; body, x, y: PNode) =
        of {attachedAsgn, attachedSink, attachedDup}:
          body.add newAsgnStmt(x, y)
        of attachedWasMoved:
-          body.add genBuiltin(c, mWasMoved, "wasMoved", x)
+          body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x)
        else:
          fillBodyObjT(c, t, body, x, y)
-      elif tfUnion in t.flags: # bug #25236
-        defaultOp(c, t, body, x, y)
      else:
-        if not considerInferDupFromCopy(c, t, body, x, y):
+        if c.kind == attachedDup:
+          var op2 = getAttachedOp(c.g, t, attachedAsgn)
+          if op2 != nil and sfOverridden in op2.flags:
+            #markUsed(c.g.config, c.info, op, c.g.usageSym)
+            onUse(c.info, op2)
+            body.add newHookCall(c, t.assignment, x, y)
+          else:
+            fillBodyObjT(c, t, body, x, y)
+        else:
          fillBodyObjT(c, t, body, x, y)
  of tyDistinct:
    if not considerUserDefinedOp(c, t, body, x, y):
-      if not considerInferDupFromCopy(c, t, body, x, y):
-        fillBody(c, t.elementType, body, x, y)
+      fillBody(c, t[0], body, x, y)
  of tyTuple:
    fillBodyTup(c, t, body, x, y)
  of tyVarargs, tyOpenArray:
@@ -1184,7 +1025,7 @@ proc fillBody(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    else:
      discard "cannot copy openArray"

-  of tyFromExpr, tyError, tyBuiltInTypeClass, tyUserTypeClass,
+  of tyFromExpr, tyProxy, tyBuiltInTypeClass, tyUserTypeClass,
     tyUserTypeClassInst, tyCompositeTypeClass, tyAnd, tyOr, tyNot, tyAnything,
     tyGenericParam, tyGenericBody, tyNil, tyUntyped, tyTyped,
     tyTypeDesc, tyGenericInvocation, tyForward, tyStatic:
@@ -1192,14 +1033,14 @@ proc fillBody(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    discard
  of tyOrdinal, tyRange, tyInferred,
     tyGenericInst, tyAlias, tySink:
-    fillBody(c, skipModifier(t), body, x, y)
+    fillBody(c, lastSon(t), body, x, y)
  of tyConcept, tyIterable: raiseAssert "unreachable"

 proc produceSymDistinctType(g: ModuleGraph; c: PContext; typ: PType;
                            kind: TTypeAttachedOp; info: TLineInfo;
                            idgen: IdGenerator): PSym =
  assert typ.kind == tyDistinct
-  let baseType = typ.elementType
+  let baseType = typ[0]
  if getAttachedOp(g, baseType, kind) == nil:
    discard produceSym(g, c, baseType, kind, info, idgen)
  result = getAttachedOp(g, baseType, kind)
@@ -1215,14 +1056,14 @@ proc symDupPrototype(g: ModuleGraph; typ: PType; owner: PSym; kind: TTypeAttache
  res.typ = typ
  src.typ = typ

-  result.typ = newType(tyProc, idgen, owner)
+  result.typ = newType(tyProc, nextTypeId idgen, owner)
  result.typ.n = newNodeI(nkFormalParams, info)
  rawAddSon(result.typ, res.typ)
  result.typ.n.add newNodeI(nkEffectList, info)

  result.typ.addParam src

-  if g.config.selectedGC in {gcOrc, gcYrc} and
+  if g.config.selectedGC == gcOrc and
    cyclicType(g, typ.skipTypes(abstractInst)):
    let cycleParam = newSym(skParam, getIdent(g.cache, "cyclic"),
                            idgen, result, info)
@@ -1236,11 +1077,11 @@ proc symDupPrototype(g: ModuleGraph; typ: PType; owner: PSym; kind: TTypeAttache
  n[bodyPos] = newNodeI(nkStmtList, info)
  n[resultPos] = newSymNode(res)
  result.ast = n
-  incl result.flagsImpl, {sfFromGeneric, sfGeneratedOp}
-  setHookDisamb(g, result, AttachedOpToStr[kind], typ)
+  incl result.flags, sfFromGeneric
+  incl result.flags, sfGeneratedOp

 proc symPrototype(g: ModuleGraph; typ: PType; owner: PSym; kind: TTypeAttachedOp;
-              info: TLineInfo; idgen: IdGenerator; isDiscriminant = false): PSym =
+              info: TLineInfo; idgen: IdGenerator): PSym =
  if kind == attachedDup:
    return symDupPrototype(g, typ, owner, kind, info, idgen)

