fixes #24721 ; Table add missing sink

fixes #24720 ; std lib iterators unnecessarily require value copies
2026-08-31 10:53:40 +00:00 · 2025-02-25 20:26:37 +08:00 · 2025-02-25 20:14:13 +08:00
552 changed files with 10127 additions and 30048 deletions
--- a/.github/ISSUE_TEMPLATE/bug_report.yml
+++ b/.github/ISSUE_TEMPLATE/bug_report.yml
@@ -10,16 +10,6 @@ body:
      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
-
 - type: textarea
  id: description
  attributes:
@@ -29,6 +19,16 @@ body:
    placeholder: Bug reports with reproducible code or detailed information will be fixed faster.
  validations:
    required: true
+    
+- 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, make sure to include the commit hash.
+  validations:
+    required: true

 - type: textarea
  id: current-logs
--- 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_docs.yml
+++ b/.github/workflows/ci_docs.yml
@@ -43,9 +43,9 @@ jobs:
          - target: linux
            os: ubuntu-22.04
          - target: windows
-            os: windows-latest
+            os: windows-2019
          - target: osx
-            os: macos-15
+            os: macos-13

    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@v4
        with:
          build_dir: doc/html
        env:
--- a/.github/workflows/ci_packages.yml
+++ b/.github/workflows/ci_packages.yml
@@ -18,13 +18,9 @@ jobs:
    strategy:
      fail-fast: false
      matrix:
-        os: [ubuntu-latest, macos-14]
+        os: [ubuntu-22.04, macos-13]
+        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
@@ -33,23 +29,23 @@ 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
--- a/.github/workflows/ci_publish.yml
+++ b/.github/workflows/ci_publish.yml
@@ -17,14 +17,14 @@ jobs:
    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
+        uses: actions/setup-node@v4
        with:
-          node-version: 24
+          node-version: ''

      - name: 'Install dependencies (Linux amd64)'
        if: runner.os == 'Linux' && matrix.cpu == 'amd64'
@@ -60,7 +60,7 @@ jobs:
        run: nim c -r -d:release ci/action.nim

      - name: 'Comment'
-        uses: actions/github-script@v8
+        uses: actions/github-script@v7
        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@v9
        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
@@ -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-13'
+        CPU: amd64
+      OSX_amd64_cpp:
+        vmImage: 'macOS-13'
+        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"

--- a/changelog.md
+++ b/changelog.md
@@ -19,58 +19,15 @@ 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`.
-
 ## 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`.

 ## Language changes

@@ -111,17 +68,7 @@ errors.

 ## Compiler changes

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

 ## Tool changes

- Added `--raw` flag when generating JSON docs to not render markup.
- Added `--stdinfile` flag to name of the file used when running program from stdin (defaults to `stdinfile.nim`)
- Added `--styleCheck:warning` flag to treat style check violations as warnings.

-## Documentation changes
-
- Added documentation for the `completeStruct` pragma in the manual.
--- a/compiler/ast.nim
+++ b/compiler/ast.nim
--- a/compiler/ast2nif.nim
+++ b/compiler/ast2nif.nim
--- a/compiler/astalgo.nim
+++ b/compiler/astalgo.nim
@@ -68,6 +68,8 @@ template mdbg*: bool {.deprecated.} =
 # ---------------------------------------------------------------------------

 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 +216,10 @@ 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)
+
 import std/tables

 const backrefStyle = "\e[90m"
@@ -478,6 +484,12 @@ proc debug(n: PNode; conf: ConfigRef) =
  this.value(n)
  echo($this.res)

+proc nextTry(h, maxHash: Hash): Hash {.inline.} =
+  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 +537,95 @@ 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
@@ -612,70 +713,6 @@ iterator items*(tab: TStrTable): PSym =
    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 =
-  for h in 0..high(data):
-    if isNil(data[h].key):
-      return true
-  result = false
-
-proc idTableRawGet[T](t: TIdTable[T], 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:
-      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))
-  if index >= 0: result = t.data[index].val
-  else: result = default(T)
-
-template idTableGet*[T](t: TIdTable[T], key: PType | PSym): T =
-  getOrDefault(t, key.itemId)
-
-proc idTableRawInsert[T](data: var TIdPairSeq[T], key: ItemId, val: T) =
-  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 = nextTry(h, high(data))
-  assert(isNil(data[h].key))
-  data[h].key = key
-  data[h].val = val
-
-proc `[]=`*[T](t: var TIdTable[T], key: ItemId, val: T) =
-  var
-    index: int
-    n: TIdPairSeq[T]
-  index = idTableRawGet(t, toId(key))
-  if index >= 0:
-    assert(not isNil(t.data[index].key))
-    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):
-          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] =
-  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
  newSeq(x.data, StartSize)
--- a/compiler/astdef.nim
+++ b/compiler/astdef.nim
--- 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/cbuilderdecls.nim
+++ b/compiler/cbuilderdecls.nim
@@ -154,14 +154,14 @@ template addField(builder: var Builder, constr: var StructInitializer, name: str
    # no name, can just add value
    valueBody
  of siOrderedStruct:
-    # positional init - name not used in output (empty allowed for anonymous unions)
+    # no name, can just add value on C
+    assert name.len != 0, "name has to be given for struct initializer field"
    valueBody
  of siNamedStruct:
-    # designated init - empty name for anonymous unions (skips .name = prefix)
-    if name.len != 0:
-      builder.add(".")
-      builder.add(name)
-      builder.add(" = ")
+    assert name.len != 0, "name has to be given for struct initializer field"
+    builder.add(".")
+    builder.add(name)
+    builder.add(" = ")
    valueBody

 proc finishStructInitializer(builder: var Builder, constr: StructInitializer) =
--- a/compiler/ccgcalls.nim
+++ b/compiler/ccgcalls.nim
@@ -230,29 +230,20 @@ proc genOpenArraySlice(p: BProc; q: PNode; formalType, destType: PType; prepareF
  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"):
+        optSeqDestructors in p.config.globalOptions:
      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)
+    var val: Snippet
+    if atyp.kind in {tyVar} and not compileToCpp(p.module):
+      val = cDeref(ra)
    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)
+      val = ra
+    result = (
+      cIfExpr(dataFieldAccessor(p, val),
+        cCast(ptrType(dest), cOp(Add, NimInt, dataField(p, val), rb)),
+        NimNil),
+      lengthExpr)
  else:
    result = ("", "")
    internalError(p.config, "openArrayLoc: " & typeToString(a.t))
@@ -296,22 +287,11 @@ proc openArrayLoc(p: BProc, formalType: PType, n: PNode; result: var Builder) =
    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"):
+          optSeqDestructors in p.config.globalOptions:
        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):
+      if ntyp.kind in {tyVar} and not compileToCpp(p.module):
        let ra = a.rdLoc
        var t = TLoc(snippet: cDeref(ra))
        let lt = lenExpr(p, t)
@@ -335,14 +315,9 @@ proc openArrayLoc(p: BProc, formalType: PType, n: PNode; result: var Builder) =
        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)
+        result.add(cIfExpr(dataFieldAccessor(p, t.snippet), dataField(p, t.snippet), NimNil))
+        result.addArgumentSeparator()
+        result.add(lt)
      of tyArray:
        let ra = rdLoc(a)
        result.add(ra)
@@ -356,21 +331,20 @@ proc withTmpIfNeeded(p: BProc, a: TLoc, needsTmp: bool): TLoc =
  # Bug https://github.com/status-im/nimbus-eth2/issues/1549
  # Aliasing is preferred over stack overflows.
  # Also don't regress for non ARC-builds, too risky.
-  if needsTmp and a.lode.typ != nil and p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc} and
+  if needsTmp and a.lode.typ != nil and p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc} and
      getSize(p.config, a.lode.typ) < 1024:
    result = getTemp(p, a.lode.typ, needsInit=false)
    genAssignment(p, result, a, {})
  else:
    result = a

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

 proc genArgStringToCString(p: BProc, n: PNode; result: var Builder; needsTmp: bool) {.inline.} =
  var a = initLocExpr(p, n[0])
-  let tmp = withTmpIfNeeded(p, a, needsTmp)
-  let ra = if p.config.isDefined("nimsso"): addrLoc(p.config, tmp) else: tmp.rdLoc
+  let ra = withTmpIfNeeded(p, a, needsTmp).rdLoc
  result.addCall(cgsymValue(p.module, "nimToCStringConv"), ra)

 proc genArg(p: BProc, n: PNode, param: PSym; call: PNode; result: var Builder; needsTmp = false) =
@@ -384,7 +358,7 @@ proc genArg(p: BProc, n: PNode, param: PSym; call: PNode; result: var Builder; n
    (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
@@ -394,8 +368,8 @@ proc genArg(p: BProc, n: PNode, param: PSym; call: PNode; result: var Builder; n
    # 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
+      n.typ() = n.typ.exactReplica
+      n.typ.flags.incl tfVarIsPtr
    a = initLocExprSingleUse(p, n)
    a = withTmpIfNeeded(p, a, needsTmp)
    if needsIndirect: a.flags.incl lfIndirect
@@ -444,6 +418,35 @@ 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:
+      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
@@ -524,7 +527,7 @@ proc genClosureCall(p: BProc, le, ri: PNode, d: var TLoc) =
      else:
        cCall(p, params, e)
    cIfExpr(e,
-      eCall,
+      eCall, 
      cCall(cCast(pTyp, p), params))

  template callIter(rp, params: Snippet): Snippet =
--- a/compiler/ccgexprs.nim
+++ b/compiler/ccgexprs.nim
@@ -170,7 +170,7 @@ proc canMove(p: BProc, n: PNode; dest: TLoc): bool =
 template simpleAsgn(builder: var Builder, dest, src: TLoc) =
  let rd = rdLoc(dest)
  let rs = rdLoc(src)
-  builder.addAssignment(rd, rs)
+  builder.addAssignment(rd, rs) 

