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what's problem os cancelled CI
2026-08-31 19:03:42 +00:00 · 2023-12-11 14:12:55 +00:00 · 2023-12-11 14:12:47 +00:00 · 2023-12-11 11:00:02 +00:00 · 2023-12-11 09:07:41 +00:00 · 2023-12-11 13:16:03 +08:00
1312 changed files with 31428 additions and 62954 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
@@ -15,16 +15,9 @@ jobs:
    name: ${{ matrix.platform }}-bisects
    runs-on: ${{ matrix.platform }}
    steps:
-      - uses: actions/checkout@v6
+      - 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'
-
-      # v2 wont work here, because uses "hardcoded" nim versions, action "dynamically" finds version with bug.
-      - uses: jiro4989/setup-nim-action@v1  
+      - uses: jiro4989/setup-nim-action@v1
        with:
          nim-version: 'devel'

--- 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: ${{ matrix.os }}
+    timeout-minutes: 60 # refs bug #18178
+    steps:
+      - name: 'Checkout'
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 2
+
+      - name: 'Install node.js 20.x'
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20.x'
+
+      - name: 'Install dependencies (Linux amd64)'
+        if: runner.os == 'Linux' && matrix.cpu == 'amd64'
+        run: |
+          sudo apt-fast update -qq
+          DEBIAN_FRONTEND='noninteractive' \
+            sudo apt-fast install --no-install-recommends -yq \
+              libcurl4-openssl-dev libgc-dev libsdl1.2-dev libsfml-dev \
+              valgrind libc6-dbg libblas-dev xorg-dev
+
+      - name: 'Add build binaries to PATH'
+        shell: bash
+        run: echo "${{ 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@v6
+        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-14]
+        os: [ubuntu-20.04, macos-11]
+        cpu: [amd64]
        batch: ["allowed_failures", "0_3", "1_3", "2_3"] # list of `index_num`
-        include:
-          - os: ubuntu-latest
-            cpu: amd64
-          - os: macos-14
-            cpu: arm64
    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@v6
+        uses: actions/checkout@v4
        with:
          fetch-depth: 2

-      - name: 'Install node.js'
-        uses: actions/setup-node@v6
+      - name: 'Install node.js 20.x'
+        uses: actions/setup-node@v4
        with:
-          node-version: 24
+          node-version: '20.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@v6
+        uses: actions/checkout@v4
        with:
          fetch-depth: 2

-      - name: 'Install node.js'
-        uses: actions/setup-node@v6
+      - name: 'Install node.js 20.x'
+        uses: actions/setup-node@v4
        with:
-          node-version: 24
+          node-version: '20.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@v8
+        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
--- 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"

@@ -80,12 +80,10 @@ jobs:
    - 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
@@ -1,127 +1,48 @@
-# 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`.
+- `-d:nimStrictDelete` becomes the default. An index error is produced when the index passed to `system.delete` was out of bounds. Use `-d:nimAuditDelete` to mimic the old behavior for backwards 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 be in the same module where their type has been defined.
+- With `-d:nimPreviewNonVarDestructor`, non-var destructors become the default.

 ## Standard library additions and changes

-[//]: # "Additions:"
-
- `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.
-
- `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.
-
 [//]: # "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`.
+- Changed `std/osfiles.copyFile` to allow to specify `bufferSize` instead of a hardcoded 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.
+
+[//]: # "Additions:"
+
+- Added `newStringUninit` to system, which creates a new string of length `len` like `newString` but with uninitialized content.
+- Added `setLenUninit` to system, which doesn't initalize
+slots when enlarging a sequence.
+- Added `hasDefaultValue` to `std/typetraits` to check if a type has a valid default value.
+- Added Viewport API for the JavaScript targets in the `dom` module.
+
+[//]: # "Deprecations:"
+
+- Deprecates `system.newSeqUninitialized`, which is replaced by `newSeqUninit`.
+
+[//]: # "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.
+- `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.htm#constructor-initializer
+- `member` can be used to attach a procedure to a C++ type.
+- C++ `constructor` now reuses `result` instead creating `this`.

 ## 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.
+- `--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

- 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.
--- 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
@@ -51,16 +51,14 @@ 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 +12,24 @@
 # the data structures here are used in various places of the compiler.

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

 import std/[hashes, intsets]
 import std/strutils except addf

-export astyaml.treeToYaml, astyaml.typeToYaml, astyaml.symToYaml, astyaml.lineInfoToStr
-
 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 +37,15 @@ 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 +80,21 @@ 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
@@ -214,6 +241,174 @@ proc getNamedParamFromList*(list: PNode, ident: PIdent): PSym =
 proc hashNode(p: RootRef): Hash =
  result = hash(cast[pointer](p))

+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\": $2", [istr, lineInfoToStr(conf, n.info)])
+      case n.kind
+      of nkCharLit..nkUInt64Lit:
+        result.addf(",$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 std/tables

 const backrefStyle = "\e[90m"
@@ -378,12 +573,14 @@ 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 +649,35 @@ 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 +725,95 @@ 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 +895,124 @@ 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 +1059,14 @@ 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
@@ -1,154 +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; indent, maxRecDepth: int)
-proc symToYamlAux(res: var string; conf: ConfigRef; n: PSym; marker: var IntSet; indent, maxRecDepth: int)
-proc typeToYamlAux(res: var string; conf: ConfigRef; n: PType; marker: var IntSet; indent, maxRecDepth: int)
-
-proc symToYamlAux(res: var string; conf: ConfigRef; n: PSym; marker: var IntSet; 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)
-
-    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, 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, 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: $2", [istr])
-    res.treeToYamlAux(conf, n.loc.lode, marker, indent + 1, maxRecDepth - 1)
-
-proc typeToYamlAux(res: var string; conf: ConfigRef; n: PType; marker: var IntSet; 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)
-    res.addf("kind: $2", [istr, makeYamlString($n.kind)])
-    res.addf("\n$1sym: ")
-    res.symToYamlAux(conf, n.sym, marker, indent + 1, maxRecDepth - 1)
-    res.addf("\n$1n: ")
-    res.treeToYamlAux(conf, n.n, marker, 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:")
-      for a in n.kids:
-        res.addf("\n  - ")
-        res.typeToYamlAux(conf, a, marker, indent + 1, maxRecDepth - 1)
-
-proc treeToYamlAux(res: var string; conf: ConfigRef; n: PNode; marker: var IntSet; indent: int;
-                   maxRecDepth: int) =
-  if n == nil:
-    res.add("null")
-  else:
-    var istr = spaces(indent * 4)
-    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 .. nkInt64Lit:
-        res.addf("\n$1intVal: $2", [istr, $(n.intVal)])
-      of nkFloatLit, nkFloat32Lit, nkFloat64Lit:
-        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, 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, indent + 1, maxRecDepth - 1)
-      if n.typ != nil:
-        res.addf("\n$1typ: ", [istr])
-        res.typeToYamlAux(conf, n.typ, marker, 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, 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, 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, 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/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.isDefined("nimsso"):
-      let bra = byRefLoc(p, a)
-      p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimPrepareStrMutationV2"),
-        bra)
-    if p.config.isDefined("nimsso") 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, ty.kind == tyString), 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, ty.kind == tyString), 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 +218,46 @@ 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)
-    case skipTypes(a.t, abstractVar+{tyStatic}).kind
+    let typKind = skipTypes(a.t, abstractVar+{tyStatic}).kind
+    case typKind
    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.isDefined("nimsso"):
-        let bra = byRefLoc(p, a)
-        p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimPrepareStrMutationV2"),
-          bra)
-      if p.config.isDefined("nimsso") 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, typKind == tyString), dataField(p, typKind == tyString),
+                      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, typKind == tyString), dataField(p, typKind == tyString), 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.isDefined("nimsso"):
-          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, typKind == tyString), dataField(p, typKind == tyString),
+                      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 +266,53 @@ 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.} =
+proc genArgStringToCString(p: BProc, n: PNode; result: var Rope; needsTmp: bool) {.inline.} =
  var a = initLocExpr(p, n[0])
-  let tmp = withTmpIfNeeded(p, a, needsTmp)
-  let ra = if p.config.isDefined("nimsso"): addrLoc(p.config, tmp) else: tmp.rdLoc
-  result.addCall(cgsymValue(p.module, "nimToCStringConv"), ra)
+  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
-      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 +338,35 @@ 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 +375,7 @@ 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 +391,25 @@ 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
@@ -502,105 +422,80 @@ proc genPrefixCall(p: BProc, le, ri: PNode, d: var TLoc) =
  # 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])

  # 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 +503,30 @@ 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 +583,11 @@ 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 +618,15 @@ 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 +636,11 @@ 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 +654,15 @@ 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
@@ -779,57 +677,60 @@ proc genInfixCall(p: BProc, le, ri: PNode, d: var TLoc) =
  # 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 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 +739,13 @@ 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 +753,33 @@ 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)
--- 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.isDefined("nimsso") 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 +92,49 @@ 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)))
+  result.addf "{$1, (NimStrPayload*)&$2}", [rope(n.strVal.len), 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])
+# ------ Version 3: destructor based strings and seqs -----------------------
+# strings are enhanced by interned strings
+
+proc toConstLenV3(len: int): string =
+  result = rope((len shl 1) or 1)
+
+proc genStringLiteralDataOnlyV3(m: BModule, s: string; result: Rope; isConst: bool) =
+  # TODO: fixme: perhaps use makeCString for clarity for C
+  m.s[cfsStrData].addf("static $4 NIM_CHAR $1[$2] = $3;$n",
+       [result, rope(s.len), makeCCharArray(s),
+       rope(if isConst: "const" else: "")])
+
+proc genStringLiteralV3(m: BModule; n: PNode; isConst: bool; result: var Rope) =
+  let id = nodeTableTestOrSet(m.dataCache, n, m.labels)
+  if id == m.labels:
+    let pureLit = getTempName(m)
+    genStringLiteralDataOnlyV3(m, n.strVal, pureLit, isConst)
+    let tmp = getTempName(m)
+    result.add tmp
+    cgsym(m, "NimStringV3")
+    # string literal not found in the cache:
+    m.s[cfsStrData].addf("static $4 NimStringV3 $1 = {$2, (NIM_CHAR*)&$3};$n",
+          [tmp, toConstLenV3(n.strVal.len), pureLit, rope(if isConst: "const" else: "")])
  else:
-    result.add(ch)
-  result.add('\'')
+    let tmp = getTempName(m)
+    result.add tmp
+    m.s[cfsStrData].addf("static $4 NimStringV3 $1 = {$2, (NIM_CHAR*)&$3};$n",
+          [tmp, toConstLenV3(n.strVal.len), m.tmpBase & rope(id),
+          rope(if isConst: "const" else: "")])

-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))
+proc genStringLiteralV3Const(m: BModule; n: PNode; isConst: bool; result: var Rope) =
+  let id = nodeTableTestOrSet(m.dataCache, n, m.labels)
+  var pureLit: Rope
+  if id == m.labels:
+    pureLit = getTempName(m)
+    cgsym(m, "NimStringV3")
+    # string literal not found in the cache:
+    genStringLiteralDataOnlyV3(m, n.strVal, pureLit, isConst)
  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))
+    pureLit = m.tmpBase & rope(id)
+  result.addf "{$1, (NIM_CHAR*)&$2}", [toConstLenV3(n.strVal.len), pureLit]

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

@@ -329,14 +147,16 @@ proc genStringLiteralDataOnly(m: BModule; s: string; info: TLineInfo;
    genStringLiteralDataOnlyV2(m, s, tmp, isConst)
    result.add tmp
  of 3:
-    localError(m.config, info, "genStringLiteralDataOnly not supported for SmallString (nimsso)")
+    let tmp = getTempName(m)
+    genStringLiteralDataOnlyV3(m, s, tmp, isConst)
+    result.add tmp
  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)
--- 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):
@@ -33,32 +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
-    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
@@ -11,9 +11,9 @@

 import
  ast, types, msgs, wordrecg,
-  platform, trees, options, cgendata, mangleutils, renderer
+  platform, trees, options, cgendata

-import std/[hashes, strutils, formatfloat]
+import std/[hashes, strutils]

 when defined(nimPreviewSlimSystem):
  import std/assertions
@@ -68,6 +68,53 @@ 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 +126,10 @@ 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
@@ -106,67 +153,3 @@ 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
-  result.add "__"
-  result.add m.g.graph.ifaces[s.itemId.module].uniqueName
-  result.add "_u"
-  result.add $s.itemId.item
-
-proc encodeSym*(m: BModule; s: PSym; makeUnique: bool = false; extra: string = ""): string =
-  #Module::Type
-  var name = s.name.s & extra
-  if makeUnique:
-    name = makeUnique(m, s, name)
-  "N" & encodeName(s.skipGenericOwner.name.s) & encodeName(name) & "E"
-
-proc encodeType*(m: BModule; t: PType; staticLists: var string): string =
-  result = ""
-  var kindName = ($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
@@ -11,7 +11,7 @@

 import
  ast, ropes, options,
-  lineinfos, pathutils, modulegraphs, cbuilderbase
+  ndi, lineinfos, pathutils, modulegraphs

 import std/[intsets, tables, sets]

@@ -43,12 +43,12 @@ 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
@@ -88,7 +88,7 @@ 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
@@ -115,11 +115,11 @@ 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
@@ -127,7 +127,7 @@ 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
@@ -137,7 +137,6 @@ 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
@@ -151,53 +150,49 @@ 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
-    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]
    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
@@ -69,23 +69,21 @@ 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):
@@ -104,10 +102,10 @@ proc sameMethodBucket(a, b: PSym; multiMethods: bool): MethodResult =
  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], {IgnoreFlags}):
+      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

@@ -123,8 +121,8 @@ 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)
  copyTypeProps(g, idgen.module, disp.typ, old)
@@ -133,8 +131,8 @@ proc createDispatcher(s: PSym; g: ModuleGraph; idgen: IdGenerator): PSym =
  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:
@@ -159,14 +157,9 @@ 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"):
+  if s.typ[1].owner.getModule != s.getModule and vtables in g.config.features and not g.config.isDefined("nimInternalNonVtablesTesting"):
    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")
-
+          "` can be defined only in the same module with its type (" & s.typ[1].typeToString() & ")")
  for i in 0..<g.methods.len:
    let disp = g.methods[i].dispatcher
    case sameMethodBucket(disp, s, multimethods = optMultiMethods in g.config.globalOptions)
@@ -186,10 +179,10 @@ proc methodDef*(g: ModuleGraph; idgen: IdGenerator; s: PSym) =
      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
+  if s.typ[1].skipTypes(skipPtrs).itemId notin g.bucketTable:
+    g.bucketTable[s.typ[1].skipTypes(skipPtrs).itemId] = 1
  else:
-    g.bucketTable.inc(s.typ.firstParamType.skipTypes(skipPtrs).itemId)
+    g.bucketTable.inc(s.typ[1].skipTypes(skipPtrs).itemId)
  g.methods.add((methods: @[s], dispatcher: createDispatcher(s, g, idgen)))
  #echo "adding ", s.info
  if witness != nil:
@@ -210,7 +203,7 @@ 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)
@@ -240,13 +233,13 @@ proc sortBucket*(a: var seq[PSym], relevantCols: IntSet) =
 proc genIfDispatcher*(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}:
@@ -255,7 +248,7 @@ 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)
@@ -270,7 +263,7 @@ 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:
@@ -299,7 +292,7 @@ proc genIfDispatcher*(g: ModuleGraph; methods: seq[PSym], relevantCols: IntSet;
 proc generateIfMethodDispatchers*(g: ModuleGraph, idgen: IdGenerator) =
  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
--- a/compiler/closureiters.nim
+++ b/compiler/closureiters.nim
--- a/compiler/cmdlinehelper.nim
+++ b/compiler/cmdlinehelper.nim
@@ -57,11 +57,6 @@ proc loadConfigsAndProcessCmdLine*(self: NimProg, cache: IdentCache; conf: Confi
  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/commands.nim
+++ b/compiler/commands.nim
@@ -24,7 +24,7 @@ bootSwitch(usedMarkAndSweep, defined(gcmarkandsweep), "--gc:markAndSweep")
 bootSwitch(usedGoGC, defined(gogc), "--gc:go")
 bootSwitch(usedNoGC, defined(nogc), "--gc:none")

-import std/[setutils, 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
@@ -118,7 +118,7 @@ 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 % "-")
@@ -203,14 +203,13 @@ 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])
+      if isSomeHint:
+        message(conf, info, hintUnknownHint, id)
      else:
        localError(conf, info, "unknown $#: $#" % [name, id])
  case id.normalize
@@ -245,11 +244,10 @@ 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"

 template warningOptionNoop(switch: string) =
  warningDeprecated(conf, info, "'$#' is deprecated, now a noop" % switch)
@@ -266,7 +264,6 @@ 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
@@ -306,12 +303,6 @@ proc testCompileOptionArg*(conf: ConfigRef; switch, arg: string, info: TLineInfo
    else:
      result = false
      localError(conf, info, errInvalidExceptionSystem % 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)
@@ -365,7 +356,6 @@ 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)
@@ -461,7 +451,7 @@ template handleStdinOrCmdInput =
    conf.outDir = getNimcacheDir(conf)

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

@@ -472,10 +462,10 @@ proc handleCmdInput*(conf: ConfigRef) =
 proc parseCommand*(command: string): Command =
  case command.normalize
  of "c", "cc", "compile", "compiletoc": cmdCompileToC
+  of "nir": cmdCompileToNir
  of "cpp", "compiletocpp": cmdCompileToCpp
  of "objc", "compiletooc": cmdCompileToOC
  of "js", "compiletojs": cmdCompileToJS
-  of "nif": cmdCompileToNif
  of "r": cmdCrun
  of "m": cmdM
  of "run": cmdTcc
@@ -495,11 +485,10 @@ 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
  else: cmdUnknown

 proc setCmd*(conf: ConfigRef, cmd: Command) =
@@ -511,12 +500,7 @@ 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
+  of cmdCompileToNir: conf.backend = backendNir
  else: discard

 proc setCommandEarly*(conf: ConfigRef, command: string) =
@@ -571,7 +555,6 @@ 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")
@@ -605,10 +588,6 @@ 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")
@@ -775,16 +754,6 @@ 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 "g": # alias for --debugger:native
    conf.globalOptions.incl optCDebug
    conf.options.incl optLineDir
@@ -907,19 +876,11 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
  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 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":
@@ -951,14 +912,8 @@ 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.
@@ -968,10 +923,6 @@ 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)
@@ -1005,8 +956,7 @@ 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
@@ -1114,9 +1064,6 @@ 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
@@ -1148,10 +1095,9 @@ 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":
--- a/compiler/concepts.nim
+++ b/compiler/concepts.nim
@@ -11,15 +11,15 @@
 ## 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 ast, astalgo, semdata, lookups, lineinfos, idents, msgs, renderer, types

-import std/sets
+import std/intsets

 when defined(nimPreviewSlimSystem):
  import std/assertions

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

 ## Code dealing with Concept declarations
 ## --------------------------------------
@@ -29,7 +29,7 @@ proc declareSelf(c: PContext; info: TLineInfo) =
  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.flags.incl {tfUnresolved, tfPacked}
  s.typ.add newType(tyEmpty, c.idgen, ow)
  addDecl(c, s, info)