@@ -1250,8 +1091,7 @@ proc symPrototype(g: ModuleGraph; typ: PType; owner: PSym; kind: TTypeAttachedOp
  let src = newSym(skParam, getIdent(g.cache, if kind == attachedTrace: "env" else: "src"),
                   idgen, result, info)

-  if kind == attachedDestructor and g.config.selectedGC in {gcArc, gcOrc, gcYrc, gcAtomicArc} and
-     ((g.config.isDefined("nimPreviewNonVarDestructor") and not isDiscriminant) or (typ.kind in {tyRef, tyString, tySequence})):
+  if kind == attachedDestructor and typ.kind in {tyRef, tyString, tySequence} and g.config.selectedGC in {gcArc, gcOrc, gcAtomicArc}:
    dest.typ = typ
  else:
    dest.typ = makeVarType(typ.owner, typ, idgen)
@@ -1261,12 +1101,12 @@ proc symPrototype(g: ModuleGraph; typ: PType; owner: PSym; kind: TTypeAttachedOp
  else:
    src.typ = typ

-  result.typ = newProcType(info, idgen, owner)
+  result.typ = newProcType(info, nextTypeId(idgen), owner)
  result.typ.addParam dest
  if kind notin {attachedDestructor, attachedWasMoved}:
    result.typ.addParam src

-  if kind == attachedAsgn and g.config.selectedGC in {gcOrc, gcYrc} and
+  if kind == attachedAsgn and g.config.selectedGC == gcOrc and
      cyclicType(g, typ.skipTypes(abstractInst)):
    let cycleParam = newSym(skParam, getIdent(g.cache, "cyclic"),
                            idgen, result, info)
@@ -1279,15 +1119,11 @@ proc symPrototype(g: ModuleGraph; typ: PType; owner: PSym; kind: TTypeAttachedOp
  n[paramsPos] = result.typ.n
  n[bodyPos] = newNodeI(nkStmtList, info)
  result.ast = n
-  incl result.flagsImpl, sfFromGeneric
-  incl result.flagsImpl, sfGeneratedOp
+  incl result.flags, sfFromGeneric
+  incl result.flags, sfGeneratedOp
  if kind == attachedWasMoved:
-    incl result.flagsImpl, sfNoSideEffect
-    incl result.typ, tfNoSideEffect
-  if not isDiscriminant:
-    # discriminant destructors derive their body from the enclosing object
-    # AND the selected field; their key is set at the call site
-    setHookDisamb(g, result, AttachedOpToStr[kind], typ)
+    incl result.flags, sfNoSideEffect
+    incl result.typ.flags, tfNoSideEffect

 proc genTypeFieldCopy(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  let xx = genBuiltin(c, mAccessTypeField, "accessTypeField", x)
@@ -1299,17 +1135,7 @@ proc genTypeFieldCopy(c: var TLiftCtx; t: PType; body, x, y: PNode) =
 proc produceSym(g: ModuleGraph; c: PContext; typ: PType; kind: TTypeAttachedOp;
              info: TLineInfo; idgen: IdGenerator): PSym =
  if typ.kind == tyDistinct:
-    # For =dup, if the distinct type has a user-defined =copy, don't delegate
-    # to the base type. Instead fall through to the normal produceSym logic
-    # so that fillBody -> considerInferDupFromCopy can synthesize =dup from =copy.
-    if kind == attachedDup:
-      let copyOp = getAttachedOp(g, typ, attachedAsgn)
-      if copyOp != nil and sfOverridden in copyOp.flags:
-        discard "fall through to normal produceSym logic"
-      else:
-        return produceSymDistinctType(g, c, typ, kind, info, idgen)
-    else:
-      return produceSymDistinctType(g, c, typ, kind, info, idgen)
+    return produceSymDistinctType(g, c, typ, kind, info, idgen)