 proc genRefAssign(p: BProc, dest, src: TLoc) =
  if (dest.storage == OnStack and p.config.selectedGC != gcGo) or not usesWriteBarrier(p.config):
@@ -216,8 +216,6 @@ proc genOptAsgnTuple(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
      flags
  let t = skipTypes(dest.t, abstractInst).getUniqueType()
  for i, t in t.ikids:
-    # Do not produce code for void types
-    if isEmptyType(t): continue
    let field = "Field$1" % [i.rope]
    genAssignment(p, optAsgnLoc(dest, t, field),
                     optAsgnLoc(src, t, field), newflags)
@@ -320,16 +318,12 @@ proc genOpenArrayConv(p: BProc; d: TLoc; a: TLoc; flags: TAssignmentFlags) =
      p.s(cpsStmts).addCallStmt(
        cgsymValue(p.module, "nimPrepareStrMutationV2"),
        bra)
+
    let rd = d.rdLoc
+    let ra = a.rdLoc
+    p.s(cpsStmts).addFieldAssignment(rd, "Field0",
+      cIfExpr(dataFieldAccessor(p, ra), dataField(p, ra), NimNil))
    let la = lenExpr(p, a)
-    if p.config.isDefined("nimsso"):
-      let bra = byRefLoc(p, a)
-      p.s(cpsStmts).addFieldAssignment(rd, "Field0",
-        cCall(cgsymValue(p.module, "nimStrData"), bra))
-    else:
-      let ra = a.rdLoc
-      p.s(cpsStmts).addFieldAssignment(rd, "Field0",
-        cIfExpr(dataFieldAccessor(p, ra), dataField(p, ra), NimNil))
    p.s(cpsStmts).addFieldAssignment(rd, "Field1", la)
  else:
    internalError(p.config, a.lode.info, "cannot handle " & $a.t.kind)
@@ -363,7 +357,7 @@ proc genAssignment(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
  of tyString:
    if optSeqDestructors in p.config.globalOptions:
      genGenericAsgn(p, dest, src, flags)
-    elif (needToCopy notin flags and src.storage != OnStatic) or canMove(p, src.lode, dest):
+    elif ({needToCopy, needToCopySinkParam} * flags == {} and src.storage != OnStatic) or canMove(p, src.lode, dest):
      genRefAssign(p, dest, src)
    else:
      if (dest.storage == OnStack and p.config.selectedGC != gcGo) or not usesWriteBarrier(p.config):
@@ -422,7 +416,7 @@ proc genAssignment(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
    else:
      simpleAsgn(p.s(cpsStmts), dest, src)
  of tyArray:
-    if containsGarbageCollectedRef(dest.t) and p.config.selectedGC notin {gcArc, gcAtomicArc, gcOrc, gcYrc, gcHooks}:
+    if containsGarbageCollectedRef(dest.t) and p.config.selectedGC notin {gcArc, gcAtomicArc, gcOrc, gcHooks}:
      genGenericAsgn(p, dest, src, flags)
    else:
      let rd = rdLoc(dest)
@@ -681,7 +675,7 @@ proc binaryArithOverflow(p: BProc, e: PNode, d: var TLoc, m: TMagic) =
      if e[2].kind in {nkIntLit..nkInt64Lit}:
        needsOverflowCheck = e[2].intVal == -1
      if canBeZero:
-        # remove extra paren from `==` op here to avoid Wparentheses-equality:
+        # remove extra paren from `==` op here to avoid Wparentheses-equality: 
        p.s(cpsStmts).addSingleIfStmt(removeSinglePar(cOp(Equal, rdLoc(b), cIntValue(0)))):
          p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "raiseDivByZero"))
          raiseInstr(p, p.s(cpsStmts))
@@ -702,7 +696,7 @@ proc unaryArithOverflow(p: BProc, e: PNode, d: var TLoc, m: TMagic) =
  let ra = rdLoc(a)
  if optOverflowCheck in p.options:
    let first = cIntLiteral(firstOrd(p.config, t))
-    # remove extra paren from `==` op here to avoid Wparentheses-equality:
+    # remove extra paren from `==` op here to avoid Wparentheses-equality: 
    p.s(cpsStmts).addSingleIfStmt(removeSinglePar(cOp(Equal, ra, first))):
      p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "raiseOverflow"))
      raiseInstr(p, p.s(cpsStmts))
@@ -755,16 +749,16 @@ proc binaryArith(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
    let t = getType()
    let at = cUintType(k)
    let bt = cUintType(s)
-    res = cCast(t, cOp(Shr, at, cCast(at, ra), cOp(BitAnd, at, cCast(bt, rb), cIntLiteral(k - 1))))
+    res = cCast(t, cOp(Shr, at, cCast(at, ra), cCast(bt, rb)))
  of mShlI:
    let t = getType()
    let at = cUintType(s)
-    res = cCast(t, cOp(Shl, at, cCast(at, ra), cOp(BitAnd, at, cCast(at, rb), cIntLiteral(k - 1))))
+    res = cCast(t, cOp(Shl, at, cCast(at, ra), cCast(at, rb)))
  of mAshrI:
    let t = getType()
    let at = cIntType(s)
    let bt = cUintType(s)
-    res = cCast(t, cOp(Shr, at, cCast(at, ra), cOp(BitAnd, at, cCast(bt, rb), cIntLiteral(k - 1))))
+    res = cCast(t, cOp(Shr, at, cCast(at, ra), cCast(bt, rb)))
  of mBitandI:
    let t = getType()
    res = cCast(t, cOp(BitAnd, t, ra, rb))
@@ -925,10 +919,6 @@ proc genDeref(p: BProc, e: PNode, d: var TLoc) =
      return
    else:
      a = initLocExprSingleUse(p, e[0])
-
-    # bug #23453 #25265
-    if e.typ != nil and e.typ.skipTypes(abstractInst).kind == tyObject:
-      discard getTypeDesc(p.module, e.typ)
    if d.k == locNone:
      # dest = *a;  <-- We do not know that 'dest' is on the heap!
      # It is completely wrong to set 'd.storage' here, unless it's not yet
@@ -962,8 +952,7 @@ proc genDeref(p: BProc, e: PNode, d: var TLoc) =
      putIntoDest(p, d, e, cDeref(rdLoc(a)), a.storage)

 proc cowBracket(p: BProc; n: PNode) =
-  if n.kind == nkBracketExpr and optSeqDestructors in p.config.globalOptions and
-      not p.config.isDefined("nimsso"):
+  if n.kind == nkBracketExpr and optSeqDestructors in p.config.globalOptions:
    let strCandidate = n[0]
    if strCandidate.typ.skipTypes(abstractInst).kind == tyString:
      var a: TLoc = initLocExpr(p, strCandidate)
@@ -973,11 +962,6 @@ proc cowBracket(p: BProc; n: PNode) =
 proc cow(p: BProc; n: PNode) {.inline.} =
  if n.kind == nkHiddenAddr: cowBracket(p, n[0])

-template ignoreConv(e: PNode): bool =
-  let destType = e.typ.skipTypes({tyVar, tyLent, tyGenericInst, tyAlias, tySink})
-  let srcType = e[1].typ.skipTypes({tyVar, tyLent, tyGenericInst, tyAlias, tySink})
-  sameBackendTypePickyAliases(destType, srcType)
-
 proc genAddr(p: BProc, e: PNode, d: var TLoc) =
  # careful  'addr(myptrToArray)' needs to get the ampersand:
  if e[0].typ.skipTypes(abstractInstOwned).kind in {tyRef, tyPtr}:
@@ -989,18 +973,8 @@ proc genAddr(p: BProc, e: PNode, d: var TLoc) =
    # bug #19497
    d.lode = e
  else:
-    let ssoStrSub = p.config.isDefined("nimsso") and e[0].kind == nkBracketExpr and
-        e[0][0].typ.skipTypes(abstractVar).kind == tyString
-    var a: TLoc = initLocExpr(p, e[0], if ssoStrSub: {lfEnforceDeref, lfPrepareForMutation} else: {})
-    if e[0].kind in {nkHiddenStdConv, nkHiddenSubConv, nkConv} and not ignoreConv(e[0]):
-      # addr (conv x) introduces a temp because `conv x` is not a rvalue
-      # transform addr ( conv ( x ) ) -> conv ( addr ( x ) )
-      var exprLoc: TLoc = initLocExpr(p, e[0][1])
-      var tmp = getTemp(p, e.typ, needsInit=false)
-      putIntoDest(p, tmp, e, cCast(getTypeDesc(p.module, e.typ), addrLoc(p.config, exprLoc)))
-      putIntoDest(p, d, e, rdLoc(tmp))
-    else:
-      putIntoDest(p, d, e, addrLoc(p.config, a), a.storage)
+    var a: TLoc = initLocExpr(p, e[0])
+    putIntoDest(p, d, e, addrLoc(p.config, a), a.storage)

 template inheritLocation(d: var TLoc, a: TLoc) =
  if d.k == locNone: d.storage = a.storage
@@ -1015,7 +989,7 @@ proc genTupleElem(p: BProc, e: PNode, d: var TLoc) =
  var
    i: int = 0
  var a: TLoc = initLocExpr(p, e[0])
-  let tupType = a.t.skipTypes(abstractInst+{tyVar}+tyUserTypeClasses) # ref #25227
+  let tupType = a.t.skipTypes(abstractInst+{tyVar})
  assert tupType.kind == tyTuple
  d.inheritLocation(a)
  discard getTypeDesc(p.module, a.t) # fill the record's fields.loc
@@ -1318,24 +1292,13 @@ proc genSeqElem(p: BProc, n, x, y: PNode, d: var TLoc) =
  if skipTypes(a.t, abstractVar).kind in {tyRef, tyPtr}:
    a.snippet = cDeref(a.snippet)

-  if p.config.isDefined("nimsso") and ty.kind == tyString:
+  if lfPrepareForMutation in d.flags and ty.kind == tyString and
+      optSeqDestructors in p.config.globalOptions:
    let bra = byRefLoc(p, a)
-    if lfPrepareForMutation in d.flags:
-      # Use nimStrAtMutV3 to get a mutable reference (char*) to the element.
-      # Only when mutation is requested: avoids calling nimPrepareStrMutationV2
-      # on const string literals (which would SIGSEGV on write to read-only memory).
-      putIntoDest(p, d, n,
-        cDeref(cCall(cgsymValue(p.module, "nimStrAtMutV3"), bra, rcb)), a.storage)
-    else:
-      putIntoDest(p, d, n,
-        cCall(cgsymValue(p.module, "nimStrAtV3"), bra, rcb), a.storage)
-  else:
-    if lfPrepareForMutation in d.flags and ty.kind == tyString and
-        optSeqDestructors in p.config.globalOptions:
-      let bra = byRefLoc(p, a)
-      p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimPrepareStrMutationV2"), bra)
-    let ra = rdLoc(a)
-    putIntoDest(p, d, n, subscript(dataField(p, ra), rcb), a.storage)
+    p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimPrepareStrMutationV2"),
+      bra)
+  let ra = rdLoc(a)
+  putIntoDest(p, d, n, subscript(dataField(p, ra), rcb), a.storage)

 proc genBracketExpr(p: BProc; n: PNode; d: var TLoc) =
  var ty = skipTypes(n[0].typ, abstractVarRange + tyUserTypeClasses)
@@ -1607,51 +1570,6 @@ proc genSeqElemAppend(p: BProc, e: PNode, d: var TLoc) =
  genAssignment(p, dest, b, {needToCopy})
  gcUsage(p.config, e)