@@ -70,418 +70,157 @@ 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 +230,30 @@ 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 +261,7 @@ 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 +269,12 @@ 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 +307,35 @@ 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
@@ -157,23 +157,12 @@ 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")
-
+  defineSymbol("nimHasSeqsV3")
--- a/compiler/deps.nim
+++ b/compiler/deps.nim
@@ -1,395 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2025 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-## Generate a .build.nif file for nifmake from a Nim project.
-## This enables incremental and parallel compilation using the `m` switch.
-
-import std / [os, tables, sets, times, osproc, strutils]
-import options, msgs, lineinfos, pathutils
-
-import "../dist/nimony/src/lib" / [nifstreams, nifcursors, bitabs, nifreader, nifbuilder]
-import "../dist/nimony/src/gear2" / modnames
-
-type
-  FilePair = object
-    nimFile: string
-    modname: string
-
-  Node = ref object
-    files: seq[FilePair]  # main file + includes
-    deps: seq[int]        # indices into DepContext.nodes
-    id: int
-
-  DepContext = object
-    config: ConfigRef
-    nifler: string
-    nodes: seq[Node]
-    processedModules: Table[string, int]  # modname -> node index
-    includeStack: seq[string]
-    systemNodeId: int  # ID of the system.nim node
-
-proc toPair(c: DepContext; f: string): FilePair =
-  FilePair(nimFile: f, modname: moduleSuffix(f, cast[seq[string]](c.config.searchPaths)))
-
-proc depsFile(c: DepContext; f: FilePair): string =
-  getNimcacheDir(c.config).string / f.modname & ".deps.nif"
-
-proc parsedFile(c: DepContext; f: FilePair): string =
-  getNimcacheDir(c.config).string / f.modname & ".p.nif"
-
-proc semmedFile(c: DepContext; f: FilePair): string =
-  getNimcacheDir(c.config).string / f.modname & ".nif"
-
-proc findNifler(): string =
-  # Look for nifler in common locations
-  let nimDir = getAppDir()
-  result = nimDir / "nifler"
-  if not fileExists(result):
-    result = findExe("nifler")
-
-proc findNifmake(): string =
-  # Look for nifmake in common locations
-  # Try relative to nim executable
-  let nimDir = getAppDir()
-  result = nimDir / "nifmake"
-  if not fileExists(result):
-    result = findExe("nifmake")
-
-proc runNifler(c: DepContext; nimFile: string): bool =
-  ## Run nifler deps on a file if needed. Returns true on success.
-  let pair = c.toPair(nimFile)
-  let depsPath = c.depsFile(pair)
-
-  # Check if deps file is up-to-date
-  if fileExists(depsPath) and fileExists(nimFile):
-    if getLastModificationTime(depsPath) > getLastModificationTime(nimFile):
-      return true  # Already up-to-date
-
-  # Create output directory if needed
-  createDir(parentDir(depsPath))
-
-  # Run nifler deps
-  let cmd = quoteShell(c.nifler) & " deps " & quoteShell(nimFile) & " " & quoteShell(depsPath)
-  let exitCode = execShellCmd(cmd)
-  result = exitCode == 0
-
-proc resolveFile(c: DepContext; origin, toResolve: string): string =
-  ## Resolve an import path relative to origin file
-  # Handle std/ prefix
-  var path = toResolve
-  if path.startsWith("std/"):
-    path = path.substr(4)
-
-  # Try relative to origin first
-  let originDir = parentDir(origin)
-  result = originDir / path.addFileExt("nim")
-  if fileExists(result):
-    return result
-
-  # Try search paths
-  for searchPath in c.config.searchPaths:
-    result = searchPath.string / path.addFileExt("nim")
-    if fileExists(result):
-      return result
-
-  result = ""
-
-proc traverseDeps(c: var DepContext; pair: FilePair; current: Node)
-
-proc processInclude(c: var DepContext; includePath: string; current: Node) =
-  let resolved = resolveFile(c, current.files[current.files.len - 1].nimFile, includePath)
-  if resolved.len == 0 or not fileExists(resolved):
-    return
-
-  # Check for recursive includes
-  for s in c.includeStack:
-    if s == resolved:
-      return  # Skip recursive include
-
-  c.includeStack.add resolved
-  current.files.add c.toPair(resolved)
-  traverseDeps(c, c.toPair(resolved), current)
-  discard c.includeStack.pop()
-
-proc processImport(c: var DepContext; importPath: string; current: Node) =
-  let resolved = resolveFile(c, current.files[0].nimFile, importPath)
-  if resolved.len == 0 or not fileExists(resolved):
-    return
-
-  let pair = c.toPair(resolved)
-  let existingIdx = c.processedModules.getOrDefault(pair.modname, -1)
-
-  if existingIdx == -1:
-    # New module - create node and process it
-    let newNode = Node(files: @[pair], id: c.nodes.len)
-    current.deps.add newNode.id
-    # Every module depends on system.nim
-    if c.systemNodeId >= 0:
-      newNode.deps.add c.systemNodeId
-    c.processedModules[pair.modname] = newNode.id
-    c.nodes.add newNode
-    traverseDeps(c, pair, newNode)
-  else:
-    # Already processed - just add dependency
-    if existingIdx notin current.deps:
-      current.deps.add existingIdx
-
-proc readDepsFile(c: var DepContext; pair: FilePair; current: Node) =
-  ## Read a .deps.nif file and process imports/includes
-  let depsPath = c.depsFile(pair)
-  if not fileExists(depsPath):
-    return
-
-  var s = nifstreams.open(depsPath)
-  defer: nifstreams.close(s)
-  discard processDirectives(s.r)
-
-  var t = next(s)
-  if t.kind != ParLe:
-    return
-
-  # Skip to content (past stmts tag)
-  t = next(s)
-
-  while t.kind != EofToken:
-    if t.kind == ParLe:
-      let tag = pool.tags[t.tagId]
-      case tag
-      of "import", "fromimport":
-        # Read import path
-        t = next(s)
-        # Check for "when" marker (conditional import)
-        if t.kind == Ident and pool.strings[t.litId] == "when":
-          t = next(s)  # skip it, still process the import
-        # Handle path expression (could be ident, string, or infix like std/foo)
-        var importPath = ""
-        if t.kind == Ident:
-          importPath = pool.strings[t.litId]
-        elif t.kind == StringLit:
-          importPath = pool.strings[t.litId]
-        elif t.kind == ParLe and pool.tags[t.tagId] == "infix":
-          # Handle std / foo style imports
-          t = next(s)  # skip infix tag
-          if t.kind == Ident:  # operator (/)
-            t = next(s)
-          if t.kind == Ident:  # first part (std)
-            importPath = pool.strings[t.litId]
-            t = next(s)
-          if t.kind == Ident:  # second part (foo)
-            importPath = importPath & "/" & pool.strings[t.litId]
-        if importPath.len > 0:
-          processImport(c, importPath, current)
-        # Skip to end of import node
-        var depth = 1
-        while depth > 0:
-          t = next(s)
-          if t.kind == ParLe: inc depth
-          elif t.kind == ParRi: dec depth
-      of "include":
-        # Read include path
-        t = next(s)
-        if t.kind == Ident and pool.strings[t.litId] == "when":
-          t = next(s)  # skip conditional marker
-        var includePath = ""
-        if t.kind == Ident:
-          includePath = pool.strings[t.litId]
-        elif t.kind == StringLit:
-          includePath = pool.strings[t.litId]
-        if includePath.len > 0:
-          processInclude(c, includePath, current)
-        # Skip to end
-        var depth = 1
-        while depth > 0:
-          t = next(s)
-          if t.kind == ParLe: inc depth
-          elif t.kind == ParRi: dec depth
-      else:
-        # Skip unknown node
-        var depth = 1
-        while depth > 0:
-          t = next(s)
-          if t.kind == ParLe: inc depth
-          elif t.kind == ParRi: dec depth
-    t = next(s)
-
-proc traverseDeps(c: var DepContext; pair: FilePair; current: Node) =
-  ## Process a module: run nifler and read deps
-  if not runNifler(c, pair.nimFile):
-    rawMessage(c.config, errGenerated, "nifler failed for: " & pair.nimFile)
-    return
-  readDepsFile(c, pair, current)
-
-proc generateBuildFile(c: DepContext): string =
-  ## Generate the .build.nif file for nifmake
-  let nimcache = getNimcacheDir(c.config).string
-  createDir(nimcache)
-  result = nimcache / c.nodes[0].files[0].modname & ".build.nif"
-
-  var b = nifbuilder.open(result)
-  defer: b.close()
-
-  b.addHeader("nim ic", "nifmake")
-  b.addTree "stmts"
-
-  # Define nifler command
-  b.addTree "cmd"
-  b.addSymbolDef "nifler"
-  b.addStrLit c.nifler
-  b.addStrLit "parse"
-  b.addStrLit "--deps"
-  b.addTree "input"
-  b.endTree()
-  b.addTree "output"
-  b.endTree()
-  b.endTree()
-
-  # Define nim m command
-  b.addTree "cmd"
-  b.addSymbolDef "nim_m"
-  b.addStrLit getAppFilename()
-  b.addStrLit "m"
-  b.addStrLit "--nimcache:" & nimcache
-  # Add search paths
-  for p in c.config.searchPaths:
-    b.addStrLit "--path:" & p.string
-  b.addTree "args"
-  b.endTree()
-  b.withTree "input":
-    b.addIntLit 0  # main parsed file
-  b.endTree()
-
-  # Define nim nifc command
-  b.addTree "cmd"
-  b.addSymbolDef "nim_nifc"
-  b.addStrLit getAppFilename()
-  b.addStrLit "nifc"
-  b.addStrLit "--nimcache:" & nimcache
-  # Add search paths
-  for p in c.config.searchPaths:
-    b.addStrLit "--path:" & p.string
-  b.addTree "input"
-  b.addIntLit 0
-  b.endTree()
-  b.endTree()
-
-  # Build rules for parsing (nifler)
-  var seenFiles = initHashSet[string]()
-  for node in c.nodes:
-    for pair in node.files:
-      let parsed = c.parsedFile(pair)
-      if not seenFiles.containsOrIncl(parsed):
-        b.addTree "do"
-        b.addIdent "nifler"
-        b.addTree "input"
-        b.addStrLit pair.nimFile
-        b.endTree()
-        b.addTree "output"
-        b.addStrLit parsed
-        b.endTree()
-        b.addTree "output"
-        b.addStrLit c.depsFile(pair)
-        b.endTree()
-        b.endTree()
-
-  # Build rules for semantic checking (nim m)
-  for i in countdown(c.nodes.len - 1, 0):
-    let node = c.nodes[i]
-    let pair = node.files[0]
-    b.addTree "do"
-    b.addIdent "nim_m"
-    # Input: all parsed files for this module
-    b.withTree "input":
-      b.addStrLit node.files[0].nimFile
-    for f in node.files:
-      b.addTree "input"
-      b.addStrLit c.parsedFile(f)
-      b.endTree()
-    # Also depend on semmed files of dependencies
-    for depIdx in node.deps:
-      b.addTree "input"
-      b.addStrLit c.semmedFile(c.nodes[depIdx].files[0])
-      b.endTree()
-    # Output: semmed file
-    b.addTree "output"
-    b.addStrLit c.semmedFile(pair)
-    b.endTree()
-    b.endTree()
-
-  # Final compilation step: generate executable from main module
-  let mainNif = c.nodes[0].files[0].nimFile
-  let exeFile = changeFileExt(c.nodes[0].files[0].nimFile, ExeExt)
-  b.addTree "do"
-  b.addIdent "nim_nifc"
-  # Input: .nim file (expanded as argument) and .nif file (dependency)
-  b.addTree "input"
-  b.addStrLit mainNif
-  b.endTree()
-  b.addTree "output"
-  b.addStrLit exeFile
-  b.endTree()
-  b.endTree()
-
-  b.endTree()  # stmts
-
-proc commandIc*(conf: ConfigRef) =
-  ## Main entry point for `nim ic`
-  when not defined(nimKochBootstrap):
-    let nifler = findNifler()
-    if nifler.len == 0:
-      rawMessage(conf, errGenerated, "nifler tool not found. Install nimony or add nifler to PATH.")
-      return
-
-    let projectFile = conf.projectFull.string
-    if not fileExists(projectFile):
-      rawMessage(conf, errGenerated, "project file not found: " & projectFile)
-      return
-
-    # Create nimcache directory
-    createDir(getNimcacheDir(conf).string)
-
-    var c = DepContext(
-      config: conf,
-      nifler: nifler,
-      nodes: @[],
-      processedModules: initTable[string, int](),
-      includeStack: @[],
-      systemNodeId: -1
-    )
-
-    # Create root node for main project file
-    let rootPair = c.toPair(projectFile)
-    let rootNode = Node(files: @[rootPair], id: 0)
-    c.nodes.add rootNode
-    c.processedModules[rootPair.modname] = 0
-
-    # model the system.nim dependency:
-    let sysNode = Node(files: @[toPair(c, (conf.libpath / RelativeFile"system.nim").string)], id: 1)
-    c.nodes.add sysNode
-    c.systemNodeId = sysNode.id
-    rootNode.deps.add sysNode.id
-
-    # Process dependencies
-    traverseDeps(c, rootPair, rootNode)
-
-    # Generate build file
-    let buildFile = generateBuildFile(c)
-    rawMessage(conf, hintSuccess, "generated: " & buildFile)
-
-    # Automatically run nifmake
-    let nifmake = findNifmake()
-    if nifmake.len == 0:
-      rawMessage(conf, hintSuccess, "run: nifmake run " & buildFile)
-    else:
-      let cmd = quoteShell(nifmake) & " run " & quoteShell(buildFile)
-      rawMessage(conf, hintExecuting, cmd)
-      let exitCode = execShellCmd(cmd)
-      if exitCode != 0:
-        rawMessage(conf, errGenerated, "nifmake failed with exit code: " & $exitCode)
-  else:
-    rawMessage(conf, errGenerated, "nim ic not available in bootstrap build")
--- a/compiler/dfa.nim
+++ b/compiler/dfa.nim
@@ -46,10 +46,10 @@ 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 +181,14 @@ 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 +213,7 @@ 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 +324,7 @@ 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 +380,7 @@ 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 +390,7 @@ 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 +449,8 @@ 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 +493,7 @@ 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
@@ -19,7 +19,7 @@ import
  wordrecg, syntaxes, renderer, lexer,
  packages/docutils/[rst, rstidx, rstgen, dochelpers],
  trees, types,
-  typesrenderer, lineinfos,
+  typesrenderer, astalgo, lineinfos,
  pathutils, nimpaths, renderverbatim, packages
 import packages/docutils/rstast except FileIndex, TLineInfo

@@ -115,7 +115,7 @@ 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 +148,7 @@ 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 +289,7 @@ 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 +433,6 @@ 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 +537,10 @@ 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 +830,8 @@ 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 +849,7 @@ 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 +863,7 @@ 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 +1000,8 @@ 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 +1030,7 @@ 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 +1058,7 @@ 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 +1085,6 @@ 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 +1095,10 @@ 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 +1121,18 @@ 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 +1153,8 @@ 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 +1162,15 @@ 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 +1199,8 @@ 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 +1401,14 @@ 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
@@ -1900,9 +1882,6 @@ 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 +1902,8 @@ 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
@@ -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)

@@ -47,7 +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}
+  incl result.flags, sfFromGeneric
+  incl result.flags, sfNeverRaises

 proc searchObjCaseImpl(obj: PNode; field: PSym): PNode =
  case obj.kind
@@ -66,8 +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 =
@@ -109,4 +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/evalffi.nim
+++ b/compiler/evalffi.nim
@@ -99,7 +99,7 @@ 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 +126,16 @@ 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 +234,19 @@ 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 +304,9 @@ 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 +387,7 @@ 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 +405,7 @@ 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 +434,7 @@ 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 +444,7 @@ 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 +453,15 @@ 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 +474,7 @@ 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
@@ -17,8 +17,8 @@ type
    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
@@ -55,8 +55,8 @@ proc expandDefaultN(n: PNode; info: TLineInfo; res: PNode) =
    discard

 proc expandDefaultObj(t: PType; info: TLineInfo; res: PNode) =
-  if t.baseClass != nil:
-    expandDefaultObj(t.baseClass, info, res)
+  if t[0] != nil:
+    expandDefaultObj(t[0], info, res)
  expandDefaultN(t.n, info, res)

 proc expandDefault(t: PType; info: TLineInfo): PNode =
@@ -82,13 +82,13 @@ proc expandDefault(t: PType; info: TLineInfo): PNode =
    result = newZero(t, info, nkIntLit)
  of tyRange:
    # Could use low(T) here to finally fix old language quirks
-    result = expandDefault(skipModifier t, info)
+    result = expandDefault(t[0], info)
  of tyVoid: result = newZero(t, info, nkEmpty)
  of tySink, tyGenericInst, tyDistinct, tyAlias, tyOwned:
-    result = expandDefault(t.skipModifier, info)
+    result = expandDefault(t.lastSon, info)
  of tyOrdinal, tyGenericBody, tyGenericParam, tyInferred, tyStatic:
-    if t.hasElementType:
-      result = expandDefault(t.skipModifier, info)
+    if t.len > 0:
+      result = expandDefault(t.lastSon, info)
    else:
      result = newZero(t, info, nkEmpty)
  of tyFromExpr:
@@ -100,16 +100,16 @@ proc expandDefault(t: PType; info: TLineInfo): PNode =
    result = newZero(t, info, nkBracket)
    let n = toInt64(lengthOrd(nil, t))
    for i in 0..<n:
-      result.add expandDefault(t.elementType, info)
+      result.add expandDefault(t[1], info)
  of tyPtr, tyRef, tyProc, tyPointer, tyCstring:
    result = newZero(t, info, nkNilLit)
  of tyVar, tyLent:
-    let e = t.elementType
+    let e = t.lastSon
    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)
+      result = newZero(t.lastSon, info, nkNilLit)
  of tySet:
    result = newZero(t, info, nkCurly)
  of tyObject:
@@ -118,14 +118,14 @@ proc expandDefault(t: PType; info: TLineInfo): PNode =
    expandDefaultObj(t, info, result)
  of tyTuple:
    result = newZero(t, info, nkTupleConstr)
-    for it in t.kids:
+    for it in t:
      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,
+     tyNil, tyGenericInvocation, tyProxy, 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

@@ -63,7 +63,7 @@ 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
@@ -162,11 +162,7 @@ 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 +172,6 @@ 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 +237,8 @@ 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 +285,7 @@ const
    envcc(),
    icl(),
    icc(),
-    clangcl(),
-    hipcc(),
-    nvcc()]
+    clangcl()]

  hExt* = ".h"

@@ -341,7 +319,7 @@ 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, backendNir: discard
  of backendInvalid:
    # during parsing of cfg files; we don't know the backend yet, no point in
    # guessing wrong thing
@@ -474,11 +452,6 @@ 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 +759,7 @@ 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 +783,6 @@ 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 +967,6 @@ 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 +982,10 @@ 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 +999,7 @@ 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 +1020,11 @@ 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 +1045,6 @@ 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 +1061,7 @@ 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/guards.nim
+++ b/compiler/guards.nim
@@ -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:
@@ -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 +1,178 @@
+## A BiTable is a table that can be seen as an optimized pair
+## of `(Table[LitId, Val], Table[Val, LitId])`.
+
+import std/hashes
+import 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 = 1
+
+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)
+
+proc sizeOnDisc*(t: BiTable[string]): int =
+  result = 4
+  for x in t.vals:
+    result += x.len + 4
+  result += t.keys.len * sizeof(LitId)
+
+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 +1,180 @@
+#
+#
+#           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)
+
+  finalCodegenActions(g, bmod, newNodeI(nkStmtList, m.module.info))
+  for disp in getDispatchers(g):
+    genProcAux(bmod, disp)
+  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..<len(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..<len(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..<len(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, tree[n].soperand)
+  of nkModuleRef:
+    let (n1, n2) = sons2(tree, n)
+    assert n1.kind == nkNone
+    assert n2.kind == nkNone
+    let m = n1.litId
+    let item = tree[n2].soperand
+    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 = tree[n.firstSon].soperand
+      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(len(g)-1, 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 +1,155 @@
+#
+#
+#           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 std/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) =
+  let t = findType(tree, n)
+  if t != nilItemId:
+    checkType(c, t)
+  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[n].soperand)
+  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 == nkNone
+    assert n2.kind == nkNone
+    checkForeignSym(c, PackedItemId(module: n1.litId, item: tree[n2].soperand))
+  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)]
+    methodsPerGenericType*: seq[(PackedItemId, int, PackedItemId)]
+    enumToStringProcs*: seq[(PackedItemId, PackedItemId)]
+    methodsPerType*: seq[(PackedItemId, PackedItemId)]
+    dispatchers*: seq[PackedItemId]
+  ]#
+
+proc checkIntegrity*(g: ModuleGraph) =
+  var c = CheckedContext(g: g)
+  for i in 0..<len(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 +1,183 @@
+#
+#
+#           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 std/sets
+
+from std/os import nil
+from std/private/miscdollars import toLocation
+
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
+import ".." / [ast, modulegraphs, msgs, options]
+import ".." / nir / nirlineinfos
+import packed_ast, bitabs, ic
+
+type
+  UnpackedLineInfo = object
+    file: LitId
+    line, col: int
+  NavContext = object
+    g: ModuleGraph
+    thisModule: int32
+    trackPos: UnpackedLineInfo
+    alreadyEmitted: HashSet[string]
+    outputSep: char # for easier testing, use short filenames and spaces instead of tabs.
+
+proc isTracked(man: LineInfoManager; current: PackedLineInfo, trackPos: UnpackedLineInfo, tokenLen: int): bool =
+  let (currentFile, currentLine, currentCol) = man.unpack(current)
+  if currentFile == trackPos.file and currentLine == trackPos.line:
+    let col = trackPos.col
+    if col >= currentCol and col < currentCol+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(c.g.packed[c.thisModule].fromDisk.man, 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(c.g.packed[c.thisModule].fromDisk.man, 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..<len(tree):
+    let i = NodePos(i)
+    case tree[i].kind
+    of nkSym:
+      let item = tree[i].soperand
+      if searchLocalSym(c, c.g.packed[c.thisModule].fromDisk.syms[item], tree[i].info):
+        return ItemId(module: c.thisModule, item: item)
+    of nkModuleRef:
+      let (currentFile, currentLine, currentCol) = c.g.packed[c.thisModule].fromDisk.man.unpack(tree[i].info)
+      if currentLine == c.trackPos.line and currentFile == c.trackPos.file:
+        let (n1, n2) = sons2(tree, i)
+        assert n1.kind == nkInt32Lit
+        assert n2.kind == nkInt32Lit
+        let pId = PackedItemId(module: n1.litId, item: tree[n2].soperand)
+        let itemId = translateId(pId, c.g.packed, c.thisModule, c.g.config)
+        if searchForeignSym(c, itemId, tree[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].kind in declarativeNodes
+
+proc usage(c: var NavContext; info: PackedLineInfo; isDecl: bool) =
+  let (fileId, line, col) = unpack(c.g.packed[c.thisModule].fromDisk.man, info)
+  var m = ""
+  var file = c.g.packed[c.thisModule].fromDisk.strings[fileId]
+  if c.outputSep == ' ':
+    file = os.extractFilename file
+  toLocation(m, file, line, col + 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..<len(tree):
+    let i = NodePos(i)
+    case tree[i].kind
+    of nkSym:
+      let item = tree[i].soperand
+      if sym.item == item and sym.module == c.thisModule:
+        usage(c, tree[i].info, isDecl(tree, parent(i)))
+    of nkModuleRef:
+      let (n1, n2) = sons2(tree, i)
+      assert n1.kind == nkNone
+      assert n2.kind == nkNone
+      let pId = PackedItemId(module: n1.litId, item: tree[n2].soperand)
+      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[i].info, isDecl(tree, parent(i)))
+    else: discard
+
+proc searchForIncludeFile(g: ModuleGraph; fullPath: string): int =
+  for i in 0..<len(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: UnpackedLineInfo(line: unpacked.line.int, col: unpacked.col.int, 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..<len(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..<len(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 +1,365 @@
+#
+#
+#           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 std/[hashes, tables, strtabs]
+import bitabs, rodfiles
+import ".." / [ast, options]
+
+import ".." / nir / nirlineinfos
+
+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: 0.int32)
+
+const
+  emptyNodeId* = NodeId(-1)
+
+type
+  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     # 8 bytes
+    x: uint32
+    info*: PackedLineInfo
+
+  PackedTree* = object ## usually represents a full Nim module
+    nodes: seq[PackedNode]
+    withFlags: seq[(int32, TNodeFlags)]
+    withTypes: seq[(int32, PackedItemId)]
+
+  PackedInstantiation* = object
+    key*, sym*: PackedItemId
+    concreteTypes*: seq[PackedItemId]
+
+const
+  NodeKindBits = 8'u32
+  NodeKindMask = (1'u32 shl NodeKindBits) - 1'u32
+
+template kind*(n: PackedNode): TNodeKind = TNodeKind(n.x and NodeKindMask)
+template uoperand*(n: PackedNode): uint32 = (n.x shr NodeKindBits)
+template soperand*(n: PackedNode): int32 = int32(uoperand(n))
+
+template toX(k: TNodeKind; operand: uint32): uint32 =
+  uint32(k) or (operand shl NodeKindBits)
+
+template toX(k: TNodeKind; operand: LitId): uint32 =
+  uint32(k) or (operand.uint32 shl NodeKindBits)
+
+template typeId*(n: PackedNode): PackedItemId = n.typ
+
+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
+
+proc addIdent*(tree: var PackedTree; s: LitId; info: PackedLineInfo) =
+  tree.nodes.add PackedNode(x: toX(nkIdent, uint32(s)), info: info)
+
+proc addSym*(tree: var PackedTree; s: int32; info: PackedLineInfo) =
+  tree.nodes.add PackedNode(x: toX(nkSym, cast[uint32](s)), info: info)
+
+proc addSymDef*(tree: var PackedTree; s: SymId; info: PackedLineInfo) =
+  tree.nodes.add PackedNode(x: toX(nkSym, cast[uint32](s)), info: info)
+
+proc isAtom*(tree: PackedTree; pos: int): bool {.inline.} = tree.nodes[pos].kind <= nkNilLit
+
+type
+  PatchPos = distinct int
+
+proc addNode*(t: var PackedTree; kind: TNodeKind; operand: int32;
+              typeId: PackedItemId = nilItemId; info: PackedLineInfo;
+              flags: TNodeFlags = {}) =
+  t.nodes.add PackedNode(x: toX(kind, cast[uint32](operand)), info: info)
+  if flags != {}:
+    t.withFlags.add (t.nodes.len.int32 - 1, flags)
+  if typeId != nilItemId:
+    t.withTypes.add (t.nodes.len.int32 - 1, typeId)
+
+proc prepare*(tree: var PackedTree; kind: TNodeKind; flags: TNodeFlags; typeId: PackedItemId; info: PackedLineInfo): PatchPos =
+  result = PatchPos tree.nodes.len
+  tree.addNode(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
+  let k = tree.nodes[pos].kind
+  assert k > nkNilLit
+  let distance = int32(tree.nodes.len - pos)
+  assert distance > 0
+  tree.nodes[pos].x = toX(k, cast[uint32](distance))
+
+proc len*(tree: PackedTree): int {.inline.} = tree.nodes.len
+
+proc `[]`*(tree: PackedTree; i: NodePos): lent PackedNode {.inline.} =
+  tree.nodes[i.int]
+
+template rawSpan(n: PackedNode): int = int(uoperand(n))
+
+proc nextChild(tree: PackedTree; pos: var int) {.inline.} =
+  if tree.nodes[pos].kind > nkNilLit:
+    assert tree.nodes[pos].uoperand > 0
+    inc pos, tree.nodes[pos].rawSpan
+  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].rawSpan
+  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].rawSpan
+  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].rawSpan
+  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].rawSpan - 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].uoperand
+proc info*(tree: PackedTree; n: NodePos): PackedLineInfo {.inline.} =
+  tree.nodes[n.int].info
+
+proc findType*(tree: PackedTree; n: NodePos): PackedItemId =
+  for x in tree.withTypes:
+    if x[0] == int32(n): return x[1]
+    if x[0] > int32(n): return nilItemId
+  return nilItemId
+
+proc findFlags*(tree: PackedTree; n: NodePos): TNodeFlags =
+  for x in tree.withFlags:
+    if x[0] == int32(n): return x[1]
+    if x[0] > int32(n): return {}
+  return {}
+
+template typ*(n: NodePos): PackedItemId =
+  tree.findType(n)
+template flags*(n: NodePos): TNodeFlags =
+  tree.findFlags(n)
+
+template uoperand*(n: NodePos): uint32 =
+  tree.nodes[n.int].uoperand
+
+proc span*(tree: PackedTree; pos: int): int {.inline.} =
+  if isAtom(tree, pos): 1 else: tree.nodes[pos].rawSpan
+
+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].uoperand
+
+template symId*(n: NodePos): SymId = SymId tree.nodes[n.int].soperand
+
+proc firstSon*(n: NodePos): NodePos {.inline.} = NodePos(n.int+1)
+
+const
+  externIntLit* = {nkCharLit,
+    nkIntLit,
+    nkInt8Lit,
+    nkInt16Lit,
+    nkInt32Lit,
+    nkInt64Lit,
+    nkUIntLit,
+    nkUInt8Lit,
+    nkUInt16Lit,
+    nkUInt32Lit,
+    nkUInt64Lit}
+
+  externSIntLit* = {nkIntLit, nkInt8Lit, nkInt16Lit, nkInt32Lit, nkInt64Lit}
+  externUIntLit* = {nkUIntLit, nkUInt8Lit, nkUInt16Lit, nkUInt32Lit, nkUInt64Lit}
+  directIntLit* = nkNone
+
+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
+
+proc getNodeId*(tree: PackedTree): NodeId {.inline.} = NodeId tree.nodes.len
+
+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)
+
+proc load*(f: var RodFile; t: var PackedTree) =
+  loadSeq f, t.nodes
+  loadSeq f, t.withFlags
+  loadSeq f, t.withTypes
+
+proc store*(f: var RodFile; t: PackedTree) =
+  storeSeq f, t.nodes
+  storeSeq f, t.withFlags
+  storeSeq f, t.withTypes
--- a/compiler/ic/replayer.nim
+++ b/compiler/ic/replayer.nim
@@ -19,6 +19,8 @@ import std/tables
 when defined(nimPreviewSlimSystem):
  import std/assertions