  result = getAttachedOp(g, typ, kind)
  if result == nil:
@@ -1319,7 +1145,7 @@ proc produceSym(g: ModuleGraph; c: PContext; typ: PType; kind: TTypeAttachedOp;
                   fn: result)

  let dest = if kind == attachedDup: result.ast[resultPos].sym else: result.typ.n[1].sym
-  let d = if result.typ.firstParamType.kind == tyVar: newDeref(newSymNode(dest)) else: newSymNode(dest)
+  let d = if result.typ[1].kind == tyVar: newDeref(newSymNode(dest)) else: newSymNode(dest)
  let src = case kind
            of {attachedDestructor, attachedWasMoved}: newNodeIT(nkSym, info, getSysType(g, info, tyPointer))
            of attachedDup: newSymNode(result.typ.n[1].sym)
@@ -1330,57 +1156,35 @@ proc produceSym(g: ModuleGraph; c: PContext; typ: PType; kind: TTypeAttachedOp;

  if kind == attachedSink and destructorOverridden(g, typ):
    ## compiler can use a combination of `=destroy` and memCopy for sink op
-    ensureMutable dest
-    dest.flagsImpl.incl sfCursor
+    dest.flags.incl sfCursor
    let op = getAttachedOp(g, typ, attachedDestructor)
-    result.ast[bodyPos].add newOpCall(a, op, if op.typ.firstParamType.kind == tyVar: d[0] else: d)
+    result.ast[bodyPos].add newOpCall(a, op, if op.typ[1].kind == tyVar: d[0] else: d)
    result.ast[bodyPos].add newAsgnStmt(d, src)
  else:
    var tk: TTypeKind
-    var skipped: PType = nil
-    if g.config.selectedGC in {gcArc, gcOrc, gcYrc, gcHooks, gcAtomicArc}:
-      skipped = skipTypes(typ, {tyOrdinal, tyRange, tyInferred, tyGenericInst, tyStatic, tyAlias, tySink})
-      tk = skipped.kind
+    if g.config.selectedGC in {gcArc, gcOrc, gcHooks, gcAtomicArc}:
+      tk = skipTypes(typ, {tyOrdinal, tyRange, tyInferred, tyGenericInst, tyStatic, tyAlias, tySink}).kind
    else:
      tk = tyNone # no special casing for strings and seqs
    case tk
    of tySequence:
-      let needsYrcLock = g.config.selectedGC == gcYrc and
-         kind in {attachedDestructor, attachedSink, attachedAsgn, attachedDeepCopy, attachedDup} and
-         types.canFormAcycle(g, skipped.elementType)
-      # YRC: topology-changing seq ops must hold the mutator (read) lock
-      if needsYrcLock:
-        result.ast[bodyPos].add callCodegenProc(g, "acquireMutatorLock", info)
      fillSeqOp(a, typ, result.ast[bodyPos], d, src)
-      if needsYrcLock:
-        result.ast[bodyPos].add callCodegenProc(g, "releaseMutatorLock", info)
    of tyString:
      fillStrOp(a, typ, result.ast[bodyPos], d, src)
    else:
      fillBody(a, typ, result.ast[bodyPos], d, src)
-      if tk == tyObject and a.kind in {attachedAsgn, attachedSink, attachedDeepCopy, attachedDup} and not isObjLackingTypeField(skipped):
+      if tk == tyObject and a.kind in {attachedAsgn, attachedSink, attachedDeepCopy, attachedDup} and not lacksMTypeField(typ):
        # bug #19205: Do not forget to also copy the hidden type field:
        genTypeFieldCopy(a, typ, result.ast[bodyPos], d, src)