-proc genSeqElemAppendV2(p: BProc, e: PNode, d: var TLoc) =
-  # s.add(x) with optSeqDestructors (arc/orc), inlined for direct slot construction:
-  #   NI oldLen = s.len;
-  #   if (s.p == NIM_NIL || (s.p->cap & ~NIM_STRLIT_FLAG) < oldLen + 1)
-  #     s.p = (PayloadType*)prepareSeqAddUninit(oldLen, s.p, 1, sizeof(T), alignof(T));
-  #   s.len = oldLen + 1;
-  #   s.p->data[oldLen] = x;  // direct assignment, no function call overhead
-  let seqtype = skipTypes(e[1].typ, abstractVarRange)
-  var a = initLocExpr(p, e[1])
-  let pt = getSeqPayloadType(p.module, seqtype)
-  let pe = seqPayloadElem(p.module, seqtype)
-  # Capture a stable pointer to the seq BEFORE evaluating the element (e[2]).
-  # Evaluating e[2] may emit move semantics (eqwasMoved) that nil a variable
-  # through which e[1]'s snippet is accessed (e.g. a closure env pointer).
-  inc(p.labels)
-  let seqPtrName = "T" & rope(p.labels) & "_"
-  p.s(cpsLocals).addVar(kind = Local, name = seqPtrName,
-                        typ = ptrType(getTypeDesc(p.module, seqtype)))
-  p.s(cpsStmts).addAssignment(seqPtrName, cAddr(rdLoc(a)))
-  var b = initLocExpr(p, e[2])
-  # All seq operations now go through the stable seqPtrName pointer.
-  let ra = wrapPar(cDeref(seqPtrName))
-  var tmpL = getIntTemp(p)
-  p.s(cpsStmts).addAssignment(tmpL.snippet, dotField(ra, "len"))
-  let pField = dotField(ra, "p")
-  p.s(cpsStmts).addSingleIfStmt(
-      cOp(Or,
-        cOp(Equal, pField, NimNil),
-        cOp(LessThan,
-          cOp(BitAnd, NimInt, derefField(pField, "cap"), cOp(BitNot, NimInt, NimStrlitFlag)),
-          cOp(Add, NimInt, tmpL.snippet, cIntValue(1))))):
-    p.s(cpsStmts).addFieldAssignmentWithValue(ra, "p"):
-      p.s(cpsStmts).addCast(ptrType(pt)):
-        p.s(cpsStmts).addCall(cgsymValue(p.module, "prepareSeqAddUninit"),
-          tmpL.snippet,
-          pField,
-          cIntValue(1),
-          cSizeof(pe),
-          cAlignof(pe))
-  p.s(cpsStmts).addFieldAssignment(ra, "len",
-    cOp(Add, NimInt, tmpL.snippet, cIntValue(1)))
-  var dest = initLoc(locExpr, e[2], OnHeap)
-  dest.snippet = subscript(dataField(p, ra), tmpL.snippet)
-  genAssignment(p, dest, b, {})
-
 proc genDefault(p: BProc; n: PNode; d: var TLoc) =
  if d.k == locNone: d = getTemp(p, n.typ, needsInit=true)
  else: resetLoc(p, d)
@@ -1787,15 +1705,15 @@ proc genNewSeq(p: BProc, e: PNode) =
    let seqtype = skipTypes(e[1].typ, abstractVarRange)
    let ra = a.rdLoc
    let rb = b.rdLoc
+    let et = getTypeDesc(p.module, seqtype.elementType)
    let pt = getSeqPayloadType(p.module, seqtype)
-    let pe = seqPayloadElem(p.module, seqtype)
    p.s(cpsStmts).addFieldAssignment(ra, "len", rb)
    p.s(cpsStmts).addFieldAssignmentWithValue(ra, "p"):
      p.s(cpsStmts).addCast(ptrType(pt)):
        p.s(cpsStmts).addCall(cgsymValue(p.module, "newSeqPayload"),
          rb,
-          cSizeof(pe),
-          cAlignof(pe))
+          cSizeof(et),
+          cAlignof(et))
  else:
    let lenIsZero = e[2].kind == nkIntLit and e[2].intVal == 0
    genNewSeqAux(p, a, b.rdLoc, lenIsZero)
@@ -1808,15 +1726,15 @@ proc genNewSeqOfCap(p: BProc; e: PNode; d: var TLoc) =
    if d.k == locNone: d = getTemp(p, e.typ, needsInit=false)
    let rd = d.rdLoc
    let ra = a.rdLoc
+    let et = getTypeDesc(p.module, seqtype.elementType)
    let pt = getSeqPayloadType(p.module, seqtype)
-    let pe = seqPayloadElem(p.module, seqtype)
    p.s(cpsStmts).addFieldAssignment(rd, "len", cIntValue(0))
    p.s(cpsStmts).addFieldAssignmentWithValue(rd, "p"):
      p.s(cpsStmts).addCast(ptrType(pt)):
        p.s(cpsStmts).addCall(cgsymValue(p.module, "newSeqPayloadUninit"),
          ra,
-          cSizeof(pe),
-          cAlignof(pe))
+          cSizeof(et),
+          cAlignof(et))
  else:
    if d.k == locNone: d = getTemp(p, e.typ, needsInit=false) # bug #22560
    let ra = a.rdLoc
@@ -1897,7 +1815,7 @@ proc genObjConstr(p: BProc, e: PNode, d: var TLoc) =

  var tmp: TLoc = default(TLoc)
  var r: Rope
-  let needsZeroMem = p.config.selectedGC notin {gcArc, gcAtomicArc, gcOrc, gcYrc} or nfAllFieldsSet notin e.flags
+  let needsZeroMem = p.config.selectedGC notin {gcArc, gcAtomicArc, gcOrc} or nfAllFieldsSet notin e.flags
  if useTemp:
    tmp = getTemp(p, t)
    r = rdLoc(tmp)
@@ -1952,15 +1870,15 @@ proc genSeqConstr(p: BProc, n: PNode, d: var TLoc) =
  if optSeqDestructors in p.config.globalOptions:
    let seqtype = n.typ
    let rd = rdLoc dest[]
+    let et = getTypeDesc(p.module, seqtype.elementType)
    let pt = getSeqPayloadType(p.module, seqtype)
-    let pe = seqPayloadElem(p.module, seqtype)
    p.s(cpsStmts).addFieldAssignment(rd, "len", lit)
    p.s(cpsStmts).addFieldAssignmentWithValue(rd, "p"):
      p.s(cpsStmts).addCast(ptrType(pt)):
        p.s(cpsStmts).addCall(cgsymValue(p.module, "newSeqPayload"),
          lit,
-          cSizeof(pe),
-          cAlignof(pe))
+          cSizeof(et),
+          cAlignof(et))
  else:
    # generate call to newSeq before adding the elements per hand:
    genNewSeqAux(p, dest[], lit, n.len == 0)
@@ -1981,7 +1899,7 @@ proc genSeqConstr(p: BProc, n: PNode, d: var TLoc) =
 proc genArrToSeq(p: BProc, n: PNode, d: var TLoc) =
  var elem, arr: TLoc
  if n[1].kind == nkBracket:
-    n[1].typ = n.typ
+    n[1].typ() = n.typ
    genSeqConstr(p, n[1], d)
    return
  if d.k == locNone:
@@ -1993,15 +1911,15 @@ proc genArrToSeq(p: BProc, n: PNode, d: var TLoc) =
    let seqtype = n.typ
    let rd = rdLoc d
    let valL = cIntValue(L)
+    let et = getTypeDesc(p.module, seqtype.elementType)
    let pt = getSeqPayloadType(p.module, seqtype)
-    let pe = seqPayloadElem(p.module, seqtype)
    p.s(cpsStmts).addFieldAssignment(rd, "len", valL)
    p.s(cpsStmts).addFieldAssignmentWithValue(rd, "p"):
      p.s(cpsStmts).addCast(ptrType(pt)):
        p.s(cpsStmts).addCall(cgsymValue(p.module, "newSeqPayload"),
          valL,
-          cSizeof(pe),
-          cAlignof(pe))
+          cSizeof(et),
+          cAlignof(et))
  else:
    let lit = cIntLiteral(L)
    genNewSeqAux(p, d, lit, L == 0)
@@ -2142,20 +2060,12 @@ proc genRepr(p: BProc, e: PNode, d: var TLoc) =
      let ra = rdLoc(a)
      putIntoDest(p, b, e, ra & cArgumentSeparator & ra & "Len_0", a.storage)
    of tyString, tySequence:
+      let ra = rdLoc(a)
      let la = lenExpr(p, a)
-      if p.config.isDefined("nimsso") and
-          skipTypes(a.t, abstractVarRange).kind == tyString:
-        let bra = byRefLoc(p, a)
-        putIntoDest(p, b, e,
-          cCall(cgsymValue(p.module, "nimStrData"), bra) &
-            cArgumentSeparator & la,
-          a.storage)
-      else:
-        let ra = rdLoc(a)
-        putIntoDest(p, b, e,
-          cIfExpr(dataFieldAccessor(p, ra), dataField(p, ra), NimNil) &
-            cArgumentSeparator & la,
-          a.storage)
+      putIntoDest(p, b, e,
+        cIfExpr(dataFieldAccessor(p, ra), dataField(p, ra), NimNil) &
+          cArgumentSeparator & la,
+        a.storage)
    of tyArray:
      let ra = rdLoc(a)
      let la = cIntValue(lengthOrd(p.config, a.t))
@@ -2288,14 +2198,7 @@ proc genArrayLen(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
    else: putIntoDest(p, d, e, cIntValue(lengthOrd(p.config, typ)))
  else: internalError(p.config, e.info, "genArrayLen()")

-proc isTrivialTypesToSnippet(t: PType): Snippet =
-  if containsGarbageCollectedRef(t) or
-                     hasDestructor(t):
-    result = NimFalse
-  else:
-    result = NimTrue
-
-proc genSetLengthSeq(p: BProc, e: PNode, d: var TLoc, noinit = false) =
+proc genSetLengthSeq(p: BProc, e: PNode, d: var TLoc) =
  if optSeqDestructors in p.config.globalOptions:
    e[1] = makeAddr(e[1], p.module.idgen)
    genCall(p, e, d)
@@ -2317,10 +2220,7 @@ proc genSetLengthSeq(p: BProc, e: PNode, d: var TLoc, noinit = false) =
    pExpr = cIfExpr(ra, cAddr(derefField(ra, "Sup")), NimNil)
  else:
    pExpr = ra
-
-  let name = if noinit: "setLengthSeqUninit" else: "setLengthSeqV2"
-  call.snippet = cCast(rt, cgCall(p, name, pExpr, rti, rb,
-          isTrivialTypesToSnippet(t.skipTypes(abstractInst)[0])))
+  call.snippet = cCast(rt, cgCall(p, "setLengthSeqV2", pExpr, rti, rb))

  genAssignment(p, a, call, {})
  gcUsage(p.config, e)
@@ -2729,16 +2629,17 @@ proc genRangeChck(p: BProc, n: PNode, d: var TLoc) =
    putIntoDest(p, d, n, cCast(destType, wrapPar(val)), a.storage)

 proc genConv(p: BProc, e: PNode, d: var TLoc) =
-  if ignoreConv(e):
+  let destType = e.typ.skipTypes({tyVar, tyLent, tyGenericInst, tyAlias, tySink})
+  if sameBackendTypeIgnoreRange(destType, e[1].typ):
    expr(p, e[1], d)
  else:
    genSomeCast(p, e, d)