+import packed_ast, ic, bitabs
+
 proc replayStateChanges*(module: PSym; g: ModuleGraph) =
  let list = module.ast
  assert list != nil
@@ -86,3 +88,84 @@ proc replayStateChanges*(module: PSym; g: ModuleGraph) =
          g.cacheSeqs[destKey].add val
      else:
        internalAssert g.config, false
+
+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)
+
+  for it in mitems(g.packed[module].fromDisk.methodsPerType):
+    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.methodsPerType.mgetOrPut(key, @[]).add LazySym(id: symId, sym: nil)
+
+  for it in mitems(g.packed[module].fromDisk.dispatchers):
+    let tmp = translateId(it, g.packed, module, g.config)
+    let symId = FullId(module: tmp.module, packed: it)
+    g.dispatchers.add 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.methodsPerGenericType):
+    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.methodsPerGenericType.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 +1,256 @@
+#
+#
+#           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 std/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
+    methodsPerGenericTypeSection
+    enumToStringProcsSection
+    methodsPerTypeSection
+    dispatchersSection
+    typeInfoSection  # required by the backend
+    backendFlagsSection
+    aliveSymsSection # beware, this is stored in a `.alivesyms` file.
+    sideChannelSection
+    namespaceSection
+    symnamesSection
+
+  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 = 2
+  defaultCookie = [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; cookie = defaultCookie) =
+  ## 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; cookie = defaultCookie) =
+  ## 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/importer.nim
+++ b/compiler/importer.nim
@@ -10,7 +10,7 @@
 ## This module implements the symbol importing mechanism.

 import
-  ast, msgs, options, idents, lookups,
+  ast, astalgo, msgs, options, idents, lookups,
  semdata, modulepaths, sigmatch, lineinfos,
  modulegraphs, wordrecg
 from std/strutils import `%`, startsWith
@@ -108,8 +108,8 @@ 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 +144,7 @@ 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 +190,22 @@ 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 +231,7 @@ 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 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 +245,13 @@ 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 +286,10 @@ 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
@@ -308,15 +306,7 @@ proc myImportModule(c: PContext, n: var PNode, importStmtResult: PNode): PSym =
    if belongsToStdlib(c.graph, result) and not startsWith(moduleName, stdPrefix) and
        not startsWith(moduleName, "system/") and not startsWith(moduleName, "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:
@@ -335,7 +325,7 @@ 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 +362,7 @@ 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 +377,7 @@ 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
@@ -24,7 +24,7 @@ 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 +69,12 @@ 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 +100,6 @@ 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 +162,12 @@ 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 +184,10 @@ 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 +196,7 @@ 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 '\''
@@ -230,7 +221,7 @@ proc makePtrType(c: var Con, baseType: PType): PType =

 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))
@@ -255,12 +246,7 @@ 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 =
@@ -288,7 +274,7 @@ 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
@@ -304,7 +290,7 @@ 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:
@@ -313,7 +299,7 @@ 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.
@@ -330,15 +316,14 @@ 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:
@@ -373,7 +358,7 @@ 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))
@@ -413,7 +398,7 @@ 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 & ")")
@@ -426,10 +411,7 @@ 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)
@@ -459,64 +441,62 @@ 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:
@@ -533,7 +513,7 @@ 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)
@@ -573,7 +553,7 @@ 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))
@@ -612,11 +592,9 @@ 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:
@@ -668,7 +646,7 @@ 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)
@@ -716,7 +694,7 @@ 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)
@@ -773,10 +751,10 @@ 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
@@ -791,18 +769,6 @@ 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)
-
 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}:
@@ -816,7 +782,15 @@ 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
@@ -836,9 +810,6 @@ 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)
@@ -882,25 +853,31 @@ 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 or (hasDestructor(c, t) and
+        getAttachedOp(c.graph, t, attachedDestructor) != nil and
+        sfOverridden in getAttachedOp(c.graph, t, attachedDestructor).flags)):
        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
@@ -909,19 +886,13 @@ 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:
@@ -929,17 +900,14 @@ 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:
@@ -949,9 +917,6 @@ 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):
@@ -967,15 +932,7 @@ 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
@@ -1004,13 +961,6 @@ 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 {nkStmtListExpr, nkBlockExpr, nkIfExpr, nkCaseStmt, nkTryStmt, nkPragmaBlock}:
-        # Distribute the assignment into each branch to avoid
-        # creating pointless temporaries for expression-based control flow.
-        let dest = p(n[0], c, s, mode)
-        template process(child, s): untyped =
-          newTree(n.kind, dest, p(child, c, s, consumed))
-        handleNestedTempl(n[1], process, willProduceStmt = true)
      else:
        result = copyNode(n)
        result.add p(n[0], c, s, mode)
@@ -1154,25 +1104,6 @@ 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
@@ -1199,7 +1130,7 @@ 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):
@@ -1217,7 +1148,7 @@ 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):
@@ -1225,7 +1156,7 @@ 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:
@@ -1235,9 +1166,9 @@ 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))
@@ -1246,24 +1177,17 @@ 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)
@@ -1273,7 +1197,7 @@ 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) =
@@ -1302,55 +1226,6 @@ 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"
@@ -1364,24 +1239,15 @@ 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
@@ -80,7 +80,6 @@ Files: "lib"
 Files: "examples"
 Files: "dist/nimble"
 Files: "dist/checksums"
-Files: "dist/nimony"

 Files: "tests"

@@ -148,4 +147,4 @@ 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
@@ -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)
@@ -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
@@ -54,18 +54,18 @@ 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 +119,14 @@ 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 +164,7 @@ 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/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
@@ -145,14 +145,11 @@ 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:
@@ -160,8 +157,8 @@ 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 addHiddenParam(routine: PSym, param: PSym) =
@@ -175,23 +172,26 @@ 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
+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
@@ -200,7 +200,7 @@ 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:
@@ -216,10 +216,6 @@ 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))
@@ -232,19 +228,28 @@ 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)
@@ -259,7 +264,8 @@ 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:
@@ -280,6 +286,15 @@ 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) =
@@ -289,12 +304,12 @@ 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])
-  incl(owner.typ, tfCapturesEnv)
+  incl(owner.typ.flags, tfCapturesEnv)
  if not isEnv:
    owner.typ.callConv = ccClosure

@@ -327,20 +342,16 @@ 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, 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.flags.incl tfHasOwned
    result.rawAddSon t
  else:
    result = t
@@ -412,37 +423,19 @@ 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:
@@ -461,12 +454,22 @@ proc detectCapturedVars(n: PNode; owner: PSym; c: var DetectionPass) =
        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 """
@@ -548,8 +551,8 @@ 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:
@@ -557,7 +560,6 @@ 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

@@ -569,7 +571,7 @@ 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)
@@ -640,7 +642,7 @@ 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:
@@ -666,27 +668,16 @@ 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:
@@ -695,14 +686,12 @@ 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:
@@ -736,7 +725,7 @@ 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)
@@ -783,6 +772,8 @@ 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,
@@ -891,18 +882,19 @@ proc liftIterToProc*(g: ModuleGraph; fn: PSym; body: PNode; ptrType: PType;

 proc liftLambdas*(g: ModuleGraph; fn: PSym, body: PNode; tooEarly: var bool;
                  idgen: IdGenerator; flags: TransformFlags): 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):

    # 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)
@@ -991,20 +983,6 @@ 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))
@@ -1015,15 +993,12 @@ 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
@@ -300,7 +300,8 @@ 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 +317,6 @@ 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 +492,6 @@ 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:
@@ -923,7 +897,7 @@ 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

--- a/compiler/liftdestructors.nim
+++ b/compiler/liftdestructors.nim
@@ -56,10 +56,10 @@ 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 +91,7 @@ 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 +139,34 @@ 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 +205,7 @@ 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 +216,20 @@ 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 +258,7 @@ 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 +266,7 @@ 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 +279,6 @@ 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 +288,7 @@ 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 +302,27 @@ 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 +344,6 @@ 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 +357,7 @@ 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 +383,7 @@ 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 +499,7 @@ 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 +509,13 @@ 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)
@@ -603,7 +545,7 @@ 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:
@@ -620,34 +562,11 @@ 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:
    body.add setLenSeqCall(c, t, x, y)
-    if supportsCopyMem(t.elementType):
-      genBulkCopySeq(c, t, body, x, y)
-    else:
-      forallElements(c, t, body, x, y)
+    forallElements(c, t, body, x, y)
  of attachedAsgn, attachedDeepCopy:
    # we generate:
    # if x.p == y.p:
@@ -656,13 +575,9 @@ 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)
    body.add setLenSeqCall(c, t, x, y)
-    if supportsCopyMem(t.elementType):
-      genBulkCopySeq(c, t, body, x, y)
-    else:
-      forallElements(c, t, body, x, y)
+    forallElements(c, t, body, x, y)
  of attachedSink:
    let moveCall = genBuiltin(c, mMove, "move", x)
    moveCall.add y
@@ -677,7 +592,7 @@ 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)
@@ -715,7 +630,7 @@ 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)
@@ -728,27 +643,20 @@ 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.isDefined("nimsso"):
-      # 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

@@ -771,43 +679,14 @@ 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
@@ -872,7 +751,7 @@ 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)
@@ -889,26 +768,7 @@ 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)
@@ -941,6 +801,7 @@ 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:
@@ -957,7 +818,7 @@ 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
@@ -985,12 +846,12 @@ 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)

@@ -1013,7 +874,7 @@ 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:
@@ -1025,7 +886,7 @@ 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
@@ -1053,7 +914,7 @@ 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)
@@ -1071,7 +932,7 @@ 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
@@ -1080,7 +941,7 @@ proc fillBody(c: var TLiftCtx; t: PType; body, x, y: PNode) =
      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):
@@ -1089,7 +950,7 @@ 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)
@@ -1121,13 +982,9 @@ 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:
@@ -1144,18 +1001,23 @@ 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:
@@ -1164,7 +1026,7 @@ 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:
@@ -1172,14 +1034,14 @@ 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)
@@ -1202,7 +1064,7 @@ proc symDupPrototype(g: ModuleGraph; typ: PType; owner: PSym; kind: TTypeAttache

  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)
@@ -1216,7 +1078,8 @@ 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}
+  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 =
@@ -1229,8 +1092,8 @@ 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 g.config.selectedGC in {gcArc, gcOrc, gcAtomicArc} and
+     ((g.config.isDefined("nimPreviewNonVarDestructor") and not isDiscriminant) or typ.kind in {tyRef, tyString, tySequence}):
    dest.typ = typ
  else:
    dest.typ = makeVarType(typ.owner, typ, idgen)
@@ -1245,7 +1108,7 @@ proc symPrototype(g: ModuleGraph; typ: PType; owner: PSym; kind: TTypeAttachedOp
  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)
@@ -1258,11 +1121,11 @@ 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
+    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)
@@ -1274,17 +1137,7 @@ 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:
@@ -1294,7 +1147,7 @@ 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)
@@ -1305,48 +1158,28 @@ 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)


@@ -1371,9 +1204,7 @@ 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) =
@@ -1408,7 +1239,7 @@ 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;
@@ -1417,13 +1248,7 @@ 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
@@ -1443,13 +1268,13 @@ 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]:
@@ -1465,9 +1290,8 @@ 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/lineinfos.nim
+++ b/compiler/lineinfos.nim
@@ -92,14 +92,8 @@ type
    warnStmtListLambda = "StmtListLambda",
    warnBareExcept = "BareExcept",
    warnImplicitDefaultValue = "ImplicitDefaultValue",
-    warnIgnoredSymbolInjection = "IgnoredSymbolInjection",
-    warnStdPrefix = "StdPrefix",
-    warnUnknownNotes = "UnknownNotes",
-    warnLongLiterals = "LongLiterals",
+    warnStdPrefix = "StdPrefix"
    warnUser = "User",
-    warnGlobalVarConstructorTemporary = "GlobalVarConstructorTemporary",
-    warnImplicitRangeConversion = "ImplicitRangeConversion",
-    warnSystemRangeConversion = "SystemRangeConversion",
    # hints
    hintSuccess = "Success", hintSuccessX = "SuccessX",
    hintCC = "CC",
@@ -113,9 +107,9 @@ type
    hintSource = "Source", hintPerformance = "Performance", hintStackTrace = "StackTrace",
    hintGCStats = "GCStats", hintGlobalVar = "GlobalVar", hintExpandMacro = "ExpandMacro",
    hintUser = "User", hintUserRaw = "UserRaw", hintExtendedContext = "ExtendedContext",
-    hintUnknownRaises = "UnknownRaises",
    hintMsgOrigin = "MsgOrigin", # since 1.3.5
    hintDeclaredLoc = "DeclaredLoc", # since 1.5.1
+    hintUnknownHint = "UnknownHint"

 const
  MsgKindToStr*: array[TMsgKind, string] = [
@@ -202,14 +196,8 @@ 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",
    hintSuccess: "operation successful: $#",
    # keep in sync with `testament.isSuccess`
    hintSuccessX: "$build\n$loc lines; ${sec}s; $mem; proj: $project; out: $output",
@@ -243,9 +231,9 @@ const
    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",
+    hintUnknownHint: "unknown hint: $1"
  ]

 const
@@ -264,9 +252,9 @@ 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, warnStdPrefix}
  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,
@@ -276,13 +264,8 @@ 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
@@ -301,7 +284,6 @@ 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/compiler/llstream.nim
+++ b/compiler/llstream.nim
@@ -11,7 +11,7 @@

 import
  pathutils
-import std/strutils
+
 when defined(nimPreviewSlimSystem):
  import std/syncio