-  if not a.canRaise:
-    ensureMutable result
-    incl result.flagsImpl, sfNeverRaises
-    result.ast[pragmasPos] = newNodeI(nkPragma, info)
-    result.ast[pragmasPos].add newTree(nkExprColonExpr,
-        newIdentNode(g.cache.getIdent("raises"),  info), newNodeI(nkBracket, info))
-
-  if kind == attachedDestructor:
-    ensureMutable result
-    incl result.optionsImpl, optQuirky
+  if not a.canRaise: incl result.flags, sfNeverRaises
  completePartialOp(g, idgen.module, typ, kind, result)


 proc produceDestructorForDiscriminator*(g: ModuleGraph; typ: PType; field: PSym,
                                        info: TLineInfo; idgen: IdGenerator): PSym =
  assert(typ.skipTypes({tyAlias, tyGenericInst}).kind == tyObject)
-  # discrimantor assignments needs pointers to destroy fields; alas, we cannot use non-var destructor here
-  result = symPrototype(g, field.typ, typ.owner, attachedDestructor, info, idgen, isDiscriminant = true)
-  setHookDisamb(g, result, "=destroy¦" & field.name.s & "¦" & $field.position, typ)
+  result = symPrototype(g, field.typ, typ.owner, attachedDestructor, info, idgen)
  var a = TLiftCtx(info: info, g: g, kind: attachedDestructor, asgnForType: typ, idgen: idgen,
                   fn: result)
  a.asgnForType = typ
@@ -1397,9 +1201,7 @@ proc produceDestructorForDiscriminator*(g: ModuleGraph; typ: PType; field: PSym,
  result.ast[bodyPos].add v
  let placeHolder = newNodeIT(nkSym, info, getSysType(g, info, tyPointer))
  fillBody(a, typ, result.ast[bodyPos], d, placeHolder)
-  if not a.canRaise:
-    ensureMutable result
-    incl result.flagsImpl, sfNeverRaises
+  if not a.canRaise: incl result.flags, sfNeverRaises


 template liftTypeBoundOps*(c: PContext; typ: PType; info: TLineInfo) =
@@ -1434,7 +1236,7 @@ proc inst(g: ModuleGraph; c: PContext; t: PType; kind: TTypeAttachedOp; idgen: I
    else:
      localError(g.config, info, "unresolved generic parameter")

-proc isTrivial*(s: PSym): bool {.inline.} =
+proc isTrival(s: PSym): bool {.inline.} =
  s == nil or (s.ast != nil and s.ast[bodyPos].len == 0)

 proc createTypeBoundOps(g: ModuleGraph; c: PContext; orig: PType; info: TLineInfo;
@@ -1443,13 +1245,7 @@ proc createTypeBoundOps(g: ModuleGraph; c: PContext; orig: PType; info: TLineInf
  ## to ensure we lift assignment, destructors and moves properly.
  ## The later 'injectdestructors' pass depends on it.
  if orig == nil or {tfCheckedForDestructor, tfHasMeta} * orig.flags != {}: return
-  # IC: review this solution again later
-  incl orig.flagsImpl, tfCheckedForDestructor
-  # for user defined generic destructors:
-  let origRoot = genericRoot(orig)
-  if origRoot != nil:
-    # IC: review this solution again later
-    incl origRoot.flagsImpl, tfGenericHasDestructor
+  incl orig.flags, tfCheckedForDestructor

  let skipped = orig.skipTypes({tyGenericInst, tyAlias, tySink})
  if isEmptyContainer(skipped) or skipped.kind == tyStatic: return
@@ -1469,13 +1265,13 @@ proc createTypeBoundOps(g: ModuleGraph; c: PContext; orig: PType; info: TLineInf

  # we do not generate '=trace' procs if we
  # have the cycle detection disabled, saves code size.
-  let lastAttached = if g.config.selectedGC in {gcOrc, gcYrc}: attachedTrace
+  let lastAttached = if g.config.selectedGC == gcOrc: attachedTrace
                     else: attachedSink

  # bug #15122: We need to produce all prototypes before entering the
  # mind boggling recursion. Hacks like these imply we should rewrite
  # this module.
-  var generics = default(array[attachedWasMoved..attachedTrace, bool])
+  var generics: array[attachedWasMoved..attachedTrace, bool] = default(array[attachedWasMoved..attachedTrace, bool])
  for k in attachedWasMoved..lastAttached:
    generics[k] = getAttachedOp(g, canon, k) != nil
    if not generics[k]:
@@ -1491,9 +1287,8 @@ proc createTypeBoundOps(g: ModuleGraph; c: PContext; orig: PType; info: TLineInf
    if canon != orig:
      setAttachedOp(g, idgen.module, orig, k, getAttachedOp(g, canon, k))