 proc convStrToCStr(p: BProc, n: PNode, d: var TLoc) =
  var a: TLoc = initLocExpr(p, n[0])
-  let arg = if p.config.isDefined("nimsso"): addrLoc(p.config, a) else: rdLoc(a)
  putIntoDest(p, d, n,
-    cgCall(p, "nimToCStringConv", arg),
+    cgCall(p, "nimToCStringConv", rdLoc(a)),
+#   "($1 ? $1->data : (NCSTRING)\"\")" % [a.rdLoc],
    a.storage)

 proc convCStrToStr(p: BProc, n: PNode, d: var TLoc) =
@@ -2809,28 +2710,22 @@ proc genWasMoved(p: BProc; n: PNode) =
    #  [addrLoc(p.config, a), getTypeDesc(p.module, a.t)])

 proc genMove(p: BProc; n: PNode; d: var TLoc) =
-  var a: TLoc = initLocExpr(p, n[1].skipAddr, {lfEnforceDeref, lfPrepareForMutation})
+  var a: TLoc = initLocExpr(p, n[1].skipAddr, {lfEnforceDeref})
  if n.len == 4:
    # generated by liftdestructors:
    var src: TLoc = initLocExpr(p, n[2])
    let destVal = rdLoc(a)
    let srcVal = rdLoc(src)
-    if p.config.isDefined("nimsso") and
-        n[1].typ.skipTypes(abstractVar).kind == tyString:
-      # SmallString: destroy dst then struct-copy src; no .p field aliasing needed
+    p.s(cpsStmts).addSingleIfStmt(
+      cOp(NotEqual,
+        dotField(destVal, "p"),
+        dotField(srcVal, "p"))):
      genStmts(p, n[3])
-      genAssignment(p, a, src, {})
-    else:
-      p.s(cpsStmts).addSingleIfStmt(
-        cOp(NotEqual,
-          dotField(destVal, "p"),
-          dotField(srcVal, "p"))):
-        genStmts(p, n[3])
-      p.s(cpsStmts).addFieldAssignment(destVal, "len", dotField(srcVal, "len"))
-      p.s(cpsStmts).addFieldAssignment(destVal, "p", dotField(srcVal, "p"))
+    p.s(cpsStmts).addFieldAssignment(destVal, "len", dotField(srcVal, "len"))
+    p.s(cpsStmts).addFieldAssignment(destVal, "p", dotField(srcVal, "p"))
  else:
    if d.k == locNone: d = getTemp(p, n.typ)
-    if p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc}:
+    if p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc}:
      genAssignment(p, d, a, {})
      var op = getAttachedOp(p.module.g.graph, n.typ, attachedWasMoved)
      if op == nil:
@@ -2854,7 +2749,13 @@ proc genMove(p: BProc; n: PNode; d: var TLoc) =
          let val = if p.module.compileToCpp: rdLoc(a) else: byRefLoc(p, a)
          p.s(cpsStmts).addCallStmt(rdLoc(b), val)
    else:
-      genAssignment(p, d, a, {})
+      if n[1].kind == nkSym and isSinkParam(n[1].sym):
+        var tmp = getTemp(p, n[1].typ.skipTypes({tySink}))
+        genAssignment(p, tmp, a, {needToCopySinkParam})
+        genAssignment(p, d, tmp, {})
+        resetLoc(p, tmp)
+      else:
+        genAssignment(p, d, a, {})
      resetLoc(p, a)

 proc genDestroy(p: BProc; n: PNode) =
@@ -2864,19 +2765,15 @@ proc genDestroy(p: BProc; n: PNode) =
    case t.kind
    of tyString:
      var a: TLoc = initLocExpr(p, arg)
-      if p.config.isDefined("nimsso"):
-        # SmallString: delegate to nimDestroyStrV1 (rc-based, handles static strings)
-        p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimDestroyStrV1"), rdLoc(a))
-      else:
-        let ra = rdLoc(a)
-        let rp = dotField(ra, "p")
-        p.s(cpsStmts).addSingleIfStmt(
-          cOp(And, rp,
-            cOp(Not, cOp(BitAnd, NimInt,
-              derefField(rp, "cap"),
-              NimStrlitFlag)))):
-          let fn = if optThreads in p.config.globalOptions: "deallocShared" else: "dealloc"
-          p.s(cpsStmts).addCallStmt(cgsymValue(p.module, fn), rp)
+      let ra = rdLoc(a)
+      let rp = dotField(ra, "p")
+      p.s(cpsStmts).addSingleIfStmt(
+        cOp(And, rp,
+          cOp(Not, cOp(BitAnd, NimInt,
+            derefField(rp, "cap"),
+            NimStrlitFlag)))):
+        let fn = if optThreads in p.config.globalOptions: "deallocShared" else: "dealloc"
+        p.s(cpsStmts).addCallStmt(cgsymValue(p.module, fn), rp)
    of tySequence:
      var a: TLoc = initLocExpr(p, arg)
      let ra = rdLoc(a)
@@ -2918,7 +2815,7 @@ proc genSlice(p: BProc; e: PNode; d: var TLoc) =
  let (x, y) = genOpenArraySlice(p, e, e.typ, e.typ.elementType,
    prepareForMutation = e[1].kind == nkHiddenDeref and
                         e[1].typ.skipTypes(abstractInst).kind == tyString and
-                         p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc})
+                         p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc})
  if d.k == locNone: d = getTemp(p, e.typ)
  let dest = rdLoc(d)
  p.s(cpsStmts).addFieldAssignment(dest, "Field0", x)
@@ -2981,15 +2878,8 @@ proc genMagicExpr(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
  of mAppendStrStr: genStrAppend(p, e, d)
  of mAppendSeqElem:
    if optSeqDestructors in p.config.globalOptions:
-      if p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc}:
-        # Inline growth + direct slot assignment: avoids the add() call overhead
-        # and lets the C compiler see the construction expression at its final
-        # destination, enabling in-place construction for nkObjConstr etc.
-        # gcYrc is excluded because its add() acquires a striped reader lock.
-        genSeqElemAppendV2(p, e, d)
-      else:
-        e[1] = makeAddr(e[1], p.module.idgen)
-        genCall(p, e, d)
+      e[1] = makeAddr(e[1], p.module.idgen)
+      genCall(p, e, d)
    else:
      genSeqElemAppend(p, e, d)
  of mEqStr: genStrEquals(p, e, d)
@@ -3075,7 +2965,6 @@ proc genMagicExpr(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
      p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimGCunref"), ra)
  of mSetLengthStr: genSetLengthStr(p, e, d)
  of mSetLengthSeq: genSetLengthSeq(p, e, d)
-  of mSetLengthSeqUninit: genSetLengthSeq(p, e, d, noinit = true)
  of mIncl, mExcl, mCard, mLtSet, mLeSet, mEqSet, mMulSet, mPlusSet, mMinusSet,
     mInSet, mXorSet:
    genSetOp(p, e, d, op)
@@ -3129,7 +3018,7 @@ proc genMagicExpr(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
      let n = semparallel.liftParallel(p.module.g.graph, p.module.idgen, p.module.module, e)
      expr(p, n, d)
  of mDeepCopy:
-    if p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc} and optEnableDeepCopy notin p.config.globalOptions:
+    if p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc} and optEnableDeepCopy notin p.config.globalOptions:
      localError(p.config, e.info,
        "for --mm:arc|atomicArc|orc 'deepcopy' support has to be enabled with --deepcopy:on")

@@ -3245,8 +3134,6 @@ proc genTupleConstr(p: BProc, n: PNode, d: var TLoc) =
    for i in 0..<n.len:
      var it = n[i]
      if it.kind == nkExprColonExpr: it = it[1]
-      # Do not produce code for void types
-      if it.typ != nil and isEmptyType(it.typ): continue
      rec = initLoc(locExpr, it, dest[].storage)
      rec.snippet = dotField(rdLoc(dest[]), "Field" & rope(i))
      rec.flags.incl(lfEnforceDeref)
@@ -3363,11 +3250,7 @@ proc upConv(p: BProc, n: PNode, d: var TLoc) =
        p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "raiseObjectConversionError"))
        raiseInstr(p, p.s(cpsStmts))

-  # skip cast when types map to the same C type
-  # this avoids invalid C code like `*(T*)&x` for types that can't have their address taken (e.g., WASM __externref_t)
-  if getTypeDesc(p.module, n.typ) == getTypeDesc(p.module, n[0].typ):
-    expr(p, n[0], d)
-  elif n[0].typ.kind != tyObject:
+  if n[0].typ.kind != tyObject:
    let destTyp = getTypeDesc(p.module, n.typ)
    let val = rdLoc(a)
    if n.isLValue:
@@ -3413,7 +3296,7 @@ proc downConv(p: BProc, n: PNode, d: var TLoc) =
        cCast(ptrType(destType),
          wrapPar(cAddr(wrapPar(val))))),
      a.storage)
-  elif p.module.compileToCpp or isImportedType(src):
+  elif p.module.compileToCpp:
    # C++ implicitly downcasts for us
    expr(p, arg, d)
  else:
@@ -3459,9 +3342,8 @@ proc genConstSetup(p: BProc; sym: PSym): bool =
  useHeader(m, sym)
  if sym.loc.k == locNone:
    fillBackendName(p.module, sym)
-    backendEnsureMutable sym
-    fillLoc(sym.locImpl, locData, sym.astdef, OnStatic)
-  if m.hcrOn: incl(sym, lfIndirect)
+    fillLoc(sym.loc, locData, sym.astdef, OnStatic)
+  if m.hcrOn: incl(sym.loc.flags, lfIndirect)
  result = lfNoDecl notin sym.loc.flags

 proc genConstHeader(m, q: BModule; p: BProc, sym: PSym) =
@@ -3531,7 +3413,7 @@ proc genConstDefinition(q: BModule; p: BProc; sym: PSym) =