@@ -68,7 +68,6 @@ when not declared(readLineFromStdin):
  # fallback implementation:
  proc readLineFromStdin(prompt: string, line: var string): bool =
    stdout.write(prompt)
-    stdout.flushFile()
    result = readLine(stdin, line)
    if not result:
      stdout.write("\n")
@@ -86,47 +85,6 @@ const
  LineContinuationOprs = {'+', '-', '*', '/', '\\', '<', '>', '!', '?', '^',
                          '|', '%', '&', '$', '@', '~', ','}
  AdditionalLineContinuationOprs = {'#', ':', '='}
-  LineContinuationTokens = [
-    "let", "var", "const", "type",  # section
-    "object", "tuple",
-    # from ./layouter.oprSet
-    "div", "mod", "shl", "shr", "in", "notin", "is",
-    "isnot", "not", "of", "as", "from", "..", "and", "or", "xor", 
-  ]  # must be all `nimIdentNormalized`-ed
-
-proc eqIdent(a, bNormalized: string): bool =
-  a.nimIdentNormalize == bNormalized
-
-proc endsWithIdent(s, subs: string): bool =
-  let le = subs.len
-  if le > s.len: return false
-  s[^le .. ^1].eqIdent subs
-
-proc continuesWithIdent(s, subs: string, start: int): bool =
-  s.substr(start, start+subs.high).eqIdent subs
-
-proc endsWithIdent(s, subs: string, endIdx: var int): bool =
-  endIdx.dec subs.len
-  result = s.continuesWithIdent(subs, endIdx+1)
-
-proc containsObjectOf(x: string): bool =
-  const sep = ' '
-  var idx = x.rfind(sep)
-  if idx == -1: return
-  template eatWord(word) =  
-    while x[idx] == sep: idx.dec
-    result = x.endsWithIdent(word, idx)
-    if not result: return
-  eatWord "of"
-  eatWord "object"
-  result = true
-
-proc endsWithLineContinuationToken(x: string): bool =
-  result = false
-  for tok in LineContinuationTokens:
-    if x.endsWithIdent(tok):
-      return true
-  result = x.containsObjectOf

 proc endsWithOpr*(x: string): bool =
  result = x.endsWith(LineContinuationOprs)
@@ -134,9 +92,7 @@ proc endsWithOpr*(x: string): bool =
 proc continueLine(line: string, inTripleString: bool): bool {.inline.} =
  result = inTripleString or line.len > 0 and (
        line[0] == ' ' or
-        line.endsWith(LineContinuationOprs+AdditionalLineContinuationOprs) or
-        line.endsWithLineContinuationToken()
-      )
+        line.endsWith(LineContinuationOprs+AdditionalLineContinuationOprs))

 proc countTriples(s: string): int =
  result = 0
@@ -152,10 +108,7 @@ proc llReadFromStdin(s: PLLStream, buf: pointer, bufLen: int): int =
  s.rd = 0
  var line = newStringOfCap(120)
  var triples = 0
-  while true:
-    if not readLineFromStdin(if s.s.len == 0: ">>> " else: "... ", line):
-      # now readLineFromStdin meets EOF (ctrl-D/Z) or ctrl-C
-      quit()
+  while readLineFromStdin(if s.s.len == 0: ">>> " else: "... ", line):
    s.s.add(line)
    s.s.add("\n")
    inc triples, countTriples(line)
@@ -163,7 +116,7 @@ proc llReadFromStdin(s: PLLStream, buf: pointer, bufLen: int): int =
  inc(s.lineOffset)
  result = min(bufLen, s.s.len - s.rd)
  if result > 0:
-    copyMem(buf, readRawData(s.s, s.rd), result)
+    copyMem(buf, addr(s.s[s.rd]), result)
    inc(s.rd, result)

 proc llStreamRead*(s: PLLStream, buf: pointer, bufLen: int): int =
@@ -173,7 +126,7 @@ proc llStreamRead*(s: PLLStream, buf: pointer, bufLen: int): int =
  of llsString:
    result = min(bufLen, s.s.len - s.rd)
    if result > 0:
-      copyMem(buf, readRawData(s.s, s.rd), result)
+      copyMem(buf, addr(s.s[0 + s.rd]), result)
      inc(s.rd, result)
  of llsFile:
    result = readBuffer(s.f, buf, bufLen)
--- a/compiler/lookups.nim
+++ b/compiler/lookups.nim
@@ -50,7 +50,7 @@ proc considerQuotedIdent*(c: PContext; n: PNode, origin: PNode = nil): PIdent =
        case x.kind
        of nkIdent: id.add(x.ident.s)
        of nkSym: id.add(x.sym.name.s)
-        of nkSymChoices, nkOpenSym:
+        of nkSymChoices:
          if x[0].kind == nkSym:
            id.add(x[0].sym.name.s)
          else:
@@ -58,7 +58,7 @@ proc considerQuotedIdent*(c: PContext; n: PNode, origin: PNode = nil): PIdent =
        of nkLiterals - nkFloatLiterals: id.add(x.renderTree)
        else: handleError(n, origin)
      result = getIdent(c.cache, id)
-  of nkOpenSymChoice, nkClosedSymChoice, nkOpenSym:
+  of nkOpenSymChoice, nkClosedSymChoice:
    if n[0].kind == nkSym:
      result = n[0].sym.name
    else:
@@ -75,13 +75,10 @@ proc addUniqueSym*(scope: PScope, s: PSym): PSym =
 proc openScope*(c: PContext): PScope {.discardable.} =
  result = PScope(parent: c.currentScope,
                  symbols: initStrTable(),
-                  depthLevel: c.scopeDepth + 1,
-                  optionStackLen: c.optionStack.len)
+                  depthLevel: c.scopeDepth + 1)
  c.currentScope = result

 proc rawCloseScope*(c: PContext) =
-  if c.currentScope.optionStackLen >= 1:
-    c.optionStack.setLen(c.currentScope.optionStackLen)
  c.currentScope = c.currentScope.parent

 proc closeScope*(c: PContext) =
@@ -140,7 +137,7 @@ proc nextIdentIter(ti: var ModuleIter; marked: var IntSet; im: ImportedModule;
        return result

 iterator symbols(im: ImportedModule; marked: var IntSet; name: PIdent; g: ModuleGraph): PSym =
-  var ti: ModuleIter = default(ModuleIter)
+  var ti: ModuleIter
  var candidate = initIdentIter(ti, marked, im, name, g)
  while candidate != nil:
    yield candidate
@@ -153,7 +150,7 @@ iterator importedItems*(c: PContext; name: PIdent): PSym =
      yield s

 proc allPureEnumFields(c: PContext; name: PIdent): seq[PSym] =
-  var ti: TIdentIter = default(TIdentIter)
+  var ti: TIdentIter
  result = @[]
  var res = initIdentIter(ti, c.pureEnumFields, name)
  while res != nil:
@@ -222,33 +219,28 @@ proc debugScopes*(c: PContext; limit=0, max = int.high) {.deprecated.} =
    if i == limit: return
    inc i

-proc searchImportsAll*(c: PContext, s: PIdent, filter: TSymKinds, holding: var seq[PSym]) =
-  var marked = initIntSet()
-  for im in c.imports.mitems:
-    for s in symbols(im, marked, s, c.graph):
-      if s.kind in filter:
-        holding.add s
-
-proc searchScopes*(c: PContext, s: PIdent, filter: TSymKinds): seq[PSym] =
+proc searchInScopesAllCandidatesFilterBy*(c: PContext, s: PIdent, filter: TSymKinds): seq[PSym] =
  result = @[]
  for scope in allScopes(c.currentScope):
-    var ti: TIdentIter = default(TIdentIter)
+    var ti: TIdentIter
    var candidate = initIdentIter(ti, scope.symbols, s)
    while candidate != nil:
      if candidate.kind in filter:
        result.add candidate
      candidate = nextIdentIter(ti, scope.symbols)

-proc searchScopesAll*(c: PContext, s: PIdent, filter: TSymKinds): seq[PSym] =
-  result = searchScopes(c,s,filter)
  if result.len == 0:
-    searchImportsAll(c, s, filter, result)
+    var marked = initIntSet()
+    for im in c.imports.mitems:
+      for s in symbols(im, marked, s, c.graph):
+        if s.kind in filter:
+          result.add s

-proc selectFromScopesElseAll*(c: PContext, s: PIdent, filter: TSymKinds): seq[PSym] =
+proc searchInScopesFilterBy*(c: PContext, s: PIdent, filter: TSymKinds): seq[PSym] =
  result = @[]
  block outer:
    for scope in allScopes(c.currentScope):
-      var ti: TIdentIter = default(TIdentIter)
+      var ti: TIdentIter
      var candidate = initIdentIter(ti, scope.symbols, s)
      while candidate != nil:
        if candidate.kind in filter:
@@ -258,25 +250,17 @@ proc selectFromScopesElseAll*(c: PContext, s: PIdent, filter: TSymKinds): seq[PS
        candidate = nextIdentIter(ti, scope.symbols)

  if result.len == 0:
-    searchImportsAll(c, s, filter, result)
-
-proc cmpScopes*(ctx: PContext, s: PSym): int =
-  # Do not return a negative number
-  if s.originatingModule == ctx.module:
-    result = 2
-    var owner = s
-    while true:
-      owner = owner.skipGenericOwner
-      if owner.kind == skModule: break
-      inc result
-  else:
-    result = 1
+    var marked = initIntSet()
+    for im in c.imports.mitems:
+      for s in symbols(im, marked, s, c.graph):
+        if s.kind in filter:
+          result.add s

 proc isAmbiguous*(c: PContext, s: PIdent, filter: TSymKinds, sym: var PSym): bool =
  result = false
  block outer:
    for scope in allScopes(c.currentScope):
-      var ti: TIdentIter = default(TIdentIter)
+      var ti: TIdentIter
      var candidate = initIdentIter(ti, scope.symbols, s)
      var scopeHasCandidate = false
      while candidate != nil:
@@ -307,16 +291,8 @@ proc isAmbiguous*(c: PContext, s: PIdent, filter: TSymKinds, sym: var PSym): boo
    # imports had a candidate but wasn't ambiguous
    return false

-proc errorSym*(c: PContext, ident: PIdent, info: TLineInfo): PSym =
-  ## creates an error symbol to avoid cascading errors (for IDE support)
-  result = newSym(skError, ident, c.idgen, getCurrOwner(c), info, {})
-  result.typ = errorType(c)
-  incl(result.flagsImpl, sfDiscardable)
-  # pretend it's from the top level scope to prevent cascading errors:
-  if c.config.cmd != cmdInteractive and c.compilesContextId == 0:
-    c.moduleScope.addSym(result)
-
 proc errorSym*(c: PContext, n: PNode): PSym =
+  ## creates an error symbol to avoid cascading errors (for IDE support)
  var m = n
  # ensure that 'considerQuotedIdent' can't fail:
  if m.kind == nkDotExpr: m = m[1]
@@ -324,7 +300,12 @@ proc errorSym*(c: PContext, n: PNode): PSym =
      considerQuotedIdent(c, m)
    else:
      getIdent(c.cache, "err:" & renderTree(m))
-  result = errorSym(c, ident, n.info)
+  result = newSym(skError, ident, c.idgen, getCurrOwner(c), n.info, {})
+  result.typ = errorType(c)
+  incl(result.flags, sfDiscardable)
+  # pretend it's from the top level scope to prevent cascading errors:
+  if c.config.cmd != cmdInteractive and c.compilesContextId == 0:
+    c.moduleScope.addSym(result)

 type
  TOverloadIterMode* = enum
@@ -351,7 +332,7 @@ proc getSymRepr*(conf: ConfigRef; s: PSym, getDeclarationPath = true): string =

 proc ensureNoMissingOrUnusedSymbols(c: PContext; scope: PScope) =
  # check if all symbols have been used and defined:
-  var it: TTabIter = default(TTabIter)
+  var it: TTabIter
  var s = initTabIter(it, scope.symbols)
  var missingImpls = 0
  var unusedSyms: seq[tuple[sym: PSym, key: string]] = @[]
@@ -388,7 +369,7 @@ proc addDeclAt*(c: PContext; scope: PScope, sym: PSym, info: TLineInfo) =
  if sym.name.id == ord(wUnderscore): return
  let conflict = scope.addUniqueSym(sym)
  if conflict != nil:
-    if sym.kind == skModule and conflict.kind == skModule and not c.config.isDefined("nimPreviewDuplicateModuleError"):
+    if sym.kind == skModule and conflict.kind == skModule:
      # e.g.: import foo; import foo
      # xxx we could refine this by issuing a different hint for the case
      # where a duplicate import happens inside an include.
@@ -412,6 +393,8 @@ proc addDecl*(c: PContext, sym: PSym) {.inline.} =
 proc addPrelimDecl*(c: PContext, sym: PSym) =
  discard c.currentScope.addUniqueSym(sym)

+from ic / ic import addHidden
+
 proc addInterfaceDeclAux(c: PContext, sym: PSym) =
  ## adds symbol to the module for either private or public access.
  if sfExported in sym.flags:
@@ -420,6 +403,8 @@ proc addInterfaceDeclAux(c: PContext, sym: PSym) =
    else: internalError(c.config, sym.info, "addInterfaceDeclAux")
  elif sym.kind in ExportableSymKinds and c.module != nil and isTopLevelInsideDeclaration(c, sym):
    strTableAdd(semtabAll(c.graph, c.module), sym)
+    if c.config.symbolFiles != disabledSf:
+      addHidden(c.encoder, c.packedRepr, sym)

 proc addInterfaceDeclAt*(c: PContext, scope: PScope, sym: PSym) =
  ## adds a symbol on the scope and the interface if appropriate
@@ -502,7 +487,7 @@ proc mustFixSpelling(c: PContext): bool {.inline.} =
  result = c.config.spellSuggestMax != 0 and c.compilesContextId == 0
    # don't slowdown inside compiles()

-proc fixSpelling(c: PContext, ident: PIdent, result: var string) =
+proc fixSpelling(c: PContext, n: PNode, ident: PIdent, result: var string) =
  ## when we cannot find the identifier, suggest nearby spellings
  var list = initHeapQueue[SpellCandidate]()
  let name0 = ident.s.nimIdentNormalize
@@ -558,47 +543,33 @@ proc errorUseQualifier(c: PContext; info: TLineInfo; s: PSym; amb: var bool): PS
    amb = false

 proc errorUseQualifier*(c: PContext; info: TLineInfo; s: PSym) =
-  var amb: bool = false
+  var amb: bool
  discard errorUseQualifier(c, info, s, amb)

-proc ambiguousIdentifierMsg*(candidates: seq[PSym], prefix = "use one of", indent = 0): string =
-  result = ""
-  for i in 0 ..< indent:
-    result.add(' ')
-  result.add "ambiguous identifier: '" & candidates[0].name.s & "'"
+proc errorUseQualifier(c: PContext; info: TLineInfo; candidates: seq[PSym]; prefix = "use one of") =
+  var err = "ambiguous identifier: '" & candidates[0].name.s & "'"
  var i = 0
  for candidate in candidates:
-    if i == 0: result.add " -- $1 the following:\n" % prefix
-    else: result.add "\n"
-    for i in 0 ..< indent:
-      result.add(' ')
-    result.add "  " & candidate.owner.name.s & "." & candidate.name.s
-    result.add ": " & typeToString(candidate.typ)
+    if i == 0: err.add " -- $1 the following:\n" % prefix
+    else: err.add "\n"
+    err.add "  " & candidate.owner.name.s & "." & candidate.name.s
+    err.add ": " & typeToString(candidate.typ)
    inc i
+  localError(c.config, info, errGenerated, err)

-proc errorUseQualifier*(c: PContext; info: TLineInfo; candidates: seq[PSym]) =
-  localError(c.config, info, errGenerated, ambiguousIdentifierMsg(candidates))
-
-proc ambiguousIdentifierMsg*(choices: PNode, indent = 0): string =
+proc errorUseQualifier*(c: PContext; info:TLineInfo; choices: PNode) =
  var candidates = newSeq[PSym](choices.len)
  let prefix = if choices[0].typ.kind != tyProc: "use one of" else: "you need a helper proc to disambiguate"
  for i, n in choices:
    candidates[i] = n.sym
-  result = ambiguousIdentifierMsg(candidates, prefix, indent)
-
-proc errorUseQualifier*(c: PContext; info:TLineInfo; choices: PNode) =
-  localError(c.config, info, errGenerated, ambiguousIdentifierMsg(choices))
+  errorUseQualifier(c, info, candidates, prefix)

 proc errorUndeclaredIdentifier*(c: PContext; info: TLineInfo; name: string, extra = "") =
  var err: string
  if name == "_":
    err = "the special identifier '_' is ignored in declarations and cannot be used"
  else:
-    err = "undeclared identifier: '" & name & "'"
-    if "`gensym" in name:
-      err.add "; if declared in a template, this identifier may be inconsistently marked inject or gensym"
-    if extra.len != 0:
-      err.add extra
+    err = "undeclared identifier: '" & name & "'" & extra
    if c.recursiveDep.len > 0:
      err.add "\nThis might be caused by a recursive module dependency:\n"
      err.add c.recursiveDep
@@ -606,11 +577,11 @@ proc errorUndeclaredIdentifier*(c: PContext; info: TLineInfo; name: string, extr
      c.recursiveDep = ""
  localError(c.config, info, errGenerated, err)

-proc errorUndeclaredIdentifierHint*(c: PContext; ident: PIdent; info: TLineInfo): PSym =
+proc errorUndeclaredIdentifierHint*(c: PContext; n: PNode, ident: PIdent): PSym =
  var extra = ""
-  if c.mustFixSpelling: fixSpelling(c, ident, extra)
-  errorUndeclaredIdentifier(c, info, ident.s, extra)
-  result = errorSym(c, ident, info)
+  if c.mustFixSpelling: fixSpelling(c, n, ident, extra)
+  errorUndeclaredIdentifier(c, n.info, ident.s, extra)
+  result = errorSym(c, n)

 proc lookUp*(c: PContext, n: PNode): PSym =
  # Looks up a symbol. Generates an error in case of nil.
@@ -618,13 +589,13 @@ proc lookUp*(c: PContext, n: PNode): PSym =
  case n.kind
  of nkIdent:
    result = searchInScopes(c, n.ident, amb)
-    if result == nil: result = errorUndeclaredIdentifierHint(c, n.ident, n.info)
+    if result == nil: result = errorUndeclaredIdentifierHint(c, n, n.ident)
  of nkSym:
    result = n.sym
  of nkAccQuoted:
    var ident = considerQuotedIdent(c, n)
    result = searchInScopes(c, ident, amb)
-    if result == nil: result = errorUndeclaredIdentifierHint(c, ident, n.info)
+    if result == nil: result = errorUndeclaredIdentifierHint(c, n, ident)
  else:
    internalError(c.config, n.info, "lookUp")
    return nil
@@ -638,30 +609,16 @@ type
  TLookupFlag* = enum
    checkAmbiguity, checkUndeclared, checkModule, checkPureEnumFields

-const allExceptModule = {low(TSymKind)..high(TSymKind)} - {skModule, skPackage}
-
-proc lookUpCandidates*(c: PContext, ident: PIdent, filter: set[TSymKind],
-                       includePureEnum = false): seq[PSym] =
-  result = selectFromScopesElseAll(c, ident, filter)
-  if skEnumField in filter and (result.len == 0 or includePureEnum):
-    result.add allPureEnumFields(c, ident)
-
 proc qualifiedLookUp*(c: PContext, n: PNode, flags: set[TLookupFlag]): PSym =
+  const allExceptModule = {low(TSymKind)..high(TSymKind)} - {skModule, skPackage}
  case n.kind
  of nkIdent, nkAccQuoted:
    var amb = false
    var ident = considerQuotedIdent(c, n)
    if checkModule in flags:
      result = searchInScopes(c, ident, amb)
-      if result == nil:
-        let candidates = allPureEnumFields(c, ident)
-        if candidates.len > 0:
-          result = candidates[0]
-          amb = candidates.len > 1
-          if amb and checkAmbiguity in flags:
-            errorUseQualifier(c, n.info, candidates)
    else:
-      let candidates = lookUpCandidates(c, ident, allExceptModule)
+      let candidates = searchInScopesFilterBy(c, ident, allExceptModule)
      if candidates.len > 0:
        result = candidates[0]
        amb = candidates.len > 1
@@ -669,47 +626,46 @@ proc qualifiedLookUp*(c: PContext, n: PNode, flags: set[TLookupFlag]): PSym =
          errorUseQualifier(c, n.info, candidates)
      else:
        result = nil
+    if result == nil:
+      let candidates = allPureEnumFields(c, ident)
+      if candidates.len > 0:
+        result = candidates[0]
+        amb = candidates.len > 1
+        if amb and checkAmbiguity in flags:
+          errorUseQualifier(c, n.info, candidates)
+
    if result == nil and checkUndeclared in flags:
-      result = errorUndeclaredIdentifierHint(c, ident, n.info)
+      result = errorUndeclaredIdentifierHint(c, n, ident)
    elif checkAmbiguity in flags and result != nil and amb:
      result = errorUseQualifier(c, n.info, result, amb)
    c.isAmbiguous = amb
  of nkSym:
    result = n.sym
-  of nkOpenSym:
-    result = qualifiedLookUp(c, n[0], flags)
  of nkDotExpr:
    result = nil
    var m = qualifiedLookUp(c, n[0], (flags * {checkUndeclared}) + {checkModule})
    if m != nil and m.kind == skModule:
      var ident: PIdent = nil
-      if n[1].kind == nkAccQuoted:
+      if n[1].kind == nkIdent:
+        ident = n[1].ident
+      elif n[1].kind == nkAccQuoted:
        ident = considerQuotedIdent(c, n[1])
-      else:
-        # this includes sym and symchoice nodes, but since we are looking in
-        # a module, it shouldn't matter what was captured
-        ident = n[1].getPIdent
      if ident != nil:
        if m == c.module:
-          var ti: TIdentIter = default(TIdentIter)
-          result = initIdentIter(ti, c.topLevelScope.symbols, ident)
-          if result != nil and nextIdentIter(ti, c.topLevelScope.symbols) != nil:
-            # another symbol exists with same name
-            c.isAmbiguous = true
+          result = strTableGet(c.topLevelScope.symbols, ident)
        else:
-          var amb: bool = false
          if c.importModuleLookup.getOrDefault(m.name.id).len > 1:
+            var amb: bool
            result = errorUseQualifier(c, n.info, m, amb)
          else:
-            result = someSymAmb(c.graph, m, ident, amb)
-            if amb: c.isAmbiguous = true
+            result = someSym(c.graph, m, ident)
        if result == nil and checkUndeclared in flags:
-          result = errorUndeclaredIdentifierHint(c, ident, n[1].info)
+          result = errorUndeclaredIdentifierHint(c, n[1], ident)
      elif n[1].kind == nkSym:
        result = n[1].sym
        if result.owner != nil and result.owner != m and checkUndeclared in flags:
          # dotExpr in templates can end up here
-          result = errorUndeclaredIdentifierHint(c, result.name, n[1].info)
+          result = errorUndeclaredIdentifierHint(c, n[1], considerQuotedIdent(c, n[1]))
      elif checkUndeclared in flags and
           n[1].kind notin {nkOpenSymChoice, nkClosedSymChoice}:
        localError(c.config, n[1].info, "identifier expected, but got: " &
@@ -721,10 +677,6 @@ proc qualifiedLookUp*(c: PContext, n: PNode, flags: set[TLookupFlag]): PSym =
    if result != nil and result.kind == skStub: loadStub(result)

 proc initOverloadIter*(o: var TOverloadIter, c: PContext, n: PNode): PSym =
-  if n.kind == nkOpenSym:
-    # maybe the logic in semexprs should be mirrored here instead
-    # for now it only seems this is called for `pickSym` in `getTypeIdent`
-    return initOverloadIter(o, c, n[0])
  o.importIdx = -1
  o.marked = initIntSet()
  case n.kind
--- a/compiler/lowerings.nim
+++ b/compiler/lowerings.nim
@@ -19,7 +19,7 @@ when defined(nimPreviewSlimSystem):
  import std/assertions

 proc newDeref*(n: PNode): PNode {.inline.} =
-  result = newNodeIT(nkHiddenDeref, n.info, n.typ.elementType)
+  result = newNodeIT(nkHiddenDeref, n.info, n.typ[0])
  result.add n

 proc newTupleAccess*(g: ModuleGraph; tup: PNode, i: int): PNode =
@@ -82,7 +82,7 @@ proc lowerTupleUnpacking*(g: ModuleGraph; n: PNode; idgen: IdGenerator; owner: P
    var temp = newSym(skTemp, getIdent(g.cache, genPrefix), idgen,
                  owner, value.info, g.config.options)
    temp.typ = skipTypes(value.typ, abstractInst)
-    incl(temp.flagsImpl, sfFromGeneric)
+    incl(temp.flags, sfFromGeneric)
    tempAsNode = newSymNode(temp)

  var v = newNodeI(nkVarSection, value.info)
@@ -103,7 +103,7 @@ proc evalOnce*(g: ModuleGraph; value: PNode; idgen: IdGenerator; owner: PSym): P
  var temp = newSym(skTemp, getIdent(g.cache, genPrefix), idgen,
                    owner, value.info, g.config.options)
  temp.typ = skipTypes(value.typ, abstractInst)
-  incl(temp.flagsImpl, sfFromGeneric)
+  incl(temp.flags, sfFromGeneric)

  var v = newNodeI(nkLetSection, value.info)
  let tempAsNode = newSymNode(temp)
@@ -127,8 +127,8 @@ proc lowerSwap*(g: ModuleGraph; n: PNode; idgen: IdGenerator; owner: PSym): PNod
  # note: cannot use 'skTemp' here cause we really need the copy for the VM :-(
  var temp = newSym(skVar, getIdent(g.cache, genPrefix), idgen, owner, n.info, owner.options)
  temp.typ = n[1].typ
-  incl(temp.flagsImpl, sfFromGeneric)
-  incl(temp.flagsImpl, sfGenSym)
+  incl(temp.flags, sfFromGeneric)
+  incl(temp.flags, sfGenSym)

  var v = newNodeI(nkVarSection, n.info)
  let tempAsNode = newSymNode(temp)
@@ -147,13 +147,13 @@ proc createObj*(g: ModuleGraph; idgen: IdGenerator; owner: PSym, info: TLineInfo
  result = newType(tyObject, idgen, owner)
  if final:
    rawAddSon(result, nil)
-    incl result, tfFinal
+    incl result.flags, tfFinal
  else:
    rawAddSon(result, getCompilerProc(g, "RootObj").typ)
  result.n = newNodeI(nkRecList, info)
  let s = newSym(skType, getIdent(g.cache, "Env_" & toFilename(g.config, info) & "_" & $owner.name.s),
                  idgen, owner, info, owner.options)
-  incl s.flagsImpl, sfAnon
+  incl s.flags, sfAnon
  s.typ = result
  result.sym = s