-  if not isTrivial(getAttachedOp(g, orig, attachedDestructor)):
-    #or not isTrivial(orig.assignment) or
-    # not isTrivial(orig.sink):
-    # IC: review this solution again later
-    orig.flagsImpl.incl tfHasAsgn
+  if not isTrival(getAttachedOp(g, orig, attachedDestructor)):
+    #or not isTrival(orig.assignment) or
+    # not isTrival(orig.sink):
+    orig.flags.incl tfHasAsgn
    # ^ XXX Breaks IC!
--- a/compiler/liftlocals.nim
+++ b/compiler/liftlocals.nim
@@ -10,11 +10,9 @@
 ## This module implements the '.liftLocals' pragma.

 import
-  options, ast, msgs,
+  strutils, options, ast, msgs,
  idents, renderer, types, lowerings, lineinfos

-import std/strutils
-
 from pragmas import getPragmaVal
 from wordrecg import wLiftLocals

--- a/compiler/lineinfos.nim
+++ b/compiler/lineinfos.nim
@@ -10,8 +10,7 @@
 ## This module contains the `TMsgKind` enum as well as the
 ## `TLineInfo` object.

-import ropes, pathutils
-import std/[hashes, tables]
+import ropes, tables, pathutils, hashes

 const
  explanationsBaseUrl* = "https://nim-lang.github.io/Nim"
@@ -92,15 +91,7 @@ type
    warnStmtListLambda = "StmtListLambda",
    warnBareExcept = "BareExcept",
    warnImplicitDefaultValue = "ImplicitDefaultValue",
-    warnIgnoredSymbolInjection = "IgnoredSymbolInjection",
-    warnStdPrefix = "StdPrefix",
-    warnUnknownNotes = "UnknownNotes",
-    warnLongLiterals = "LongLiterals",
    warnUser = "User",
-    warnGlobalVarConstructorTemporary = "GlobalVarConstructorTemporary",
-    warnImplicitRangeConversion = "ImplicitRangeConversion",
-    warnSystemRangeConversion = "SystemRangeConversion",
-    warnInvalidCmpOp = "InvalidCmpOp",
    # hints
    hintSuccess = "Success", hintSuccessX = "SuccessX",
    hintCC = "CC",
@@ -113,8 +104,8 @@ type
    hintPattern = "Pattern", hintExecuting = "Exec", hintLinking = "Link", hintDependency = "Dependency",
    hintSource = "Source", hintPerformance = "Performance", hintStackTrace = "StackTrace",
    hintGCStats = "GCStats", hintGlobalVar = "GlobalVar", hintExpandMacro = "ExpandMacro",
+    hintAmbiguousEnum = "AmbiguousEnum",
    hintUser = "User", hintUserRaw = "UserRaw", hintExtendedContext = "ExtendedContext",
-    hintUnknownRaises = "UnknownRaises",
    hintMsgOrigin = "MsgOrigin", # since 1.3.5
    hintDeclaredLoc = "DeclaredLoc", # since 1.5.1

@@ -194,7 +185,7 @@ const
    warnAnyEnumConv: "$1",
    warnHoleEnumConv: "$1",
    warnCstringConv: "$1",
-    warnPtrToCstringConv: "unsafe conversion to 'cstring' from '$1'; Use a `cast` operation like `cast[cstring](x)`; this will become a compile time error in the future",
+    warnPtrToCstringConv: "unsafe conversion to 'cstring' from '$1'; this will become a compile time error in the future",
    warnEffect: "$1",
    warnCastSizes: "$1", # deadcode
    warnAboveMaxSizeSet: "$1",
@@ -203,15 +194,7 @@ const
    warnStmtListLambda: "statement list expression assumed to be anonymous proc; this is deprecated, use `do (): ...` or `proc () = ...` instead",
    warnBareExcept: "$1",
    warnImplicitDefaultValue: "$1",
-    warnIgnoredSymbolInjection: "$1",
-    warnStdPrefix: "$1 needs the 'std' prefix",
-    warnUnknownNotes: "$1",
-    warnLongLiterals: "$1",
    warnUser: "$1",
-    warnGlobalVarConstructorTemporary: "global variable '$1' initialization requires a temporary variable",
-    warnImplicitRangeConversion: "implicit range conversion $1",
-    warnSystemRangeConversion: "implicit range conversion $1",
-    warnInvalidCmpOp: "$1",
    hintSuccess: "operation successful: $#",
    # keep in sync with `testament.isSuccess`
    hintSuccessX: "$build\n$loc lines; ${sec}s; $mem; proj: $project; out: $output",
@@ -242,12 +225,12 @@ const
    hintGCStats: "$1",
    hintGlobalVar: "global variable declared here",
    hintExpandMacro: "expanded macro: $1",
+    hintAmbiguousEnum: "$1",
    hintUser: "$1",
    hintUserRaw: "$1",
    hintExtendedContext: "$1",
-    hintUnknownRaises: "$1 is a forward declaration without explicit .raises, assuming it can raise anything",
    hintMsgOrigin: "$1",
-    hintDeclaredLoc: "$1"
+    hintDeclaredLoc: "$1",
  ]