 proc genConstStmt(p: BProc, n: PNode) =
  # This code is only used in the new DCE implementation.
-  assert delayedCodegen(p.module)
+  assert useAliveDataFromDce in p.module.flags
  let m = p.module
  for it in n:
    if it[0].kind == nkSym:
@@ -3549,7 +3431,7 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
    var sym = n.sym
    case sym.kind
    of skMethod:
-      if delayedCodegen(p.module) or {sfDispatcher, sfForward} * sym.flags != {}:
+      if useAliveDataFromDce in p.module.flags or {sfDispatcher, sfForward} * sym.flags != {}:
        # we cannot produce code for the dispatcher yet:
        fillProcLoc(p.module, n)
        genProcPrototype(p.module, sym)
@@ -3562,15 +3444,11 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
      if sfCompileTime in sym.flags:
        localError(p.config, n.info, "request to generate code for .compileTime proc: " &
           sym.name.s)
-      if delayedCodegen(p.module) and sym.typ.callConv != ccInline:
+      if useAliveDataFromDce in p.module.flags and sym.typ.callConv != ccInline:
        fillProcLoc(p.module, n)
        genProcPrototype(p.module, sym)
      else:
        genProc(p.module, sym)
-        # For cross-module inline procs with optCompress, ensure prototype is emitted
-        if sym.typ.callConv == ccInline and optCompress in p.config.globalOptions and
-           sym.itemId.module != p.module.module.position:
-          genProcPrototype(p.module, sym)
      if sym.loc.snippet == "" or sym.loc.lode == nil:
        internalError(p.config, n.info, "expr: proc not init " & sym.name.s)
      putLocIntoDest(p, d, sym.loc)
@@ -3579,13 +3457,7 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
        var lit = newBuilder("")
        genLiteral(p, sym.astdef, sym.typ, lit)
        putIntoDest(p, d, n, extract(lit), OnStatic)
-      elif optCompress in p.config.globalOptions:
-        # With delayed codegen, we need to ensure the definition is generated
-        # not just the extern header declaration
-        requestConstImpl(p, sym)
-        assert((sym.loc.snippet != "") and (sym.loc.t != nil))
-        putLocIntoDest(p, d, sym.loc)
-      elif delayedCodegen(p.module):
+      elif useAliveDataFromDce in p.module.flags:
        genConstHeader(p.module, p.module, p, sym)
        assert((sym.loc.snippet != "") and (sym.loc.t != nil))
        putLocIntoDest(p, d, sym.loc)
@@ -3717,7 +3589,7 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
  of nkWhileStmt: genWhileStmt(p, n)
  of nkVarSection, nkLetSection: genVarStmt(p, n)
  of nkConstSection:
-    if delayedCodegen(p.module):
+    if useAliveDataFromDce in p.module.flags:
      genConstStmt(p, n)
    else: # enforce addressable consts for exportc
      let m = p.module
@@ -3783,10 +3655,7 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
  of nkProcDef, nkFuncDef, nkMethodDef, nkConverterDef:
    if n[genericParamsPos].kind == nkEmpty:
      var prc = n[namePos].sym
-      if optCompress in p.config.globalOptions:
-        if prc.magic in generatedMagics:
-          genProc(p.module, prc)
-      elif delayedCodegen(p.module):
+      if useAliveDataFromDce in p.module.flags:
        if p.module.alive.contains(prc.itemId.item) and
            prc.magic in generatedMagics:
          genProc(p.module, prc)
@@ -3806,68 +3675,9 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
    inc p.splitDecls
    genGotoState(p, n)
  of nkBreakState: genBreakState(p, n, d)
-  of nkMixinStmt, nkBindStmt, nkReplayAction: discard
+  of nkMixinStmt, nkBindStmt: discard
  else: internalError(p.config, n.info, "expr(" & $n.kind & "); unknown node kind")

-proc isOpaqueImportcType(t: PType): bool =
-  # importc type without completeStruct that can't use aggregate init (e.g. C11 _Atomic)
-  if t.sym != nil and sfImportc in t.sym.flags:
-    if tfCompleteStruct notin t.flags:
-      if tfIncompleteStruct in t.flags:
-        return true
-      if t.kind == tyObject and (t.n == nil or t.n.len == 0):
-        return true
-  return false
-
-proc containsOpaqueImportcField(typ: PType): bool
-
-proc containsOpaqueImportcFieldAux(t: PType; n: PNode): bool =
-  if n == nil: return false
-  case n.kind
-  of nkRecList:
-    for child in n.sons:
-      if containsOpaqueImportcFieldAux(t, child):
-        return true
-  of nkRecCase:
-    if containsOpaqueImportcFieldAux(t, n[0]):
-      return true
-    for i in 1..<n.len:
-      let branch = n[i]
-      if branch.kind == nkOfBranch or branch.kind == nkElse:
-        if containsOpaqueImportcFieldAux(t, branch.lastSon):
-          return true
-  of nkSym:
-    if containsOpaqueImportcField(n.sym.typ):
-      return true
-  else:
-    discard
-  return false
-
-proc containsOpaqueImportcField(typ: PType): bool =
-  # Check if type contains opaque importc fields that need designated initializers
-  if typ == nil: return false
-  let t = skipTypes(typ, abstractRange+{tyOwned}-{tyTypeDesc})
-  if isOpaqueImportcType(t):
-    return true
-  case t.kind
-  of tyObject:
-    if t.baseClass != nil:
-      if containsOpaqueImportcField(t.baseClass):
-        return true
-    if containsOpaqueImportcFieldAux(t, t.n):
-      return true
-  of tyTuple:
-    for i, a in t.ikids:
-      if isEmptyType(a): continue
-      if containsOpaqueImportcField(a):
-        return true
-  of tyArray:
-    if containsOpaqueImportcField(t.elementType):
-      return true
-  else:
-    discard
-  return false
-
 proc getDefaultValue(p: BProc; typ: PType; info: TLineInfo; result: var Builder) =
  var t = skipTypes(typ, abstractRange+{tyOwned}-{tyTypeDesc})
  case t.kind
@@ -3898,36 +3708,24 @@ proc getDefaultValue(p: BProc; typ: PType; info: TLineInfo; result: var Builder)
        result.addField(closureInit, name = "ClE_0"):
          result.add(NimNil)
  of tyObject:
-    # Use designated initializers when opaque importc fields present
    var objInit: StructInitializer
-    let initKind = if containsOpaqueImportcField(t): siNamedStruct else: siOrderedStruct
-    result.addStructInitializer(objInit, kind = initKind):
+    result.addStructInitializer(objInit, kind = siOrderedStruct):
      getNullValueAuxT(p, t, t, t.n, nil, result, objInit, true, info)
  of tyTuple:
-    # Use designated initializers when opaque importc fields present
    var tupleInit: StructInitializer
-    let initKind = if containsOpaqueImportcField(t): siNamedStruct else: siOrderedStruct
-    result.addStructInitializer(tupleInit, kind = initKind):
-      if p.vccAndC and validTupleTypeFields(t) == 0:
+    result.addStructInitializer(tupleInit, kind = siOrderedStruct):
+      if p.vccAndC and t.isEmptyTupleType:
        result.addField(tupleInit, name = "dummy"):
          result.addIntValue(0)
      for i, a in t.ikids:
-        # Do not produce code for void types
-        if isEmptyType(a): continue
-        let elemTyp = skipTypes(a, abstractRange+{tyOwned}-{tyTypeDesc})
-        if not isOpaqueImportcType(elemTyp):
-          result.addField(tupleInit, name = "Field" & $i):
-            getDefaultValue(p, a, info, result)
+        result.addField(tupleInit, name = "Field" & $i):
+          getDefaultValue(p, a, info, result)
  of tyArray:
-    let elemTyp = skipTypes(t.elementType, abstractRange+{tyOwned}-{tyTypeDesc})
-    if isOpaqueImportcType(elemTyp):
-      result.add "{0}"
-    else:
-      var arrInit: StructInitializer
-      result.addStructInitializer(arrInit, kind = siArray):
-        for i in 0..<toInt(lengthOrd(p.config, t.indexType)):
-          result.addField(arrInit, name = ""):
-            getDefaultValue(p, t.elementType, info, result)
+    var arrInit: StructInitializer
+    result.addStructInitializer(arrInit, kind = siArray):
+      for i in 0..<toInt(lengthOrd(p.config, t.indexType)):
+        result.addField(arrInit, name = ""):
+          getDefaultValue(p, t.elementType, info, result)
    #result = rope"{}"
  of tyOpenArray, tyVarargs:
    var openArrInit: StructInitializer
@@ -3982,7 +3780,8 @@ proc getNullValueAux(p: BProc; t: PType; obj, constOrNil: PNode,
    var fieldName: string = ""
    if b.kind == nkRecList and not isEmptyCaseObjectBranch(b):
      fieldName = "_" & mangleRecFieldName(p.module, obj[0].sym) & "_" & $selectedBranch
-      result.addField(init, name = ""): # anonymous union
+      result.addField(init, name = "<anonymous union>"):
+        # XXX figure out name for the union, see use of `addAnonUnion`
        var branchInit: StructInitializer
        result.addStructInitializer(branchInit, kind = siNamedStruct):
          result.addField(branchInit, name = fieldName):
@@ -3991,7 +3790,8 @@ proc getNullValueAux(p: BProc; t: PType; obj, constOrNil: PNode,
              getNullValueAux(p, t, b, constOrNil, result, branchObjInit, isConst, info)
    elif b.kind == nkSym:
      fieldName = mangleRecFieldName(p.module, b.sym)
-      result.addField(init, name = ""): # anonymous union
+      result.addField(init, name = "<anonymous union>"):
+        # XXX figure out name for the union, see use of `addAnonUnion`
        var branchInit: StructInitializer
        result.addStructInitializer(branchInit, kind = siNamedStruct):
          result.addField(branchInit, name = fieldName):
@@ -4006,9 +3806,6 @@ proc getNullValueAux(p: BProc; t: PType; obj, constOrNil: PNode,

  of nkSym:
    let field = obj.sym
-    let fieldTyp = skipTypes(field.typ, abstractRange+{tyOwned}-{tyTypeDesc})
-    if isOpaqueImportcType(fieldTyp):
-      return # C zero-initializes omitted fields
    let sname = mangleRecFieldName(p.module, field)
    result.addField(init, name = sname):
      block fieldInit:
@@ -4053,10 +3850,11 @@ proc getNullValueAuxT(p: BProc; orig, t: PType; obj, constOrNil: PNode,

 proc genConstObjConstr(p: BProc; n: PNode; isConst: bool; result: var Builder) =
  let t = n.typ.skipTypes(abstractInstOwned)
-  # Use designated initializers when opaque importc fields present
+  #if not isObjLackingTypeField(t) and not p.module.compileToCpp:
+  #  result.addf("{$1}", [genTypeInfo(p.module, t)])
+  #  inc count
  var objInit: StructInitializer
-  let initKind = if t.kind == tyObject and containsOpaqueImportcField(t): siNamedStruct else: siOrderedStruct
-  result.addStructInitializer(objInit, kind = initKind):
+  result.addStructInitializer(objInit, kind = siOrderedStruct):
    if t.kind == tyObject:
      getNullValueAuxT(p, t, t, t.n, n, result, objInit, isConst, n.info)

@@ -4088,8 +3886,6 @@ proc genConstTuple(p: BProc, n: PNode; isConst: bool; tup: PType; result: var Bu
      var it = n[i]
      if it.kind == nkExprColonExpr:
        it = it[1]
-      # Do not produce code for void types
-      if isEmptyType(tup[i]): continue
      result.addField(tupleInit, name = "Field" & $i):
        genBracedInit(p, it, isConst, tup[i], result)

@@ -4236,10 +4032,7 @@ proc genBracedInit(p: BProc, n: PNode; isConst: bool; optionalType: PType; resul
      genConstObjConstr(p, n, isConst, result)
    of tyString, tyCstring:
      if optSeqDestructors in p.config.globalOptions and n.kind != nkNilLit and ty == tyString:
-        if p.config.isDefined("nimsso"):
-          genStringLiteralV3Const(p.module, n, isConst, result)
-        else:
-          genStringLiteralV2Const(p.module, n, isConst, result)
+        genStringLiteralV2Const(p.module, n, isConst, result)
      else:
        var d: TLoc = initLocExpr(p, n)
        result.add rdLoc(d)
--- 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")
@@ -132,192 +131,6 @@ proc genStringLiteralV2Const(m: BModule; n: PNode; isConst: bool; result: var Bu
    result.addField(strInit, name = "p"):
      result.add(cCast(ptrType("NimStrPayload"), cAddr(pureLit)))