@@ -255,14 +255,14 @@ proc newDotExpr*(obj, b: PSym): PNode =
 proc indirectAccess*(a: PNode, b: ItemId, info: TLineInfo): PNode =
  # returns a[].b as a node
  var deref = newNodeI(nkHiddenDeref, info)
-  deref.typ = a.typ.skipTypes(abstractInst).elementType
+  deref.typ = a.typ.skipTypes(abstractInst)[0]
  var t = deref.typ.skipTypes(abstractInst)
  var field: PSym
  while true:
    assert t.kind == tyObject
    field = lookupInRecord(t.n, b)
    if field != nil: break
-    t = t.baseClass
+    t = t[0]
    if t == nil: break
    t = t.skipTypes(skipPtrs)
  #if field == nil:
@@ -278,7 +278,7 @@ proc indirectAccess*(a: PNode, b: ItemId, info: TLineInfo): PNode =
 proc indirectAccess*(a: PNode, b: string, info: TLineInfo; cache: IdentCache): PNode =
  # returns a[].b as a node
  var deref = newNodeI(nkHiddenDeref, info)
-  deref.typ = a.typ.skipTypes(abstractInst).elementType
+  deref.typ = a.typ.skipTypes(abstractInst)[0]
  var t = deref.typ.skipTypes(abstractInst)
  var field: PSym
  let bb = getIdent(cache, b)
@@ -286,7 +286,7 @@ proc indirectAccess*(a: PNode, b: string, info: TLineInfo; cache: IdentCache): P
    assert t.kind == tyObject
    field = getSymFromList(t.n, bb)
    if field != nil: break
-    t = t.baseClass
+    t = t[0]
    if t == nil: break
    t = t.skipTypes(skipPtrs)
  #if field == nil:
@@ -306,7 +306,7 @@ proc getFieldFromObj*(t: PType; v: PSym): PSym =
    assert t.kind == tyObject
    result = lookupInRecord(t.n, v.itemId)
    if result != nil: break
-    t = t.baseClass
+    t = t[0]
    if t == nil: break
    t = t.skipTypes(skipPtrs)

@@ -325,7 +325,7 @@ proc genAddrOf*(n: PNode; idgen: IdGenerator; typeKind = tyPtr): PNode =

 proc genDeref*(n: PNode; k = nkHiddenDeref): PNode =
  result = newNodeIT(k, n.info,
-                     n.typ.skipTypes(abstractInst).elementType)
+                     n.typ.skipTypes(abstractInst)[0])
  result.add n

 proc callCodegenProc*(g: ModuleGraph; name: string;
@@ -344,7 +344,7 @@ proc callCodegenProc*(g: ModuleGraph; name: string;
    if optionalArgs != nil:
      for i in 1..<optionalArgs.len-2:
        result.add optionalArgs[i]
-    result.typ = sym.typ.returnType
+    result.typ = sym.typ[0]

 proc newIntLit*(g: ModuleGraph; info: TLineInfo; value: BiggestInt): PNode =
  result = nkIntLit.newIntNode(value)
--- a/compiler/magicsys.nim
+++ b/compiler/magicsys.nim
@@ -10,8 +10,8 @@
 # Built-in types and compilerprocs are registered here.

 import
-  ast, msgs, platform, idents,
-  modulegraphs, lineinfos, types
+  ast, astalgo, msgs, platform, idents,
+  modulegraphs, lineinfos

 export createMagic

@@ -35,7 +35,7 @@ proc getSysMagic*(g: ModuleGraph; info: TLineInfo; name: string, m: TMagic): PSy
  for r in systemModuleSyms(g, id):
    if r.magic == m:
      # prefer the tyInt variant:
-      if r.typ.returnType != nil and r.typ.returnType.kind == tyInt: return r
+      if r.typ[0] != nil and r.typ[0].kind == tyInt: return r
      result = r
  if result != nil: return result
  localError(g.config, info, "system module needs: " & name)
@@ -134,7 +134,7 @@ proc getNimScriptSymbol*(g: ModuleGraph; name: string): PSym =
 proc resetNimScriptSymbols*(g: ModuleGraph) = g.exposed = initStrTable()

 proc getMagicEqSymForType*(g: ModuleGraph; t: PType; info: TLineInfo): PSym =
-  case t.skipTypes(abstractRange).kind
+  case t.kind
  of tyInt,  tyInt8, tyInt16, tyInt32, tyInt64,
     tyUInt, tyUInt8, tyUInt16, tyUInt32, tyUInt64:
    result = getSysMagic(g, info, "==", mEqI)
@@ -166,4 +166,4 @@ proc makeAddr*(n: PNode; idgen: IdGenerator): PNode =
    result = n
  else:
    result = newTree(nkHiddenAddr, n)
-    result.typ = makePtrType(n.typ.skipTypes({tySink}), idgen)
+    result.typ = makePtrType(n.typ, idgen)
--- a/compiler/main.nim
+++ b/compiler/main.nim
@@ -22,18 +22,18 @@ import
  modules,
  modulegraphs, lineinfos, pathutils, vmprofiler

+# ensure NIR compiles:
+import nir / nir

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

+import ic / [cbackend, integrity, navigator, ic]
+
 import ../dist/checksums/src/checksums/sha1

 import pipelines

-when not defined(nimKochBootstrap):
-  import nifbackend
-  import deps
-
 when not defined(leanCompiler):
  import docgen

@@ -48,6 +48,9 @@ proc writeDepsFile(g: ModuleGraph) =
      f.writeLine(toFullPath(g.config, k))
  f.close()

+proc writeNinjaFile(g: ModuleGraph) =
+  discard "to implement"
+
 proc writeCMakeDepsFile(conf: ConfigRef) =
  ## write a list of C files for build systems like CMake.
  ## only updated when the C file list changes.
@@ -97,6 +100,14 @@ proc commandCheck(graph: ModuleGraph) =
  setPipeLinePass(graph, SemPass)
  compilePipelineProject(graph)

+  if conf.symbolFiles != disabledSf:
+    case conf.ideCmd
+    of ideDef: navDefinition(graph)
+    of ideUse: navUsages(graph)
+    of ideDus: navDefusages(graph)
+    else: discard
+    writeRodFiles(graph)
+
 when not defined(leanCompiler):
  proc commandDoc2(graph: ModuleGraph; ext: string) =
    handleDocOutputOptions graph.config
@@ -111,38 +122,6 @@ when not defined(leanCompiler):
    else: raiseAssert $ext
    compilePipelineProject(graph)

-proc commandCompileToNif(graph: ModuleGraph) =
-  let conf = graph.config
-  extccomp.initVars(conf)
-  if conf.symbolFiles == disabledSf:
-    if {optRun, optForceFullMake} * conf.globalOptions == {optRun} or isDefined(conf, "nimBetterRun"):
-      if not changeDetectedViaJsonBuildInstructions(conf, conf.jsonBuildInstructionsFile):
-        # nothing changed
-        graph.config.notes = graph.config.mainPackageNotes
-        return
-
-  if not extccomp.ccHasSaneOverflow(conf):
-    conf.symbols.defineSymbol("nimEmulateOverflowChecks")
-
-  setPipeLinePass(graph, NifgenPass)
-  compilePipelineProject(graph)
-
-proc commandNifC(graph: ModuleGraph) =
-  ## Generate C code from precompiled NIF files.
-  ## This is the new IC approach: compile modules to NIF first with `nim m`,
-  ## then generate C code from the entry.nif file with whole-program DCE.
-  when not defined(nimKochBootstrap):
-    let conf = graph.config
-    extccomp.initVars(conf)
-
-    if not extccomp.ccHasSaneOverflow(conf):
-      conf.symbols.defineSymbol("nimEmulateOverflowChecks")
-
-    # Use the NIF backend to generate C code
-    nifbackend.generateCode(graph, conf.projectMainIdx)
-  else:
-    rawMessage(graph.config, errGenerated, "NIF backend not available during bootstrap build")
-
 proc commandCompileToC(graph: ModuleGraph) =
  let conf = graph.config
  extccomp.initVars(conf)
@@ -163,17 +142,45 @@ proc commandCompileToC(graph: ModuleGraph) =
  compilePipelineProject(graph)
  if graph.config.errorCounter > 0:
    return # issue #9933
-  cgenWriteModules(graph.backend, conf)
+  if conf.symbolFiles == disabledSf:
+    cgenWriteModules(graph.backend, conf)
+  else:
+    if isDefined(conf, "nimIcIntegrityChecks"):
+      checkIntegrity(graph)
+    generateCode(graph)
+    # graph.backend can be nil under IC when nothing changed at all:
+    if graph.backend != nil:
+      cgenWriteModules(graph.backend, conf)
  if conf.cmd != cmdTcc and graph.backend != nil:
    extccomp.callCCompiler(conf)
    # for now we do not support writing out a .json file with the build instructions when HCR is on
    if not conf.hcrOn:
-      extccomp.writeJsonBuildInstructions(conf, graph.cachedFiles)
+      extccomp.writeJsonBuildInstructions(conf)
    if optGenScript in graph.config.globalOptions:
      writeDepsFile(graph)
    if optGenCDeps in graph.config.globalOptions:
      writeCMakeDepsFile(conf)

+proc commandCompileToNir(graph: ModuleGraph) =
+  let conf = graph.config
+  extccomp.initVars(conf)
+  if conf.symbolFiles == disabledSf:
+    if {optRun, optForceFullMake} * conf.globalOptions == {optRun}:
+      if not changeDetectedViaJsonBuildInstructions(conf, conf.jsonBuildInstructionsFile):
+        # nothing changed
+        graph.config.notes = graph.config.mainPackageNotes
+        return
+
+  if not extccomp.ccHasSaneOverflow(conf):
+    conf.symbols.defineSymbol("nimEmulateOverflowChecks")
+
+  if conf.symbolFiles == disabledSf:
+    setPipeLinePass(graph, NirPass)
+  else:
+    setPipeLinePass(graph, SemPass)
+  compilePipelineProject(graph)
+  writeNinjaFile(graph)
+
 proc commandJsonScript(graph: ModuleGraph) =
  extccomp.runJsonBuildInstructions(graph.config, graph.config.jsonBuildInstructionsFile)

@@ -190,19 +197,22 @@ proc commandCompileToJS(graph: ModuleGraph) =
    if optGenScript in conf.globalOptions:
      writeDepsFile(graph)

-proc commandInteractive(graph: ModuleGraph) =
+proc commandInteractive(graph: ModuleGraph; useNir: bool) =
  graph.config.setErrorMaxHighMaybe
  initDefines(graph.config.symbols)
-  defineSymbol(graph.config.symbols, "nimscript")
+  if useNir:
+    defineSymbol(graph.config.symbols, "noSignalHandler")
+  else:
+    defineSymbol(graph.config.symbols, "nimscript")
  # note: seems redundant with -d:nimHasLibFFI
  when hasFFI: defineSymbol(graph.config.symbols, "nimffi")
-  setPipeLinePass(graph, InterpreterPass)
+  setPipeLinePass(graph, if useNir: NirReplPass else: InterpreterPass)
  compilePipelineSystemModule(graph)
  if graph.config.commandArgs.len > 0:
    discard graph.compilePipelineModule(fileInfoIdx(graph.config, graph.config.projectFull), {})
  else:
    var m = graph.makeStdinModule()
-    incl(m, sfMainModule)
+    incl(m.flags, sfMainModule)
    var idgen = IdGenerator(module: m.itemId.module, symId: m.itemId.item, typeId: 0)
    let s = llStreamOpenStdIn(onPrompt = proc() = flushDot(graph.config))
    discard processPipelineModule(graph, m, idgen, s)
@@ -212,7 +222,7 @@ proc commandScan(cache: IdentCache, config: ConfigRef) =
  var stream = llStreamOpen(f, fmRead)
  if stream != nil:
    var
-      L: Lexer = default(Lexer)
+      L: Lexer
      tok: Token = default(Token)
    openLexer(L, f, stream, cache, config)
    while true:
@@ -223,6 +233,10 @@ proc commandScan(cache: IdentCache, config: ConfigRef) =
  else:
    rawMessage(config, errGenerated, "cannot open file: " & f.string)

+proc commandView(graph: ModuleGraph) =
+  let f = toAbsolute(mainCommandArg(graph.config), AbsoluteDir getCurrentDir()).addFileExt(RodExt)
+  rodViewer(f, graph.config, graph.cache)
+
 const
  PrintRopeCacheStats = false

@@ -271,7 +285,7 @@ proc mainCommand*(graph: ModuleGraph) =
      if conf.exc == excNone: conf.exc = excSetjmp
    of backendCpp:
      if conf.exc == excNone: conf.exc = excCpp
-    of backendObjc, backendNif: discard
+    of backendObjc: discard
    of backendJs:
      if conf.hcrOn:
        # XXX: At the moment, system.nim cannot be compiled in JS mode
@@ -279,6 +293,8 @@ proc mainCommand*(graph: ModuleGraph) =
        # and it has added this define implictly, so we must undo that here.
        # A better solution might be to fix system.nim
        undefSymbol(conf.symbols, "useNimRtl")
+    of backendNir:
+      if conf.exc == excNone: conf.exc = excGoto
    of backendInvalid: raiseAssert "unreachable"

  proc compileToBackend() =
@@ -289,7 +305,7 @@ proc mainCommand*(graph: ModuleGraph) =
    of backendCpp: commandCompileToC(graph)
    of backendObjc: commandCompileToC(graph)
    of backendJs: commandCompileToJS(graph)
-    of backendNif: commandCompileToNif(graph)
+    of backendNir: commandCompileToNir(graph)
    of backendInvalid: raiseAssert "unreachable"

  template docLikeCmd(body) =
@@ -310,8 +326,7 @@ proc mainCommand*(graph: ModuleGraph) =
    # so by default should not end up in $PWD nor in $projectPath.
    var ret = if optUseNimcache in conf.globalOptions: getNimcacheDir(conf)
              else: conf.projectPath
-    if not ret.string.isAbsolute: # `AbsoluteDir` is not a real guarantee
-      rawMessage(conf, errCannotOpenFile, ret.string & "/")
+    doAssert ret.string.isAbsolute # `AbsoluteDir` is not a real guarantee
    if conf.cmd in cmdDocLike + {cmdRst2html, cmdRst2tex, cmdMd2html, cmdMd2tex}:
      ret = ret / htmldocsDir
    conf.outDir = ret
@@ -320,6 +335,8 @@ proc mainCommand*(graph: ModuleGraph) =
  case conf.cmd
  of cmdBackends:
    compileToBackend()
+    when BenchIC:
+      echoTimes graph.packed
  of cmdTcc:
    when hasTinyCBackend:
      extccomp.setCC(conf, "tcc", unknownLineInfo)
@@ -416,28 +433,17 @@ proc mainCommand*(graph: ModuleGraph) =
  of cmdCheck:
    commandCheck(graph)
  of cmdM:
-    # cmdM uses NIF files, not ROD files
-    graph.config.symbolFiles = disabledSf
-    setUseIc(true)
+    graph.config.symbolFiles = v2Sf
+    setUseIc(graph.config.symbolFiles != disabledSf)
    commandCheck(graph)
-  of cmdNifC:
-    setUseIc(true)
-    # Generate C code from NIF files
-    wantMainModule(conf)
-    setOutFile(conf)
-    commandNifC(graph)
-  of cmdIc:
-    # Generate .build.nif for nifmake
-    setUseIc(true)
-    wantMainModule(conf)
-    when not defined(nimKochBootstrap):
-      commandIc(conf)
-    else:
-      rawMessage(conf, errGenerated, "nim deps not available in bootstrap build")
  of cmdParse:
    wantMainModule(conf)
    discard parseFile(conf.projectMainIdx, cache, conf)
-  of cmdInteractive: commandInteractive(graph)
+  of cmdRod:
+    wantMainModule(conf)
+    commandView(graph)
+    #msgWriteln(conf, "Beware: Indentation tokens depend on the parser's state!")
+  of cmdInteractive: commandInteractive(graph, isDefined(conf, "nir"))
  of cmdNimscript:
    if conf.projectIsCmd or conf.projectIsStdin: discard
    elif not fileExists(conf.projectFull):
--- a/compiler/mangleutils.nim
+++ b/compiler/mangleutils.nim
@@ -1,59 +0,0 @@
-import std/strutils
-import ast, modulegraphs
-
-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 mangleParamExt*(s: PSym): string =
-  result = "_p"
-  result.addInt s.position
-
-proc mangleProcNameExt*(graph: ModuleGraph, s: PSym): string =
-  result = "__"
-  result.add graph.ifaces[s.itemId.module].uniqueName
-  result.add "_u"
-  result.addInt s.itemId.item # s.disamb #
--- a/compiler/modulegraphs.nim
+++ b/compiler/modulegraphs.nim
@@ -11,15 +11,11 @@
 ## represents a complete Nim project. Single modules can either be kept in RAM
 ## or stored in a rod-file.