 const
@@ -266,9 +249,9 @@ type

 proc computeNotesVerbosity(): array[0..3, TNoteKinds] =
  result = default(array[0..3, TNoteKinds])
-  result[3] = {low(TNoteKind)..high(TNoteKind)} - {warnObservableStores, warnResultUsed, warnAnyEnumConv, warnBareExcept, warnStdPrefix, warnSystemRangeConversion}
+  result[3] = {low(TNoteKind)..high(TNoteKind)} - {warnObservableStores, warnResultUsed, warnAnyEnumConv, warnBareExcept}
  result[2] = result[3] - {hintStackTrace, hintExtendedContext, hintDeclaredLoc, hintProcessingStmt}
-  result[1] = result[2] - {warnImplicitRangeConversion, warnProveField, warnProveIndex,
+  result[1] = result[2] - {warnProveField, warnProveIndex,
    warnGcUnsafe, hintPath, hintDependency, hintCodeBegin, hintCodeEnd,
    hintSource, hintGlobalVar, hintGCStats, hintMsgOrigin, hintPerformance}
  result[0] = result[1] - {hintSuccessX, hintSuccess, hintConf,
@@ -278,13 +261,8 @@ const
  NotesVerbosity* = computeNotesVerbosity()
  errXMustBeCompileTime* = "'$1' can only be used in compile-time context"
  errArgsNeedRunOption* = "arguments can only be given if the '--run' option is selected"
-  errFloatToString* = "cannot convert '$1' to '$2'"

 type
-  FileInfoKind* = enum
-    fikSource,      ## A real source file path
-    fikNifModule    ## A NIF module suffix (not a real path)
-
  TFileInfo* = object
    fullPath*: AbsoluteFile    # This is a canonical full filesystem path
    projPath*: RelativeFile    # This is relative to the project's root
@@ -303,7 +281,6 @@ type
                               # for 'nimsuggest'
    hash*: string              # the checksum of the file
    dirty*: bool               # for 'nimpretty' like tooling
-    kind*: FileInfoKind        # distinguishes real files from NIF suffixes
    when defined(nimpretty):
      fullContent*: string
  FileIndex* = distinct int32
--- a/compiler/linter.nim
+++ b/compiler/linter.nim
@@ -12,7 +12,7 @@
 import std/strutils
 from std/sugar import dup

-import options, ast, msgs, idents, lineinfos, wordrecg, astmsgs, semdata, packages, modulegraphs
+import options, ast, msgs, idents, lineinfos, wordrecg, astmsgs, semdata, packages
 export packages