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

 proc genStringLiteralDataOnly(m: BModule; s: string; info: TLineInfo;
@@ -328,8 +141,6 @@ proc genStringLiteralDataOnly(m: BModule; s: string; info: TLineInfo;
    let tmp = getTempName(m)
    genStringLiteralDataOnlyV2(m, s, tmp, isConst)
    result.add tmp
-  of 3:
-    localError(m.config, info, "genStringLiteralDataOnly not supported for SmallString (nimsso)")
  else:
    localError(m.config, info, "cannot determine how to produce code for string literal")

@@ -340,6 +151,5 @@ proc genStringLiteral(m: BModule; n: PNode; result: var Builder) =
  case detectStrVersion(m)
  of 0, 1: genStringLiteralV1(m, n, result)
  of 2: genStringLiteralV2(m, n, isConst = true, result)
-  of 3: genStringLiteralV3(m, n, isConst = true, result)
  else:
    localError(m.config, n.info, "cannot determine how to produce code for string literal")
--- a/compiler/ccgreset.nim
+++ b/compiler/ccgreset.nim
@@ -67,14 +67,7 @@ proc specializeResetT(p: BProc, accessor: Rope, typ: PType) =
    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)
+    if typ.n != nil: specializeResetN(p, accessor, typ.n, typ)
  of tyTuple:
    let typ = getUniqueType(typ)
    for i, a in typ.ikids:
--- a/compiler/ccgstmts.nim
+++ b/compiler/ccgstmts.nim
@@ -18,7 +18,7 @@ proc registerTraverseProc(p: BProc, v: PSym) =
  var traverseProc = ""
  if p.config.selectedGC in {gcMarkAndSweep, gcHooks, gcRefc} and
      optOwnedRefs notin p.config.globalOptions and
-      containsManagedMemory(v.loc.t):
+      containsGarbageCollectedRef(v.loc.t):
    # we register a specialized marked proc here; this has the advantage
    # that it works out of the box for thread local storage then :-)
    traverseProc = genTraverseProcForGlobal(p.module, v, v.info)
@@ -126,26 +126,25 @@ proc genVarTuple(p: BProc, n: PNode) =
    let vn = n[i]
    let v = vn.sym
    if sfCompileTime in v.flags: continue
-    backendEnsureMutable v
    if sfGlobal in v.flags:
      assignGlobalVar(p, vn, "")
-      genObjectInit(p, cpsInit, v.typ, v.locImpl, constructObj)
+      genObjectInit(p, cpsInit, v.typ, v.loc, constructObj)
      registerTraverseProc(p, v)
    else:
      assignLocalVar(p, vn)
      initLocalVar(p, v, immediateAsgn=isAssignedImmediately(p.config, n[^1]))
    var field = initLoc(locExpr, vn, tup.storage)
    let rtup = rdLoc(tup)
-    let fieldName =
+    let fieldName = 
      if t.kind == tyTuple:
        "Field" & $i
      else:
        if t.n[i].kind != nkSym: internalError(p.config, n.info, "genVarTuple")
        mangleRecFieldName(p.module, t.n[i].sym)
    field.snippet = dotField(rtup, fieldName)
-    putLocIntoDest(p, v.locImpl, field)
+    putLocIntoDest(p, v.loc, field)
    if forHcr or isGlobalInBlock:
-      hcrGlobals.add((loc: v.locImpl, tp: CNil))
+      hcrGlobals.add((loc: v.loc, tp: CNil))

  if forHcr:
    # end the block where the tuple gets initialized
@@ -226,7 +225,7 @@ proc genState(p: BProc, n: PNode) =
  elif n0.kind == nkStrLit:
    p.s(cpsStmts).addLabel(n0.strVal)

-proc blockLeaveActions(p: BProc, howManyTrys, howManyExcepts: int, isReturnStmt = false) =
+proc blockLeaveActions(p: BProc, howManyTrys, howManyExcepts: int) =
  # Called by return and break stmts.
  # Deals with issues faced when jumping out of try/except/finally stmts.

@@ -258,7 +257,7 @@ proc blockLeaveActions(p: BProc, howManyTrys, howManyExcepts: int, isReturnStmt

  # Pop exceptions that was handled by the
  # except-blocks we are in
-  if noSafePoints notin p.flags and not (isReturnStmt and isClosureIterator(p.prc.typ)):
+  if noSafePoints notin p.flags:
    for i in countdown(howManyExcepts-1, 0):
      p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "popCurrentException"))

@@ -366,7 +365,6 @@ proc genSingleVar(p: BProc, v: PSym; vn, value: PNode) =
    if v.flags * {sfImportc, sfExportc} == {sfImportc} and
        value.kind == nkEmpty and
        v.loc.flags * {lfHeader, lfNoDecl} != {}:
-      # IC XXX: this is bad, we should set v.loc regardless here
      return
    if sfPure in v.flags:
      # v.owner.kind != skModule:
@@ -462,8 +460,7 @@ proc genSingleVar(p: BProc, v: PSym; vn, value: PNode) =
  if value.kind != nkEmpty and valueAsRope.len == 0:
    genLineDir(targetProc, vn)
    if not isCppCtorCall:
-      backendEnsureMutable v
-      loadInto(targetProc, vn, value, v.locImpl)
+      loadInto(targetProc, vn, value, v.loc)
  if forHcr:
    endBlockWith(targetProc):
      finishBranch(p.s(cpsStmts), hcrInit)
@@ -490,17 +487,14 @@ proc genClosureVar(p: BProc, a: PNode) =
    constructLoc(p, v)

 proc genVarStmt(p: BProc, n: PNode) =
-  for it in n:
-    case it.kind
-    of nkCommentStmt: discard
-    of nkIdentDefs:
+  for it in n.sons:
+    if it.kind == nkCommentStmt: continue
+    if it.kind == nkIdentDefs:
      # can be a lifted var nowadays ...
      if it[0].kind == nkSym:
        genSingleVar(p, it)
      else:
        genClosureVar(p, it)
-    of nkSym:
-      genSingleVar(p, it.sym, newSymNode(it.sym), it.sym.astdef)
    else:
      genVarTuple(p, it)

@@ -560,8 +554,7 @@ proc genReturnStmt(p: BProc, t: PNode) =
  if (t[0].kind != nkEmpty): genStmts(p, t[0])
  blockLeaveActions(p,
    howManyTrys    = p.nestedTryStmts.len,
-    howManyExcepts = p.inExceptBlockLen,
-    isReturnStmt = true)
+    howManyExcepts = p.inExceptBlockLen)
  if (p.finallySafePoints.len > 0) and noSafePoints notin p.flags:
    # If we're in a finally block, and we came here by exception
    # consume it before we return.
@@ -743,10 +736,8 @@ proc genBlock(p: BProc, n: PNode, d: var TLoc) =
      # named block?
      assert(n[0].kind == nkSym)
      var sym = n[0].sym
-      backendEnsureMutable sym
-      sym.locImpl.k = locOther
-      sym.positionImpl = p.breakIdx+1
-      # ^ IC: review this
+      sym.loc.k = locOther
+      sym.position = p.breakIdx+1
    expr(p, n[1], d)
    endSimpleBlock(p, scope)

@@ -1259,8 +1250,7 @@ proc genTryCpp(p: BProc, t: PNode, d: var TLoc) =
          initElifBranch(p.s(cpsStmts), ifStmt, orExpr)
        if exvar != nil:
          fillLocalName(p, exvar.sym)
-          backendEnsureMutable exvar.sym
-          fillLoc(exvar.sym.locImpl, locTemp, exvar, OnStack)
+          fillLoc(exvar.sym.loc, locTemp, exvar, OnStack)
          linefmt(p, cpsStmts, "$1 $2 = T$3_;$n", [getTypeDesc(p.module, exvar.sym.typ),
            rdLoc(exvar.sym.loc), rope(etmp+1)])
        # we handled the error:
@@ -1308,8 +1298,7 @@ proc genTryCpp(p: BProc, t: PNode, d: var TLoc) =
            if isImportedException(typeNode.typ, p.config):
              let exvar = t[i][j][2] # ex1 in `except ExceptType as ex1:`
              fillLocalName(p, exvar.sym)
-              backendEnsureMutable exvar.sym
-              fillLoc(exvar.sym.locImpl, locTemp, exvar, OnStack)
+              fillLoc(exvar.sym.loc, locTemp, exvar, OnStack)
              startBlockWith(p):
                lineCg(p, cpsStmts, "catch ($1& $2) {$n", [getTypeDesc(p.module, typeNode.typ), rdLoc(exvar.sym.loc)])
              genExceptBranchBody(t[i][^1])  # exception handler body will duplicated for every type
@@ -1400,8 +1389,7 @@ proc genTryCppOld(p: BProc, t: PNode, d: var TLoc) =
        if t[i][j].isInfixAs():
          let exvar = t[i][j][2] # ex1 in `except ExceptType as ex1:`
          fillLocalName(p, exvar.sym)
-          backendEnsureMutable exvar.sym
-          fillLoc(exvar.sym.locImpl, locTemp, exvar, OnUnknown)
+          fillLoc(exvar.sym.loc, locTemp, exvar, OnUnknown)
          startBlockWith(p):
            lineCg(p, cpsStmts, "catch ($1& $2) {$n", [getTypeDesc(p.module, t[i][j][1].typ), rdLoc(exvar.sym.loc)])
        else:
@@ -1940,15 +1928,6 @@ proc genAsgn(p: BProc, e: PNode, fastAsgn: bool) =
  elif optFieldCheck in p.options and isDiscriminantField(e[0]):
    genLineDir(p, e)
    asgnFieldDiscriminant(p, e)
-  elif p.config.isDefined("nimsso") and e[0].kind == nkBracketExpr and
-      e[0][0].typ.skipTypes(abstractVar).kind == tyString:
-    # nimsso: s[i] = c  →  nimStrPutV3(&s, i, c)  (handles COW internally)
-    genLineDir(p, e)
-    var base = initLocExpr(p, e[0][0])
-    var idx  = initLocExpr(p, e[0][1])
-    var rhs  = initLocExpr(p, e[1])
-    p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimStrPutV3"),
-      byRefLoc(p, base), rdLoc(idx), rdCharLoc(rhs))
  else:
    let le = e[0]
    let ri = e[1]
--- a/compiler/ccgtypes.nim
+++ b/compiler/ccgtypes.nim
@@ -11,7 +11,7 @@

 # ------------------------- Name Mangling --------------------------------

-import sighashes, std/strscans
+import sighashes, modulegraphs, std/strscans
 import ../dist/checksums/src/checksums/md5
 import std/sequtils