-import std/[intsets, tables, hashes, strtabs, os, strutils, parseutils]
+import std/[intsets, tables, hashes]
 import ../dist/checksums/src/checksums/md5
-import ast, astalgo, options, lineinfos,idents, btrees, ropes, msgs, pathutils, packages, suggestsymdb
+import ast, astalgo, options, lineinfos,idents, btrees, ropes, msgs, pathutils, packages
+import ic / [packed_ast, ic]

-when not defined(nimKochBootstrap):
-  import ast2nif
-  import "../dist/nimony/src/lib" / [nifstreams, bitabs]
-
-import typekeys

 when defined(nimPreviewSlimSystem):
  import std/assertions
@@ -27,12 +23,16 @@ when defined(nimPreviewSlimSystem):
 type
  SigHash* = distinct MD5Digest

+  LazySym* = object
+    id*: FullId
+    sym*: PSym
+
  Iface* = object       ## data we don't want to store directly in the
                        ## ast.PSym type for s.kind == skModule
    module*: PSym       ## module this "Iface" belongs to
-    converters*: seq[PSym]
-    patterns*: seq[PSym]
-    pureEnums*: seq[PSym]
+    converters*: seq[LazySym]
+    patterns*: seq[LazySym]
+    pureEnums*: seq[LazySym]
    interf: TStrTable
    interfHidden: TStrTable
    uniqueName*: Rope
@@ -41,14 +41,34 @@ type
    opNot*, opContains*, opLe*, opLt*, opAnd*, opOr*, opIsNil*, opEq*: PSym
    opAdd*, opSub*, opMul*, opDiv*, opLen*: PSym

+  FullId* = object
+    module*: int
+    packed*: PackedItemId
+
+  LazyType* = object
+    id*: FullId
+    typ*: PType
+
+  LazyInstantiation* = object
+    module*: int
+    sym*: FullId
+    concreteTypes*: seq[FullId]
+    inst*: PInstantiation
+
+  SymInfoPair* = object
+    sym*: PSym
+    info*: TLineInfo
+    isDecl*: bool
+
  PipelinePass* = enum
    NonePass
    SemPass
    JSgenPass
    CgenPass
-    NifgenPass
    EvalPass
    InterpreterPass
+    NirPass
+    NirReplPass
    GenDependPass
    Docgen2TexPass
    Docgen2JsonPass
@@ -56,26 +76,25 @@ type

  ModuleGraph* {.acyclic.} = ref object
    ifaces*: seq[Iface]  ## indexed by int32 fileIdx
+    packed*: PackedModuleGraph
+    encoders*: seq[PackedEncoder]

-    typeInstCache*: Table[ItemId, seq[PType]] # A symbol's ItemId.
-    procInstCache*: Table[ItemId, seq[PInstantiation]] # A symbol's ItemId.
-    attachedOps*: array[TTypeAttachedOp, Table[ItemId, PSym]] # Type ID, destructors, etc.
-    loadedOps: array[TTypeAttachedOp, Table[string, PSym]] # This can later by unified with `attachedOps` once it's stable
-    opsLog*: seq[LogEntry]
-    methodsPerGenericType*: Table[ItemId, seq[(int, PSym)]] # Type ID, attached methods
+    typeInstCache*: Table[ItemId, seq[LazyType]] # A symbol's ItemId.
+    procInstCache*: Table[ItemId, seq[LazyInstantiation]] # A symbol's ItemId.
+    attachedOps*: array[TTypeAttachedOp, Table[ItemId, LazySym]] # Type ID, destructors, etc.
+    methodsPerGenericType*: Table[ItemId, seq[(int, LazySym)]] # Type ID, attached methods
    memberProcsPerType*: Table[ItemId, seq[PSym]] # Type ID, attached member procs (only c++, virtual,member and ctor so far).
    initializersPerType*: Table[ItemId, PNode] # Type ID, AST call to the default ctor (c++ only)
-    enumToStringProcs*: Table[ItemId, PSym]
-    loadedEnumToStringProcs: Table[string, PSym]
+    enumToStringProcs*: Table[ItemId, LazySym]
    emittedTypeInfo*: Table[string, FileIndex]

+    startupPackedConfig*: PackedConfig
    packageSyms*: TStrTable
    deps*: IntSet # the dependency graph or potentially its transitive closure.
    importDeps*: Table[FileIndex, seq[FileIndex]] # explicit import module dependencies
    suggestMode*: bool # whether we are in nimsuggest mode or not.
    invalidTransitiveClosure: bool
    interactive*: bool
-    withinSystem*: bool # in system.nim or a module imported by system.nim
    inclToMod*: Table[FileIndex, FileIndex] # mapping of include file to the
                                            # first module that included it
    importStack*: seq[FileIndex]  # The current import stack. Used for detecting recursive
@@ -89,13 +108,13 @@ type
    doStopCompile*: proc(): bool {.closure.}
    usageSym*: PSym # for nimsuggest
    owners*: seq[PSym]
-    suggestSymbols*: SuggestSymbolDatabase
+    suggestSymbols*: Table[FileIndex, seq[SymInfoPair]]
    suggestErrors*: Table[FileIndex, seq[Suggest]]
    methods*: seq[tuple[methods: seq[PSym], dispatcher: PSym]] # needs serialization!
    bucketTable*: CountTable[ItemId]
    objectTree*: Table[ItemId, seq[tuple[depth: int, value: PType]]]
-    methodsPerType*: Table[ItemId, seq[PSym]]
-    dispatchers*: seq[PSym]
+    methodsPerType*: Table[ItemId, seq[LazySym]]
+    dispatchers*: seq[LazySym]

    systemModule*: PSym
    sysTypes*: array[TTypeKind, PType]
@@ -121,12 +140,6 @@ type
    idgen*: IdGenerator
    operators*: Operators

-    cachedFiles*: StringTableRef
-
-    procGlobals*: seq[PNode]
-    nifReplayActions*: Table[int32, seq[PNode]]  # module position -> replay actions for NIF
-    cachedMods: IntSet
-
  TPassContext* = object of RootObj # the pass's context
    idgen*: IdGenerator
  PPassContext* = ref TPassContext
@@ -148,12 +161,8 @@ proc resetForBackend*(g: ModuleGraph) =
    a.clear()
  g.methodsPerGenericType.clear()
  g.enumToStringProcs.clear()
-  g.loadedEnumToStringProcs.clear()
  g.dispatchers.setLen(0)
  g.methodsPerType.clear()
-  for a in mitems(g.loadedOps):
-    a.clear()
-  g.opsLog.setLen(0)

 const
  cb64 = [
@@ -209,161 +218,180 @@ proc strTableAdds*(g: ModuleGraph, m: PSym, s: PSym) =
  strTableAdd(semtabAll(g, m), s)

 proc isCachedModule(g: ModuleGraph; module: int): bool {.inline.} =
-  result = module in g.cachedMods
+  result = module < g.packed.len and g.packed[module].status == loaded

 proc isCachedModule*(g: ModuleGraph; m: PSym): bool {.inline.} =
  isCachedModule(g, m.position)

+proc simulateCachedModule(g: ModuleGraph; moduleSym: PSym; m: PackedModule) =
+  when false:
+    echo "simulating ", moduleSym.name.s, " ", moduleSym.position
+  simulateLoadedModule(g.packed, g.config, g.cache, moduleSym, m)
+
+proc initEncoder*(g: ModuleGraph; module: PSym) =
+  let id = module.position
+  if id >= g.encoders.len:
+    setLen g.encoders, id+1
+  ic.initEncoder(g.encoders[id],
+    g.packed[id].fromDisk, module, g.config, g.startupPackedConfig)
+
 type
  ModuleIter* = object
+    fromRod: bool
    modIndex: int
    ti: TIdentIter
+    rodIt: RodIter
    importHidden: bool

 proc initModuleIter*(mi: var ModuleIter; g: ModuleGraph; m: PSym; name: PIdent): PSym =
  assert m.kind == skModule
  mi.modIndex = m.position
+  mi.fromRod = isCachedModule(g, mi.modIndex)
  mi.importHidden = optImportHidden in m.options
-  result = initIdentIter(mi.ti, g.ifaces[mi.modIndex].interfSelect(mi.importHidden), name)
+  if mi.fromRod:
+    result = initRodIter(mi.rodIt, g.config, g.cache, g.packed, FileIndex mi.modIndex, name, mi.importHidden)
+  else:
+    result = initIdentIter(mi.ti, g.ifaces[mi.modIndex].interfSelect(mi.importHidden), name)

 proc nextModuleIter*(mi: var ModuleIter; g: ModuleGraph): PSym =
-  result = nextIdentIter(mi.ti, g.ifaces[mi.modIndex].interfSelect(mi.importHidden))
+  if mi.fromRod:
+    result = nextRodIter(mi.rodIt, g.packed)
+  else:
+    result = nextIdentIter(mi.ti, g.ifaces[mi.modIndex].interfSelect(mi.importHidden))

 iterator allSyms*(g: ModuleGraph; m: PSym): PSym =
  let importHidden = optImportHidden in m.options
-  for s in g.ifaces[m.position].interfSelect(importHidden).data:
-    if s != nil:
-      yield s
+  if isCachedModule(g, m):
+    var rodIt: RodIter
+    var r = initRodIterAllSyms(rodIt, g.config, g.cache, g.packed, FileIndex m.position, importHidden)
+    while r != nil:
+      yield r
+      r = nextRodIter(rodIt, g.packed)
+  else:
+    for s in g.ifaces[m.position].interfSelect(importHidden).data:
+      if s != nil:
+        yield s

 proc someSym*(g: ModuleGraph; m: PSym; name: PIdent): PSym =
  let importHidden = optImportHidden in m.options
-  result = strTableGet(g.ifaces[m.position].interfSelect(importHidden), name)
-
-proc someSymAmb*(g: ModuleGraph; m: PSym; name: PIdent; amb: var bool): PSym =
-  let importHidden = optImportHidden in m.options
-  var ti: TIdentIter = default(TIdentIter)
-  result = initIdentIter(ti, g.ifaces[m.position].interfSelect(importHidden), name)
-  if result != nil and nextIdentIter(ti, g.ifaces[m.position].interfSelect(importHidden)) != nil:
-    # another symbol exists with same name
-    amb = true
+  if isCachedModule(g, m):
+    result = interfaceSymbol(g.config, g.cache, g.packed, FileIndex(m.position), name, importHidden)
+  else:
+    result = strTableGet(g.ifaces[m.position].interfSelect(importHidden), name)

 proc systemModuleSym*(g: ModuleGraph; name: PIdent): PSym =
  result = someSym(g, g.systemModule, name)

 iterator systemModuleSyms*(g: ModuleGraph; name: PIdent): PSym =
-  var mi: ModuleIter = default(ModuleIter)
+  var mi: ModuleIter
  var r = initModuleIter(mi, g, g.systemModule, name)
  while r != nil:
    yield r
    r = nextModuleIter(mi, g)

+proc resolveType(g: ModuleGraph; t: var LazyType): PType =
+  result = t.typ
+  if result == nil and isCachedModule(g, t.id.module):
+    result = loadTypeFromId(g.config, g.cache, g.packed, t.id.module, t.id.packed)
+    t.typ = result
+  assert result != nil
+
+proc resolveSym(g: ModuleGraph; t: var LazySym): PSym =
+  result = t.sym
+  if result == nil and isCachedModule(g, t.id.module):
+    result = loadSymFromId(g.config, g.cache, g.packed, t.id.module, t.id.packed)
+    t.sym = result
+  assert result != nil
+
+proc resolveInst(g: ModuleGraph; t: var LazyInstantiation): PInstantiation =
+  result = t.inst
+  if result == nil and isCachedModule(g, t.module):
+    result = PInstantiation(sym: loadSymFromId(g.config, g.cache, g.packed, t.sym.module, t.sym.packed))
+    result.concreteTypes = newSeq[PType](t.concreteTypes.len)
+    for i in 0..high(result.concreteTypes):
+      result.concreteTypes[i] = loadTypeFromId(g.config, g.cache, g.packed,
+          t.concreteTypes[i].module, t.concreteTypes[i].packed)
+    t.inst = result
+  assert result != nil
+
+proc resolveAttachedOp(g: ModuleGraph; t: var LazySym): PSym =
+  result = t.sym
+  if result == nil:
+    result = loadSymFromId(g.config, g.cache, g.packed, t.id.module, t.id.packed)
+    t.sym = result
+  assert result != nil
+
 iterator typeInstCacheItems*(g: ModuleGraph; s: PSym): PType =
  if g.typeInstCache.contains(s.itemId):
    let x = addr(g.typeInstCache[s.itemId])
    for t in mitems(x[]):
-      yield t
+      yield resolveType(g, t)

 iterator procInstCacheItems*(g: ModuleGraph; s: PSym): PInstantiation =
  if g.procInstCache.contains(s.itemId):
    let x = addr(g.procInstCache[s.itemId])
    for t in mitems(x[]):
-      yield t
+      yield resolveInst(g, t)


 proc getAttachedOp*(g: ModuleGraph; t: PType; op: TTypeAttachedOp): PSym =
  ## returns the requested attached operation for type `t`. Can return nil
  ## if no such operation exists.
  if g.attachedOps[op].contains(t.itemId):
-    result = g.attachedOps[op][t.itemId]
-  elif g.config.cmd in {cmdNifC, cmdM}:
-    # Fall back to key-based lookup for NIF-loaded hooks
-    let key = typeKey(t, g.config, loadTypeCallback, loadSymCallback)
-    result = g.loadedOps[op].getOrDefault(key)
-    #echo "fallback ", key, " ", op, " ", result
+    result = resolveAttachedOp(g, g.attachedOps[op][t.itemId])
  else:
    result = nil

 proc setAttachedOp*(g: ModuleGraph; module: int; t: PType; op: TTypeAttachedOp; value: PSym) =
  ## we also need to record this to the packed module.
-  if not g.attachedOps[op].contains(t.itemId):
-    let key = typeKey(t, g.config, loadTypeCallback, loadSymCallback)
-    # Use key-based deduplication for opsLog because different type objects
-    # (e.g. canon vs orig) can have different itemIds but same structural key
-    if key notin g.loadedOps[op]:
-      # Hooks should be written to the module where the type is defined,
-      # not the module that triggered the registration
-      let ownerModule = if t.sym != nil: t.sym.itemId.module.int else: module
-      g.opsLog.add LogEntry(kind: HookEntry, op: op, module: ownerModule, key: key, sym: value)
-      g.loadedOps[op][key] = value
-  g.attachedOps[op][t.itemId] = value
-
-proc setAttachedOp*(g: ModuleGraph; module: int; typeId: ItemId; op: TTypeAttachedOp; value: PSym) =
-  ## Overload that takes ItemId directly, useful for registering hooks from NIF index.
-  g.attachedOps[op][typeId] = value
+  g.attachedOps[op][t.itemId] = LazySym(sym: value)

 proc setAttachedOpPartial*(g: ModuleGraph; module: int; t: PType; op: TTypeAttachedOp; value: PSym) =
  ## we also need to record this to the packed module.
-  g.attachedOps[op][t.itemId] = value
+  g.attachedOps[op][t.itemId] = LazySym(sym: value)

-proc completePartialOp*(g: ModuleGraph; module: int; t: PType; op: TTypeAttachedOp; value: PSym) {.inline.} =
-  discard
+proc completePartialOp*(g: ModuleGraph; module: int; t: PType; op: TTypeAttachedOp; value: PSym) =
+  if g.config.symbolFiles != disabledSf:
+    assert module < g.encoders.len
+    assert isActive(g.encoders[module])
+    toPackedGeneratedProcDef(value, g.encoders[module], g.packed[module].fromDisk)
+    #storeAttachedProcDef(t, op, value, g.encoders[module], g.packed[module].fromDisk)

 iterator getDispatchers*(g: ModuleGraph): PSym =
  for i in g.dispatchers.mitems:
-    yield i
+    yield resolveSym(g, i)

 proc addDispatchers*(g: ModuleGraph, value: PSym) =
  # TODO: add it for packed modules
-  g.dispatchers.add value
+  g.dispatchers.add LazySym(sym: value)

-iterator resolveLazySymSeq(g: ModuleGraph, list: var seq[PSym]): PSym =
+iterator resolveLazySymSeq(g: ModuleGraph, list: var seq[LazySym]): PSym =
  for it in list.mitems:
-    yield it
+    yield resolveSym(g, it)

-proc setMethodsPerType*(g: ModuleGraph; id: ItemId, methods: seq[PSym]) =
+proc setMethodsPerType*(g: ModuleGraph; id: ItemId, methods: seq[LazySym]) =
  # TODO: add it for packed modules
  g.methodsPerType[id] = methods

-proc addNifReplayAction*(g: ModuleGraph; module: int32; n: PNode) =
-  ## Stores a replay action for NIF-based incremental compilation.
-  g.nifReplayActions.mgetOrPut(module, @[]).add n
-
 iterator getMethodsPerType*(g: ModuleGraph; t: PType): PSym =
  if g.methodsPerType.contains(t.itemId):
    for it in mitems g.methodsPerType[t.itemId]:
-      yield it
+      yield resolveSym(g, it)

 proc getToStringProc*(g: ModuleGraph; t: PType): PSym =
-  result = g.enumToStringProcs.getOrDefault(t.itemId)
-  if result == nil and g.config.cmd in {cmdNifC, cmdM}:
-    let key = typeKey(t, g.config, loadTypeCallback, loadSymCallback)
-    result = g.loadedEnumToStringProcs.getOrDefault(key)
+  result = resolveSym(g, g.enumToStringProcs[t.itemId])
  assert result != nil

 proc setToStringProc*(g: ModuleGraph; t: PType; value: PSym) =
-  g.enumToStringProcs[t.itemId] = value
-  let key = typeKey(t, g.config, loadTypeCallback, loadSymCallback)
-  let ownerModule = if t.sym != nil: t.sym.itemId.module.int else: value.itemId.module.int
-  g.opsLog.add LogEntry(kind: EnumToStrEntry, module: ownerModule, key: key, sym: value)
+  g.enumToStringProcs[t.itemId] = LazySym(sym: value)

 iterator methodsForGeneric*(g: ModuleGraph; t: PType): (int, PSym) =
  if g.methodsPerGenericType.contains(t.itemId):
    for it in mitems g.methodsPerGenericType[t.itemId]:
-      yield (it[0], it[1])
+      yield (it[0], resolveSym(g, it[1]))

 proc addMethodToGeneric*(g: ModuleGraph; module: int; t: PType; col: int; m: PSym) =
-  g.methodsPerGenericType.mgetOrPut(t.itemId, @[]).add (col, m)
-  let key = typeKey(t, g.config, loadTypeCallback, loadSymCallback)
-  let ownerModule = if t.sym != nil: t.sym.itemId.module.int else: module
-  g.opsLog.add LogEntry(kind: MethodEntry, module: ownerModule, key: key, sym: m)
-
-proc logGenericInstance*(g: ModuleGraph; inst: PSym) =
-  ## Log a generic instance so it gets written to the NIF file.
-  ## This is needed when generic instances are created during compile-time
-  ## evaluation and may be referenced from other modules compiled in the same run.
-  if g.config.cmd in {cmdNifC, cmdM}:
-    let ownerModule = inst.itemId.module.int
-    g.opsLog.add LogEntry(kind: GenericInstEntry, module: ownerModule, sym: inst)
+  g.methodsPerGenericType.mgetOrPut(t.itemId, @[]).add (col, LazySym(sym: m))

 proc hasDisabledAsgn*(g: ModuleGraph; t: PType): bool =
  let op = getAttachedOp(g, t, attachedAsgn)
@@ -377,31 +405,21 @@ proc copyTypeProps*(g: ModuleGraph; module: int; dest, src: PType) =

 proc loadCompilerProc*(g: ModuleGraph; name: string): PSym =
  result = nil
-  if g.config.symbolFiles == disabledSf and optWithinConfigSystem notin g.config.globalOptions:
-    # For NIF-based compilation, search in loaded NIF modules
-    when not defined(nimKochBootstrap):
-      # Try to resolve from NIF for both cmdNifC and cmdM (which uses NIF files)
-      if g.config.cmd in {cmdNifC, cmdM}:
-        # First try system module (most compilerprocs are there)
-        let systemFileIdx = g.config.m.systemFileIdx
-        if systemFileIdx != InvalidFileIdx and not g.withinSystem:
-          # Only try to load from NIF if the file exists (it may not during initial ic build)
-          result = tryResolveCompilerProc(ast.program, name, systemFileIdx)
-          if result != nil:
-            strTableAdd(g.compilerprocs, result)
-            return result
+  if g.config.symbolFiles == disabledSf: return nil

-        # Try threadpool module (some compilerprocs like FlowVar are there)
-        # Find threadpool module by searching loaded modules
-        for moduleIdx in 0..<g.ifaces.len:
-          let module = g.ifaces[moduleIdx].module
-          if module != nil and module.name.s == "threadpool":
-            let threadpoolFileIdx = module.position.FileIndex
-            result = tryResolveCompilerProc(ast.program, name, threadpoolFileIdx)
-            if result != nil:
-              strTableAdd(g.compilerprocs, result)
-              return result
-    return nil
+  # slow, linear search, but the results are cached:
+  for module in 0..<len(g.packed):
+    #if isCachedModule(g, module):
+    let x = searchForCompilerproc(g.packed[module], name)
+    if x >= 0:
+      result = loadSymFromId(g.config, g.cache, g.packed, module, toPackedItemId(x))
+      if result != nil:
+        strTableAdd(g.compilerprocs, result)
+      return result
+
+proc loadPackedSym*(g: ModuleGraph; s: var LazySym) =
+  if s.sym == nil:
+    s.sym = loadSymFromId(g.config, g.cache, g.packed, s.id.module, s.id.packed)

 proc `$`*(u: SigHash): string =
  toBase64a(cast[cstring](unsafeAddr u), sizeof(u))
@@ -421,10 +439,10 @@ template getPContext(): untyped =
  else: c.c

 when defined(nimsuggest):
-  template onUse*(info: TLineInfo; s: PSym; isGenericInstance = false) = discard
+  template onUse*(info: TLineInfo; s: PSym) = discard
  template onDefResolveForward*(info: TLineInfo; s: PSym) = discard
 else:
-  template onUse*(info: TLineInfo; s: PSym; isGenericInstance = false) = discard
+  template onUse*(info: TLineInfo; s: PSym) = discard
  template onDef*(info: TLineInfo; s: PSym) = discard
  template onDefResolveForward*(info: TLineInfo; s: PSym) = discard

@@ -439,49 +457,6 @@ proc createMagic*(g: ModuleGraph; idgen: IdGenerator; name: string, m: TMagic):
 proc createMagic(g: ModuleGraph; name: string, m: TMagic): PSym =
  result = createMagic(g, g.idgen, name, m)

-proc uniqueModuleName*(conf: ConfigRef; m: PSym): string =
-  ## The unique module name is guaranteed to only contain {'A'..'Z', 'a'..'z', '0'..'9', '_'}
-  ## so that it is useful as a C identifier snippet.
-  let fid = FileIndex(m.position)
-  let path = AbsoluteFile toFullPath(conf, fid)
-  var isLib = false
-  var rel = ""
-  if path.string.startsWith(conf.libpath.string):
-    isLib = true
-    rel = relativeTo(path, conf.libpath).string
-  else:
-    rel = relativeTo(path, conf.projectPath).string
-
-  if not isLib and not belongsToProjectPackage(conf, m):
-    # special handlings for nimble packages
-    when DirSep == '\\':
-      let rel2 = replace(rel, '\\', '/')
-    else:
-      let rel2 = rel
-    const pkgs2 = "pkgs2/"
-    var start = rel2.find(pkgs2)
-    if start >= 0:
-      start += pkgs2.len
-      start += skipUntil(rel2, {'/'}, start)
-      if start+1 < rel2.len:
-        rel = "pkg/" & rel2[start+1..<rel.len] # strips paths
-
-  let trunc = if rel.endsWith(".nim"): rel.len - len(".nim") else: rel.len
-  result = newStringOfCap(trunc)
-  for i in 0..<trunc:
-    let c = rel[i]
-    case c
-    of 'a'..'z', '0'..'9':
-      result.add c
-    of {os.DirSep, os.AltSep}:
-      result.add 'Z' # because it looks a bit like '/'
-    of '.':
-      result.add 'O' # a circle
-    else:
-      # We mangle upper letters too so that there cannot
-      # be clashes with our special meanings of 'Z' and 'O'
-      result.addInt ord(c)
-
 proc registerModule*(g: ModuleGraph; m: PSym) =
  assert m != nil
  assert m.kind == skModule
@@ -489,32 +464,32 @@ proc registerModule*(g: ModuleGraph; m: PSym) =
  if m.position >= g.ifaces.len:
    setLen(g.ifaces, m.position + 1)