 const
@@ -95,9 +95,9 @@ proc nep1CheckDefImpl(conf: ConfigRef; info: TLineInfo; s: PSym; k: TSymKind) =
 template styleCheckDef*(ctx: PContext; info: TLineInfo; sym: PSym; k: TSymKind) =
  ## Check symbol definitions adhere to NEP1 style rules.
  if optStyleCheck in ctx.config.options and # ignore if styleChecks are off
-     {optStyleHint, optStyleError, optStyleWarning} * ctx.config.globalOptions != {} and # check only if hint/error/warning is enabled
+     {optStyleHint, optStyleError} * ctx.config.globalOptions != {} and # check only if hint/error is enabled
     hintName in ctx.config.notes and # ignore if name checks are not requested
-     ctx.config.belongsToProjectPackageMaybeNil(getModule(ctx.graph, info.fileIndex)) and # ignore foreign packages
+     ctx.config.belongsToProjectPackage(sym) and # ignore foreign packages
     optStyleUsages notin ctx.config.globalOptions and # ignore if requested to only check name usage
     sym.kind != skResult and # ignore `result`
     sym.kind != skTemp and # ignore temporary variables created by the compiler
@@ -136,9 +136,9 @@ proc styleCheckUseImpl(conf: ConfigRef; info: TLineInfo; s: PSym) =

 template styleCheckUse*(ctx: PContext; info: TLineInfo; sym: PSym) =
  ## Check symbol uses match their definition's style.
-  if {optStyleHint, optStyleError, optStyleWarning} * ctx.config.globalOptions != {} and # ignore if styleChecks are off
+  if {optStyleHint, optStyleError} * ctx.config.globalOptions != {} and # ignore if styleChecks are off
     hintName in ctx.config.notes and # ignore if name checks are not requested
-     ctx.config.belongsToProjectPackageMaybeNil(getModule(ctx.graph, info.fileIndex)) and # ignore foreign packages
+     ctx.config.belongsToProjectPackage(sym) and # ignore foreign packages
     sym.kind != skTemp and # ignore temporary variables created by the compiler
     sym.name.s[0] in Letters and # ignore operators TODO: what about unicode symbols???
     sfAnon notin sym.flags: # ignore temporary variables created by the compiler
@@ -152,7 +152,7 @@ proc checkPragmaUseImpl(conf: ConfigRef; info: TLineInfo; w: TSpecialWord; pragm
 template checkPragmaUse*(ctx: PContext; info: TLineInfo; w: TSpecialWord; pragmaName: string, sym: PSym) =
  ## Check builtin pragma uses match their definition's style.
  ## Note: This only applies to builtin pragmas, not user pragmas.
-  if {optStyleHint, optStyleError, optStyleWarning} * ctx.config.globalOptions != {} and # ignore if styleChecks are off
+  if {optStyleHint, optStyleError} * ctx.config.globalOptions != {} and # ignore if styleChecks are off
     hintName in ctx.config.notes and # ignore if name checks are not requested
-     ctx.config.belongsToProjectPackageMaybeNil(getModule(ctx.graph, info.fileIndex)): # ignore foreign packages
+     (sym != nil and ctx.config.belongsToProjectPackage(sym)): # ignore foreign packages
    checkPragmaUseImpl(ctx.config, info, w, pragmaName)
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
ringabout	88f556b486	merge upstream code	2023-10-04 15:07:11 +08:00
ringabout	343b304461	Merge remote-tracking branch 'upstream/araq-nir' into pr_ast2ir	2023-10-04 15:03:36 +08:00
Araq	37e3573b61	NIR: implemented builtin	2023-10-03 23:57:38 +02:00
ringabout	09d40ea41b	adds entry point and debug code	2023-10-03 22:27:19 +08:00
Araq	326a4592f1	progress	2023-10-03 09:08:20 +02:00
araq	df71f4602e	baby steps	2023-10-02 14:23:42 +02:00
araq	f496c0e14c	progress	2023-10-01 12:53:38 +02:00
araq	9d9d860797	support for annotations that can be used for calling conventions	2023-10-01 10:34:37 +02:00
araq	ef5c4ffaa2	same chance recursive types work [CI skip]	2023-10-01 09:41:37 +02:00
Araq	95c9d4cd7b	bugfix	2023-10-01 07:49:05 +02:00
araq	7f92d26470	type generation for closures	2023-10-01 01:43:06 +02:00
araq	284bbe2eb7	some varargs handling	2023-10-01 01:28:19 +02:00
araq	42ebed76e6	progress	2023-10-01 01:15:53 +02:00
araq	4fada54c6b	WIP: translate the AST into the IR	2023-10-01 00:06:56 +02:00
araq	9510e1a55c	NIR: An immediate representation for Nim. WIP	2023-09-30 21:02:01 +02:00