@@ -57,15 +57,11 @@ proc mangleField(m: BModule; name: PIdent): string =

 proc mangleProc(m: BModule; s: PSym; makeUnique: bool): string =
  result = "_Z"  # Common prefix in Itanium ABI
-  var params = ""
-  var staticLists = ""
+  result.add encodeSym(m, s, makeUnique)
  if s.typ.len > 1: #we dont care about the return param
    for i in 1..<s.typ.len:
      if s.typ[i].isNil: continue
-      params.add encodeType(m, s.typ[i], staticLists)
-
-  result.add encodeSym(m, s, makeUnique, staticLists)
-  result.add params
+      result.add encodeType(m, s.typ[i])

  if result in m.g.mangledPrcs:
    result = mangleProc(m, s, true)
@@ -75,7 +71,7 @@ proc mangleProc(m: BModule; s: PSym; makeUnique: bool): string =
 proc fillBackendName(m: BModule; s: PSym) =
  if s.loc.snippet == "":
    var result: Rope
-    if s.kind in routineKinds and {optCDebug, optItaniumMangle} * m.g.config.globalOptions == {optCDebug, optItaniumMangle} and
+    if not m.compileToCpp and s.kind in routineKinds and optCDebug in m.g.config.globalOptions and
      m.g.config.symbolFiles == disabledSf:
      result = mangleProc(m, s, false).rope
    else:
@@ -84,8 +80,7 @@ proc fillBackendName(m: BModule; s: PSym) =
    if m.hcrOn:
      result.add '_'
      result.add(idOrSig(s, m.module.name.s.mangle, m.sigConflicts, m.config))
-    backendEnsureMutable s
-    s.locImpl.snippet = result
+    s.loc.snippet = result

 proc fillParamName(m: BModule; s: PSym) =
  if s.loc.snippet == "":
@@ -108,8 +103,7 @@ proc fillParamName(m: BModule; s: PSym) =
    # and a function called in main or proxy uses `socket` as a parameter name.
    # That would lead to either needing to reload `proxy` or to overwrite the
    # executable file for the main module, which is running (or both!) -> error.
-    backendEnsureMutable s
-    s.locImpl.snippet = res.rope
+    s.loc.snippet = res.rope

 proc fillLocalName(p: BProc; s: PSym) =
  assert s.kind in skLocalVars+{skTemp}
@@ -124,8 +118,7 @@ proc fillLocalName(p: BProc; s: PSym) =
    elif s.kind != skResult:
      result.add "_" & rope(counter+1)
    p.sigConflicts.inc(key)
-    backendEnsureMutable s
-    s.locImpl.snippet = result
+    s.loc.snippet = result

 proc scopeMangledParam(p: BProc; param: PSym) =
  ## parameter generation only takes BModule, not a BProc, so we have to
@@ -159,9 +152,8 @@ proc getTypeName(m: BModule; typ: PType; sig: SigHash): Rope =
      break
  let typ = if typ.kind in {tyAlias, tySink, tyOwned}: typ.elementType else: typ
  if typ.loc.snippet == "":
-    backendEnsureMutable typ
-    typ.typeName(typ.locImpl.snippet)
-    typ.locImpl.snippet.add $sig
+    typ.typeName(typ.loc.snippet)
+    typ.loc.snippet.add $sig
  else:
    when defined(debugSigHashes):
      # check consistency:
@@ -251,11 +243,14 @@ proc isOrHasImportedCppType(typ: PType): bool =
  searchTypeFor(typ.skipTypes({tyRef}), isImportedCppType)

 proc hasNoInit(t: PType): bool =
-  let t = skipTypes(t, {tyGenericInst})
  result = t.sym != nil and sfNoInit in t.sym.flags

 proc getTypeDescAux(m: BModule; origTyp: PType, check: var IntSet; kind: TypeDescKind): Rope

+proc isObjLackingTypeField(typ: PType): bool {.inline.} =
+  result = (typ.kind == tyObject) and ((tfFinal in typ.flags) and
+      (typ.baseClass == nil) or isPureObject(typ))
+
 proc isInvalidReturnType(conf: ConfigRef; typ: PType, isProc = true): bool =
  # Arrays and sets cannot be returned by a C procedure, because C is
  # such a poor programming language.
@@ -277,7 +272,7 @@ proc isInvalidReturnType(conf: ConfigRef; typ: PType, isProc = true): bool =
    of ctStruct:
      let t = skipTypes(rettype, typedescInst)
      if rettype.isImportedCppType or t.isImportedCppType or
-          (typ.callConv == ccCDecl and conf.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc}):
+          (typ.callConv == ccCDecl and conf.selectedGC in {gcArc, gcAtomicArc, gcOrc}):
        # prevents nrvo for cdecl procs; # bug #23401
        result = false
      else:
@@ -294,12 +289,7 @@ proc cacheGetType(tab: TypeCache; sig: SigHash): Rope =
  result = tab.getOrDefault(sig)

 proc addAbiCheck(m: BModule; t: PType, name: Rope) =
-  if isDefined(m.config, "checkAbi") and (let size = getSize(m.config, t); size != szUnknownSize) and
-    not (t.kind == tyObject and searchTypeFor(t, proc (t: PType): bool {.nimcall.} = t.kind == tyUncheckedArray)):
-    # `UncheckedArray`, not `ptr UncheckedArray` type field in object types is a flexible array.
-    # `sizeof` in C and Nim doesn't always return the same value for object types containing it.
-    # making `getSize` in Nim always returns the same value as `sizeof` in C from flexible arrays seems hard.
-    # See `SEQ_DECL_SIZE` in lib/nimbase.h
+  if isDefined(m.config, "checkAbi") and (let size = getSize(m.config, t); size != szUnknownSize):
    var msg = "backend & Nim disagree on size for: "
    msg.addTypeHeader(m.config, t)
    var msg2 = ""
@@ -309,13 +299,12 @@ proc addAbiCheck(m: BModule; t: PType, name: Rope) =


 proc fillResult(conf: ConfigRef; param: PNode, proctype: PType) =
-  backendEnsureMutable param.sym
-  fillLoc(param.sym.locImpl, locParam, param, "Result",
+  fillLoc(param.sym.loc, locParam, param, "Result",
          OnStack)
  let t = param.sym.typ
  if mapReturnType(conf, t) != ctArray and isInvalidReturnType(conf, proctype):
-    incl(param.sym.locImpl.flags, lfIndirect)
-    param.sym.locImpl.storage = OnUnknown
+    incl(param.sym.loc.flags, lfIndirect)
+    param.sym.loc.storage = OnUnknown

 proc typeNameOrLiteral(m: BModule; t: PType, literal: string): Rope =
  if t.sym != nil and sfImportc in t.sym.flags and t.sym.magic == mNone:
@@ -339,10 +328,6 @@ proc getSimpleTypeDesc(m: BModule; typ: PType): Rope =
      cgsym(m, "NimStrPayload")
      cgsym(m, "NimStringV2")
      result = typeNameOrLiteral(m, typ, "NimStringV2")
-    of 3:
-      cgsym(m, "LongString")
-      cgsym(m, "SmallString")
-      result = typeNameOrLiteral(m, typ, "SmallString")
    else:
      cgsym(m, "NimStringDesc")
      result = typeNameOrLiteral(m, typ, "NimStringDesc*")
@@ -457,14 +442,6 @@ proc getSeqPayloadType(m: BModule; t: PType): Rope =
  result = getTypeDescWeak(m, t, check, dkParam) & "_Content"
  #result = getTypeForward(m, t, hashType(t)) & "_Content"

-proc seqPayloadElem(m: BModule; t: PType): Snippet =
-  ## Returns the C type name for a seq's element as stored in the payload,
-  ## suitable for sizeof()/alignof(). Must use dkVar, not the dkParam default,
-  ## because reified openArrays (experimental views) differ: dkParam gives a
-  ## bare pointer (T*) while dkVar gives the two-word struct actually stored.
-  var check = initIntSet()
-  result = getTypeDescAux(m, t.elementType, check, dkVar)
-
 proc seqV2ContentType(m: BModule; t: PType; check: var IntSet) =
  let sig = hashType(t, m.config)
  let result = cacheGetType(m.typeCache, sig)
@@ -546,15 +523,14 @@ proc genMemberProcParams(m: BModule; prc: PSym, superCall, rettype, name, params
  var types, names, args: seq[string] = @[]
  if not isCtor:
    var this = t.n[1].sym
-    backendEnsureMutable this
    fillParamName(m, this)
-    fillLoc(this.locImpl, locParam, t.n[1],
+    fillLoc(this.loc, locParam, t.n[1],
            this.paramStorageLoc)
    if this.typ.kind == tyPtr:
-      this.locImpl.snippet = "this"
+      this.loc.snippet = "this"
    else:
-      this.locImpl.snippet = "(*this)"
-    names.add this.locImpl.snippet
+      this.loc.snippet = "(*this)"
+    names.add this.loc.snippet
    types.add getTypeDescWeak(m, this.typ, check, dkParam)

  let firstParam = if isCtor: 1 else: 2
@@ -568,14 +544,13 @@ proc genMemberProcParams(m: BModule; prc: PSym, superCall, rettype, name, params
      else:
        descKind = dkRefParam
    var typ, name: string
-    backendEnsureMutable param
    fillParamName(m, param)
-    fillLoc(param.locImpl, locParam, t.n[i],
+    fillLoc(param.loc, locParam, t.n[i],
            param.paramStorageLoc)
    if ccgIntroducedPtr(m.config, param, t.returnType) and descKind == dkParam:
      typ = getTypeDescWeak(m, param.typ, check, descKind) & "*"
-      incl(param.locImpl.flags, lfIndirect)
-      param.locImpl.storage = OnUnknown
+      incl(param.loc.flags, lfIndirect)
+      param.loc.storage = OnUnknown
    elif weakDep:
      typ = getTypeDescWeak(m, param.typ, check, descKind)
    else:
@@ -583,7 +558,7 @@ proc genMemberProcParams(m: BModule; prc: PSym, superCall, rettype, name, params
    if sfNoalias in param.flags:
      typ.add("NIM_NOALIAS ")