-  if g.ifaces[m.position].module == nil:
-    g.ifaces[m.position] = Iface(module: m, converters: @[], patterns: @[],
-                                uniqueName: rope(uniqueModuleName(g.config, m)))
-    initStrTables(g, m)
+  if m.position >= g.packed.len:
+    setLen(g.packed.pm, m.position + 1)
+
+  g.ifaces[m.position] = Iface(module: m, converters: @[], patterns: @[],
+                               uniqueName: rope(uniqueModuleName(g.config, FileIndex(m.position))))
+  initStrTables(g, m)

 proc registerModuleById*(g: ModuleGraph; m: FileIndex) =
-  registerModule(g, g.ifaces[int m].module)
+  registerModule(g, g.packed[int m].module)

 proc initOperators*(g: ModuleGraph): Operators =
  # These are safe for IC.
  # Public because it's used by DrNim.
-  result = Operators(
-    opLe: createMagic(g, "<=", mLeI),
-    opLt: createMagic(g, "<", mLtI),
-    opAnd: createMagic(g, "and", mAnd),
-    opOr: createMagic(g, "or", mOr),
-    opIsNil: createMagic(g, "isnil", mIsNil),
-    opEq: createMagic(g, "==", mEqI),
-    opAdd: createMagic(g, "+", mAddI),
-    opSub: createMagic(g, "-", mSubI),
-    opMul: createMagic(g, "*", mMulI),
-    opDiv: createMagic(g, "div", mDivI),
-    opLen: createMagic(g, "len", mLengthSeq),
-    opNot: createMagic(g, "not", mNot),
-    opContains: createMagic(g, "contains", mInSet)
-  )
+  result.opLe = createMagic(g, "<=", mLeI)
+  result.opLt = createMagic(g, "<", mLtI)
+  result.opAnd = createMagic(g, "and", mAnd)
+  result.opOr = createMagic(g, "or", mOr)
+  result.opIsNil = createMagic(g, "isnil", mIsNil)
+  result.opEq = createMagic(g, "==", mEqI)
+  result.opAdd = createMagic(g, "+", mAddI)
+  result.opSub = createMagic(g, "-", mSubI)
+  result.opMul = createMagic(g, "*", mMulI)
+  result.opDiv = createMagic(g, "div", mDivI)
+  result.opLen = createMagic(g, "len", mLengthSeq)
+  result.opNot = createMagic(g, "not", mNot)
+  result.opContains = createMagic(g, "contains", mInSet)

 proc initModuleGraphFields(result: ModuleGraph) =
  # A module ID of -1 means that the symbol is not attached to a module at all,
@@ -527,7 +502,7 @@ proc initModuleGraphFields(result: ModuleGraph) =
  result.importStack = @[]
  result.inclToMod = initTable[FileIndex, FileIndex]()
  result.owners = @[]
-  result.suggestSymbols = initTable[FileIndex, SuggestFileSymbolDatabase]()
+  result.suggestSymbols = initTable[FileIndex, seq[SymInfoPair]]()
  result.suggestErrors = initTable[FileIndex, seq[Suggest]]()
  result.methods = @[]
  result.compilerprocs = initStrTable()
@@ -541,15 +516,12 @@ proc initModuleGraphFields(result: ModuleGraph) =
  result.symBodyHashes = initTable[int, SigHash]()
  result.operators = initOperators(result)
  result.emittedTypeInfo = initTable[string, FileIndex]()
-  result.cachedFiles = newStringTable()
-  result.cachedMods = initIntSet()

 proc newModuleGraph*(cache: IdentCache; config: ConfigRef): ModuleGraph =
  result = ModuleGraph()
  result.config = config
  result.cache = cache
  initModuleGraphFields(result)
-  ast.setupProgram(config, cache)

 proc resetAllModules*(g: ModuleGraph) =
  g.packageSyms = initStrTable()
@@ -565,13 +537,49 @@ proc resetAllModules*(g: ModuleGraph) =
  initModuleGraphFields(g)

 proc getModule*(g: ModuleGraph; fileIdx: FileIndex): PSym =
-  if fileIdx.int32 >= 0 and fileIdx.int32 < g.ifaces.len:
-    result = g.ifaces[fileIdx.int32].module
-  else:
-    result = nil
+  result = nil
+  if fileIdx.int32 >= 0:
+    if isCachedModule(g, fileIdx.int32):
+      result = g.packed[fileIdx.int32].module
+    elif fileIdx.int32 < g.ifaces.len:
+      result = g.ifaces[fileIdx.int32].module

 proc moduleOpenForCodegen*(g: ModuleGraph; m: FileIndex): bool {.inline.} =
-  result = true
+  if g.config.symbolFiles == disabledSf:
+    result = true
+  else:
+    result = g.packed[m.int32].status notin {undefined, stored, loaded}
+
+proc rememberEmittedTypeInfo*(g: ModuleGraph; m: FileIndex; ti: string) =
+  #assert(not isCachedModule(g, m.int32))
+  if g.config.symbolFiles != disabledSf:
+    #assert g.encoders[m.int32].isActive
+    assert g.packed[m.int32].status != stored
+    g.packed[m.int32].fromDisk.emittedTypeInfo.add ti
+    #echo "added typeinfo ", m.int32, " ", ti, " suspicious ", not g.encoders[m.int32].isActive
+
+proc rememberFlag*(g: ModuleGraph; m: PSym; flag: ModuleBackendFlag) =
+  if g.config.symbolFiles != disabledSf:
+    #assert g.encoders[m.int32].isActive
+    assert g.packed[m.position].status != stored
+    g.packed[m.position].fromDisk.backendFlags.incl flag
+
+proc closeRodFile*(g: ModuleGraph; m: PSym) =
+  if g.config.symbolFiles in {readOnlySf, v2Sf}:
+    # For stress testing we seek to reload the symbols from memory. This
+    # way much of the logic is tested but the test is reproducible as it does
+    # not depend on the hard disk contents!
+    let mint = m.position
+    saveRodFile(toRodFile(g.config, AbsoluteFile toFullPath(g.config, FileIndex(mint))),
+                g.encoders[mint], g.packed[mint].fromDisk)
+    g.packed[mint].status = stored
+
+  elif g.config.symbolFiles == stressTest:
+    # debug code, but maybe a good idea for production? Could reduce the compiler's
+    # memory consumption considerably at the cost of more loads from disk.
+    let mint = m.position
+    simulateCachedModule(g, m, g.packed[mint].fromDisk)
+    g.packed[mint].status = loaded

 proc dependsOn(a, b: int): int {.inline.} = (a shl 15) + b

@@ -609,13 +617,14 @@ proc markDirty*(g: ModuleGraph; fileIdx: FileIndex) =
  if m != nil:
    g.suggestSymbols.del(fileIdx)
    g.suggestErrors.del(fileIdx)
-    incl m.flagsImpl, sfDirty
+    g.resetForBackend
+    incl m.flags, sfDirty

 proc unmarkAllDirty*(g: ModuleGraph) =
  for i in 0i32..<g.ifaces.len.int32:
    let m = g.ifaces[i].module
    if m != nil:
-      m.flagsImpl.excl sfDirty
+      m.flags.excl sfDirty

 proc isDirty*(g: ModuleGraph; m: PSym): bool =
  result = g.suggestMode and sfDirty in m.flags
@@ -655,59 +664,25 @@ proc needsCompilation*(g: ModuleGraph, fileIdx: FileIndex): bool =

 proc getBody*(g: ModuleGraph; s: PSym): PNode {.inline.} =
  result = s.ast[bodyPos]
+  if result == nil and g.config.symbolFiles in {readOnlySf, v2Sf, stressTest}:
+    result = loadProcBody(g.config, g.cache, g.packed, s)
+    s.ast[bodyPos] = result
  assert result != nil

-when not defined(nimKochBootstrap):
-  proc moduleFromNifFile*(g: ModuleGraph; fileIdx: FileIndex;
-                          flags: set[LoadFlag] = {}): PrecompiledModule =
-    ## Returns 'nil' if the module needs to be recompiled.
-    ## Loads module from NIF file when optCompress is enabled.
-    ## When loadFullAst is true, loads the complete module AST for code generation.
-    if not fileExists(toNifFilename(g.config, fileIdx)):
-      return PrecompiledModule(module: nil)
-
-    # Create module symbol
-    let filename = AbsoluteFile toFullPath(g.config, fileIdx)
-
-    let m = PSym(
-      kindImpl: skModule,
-      itemId: ItemId(module: int32(fileIdx), item: 0'i32),
-      name: getIdent(g.cache, splitFile(filename).name),
-      infoImpl: newLineInfo(fileIdx, 1, 1),
-      positionImpl: int(fileIdx))
-    setOwner(m, getPackage(g.config, g.cache, fileIdx))
-    # Register module in graph
-    registerModule(g, m)
-
-    result = loadNifModule(ast.program, fileIdx,
-                           g.ifaces[fileIdx.int].interf,
-                           g.ifaces[fileIdx.int].interfHidden, flags)
-    result.module = m
-
-    # Mark module as cached
-    g.cachedMods.incl fileIdx.int
-
-    # Register hooks from NIF index with the module graph
-    for x in result.logOps:
-      case x.kind
-      of HookEntry:
-        g.loadedOps[x.op][x.key] = x.sym
-      of ConverterEntry:
-        g.ifaces[fileIdx.int].converters.add x.sym
-      of MethodEntry:
-        discard "todo"
-      of EnumToStrEntry:
-        g.loadedEnumToStringProcs[x.key] = x.sym
-      of GenericInstEntry:
-        raiseAssert "GenericInstEntry should not be in the NIF index"
-    # Register methods per type from NIF index
-    discard "todo"
+proc moduleFromRodFile*(g: ModuleGraph; fileIdx: FileIndex;
+                        cachedModules: var seq[FileIndex]): PSym =
+  ## Returns 'nil' if the module needs to be recompiled.
+  if g.config.symbolFiles in {readOnlySf, v2Sf, stressTest}:
+    result = moduleFromRodFile(g.packed, g.config, g.cache, fileIdx, cachedModules)
+  else:
+    result = nil

 proc configComplete*(g: ModuleGraph) =
-  #rememberStartupConfig(g.startupPackedConfig, g.config)
-  discard
+  rememberStartupConfig(g.startupPackedConfig, g.config)

-proc onProcessing*(graph: ModuleGraph, fileIdx: FileIndex, moduleStatus: string, fromModule: PSym) =
+from std/strutils import repeat, `%`
+
+proc onProcessing*(graph: ModuleGraph, fileIdx: FileIndex, moduleStatus: string, fromModule: PSym, ) =
  let conf = graph.config
  let isNimscript = conf.isDefined("nimscript")
  if (not isNimscript) or hintProcessing in conf.cmdlineNotes:
@@ -728,18 +703,20 @@ proc getPackage*(graph: ModuleGraph; fileIdx: FileIndex): PSym =
    result = pkgSym
    graph.packageSyms.strTableAdd(pkgSym)

-proc belongsToStdlib*(graph: ModuleGraph, sym: PSym): bool =
+func belongsToStdlib*(graph: ModuleGraph, sym: PSym): bool =
  ## Check if symbol belongs to the 'stdlib' package.
  sym.getPackageSymbol.getPackageId == graph.systemModule.getPackageId

-proc fileSymbols*(graph: ModuleGraph, fileIdx: FileIndex): SuggestFileSymbolDatabase =
-  result = graph.suggestSymbols.getOrDefault(fileIdx, newSuggestFileSymbolDatabase(fileIdx, optIdeExceptionInlayHints in graph.config.globalOptions))
-  doAssert(result.fileIndex == fileIdx)
+proc `==`*(a, b: SymInfoPair): bool =
+  result = a.sym == b.sym and a.info.exactEquals(b.info)
+
+proc fileSymbols*(graph: ModuleGraph, fileIdx: FileIndex): seq[SymInfoPair] =
+  result = graph.suggestSymbols.getOrDefault(fileIdx, @[])

 iterator suggestSymbolsIter*(g: ModuleGraph): SymInfoPair =
  for xs in g.suggestSymbols.values:
-    for i in xs.lineInfo.low..xs.lineInfo.high:
-      yield xs.getSymInfoPair(i)
+    for x in xs:
+      yield x

 iterator suggestErrorsIter*(g: ModuleGraph): Suggest =
  for xs in g.suggestErrors.values:
--- a/compiler/modulepaths.nim
+++ b/compiler/modulepaths.nim
@@ -38,18 +38,11 @@ proc getModuleName*(conf: ConfigRef; n: PNode): string =
          localError(n.info, "only '/' supported with $package notation")
          result = ""
    else:
-      if n0.kind in nkIdentKinds:
-        let ident = n0.getPIdent
-        if ident != nil and ident.s[0] == '/':
-          let modname = getModuleName(conf, n[2])
-          # hacky way to implement 'x / y /../ z':
-          result = getModuleName(conf, n1)
-          result.add renderTree(n0, {renderNoComments}).replace(" ")
-          result.add modname
-        else:
-          result = ""
-      else:
-        result = ""
+      let modname = getModuleName(conf, n[2])
+      # hacky way to implement 'x / y /../ z':
+      result = getModuleName(conf, n1)
+      result.add renderTree(n0, {renderNoComments}).replace(" ")
+      result.add modname
  of nkPrefix:
    when false:
      if n[0].kind == nkIdent and n[0].ident.s == "$":
@@ -79,10 +72,6 @@ proc checkModuleName*(conf: ConfigRef; n: PNode; doLocalError=true): FileIndex =
  else:
    result = fileInfoIdx(conf, fullPath)

-type
-  SelectedBase = enum
-    FromProject, FromSearchPath, FromNimblePath
-
 proc mangleModuleName*(conf: ConfigRef; path: AbsoluteFile): string =
  ## Mangle a relative module path to avoid path and symbol collisions.
  ##
@@ -91,29 +80,9 @@ proc mangleModuleName*(conf: ConfigRef; path: AbsoluteFile): string =
  ##
  ## Example:
  ## `foo-#head/../bar` becomes `@foo-@hhead@s..@sbar`
-  var best = relativeTo(path, conf.projectPath).string
-  var selectedBase = FromProject
-  for x in conf.searchPaths:
-    let other = relativeTo(path, x).string
-    if other.len < best.len:
-      best = other
-      selectedBase = FromSearchPath
-  for x in conf.nimblePaths:
-    let other = relativeTo(path, x).string
-    if other.len < best.len:
-      best = other
-      selectedBase = FromNimblePath
-  let prefix =
-    case selectedBase
-    of FromProject: "@m"
-    of FromSearchPath: "@p"
-    of FromNimblePath: "@n"
-
-  # Note: We encode ".." specially as "@d" to avoid issues with changeFileExt
-  # which would misinterpret ".." as "name.ext" and strip the second part.
-  prefix & best.multiReplace(
-    {"..": "@d", $os.DirSep: "@s", $os.AltSep: "@s", "#": "@h", "@": "@@", ":": "@c"})
+  "@m" & relativeTo(path, conf.projectPath).string.multiReplace(
+    {$os.DirSep: "@s", $os.AltSep: "@s", "#": "@h", "@": "@@", ":": "@c"})

 proc demangleModuleName*(path: string): string =
  ## Demangle a relative module path.
-  result = path.multiReplace({"@@": "@", "@d": "..", "@h": "#", "@s": "/", "@m": "", "@p": "", "@n": "", "@c": ":"})
+  result = path.multiReplace({"@@": "@", "@h": "#", "@s": "/", "@m": "", "@c": ":"})
--- a/compiler/modules.nim
+++ b/compiler/modules.nim
@@ -14,9 +14,6 @@ import
  idents, lexer, syntaxes, modulegraphs,
  lineinfos, pathutils

-import ../dist/checksums/src/checksums/sha1
-import std/strtabs
-
 proc resetSystemArtifacts*(g: ModuleGraph) =
  magicsys.resetSysTypes(g)

@@ -25,16 +22,16 @@ template getModuleIdent(graph: ModuleGraph, filename: AbsoluteFile): PIdent =

 proc partialInitModule*(result: PSym; graph: ModuleGraph; fileIdx: FileIndex; filename: AbsoluteFile) =
  let packSym = getPackage(graph, fileIdx)
-  setOwner(result, packSym)
+  result.owner = packSym
  result.position = int fileIdx

 proc newModule*(graph: ModuleGraph; fileIdx: FileIndex): PSym =
  let filename = AbsoluteFile toFullPath(graph.config, fileIdx)
  # We cannot call ``newSym`` here, because we have to circumvent the ID
  # mechanism, which we do in order to assign each module a persistent ID.
-  result = PSym(kindImpl: skModule, itemId: ItemId(module: int32(fileIdx), item: 0'i32),
+  result = PSym(kind: skModule, itemId: ItemId(module: int32(fileIdx), item: 0'i32),
                name: getModuleIdent(graph, filename),
-                infoImpl: newLineInfo(fileIdx, 1, 1))
+                info: newLineInfo(fileIdx, 1, 1))
  if not isNimIdentifier(result.name.s):
    rawMessage(graph.config, errGenerated, "invalid module name: '" & result.name.s &
              "'; a module name must be a valid Nim identifier.")
@@ -45,8 +42,6 @@ proc includeModule*(graph: ModuleGraph; s: PSym, fileIdx: FileIndex): PNode =
  result = syntaxes.parseFile(fileIdx, graph.cache, graph.config)
  graph.addDep(s, fileIdx)
  graph.addIncludeDep(s.position.FileIndex, fileIdx)
-  let path = toFullPath(graph.config, fileIdx)
-  graph.cachedFiles[path] = $secureHashFile(path)

 proc wantMainModule*(conf: ConfigRef) =
  if conf.projectFull.isEmpty:
--- a/compiler/msgs.nim
+++ b/compiler/msgs.nim
@@ -30,6 +30,7 @@ proc toLowerAscii(a: var string) {.inline.} =

 proc flushDot*(conf: ConfigRef) =
  ## safe to call multiple times
+  # xxx one edge case not yet handled is when `printf` is called at CT with `compiletimeFFI`.
  let stdOrr = if optStdout in conf.globalOptions: stdout else: stderr
  let stdOrrKind = toStdOrrKind(stdOrr)
  if stdOrrKind in conf.lastMsgWasDot:
@@ -51,7 +52,7 @@ proc makeCString*(s: string): Rope =
  result = newStringOfCap(int(s.len.toFloat * 1.1) + 1)
  result.add("\"")
  for i in 0..<s.len:
-    # line wrapping of string literals in cgen'd code was a bad idea, e.g. causes: bug #16265
+    # line wrapping of string litterals in cgen'd code was a bad idea, e.g. causes: bug #16265
    # It also makes reading c sources or grepping harder, for zero benefit.
    # const MaxLineLength = 64
    # if (i + 1) mod MaxLineLength == 0:
@@ -59,13 +60,31 @@ proc makeCString*(s: string): Rope =
    toCChar(s[i], result)
  result.add('\"')

-proc newFileInfo(fullPath: AbsoluteFile, projPath: RelativeFile; kind = fikSource): TFileInfo =
-  result = TFileInfo(fullPath: fullPath, projPath: projPath,
-                    shortName: fullPath.extractFilename,
-                    quotedFullName: fullPath.string.makeCString,
-                    lines: @[],
-                    kind: kind)
+proc makeCCharArray*(s: string): Rope =
+  result = newStringOfCap(int(s.len.toFloat * 1.1) + 1)
+  result.add("{")
+  for i in 0..<s.len:
+    # line wrapping of string litterals in cgen'd code was a bad idea, e.g. causes: bug #16265
+    # It also makes reading c sources or grepping harder, for zero benefit.
+    # const MaxLineLength = 64
+    # if (i + 1) mod MaxLineLength == 0:
+    #   res.add("\"\L\"")
+    if i != 0:
+      result.add ", "
+    result.add '\''
+    toCChar(s[i], result)
+    result.add '\''
+  result.add('}')
+
+proc newFileInfo(fullPath: AbsoluteFile, projPath: RelativeFile): TFileInfo =
+  result.fullPath = fullPath
+  #shallow(result.fullPath)
+  result.projPath = projPath
+  #shallow(result.projPath)
+  result.shortName = fullPath.extractFilename
  result.quotedName = result.shortName.makeCString
+  result.quotedFullName = fullPath.string.makeCString
+  result.lines = @[]
  when defined(nimpretty):
    if not result.fullPath.isEmpty:
      try:
@@ -122,35 +141,18 @@ proc fileInfoIdx*(conf: ConfigRef; filename: AbsoluteFile; isKnownFile: var bool
    conf.m.filenameToIndexTbl[canon2] = result

 proc fileInfoIdx*(conf: ConfigRef; filename: AbsoluteFile): FileIndex =
-  var dummy: bool = false
+  var dummy: bool
  result = fileInfoIdx(conf, filename, dummy)

 proc fileInfoIdx*(conf: ConfigRef; filename: RelativeFile; isKnownFile: var bool): FileIndex =
  fileInfoIdx(conf, AbsoluteFile expandFilename(filename.string), isKnownFile)

 proc fileInfoIdx*(conf: ConfigRef; filename: RelativeFile): FileIndex =
-  var dummy: bool = false
+  var dummy: bool
  fileInfoIdx(conf, AbsoluteFile expandFilename(filename.string), dummy)

-proc registerNifSuffix*(conf: ConfigRef; suffix: string; isKnownFile: var bool): FileIndex =
-  result = conf.m.filenameToIndexTbl.getOrDefault(suffix, InvalidFileIdx)
-  if result == InvalidFileIdx:
-    isKnownFile = false
-    result = conf.m.fileInfos.len.FileIndex
-    conf.m.fileInfos.add(newFileInfo(AbsoluteFile suffix, RelativeFile suffix, fikNifModule))
-    conf.m.filenameToIndexTbl[suffix] = result
-  else:
-    isKnownFile = true
-
-proc fileInfoKind*(conf: ConfigRef; fileIdx: FileIndex): FileInfoKind =
-  ## Returns the kind of a FileIndex (source file or NIF module suffix).
-  if fileIdx.int >= 0 and fileIdx.int < conf.m.fileInfos.len:
-    result = conf.m.fileInfos[fileIdx.int].kind
-  else:
-    result = fikSource  # Default to source for unknown indices
-
 proc newLineInfo*(fileInfoIdx: FileIndex, line, col: int): TLineInfo =
-  result = TLineInfo(fileIndex: fileInfoIdx)
+  result.fileIndex = fileInfoIdx
  if line < int high(uint16):
    result.line = uint16(line)
  else:
@@ -240,7 +242,7 @@ proc setDirtyFile*(conf: ConfigRef; fileIdx: FileIndex; filename: AbsoluteFile)

 proc setHash*(conf: ConfigRef; fileIdx: FileIndex; hash: string) =
  assert fileIdx.int32 >= 0
-  when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc) or defined(gcYrc):
+  when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc):
    conf.m.fileInfos[fileIdx.int32].hash = hash
  else:
    shallowCopy(conf.m.fileInfos[fileIdx.int32].hash, hash)
@@ -248,7 +250,7 @@ proc setHash*(conf: ConfigRef; fileIdx: FileIndex; hash: string) =

 proc getHash*(conf: ConfigRef; fileIdx: FileIndex): string =
  assert fileIdx.int32 >= 0
-  when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc) or defined(gcYrc):
+  when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc):
    result = conf.m.fileInfos[fileIdx.int32].hash
  else:
    shallowCopy(result, conf.m.fileInfos[fileIdx.int32].hash)
@@ -445,8 +447,7 @@ To create a stacktrace, rerun compilation with './koch temp $1 <file>', see $2 f
 proc handleError(conf: ConfigRef; msg: TMsgKind, eh: TErrorHandling, s: string, ignoreMsg: bool) =
  if msg in fatalMsgs:
    if conf.cmd == cmdIdeTools: log(s)
-    if conf.cmd != cmdIdeTools or msg != errFatal:
-      quit(conf, msg)
+    quit(conf, msg)
  if msg >= errMin and msg <= errMax or
      (msg in warnMin..hintMax and msg in conf.warningAsErrors and not ignoreMsg):
    inc(conf.errorCounter)
@@ -454,11 +455,7 @@ proc handleError(conf: ConfigRef; msg: TMsgKind, eh: TErrorHandling, s: string,
    if conf.errorCounter >= conf.errorMax:
      # only really quit when we're not in the new 'nim check --def' mode:
      if conf.ideCmd == ideNone:
-        when defined(nimsuggest):
-          #we need to inform the user that something went wrong when initializing NimSuggest
-          raiseRecoverableError(s)
-        else:
-          quit(conf, msg)
+        quit(conf, msg)
    elif eh == doAbort and conf.cmd != cmdIdeTools:
      quit(conf, msg)
    elif eh == doRaise:
@@ -576,10 +573,9 @@ proc liMessage*(conf: ConfigRef; info: TLineInfo, msg: TMsgKind, arg: string,
    ignoreMsg = not conf.hasHint(msg)
    if not ignoreMsg and msg in conf.warningAsErrors:
      title = ErrorTitle
-      color = ErrorColor
    else:
      title = HintTitle
-      color = HintColor
+    color = HintColor
    inc(conf.hintCounter)

  let s = if isRaw: arg else: getMessageStr(msg, arg)
@@ -645,7 +641,7 @@ proc warningDeprecated*(conf: ConfigRef, info: TLineInfo = gCmdLineInfo, msg = "
  message(conf, info, warnDeprecated, msg)

 proc internalErrorImpl(conf: ConfigRef; info: TLineInfo, errMsg: string, info2: InstantiationInfo) =
-  if conf.cmd in {cmdIdeTools, cmdCheck} and conf.structuredErrorHook.isNil: return
+  if conf.cmd == cmdIdeTools and conf.structuredErrorHook.isNil: return
  writeContext(conf, info)
  liMessage(conf, info, errInternal, errMsg, doAbort, info2)

@@ -664,21 +660,16 @@ template internalAssert*(conf: ConfigRef, e: bool) =

 template lintReport*(conf: ConfigRef; info: TLineInfo, beau, got: string, extraMsg = "") =
  let m = "'$1' should be: '$2'$3" % [got, beau, extraMsg]
-  let msg = if optStyleError in conf.globalOptions: errGenerated
-            elif optStyleWarning in conf.globalOptions: warnUser
-            else: hintName
+  let msg = if optStyleError in conf.globalOptions: errGenerated else: hintName
  liMessage(conf, info, msg, m, doNothing, instLoc())

-proc quotedFilename*(conf: ConfigRef; fi: FileIndex): Rope =
-  if fi.int32 < 0:
+proc quotedFilename*(conf: ConfigRef; i: TLineInfo): Rope =
+  if i.fileIndex.int32 < 0:
    result = makeCString "???"
  elif optExcessiveStackTrace in conf.globalOptions:
-    result = conf.m.fileInfos[fi.int32].quotedFullName
+    result = conf.m.fileInfos[i.fileIndex.int32].quotedFullName
  else:
-    result = conf.m.fileInfos[fi.int32].quotedName
-
-proc quotedFilename*(conf: ConfigRef; i: TLineInfo): Rope =
-  quotedFilename(conf, i.fileIndex)
+    result = conf.m.fileInfos[i.fileIndex.int32].quotedName

 template listMsg(title, r) =
  msgWriteln(conf, title, {msgNoUnitSep})
@@ -687,6 +678,31 @@ template listMsg(title, r) =
 proc listWarnings*(conf: ConfigRef) = listMsg("Warnings:", warnMin..warnMax)
 proc listHints*(conf: ConfigRef) = listMsg("Hints:", hintMin..hintMax)

+proc uniqueModuleName*(conf: ConfigRef; fid: FileIndex): string =
+  ## The unique module name is guaranteed to only contain {'A'..'Z', 'a'..'z', '0'..'9', '_'}
+  ## so that it is useful as a C identifier snippet.
+  let path = AbsoluteFile toFullPath(conf, fid)
+  let rel =
+    if path.string.startsWith(conf.libpath.string):
+      relativeTo(path, conf.libpath).string
+    else:
+      relativeTo(path, conf.projectPath).string
+  let trunc = if rel.endsWith(".nim"): rel.len - len(".nim") else: rel.len
+  result = newStringOfCap(trunc)
+  for i in 0..<trunc:
+    let c = rel[i]
+    case c
+    of 'a'..'z':
+      result.add c
+    of {os.DirSep, os.AltSep}:
+      result.add 'Z' # because it looks a bit like '/'
+    of '.':
+      result.add 'O' # a circle
+    else:
+      # We mangle upper letters and digits too so that there cannot
+      # be clashes with our special meanings of 'Z' and 'O'
+      result.addInt ord(c)
+
 proc genSuccessX*(conf: ConfigRef) =
  let mem =
    when declared(system.getMaxMem): formatSize(getMaxMem()) & " peakmem"
--- a/compiler/ndi.nim
+++ b/compiler/ndi.nim
@@ -0,0 +1,52 @@
+#
+#
+#           The Nim Compiler
+#        (c) Copyright 2017 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## This module implements the generation of ``.ndi`` files for better debugging
+## support of Nim code. "ndi" stands for "Nim debug info".
+
+import ast, msgs, ropes, options, pathutils
+
+when defined(nimPreviewSlimSystem):
+  import std/[syncio, assertions]
+
+type
+  NdiFile* = object
+    enabled: bool
+    f: File
+    buf: string
+    filename: AbsoluteFile
+    syms: seq[PSym]
+
+proc doWrite(f: var NdiFile; s: PSym; conf: ConfigRef) =
+  f.buf.setLen 0
+  f.buf.addInt s.info.line.int
+  f.buf.add "\t"
+  f.buf.addInt s.info.col.int
+  f.f.write(s.name.s, "\t")
+  f.f.writeRope(s.loc.r)
+  f.f.writeLine("\t", toFullPath(conf, s.info), "\t", f.buf)
+
+template writeMangledName*(f: NdiFile; s: PSym; conf: ConfigRef) =
+  if f.enabled: f.syms.add s
+
+proc open*(f: var NdiFile; filename: AbsoluteFile; conf: ConfigRef) =
+  f.enabled = not filename.isEmpty
+  if f.enabled:
+    f.filename = filename
+    f.buf = newStringOfCap(20)
+
+proc close*(f: var NdiFile, conf: ConfigRef) =
+  if f.enabled:
+    f.f = open(f.filename.string, fmWrite, 8000)
+    doAssert f.f != nil, f.filename.string
+    for s in f.syms:
+      doWrite(f, s, conf)
+    close(f.f)
+    f.syms.reset
+    f.filename.reset
--- a/compiler/nifbackend.nim
+++ b/compiler/nifbackend.nim
@@ -1,156 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2025 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-## NIF-based C/C++ code generator backend.
-##
-## This module implements C code generation from precompiled NIF files.
-## It traverses the module dependency graph starting from the main module
-## and generates C code for all reachable modules.
-##
-## Usage:
-##   1. Compile modules to NIF: nim m mymodule.nim
-##   2. Generate C from NIF: nim nifc myproject.nim
-
-import std/[intsets, tables, sets, os]
-
-when defined(nimPreviewSlimSystem):
-  import std/assertions
-
-import ast, options, lineinfos, modulegraphs, cgendata, cgen,
-  pathutils, extccomp, msgs, modulepaths, idents, types, ast2nif
-
-proc loadModuleDependencies(g: ModuleGraph; mainFileIdx: FileIndex): seq[PrecompiledModule] =
-  ## Traverse the module dependency graph using a stack.
-  ## Returns all modules that need code generation, in dependency order.
-  let mainModule = moduleFromNifFile(g, mainFileIdx, {LoadFullAst})
-
-  var stack: seq[ModuleSuffix] = @[]
-  result = @[]
-
-  if mainModule.module != nil:
-    incl mainModule.module.flagsImpl, sfMainModule
-    for dep in mainModule.deps:
-      stack.add dep
-
-  var visited = initHashSet[string]()
-
-  while stack.len > 0:
-    let suffix = stack.pop()
-
-    if not visited.containsOrIncl(suffix.string):
-      var isKnownFile = false
-      let fileIdx = g.config.registerNifSuffix(suffix.string, isKnownFile)
-      let precomp = moduleFromNifFile(g, fileIdx, {LoadFullAst})
-      if precomp.module != nil:
-        result.add precomp
-        for dep in precomp.deps:
-          if not visited.contains(dep.string):
-            stack.add dep
-      else:
-        assert false, "Recompiling module is not implemented."
-
-  if mainModule.module != nil:
-    result.add mainModule
-
-proc setupNifBackendModule(g: ModuleGraph; module: PSym): BModule =
-  ## Set up a BModule for code generation from a NIF module.
-  if g.backend == nil:
-    g.backend = cgendata.newModuleList(g)
-  result = cgen.newModule(BModuleList(g.backend), module, g.config, idGeneratorFromModule(module))
-
-proc finishModule(g: ModuleGraph; bmod: BModule) =
-  # Finalize the module (this adds it to modulesClosed)
-  # Create an empty stmt list as the init body - genInitCode in writeModule will set it up properly
-  let initStmt = newNode(nkStmtList)
-  finalCodegenActions(g, bmod, initStmt)
-
-  # Generate dispatcher methods
-  for disp in getDispatchers(g):
-    genProcLvl3(bmod, disp)
-
-proc generateCodeForModule(g: ModuleGraph; precomp: PrecompiledModule) =
-  ## Generate C code for a single module.
-  let moduleId = precomp.module.position
-  var bmod = BModuleList(g.backend).mods[moduleId]
-  if bmod == nil:
-    bmod = setupNifBackendModule(g, precomp.module)
-
-  # Generate code for the module's top-level statements
-  if precomp.topLevel != nil:
-    cgen.genTopLevelStmt(bmod, precomp.topLevel)
-
-proc generateCode*(g: ModuleGraph; mainFileIdx: FileIndex) =
-  ## Main entry point for NIF-based C code generation.
-  ## Traverses the module dependency graph and generates C code.
-
-  # Reset backend state
-  resetForBackend(g)
-
-  var isKnownFile = false
-  let systemFileIdx = registerNifSuffix(g.config, "sysma2dyk", isKnownFile)
-  g.config.m.systemFileIdx = systemFileIdx
-  #msgs.fileInfoIdx(g.config,
-  #    g.config.libpath / RelativeFile"system.nim")
-
-  # Load system module first - it's always needed and contains essential hooks
-  var precompSys = PrecompiledModule(module: nil)
-  precompSys = moduleFromNifFile(g, systemFileIdx, {LoadFullAst, AlwaysLoadInterface})
-  g.systemModule = precompSys.module
-
-  # Load all modules in dependency order using stack traversal
-  # This must happen BEFORE any code generation so that hooks are loaded into loadedOps
-  let modules = loadModuleDependencies(g, mainFileIdx)
-  if modules.len == 0:
-    rawMessage(g.config, errGenerated,
-      "Cannot load NIF file for main module: " & toFullPath(g.config, mainFileIdx))
-    return
-
-  # Set up backend modules for all modules that need code generation
-  for m in modules:
-    discard setupNifBackendModule(g, m.module)
-
-  # Also ensure system module is set up and generated first if it exists
-  if precompSys.module != nil:
-    discard setupNifBackendModule(g, precompSys.module)
-    generateCodeForModule(g, precompSys)
-
-  # Track which modules have been processed to avoid duplicates
-  var processed = initIntSet()
-  if precompSys.module != nil:
-    processed.incl precompSys.module.position
-
-  # Generate code for all modules (skip system since it's already processed)
-  for m in modules:
-    if not processed.containsOrIncl(m.module.position):
-      generateCodeForModule(g, m)
-
-  # during code generation of `main.nim` we can trigger the code generation
-  # of symbols in different modules so we need to finish these modules
-  # here later, after the above loop!
-  # Important: The main module must be finished LAST so that all other modules
-  # have registered their init procs before genMainProc uses them.
-  var mainModule: BModule = nil
-  for m in BModuleList(g.backend).mods:
-    if m != nil:
-      assert m.module != nil
-      if sfMainModule in m.module.flags:
-        mainModule = m
-      else:
-        finishModule g, m
-  if mainModule != nil:
-    finishModule g, mainModule
-
-  # Write C files
-  cgenWriteModules(g.backend, g.config)
-
-  # Run C compiler
-  if g.config.cmd != cmdTcc:
-    extccomp.callCCompiler(g.config)
-    if not g.config.hcrOn:
-      extccomp.writeJsonBuildInstructions(g.config, g.cachedFiles)
--- a/compiler/nifgen.nim
+++ b/compiler/nifgen.nim
--- a/compiler/nilcheck.nim
+++ b/compiler/nilcheck.nim
@@ -498,7 +498,7 @@ proc checkCall(n, ctx, map): Check =
  # check args and handle possible mutations

  var isNew = false
-  result = Check(map: map)
+  result.map = map
  for i, child in n:
    discard check(child, ctx, map)

@@ -507,7 +507,7 @@ proc checkCall(n, ctx, map): Check =
      # as it might have been mutated
      # TODO similar for normal refs and fields: find dependent exprs: brackets

-      if child.kind == nkHiddenAddr and not child.typ.isNil and child.typ.kind == tyVar and child.typ.elementType.kind == tyRef:
+      if child.kind == nkHiddenAddr and not child.typ.isNil and child.typ.kind == tyVar and child.typ[0].kind == tyRef:
        if not isNew:
          result.map = newNilMap(map)
          isNew = true
@@ -753,7 +753,6 @@ proc checkReturn(n, ctx, map): Check =

 proc checkIf(n, ctx, map): Check =
  ## check branches based on condition
-  result = default(Check)
  var mapIf: NilMap = map

  # first visit the condition
@@ -826,7 +825,7 @@ proc checkFor(n, ctx, map): Check =
  var check2 = check(n.sons[2], ctx, m)
  var map2 = check2.map

-  result = Check(map: ctx.union(map0, m))
+  result.map = ctx.union(map0, m)
  result.map = ctx.union(result.map, map2)
  result.nilability = Safe

@@ -854,7 +853,7 @@ proc checkWhile(n, ctx, map): Check =
  var check2 = check(n.sons[1], ctx, m)
  var map2 = check2.map

-  result = Check(map: ctx.union(map0, map1))
+  result.map = ctx.union(map0, map1)
  result.map = ctx.union(result.map, map2)
  result.nilability = Safe

@@ -900,7 +899,7 @@ proc checkInfix(n, ctx, map): Check =
 proc checkIsNil(n, ctx, map; isElse: bool = false): Check =
  ## check isNil calls
  ## update the map depending on if it is not isNil or isNil
-  result = Check(map: newNilMap(map))
+  result.map = newNilMap(map)
  let value = n[1]
  result.map.store(ctx, ctx.index(n[1]), if not isElse: Nil else: Safe, TArg, n.info, n)

@@ -948,7 +947,7 @@ proc checkCase(n, ctx, map): Check =
  #   c2
  # also a == true is a , a == false is not a
  let base = n[0]
-  result = Check(map: map.copyMap())
+  result.map = map.copyMap()
  result.nilability = Safe
  var a: PNode = nil
  for child in n:
@@ -1220,7 +1219,7 @@ proc check(n: PNode, ctx: NilCheckerContext, map: NilMap): Check =
    result = check(n.sons[1], ctx, map)
  of nkStmtList, nkStmtListExpr, nkChckRangeF, nkChckRange64, nkChckRange,
     nkBracket, nkCurly, nkPar, nkTupleConstr, nkClosure, nkObjConstr, nkElse:
-    result = Check(map: map)
+    result.map = map
    if n.kind in {nkObjConstr, nkTupleConstr}:
      # TODO deeper nested elements?
      # A(field: B()) #
@@ -1247,10 +1246,10 @@ proc check(n: PNode, ctx: NilCheckerContext, map: NilMap): Check =
    result = checkIf(n, ctx, map)
  of nkAsgn, nkFastAsgn, nkSinkAsgn:
    result = checkAsgn(n[0], n[1], ctx, map)
-  of nkVarSection, nkLetSection:
-    result = Check(map: map)
+  of nkVarSection:
+    result.map = map
    for child in n:
-      result = checkAsgn(child[0].skipPragmaExpr, child[2], ctx, result.map)
+      result = checkAsgn(child[0], child[2], ctx, result.map)
  of nkForStmt:
    result = checkFor(n, ctx, map)
  of nkCaseStmt:
@@ -1274,7 +1273,8 @@ proc check(n: PNode, ctx: NilCheckerContext, map: NilMap): Check =
  else:

    var elementMap = map.copyMap()
-    var elementCheck = Check(map: elementMap)
+    var elementCheck: Check
+    elementCheck.map = elementMap
    for element in n:
      elementCheck = check(element, ctx, elementCheck.map)

@@ -1367,7 +1367,7 @@ proc checkNil*(s: PSym; body: PNode; conf: ConfigRef, idgen: IdGenerator) =
        continue
      map.store(context, context.index(child), typeNilability(child.typ), TArg, child.info, child)

-  map.store(context, resultExprIndex, if not s.typ.returnType.isNil and s.typ.returnType.kind == tyRef: Nil else: Safe, TResult, s.ast.info)
+  map.store(context, resultExprIndex, if not s.typ[0].isNil and s.typ[0].kind == tyRef: Nil else: Safe, TResult, s.ast.info)

  # echo "checking ", s.name.s, " ", filename

@@ -1383,5 +1383,5 @@ proc checkNil*(s: PSym; body: PNode; conf: ConfigRef, idgen: IdGenerator) =
  # (ANotNil, BNotNil) :
  # do we check on asgn nilability at all?

-  if not s.typ.returnType.isNil and s.typ.returnType.kind == tyRef and tfNotNil in s.typ.returnType.flags:
+  if not s.typ[0].isNil and s.typ[0].kind == tyRef and tfNotNil in s.typ[0].flags:
    checkResult(s.ast, context, res.map)
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
ringabout	112e274804	switch on	2023-12-11 14:12:55 +00:00
ringabout	f1a7bfce47	switch on	2023-12-11 14:12:47 +00:00
ringabout	68bf6c7f93	what's problem os cancelled CI	2023-12-11 11:00:02 +00:00
ringabout	7cd431804b	test CI	2023-12-11 09:07:41 +00:00
ringabout	01388dc816	Merge branch 'devel' into pr_string_v3	2023-12-11 13:16:03 +08:00
ringabout	bee9baa8bf	reprieve IC	2023-12-09 11:56:17 +00:00
ringabout	147621ec21	fixes a critical issue	2023-12-09 02:41:05 +00:00
ringabout	5bde480596	workaround a cstring conversion bug	2023-12-09 02:34:22 +00:00
ringabout	33f911e691	fixes C++ compilation	2023-12-08 14:13:21 +00:00
ringabout	ec03e476d5	fixes more problems	2023-12-08 08:41:16 +00:00
ringabout	4adb79f7cb	a small fix	2023-12-08 07:29:36 +00:00
ringabout	1da417b818	tests nimSeqsV3	2023-12-08 07:26:32 +00:00
ringabout	7ef0f43f35	basic examples work now	2023-12-08 07:04:15 +00:00
ringabout	da277cf1b8	more fixes	2023-12-07 14:47:51 +00:00
ringabout	cb172328ba	simple cases compile	2023-12-07 13:56:33 +00:00
ringabout	9af21cf719	progress	2023-12-07 12:53:06 +00:00
ringabout	f7bdec6f0d	progress	2023-12-06 14:25:34 +00:00
ringabout	88c0ac44fc	simple additions	2023-12-06 06:09:25 +00:00
ringabout	119cfe8bc8	some improvements	2023-12-06 02:27:05 +00:00
ringabout	ae99903236	wip: intern strings	2023-12-05 14:51:24 +00:00