-    name = param.locImpl.snippet
+    name = param.loc.snippet
    types.add typ
    names.add name
    if sfCodegenDecl notin param.flags:
@@ -612,7 +587,7 @@ proc genProcParams(m: BModule; t: PType, rettype: var Rope, params: var Builder,
  if t.returnType == nil or isInvalidReturnType(m.config, t):
    rettype = CVoid
  else:
-    rettype = getTypeDescWeak(m, t.returnType, check, dkResult)
+    rettype = getTypeDescAux(m, t.returnType, check, dkResult)
  var paramBuilder: ProcParamBuilder
  params.addProcParams(paramBuilder):
    for i in 1..<t.n.len:
@@ -625,15 +600,14 @@ proc genProcParams(m: BModule; t: PType, rettype: var Rope, params: var Builder,
        else:
          descKind = dkRefParam
      if isCompileTimeOnly(param.typ): continue
-      backendEnsureMutable param
      fillParamName(m, param)
-      fillLoc(param.locImpl, locParam, t.n[i],
+      fillLoc(param.loc, locParam, t.n[i],
              param.paramStorageLoc)
      var typ: Rope
      if ccgIntroducedPtr(m.config, param, t.returnType) and descKind == dkParam:
        typ = ptrType(getTypeDescWeak(m, param.typ, check, descKind))
-        incl(param.locImpl.flags, lfIndirect)
-        param.locImpl.storage = OnUnknown
+        incl(param.loc.flags, lfIndirect)
+        param.loc.storage = OnUnknown
      elif weakDep:
        typ = (getTypeDescWeak(m, param.typ, check, descKind))
      else:
@@ -645,9 +619,9 @@ proc genProcParams(m: BModule; t: PType, rettype: var Rope, params: var Builder,
      var j = 0
      while arr.kind in {tyOpenArray, tyVarargs}:
        # this fixes the 'sort' bug:
-        if param.typ.kind in {tyVar, tyLent}: param.locImpl.storage = OnUnknown
+        if param.typ.kind in {tyVar, tyLent}: param.loc.storage = OnUnknown
        # need to pass hidden parameter:
-        params.addParam(paramBuilder, name = param.locImpl.snippet & "Len_" & $j, typ = NimInt)
+        params.addParam(paramBuilder, name = param.loc.snippet & "Len_" & $j, typ = NimInt)
        inc(j)
        arr = arr[0].skipTypes({tySink})
    if t.returnType != nil and isInvalidReturnType(m.config, t):
@@ -732,13 +706,12 @@ proc genRecordFieldsAux(m: BModule; n: PNode,
    if field.typ.kind == tyVoid: return
    #assert(field.ast == nil)
    let sname = mangleRecFieldName(m, field)
-    backendEnsureMutable field
-    fillLoc(field.locImpl, locField, n, unionPrefix & sname, OnUnknown)
+    fillLoc(field.loc, locField, n, unionPrefix & sname, OnUnknown)
    # for importcpp'ed objects, we only need to set field.loc, but don't
    # have to recurse via 'getTypeDescAux'. And not doing so prevents problems
    # with heavily templatized C++ code:
    if not isImportedCppType(rectype):
-      let fieldType = field.loc.t.skipTypes(abstractInst)
+      let fieldType = field.loc.lode.typ.skipTypes(abstractInst)
      var typ: Rope = ""
      var isFlexArray = false
      var initializer = ""
@@ -786,8 +759,6 @@ proc fillObjectFields*(m: BModule; typ: PType) =
  var check = initIntSet()
  var ignored = newBuilder("")
  addRecordFields(ignored, m, typ, check)
-  if typ.baseClass != nil:
-    fillObjectFields(m, typ.baseClass.skipTypes(skipPtrs))

 proc mangleDynLibProc(sym: PSym): Rope

@@ -812,8 +783,6 @@ proc getTupleDesc(m: BModule; typ: PType, name: Rope,
  var res = newBuilder("")
  res.addStruct(m, typ, name, ""):
    for i, a in typ.ikids:
-      # Do not produce code for void types
-      if isEmptyType(a): continue
      res.addField(
        name = "Field" & $i,
        typ = getTypeDescAux(m, a, check, dkField))
@@ -863,54 +832,6 @@ proc getOpenArrayDesc(m: BModule; t: PType, check: var IntSet; kind: TypeDescKin
          m.s[cfsTypes].addField(name = "Field0", typ = ptrType(elemType))
          m.s[cfsTypes].addField(name = "Field1", typ = NimInt)

-proc importedCppObject(m: BModule; t, tt: PType; check: var IntSet; kind: TypeDescKind; sig: SigHash; result: var Rope) =
-  let cppNameAsRope = getTypeName(m, t, sig)
-  let cppName = $cppNameAsRope
-  var i = 0
-  var chunkStart = 0
-
-  template addResultType(ty: untyped) =
-    if ty == nil or ty.kind == tyVoid:
-      result.add(CVoid)
-    elif ty.kind == tyStatic:
-      internalAssert m.config, ty.n != nil
-      result.add ty.n.renderTree
-    else:
-      result.add getTypeDescAux(m, ty, check, kind)
-
-  while i < cppName.len:
-    if cppName[i] == '\'':
-      var chunkEnd = i-1
-      var idx, stars: int = 0
-      if scanCppGenericSlot(cppName, i, idx, stars):
-        result.add cppName.substr(chunkStart, chunkEnd)
-        chunkStart = i
-
-        let typeInSlot = resolveStarsInCppType(tt, idx + 1, stars)
-        addResultType(typeInSlot)
-    else:
-      inc i
-
-  if chunkStart != 0:
-    result.add cppName.substr(chunkStart)
-  else:
-    result = cppNameAsRope & "<"
-    for needsComma, a in tt.genericInstParams:
-      if needsComma: result.add(" COMMA ")
-      addResultType(a)
-    result.add("> ")
-  # always call for sideeffects:
-  assert t.kind != tyTuple
-  discard getRecordDesc(m, t, result, check)
-  # The resulting type will include commas and these won't play well
-  # with the C macros for defining procs such as N_NIMCALL. We must
-  # create a typedef for the type and use it in the proc signature:
-  let typedefName = "TY" & $sig
-  m.s[cfsTypes].addTypedef(name = typedefName):
-    m.s[cfsTypes].add(result)
-  m.typeCache[sig] = typedefName
-  result = typedefName
-
 proc getTypeDescAux(m: BModule; origTyp: PType, check: var IntSet; kind: TypeDescKind): Rope =
  # returns only the type's name
  var t = origTyp.skipTypes(irrelevantForBackend-{tyOwned})
@@ -926,7 +847,7 @@ proc getTypeDescAux(m: BModule; origTyp: PType, check: var IntSet; kind: TypeDes

  # tyDistinct matters if it is an importc type
  result = getTypePre(m, origTyp.skipTypes(irrelevantForBackend-{tyOwned, tyDistinct}), sig)
-  defer:
+  defer: # defer is the simplest in this case
    if isImportedType(t) and not m.typeABICache.containsOrIncl(sig):
      addAbiCheck(m, t, result)

@@ -1060,7 +981,7 @@ proc getTypeDescAux(m: BModule; origTyp: PType, check: var IntSet; kind: TypeDes
      m.s[cfsTypes].addArrayTypedef(name = result, len = 1):
        m.s[cfsTypes].add(et)
  of tyArray:
-    var n = toInt64(lengthOrd(m.config, t))
+    var n: BiggestInt = toInt64(lengthOrd(m.config, t))
    if n <= 0: n = 1   # make an array of at least one element
    result = getTypeName(m, origTyp, sig)
    m.typeCache[sig] = result
@@ -1071,7 +992,52 @@ proc getTypeDescAux(m: BModule; origTyp: PType, check: var IntSet; kind: TypeDes
  of tyObject, tyTuple:
    let tt = origTyp.skipTypes({tyDistinct})
    if isImportedCppType(t) and tt.kind == tyGenericInst:
-      importedCppObject(m, t, tt, check, kind, sig, result)
+      let cppNameAsRope = getTypeName(m, t, sig)
+      let cppName = $cppNameAsRope
+      var i = 0
+      var chunkStart = 0
+
+      template addResultType(ty: untyped) =
+        if ty == nil or ty.kind == tyVoid:
+          result.add(CVoid)
+        elif ty.kind == tyStatic:
+          internalAssert m.config, ty.n != nil
+          result.add ty.n.renderTree
+        else:
+          result.add getTypeDescAux(m, ty, check, kind)
+
+      while i < cppName.len:
+        if cppName[i] == '\'':
+          var chunkEnd = i-1
+          var idx, stars: int = 0
+          if scanCppGenericSlot(cppName, i, idx, stars):
+            result.add cppName.substr(chunkStart, chunkEnd)
+            chunkStart = i
+
+            let typeInSlot = resolveStarsInCppType(tt, idx + 1, stars)
+            addResultType(typeInSlot)
+        else:
+          inc i
+
+      if chunkStart != 0:
+        result.add cppName.substr(chunkStart)
+      else:
+        result = cppNameAsRope & "<"
+        for needsComma, a in tt.genericInstParams:
+          if needsComma: result.add(" COMMA ")
+          addResultType(a)
+        result.add("> ")
+      # always call for sideeffects:
+      assert t.kind != tyTuple
+      discard getRecordDesc(m, t, result, check)
+      # The resulting type will include commas and these won't play well
+      # with the C macros for defining procs such as N_NIMCALL. We must
+      # create a typedef for the type and use it in the proc signature:
+      let typedefName = "TY" & $sig
+      m.s[cfsTypes].addTypedef(name = typedefName):
+        m.s[cfsTypes].add(result)
+      m.typeCache[sig] = typedefName
+      result = typedefName
    else:
      result = cacheGetType(m.forwTypeCache, sig)
      if result == "":
@@ -1086,7 +1052,6 @@ proc getTypeDescAux(m: BModule; origTyp: PType, check: var IntSet; kind: TypeDes
                      else: getTupleDesc(m, t, result, check)
        if not isImportedType(t):
          m.s[cfsTypes].add(recdesc)
-          addAbiCheck(m, t, result)
        elif tfIncompleteStruct notin t.flags:
          discard # addAbiCheck(m, t, result) # already handled elsewhere
  of tySet:
@@ -1187,8 +1152,7 @@ proc genMemberProcHeader(m: BModule; prc: PSym; result: var Builder; asPtr: bool
  let isCtor = sfConstructor in prc.flags
  var check = initIntSet()
  fillBackendName(m, prc)
-  backendEnsureMutable prc
-  fillLoc(prc.locImpl, locProc, prc.ast[namePos], OnUnknown)
+  fillLoc(prc.loc, locProc, prc.ast[namePos], OnUnknown)
  var memberOp = "#." #only virtual
  var typ: PType
  if isCtor:
@@ -1220,7 +1184,7 @@ proc genMemberProcHeader(m: BModule; prc: PSym; result: var Builder; asPtr: bool
    superCall = ""
  else:
    if not isCtor:
-      prc.locImpl.snippet = "$1$2(@)" % [memberOp, name]
+      prc.loc.snippet = "$1$2(@)" % [memberOp, name]
    elif superCall != "":
      superCall = " : " & superCall

@@ -1235,15 +1199,14 @@ proc genProcHeader(m: BModule; prc: PSym; result: var Builder; visibility: var D
  # using static is needed for inline procs
  var check = initIntSet()
  fillBackendName(m, prc)
-  backendEnsureMutable prc
-  fillLoc(prc.locImpl, locProc, prc.ast[namePos], OnUnknown)
+  fillLoc(prc.loc, locProc, prc.ast[namePos], OnUnknown)
  var rettype: Snippet = ""
  var desc = newBuilder("")
  genProcParams(m, prc.typ, rettype, desc, check, true, false)
  let params = extract(desc)
  # handle the 2 options for hotcodereloading codegen - function pointer
  # (instead of forward declaration) or header for function body with "_actual" postfix
-  var name = prc.locImpl.snippet
+  var name = prc.loc.snippet
  if not asPtr and isReloadable(m, prc):
    name.add("_actual")
  # careful here! don't access ``prc.ast`` as that could reload large parts of
@@ -1483,41 +1446,30 @@ proc genObjectInfo(m: BModule; typ, origType: PType, name: Rope; info: TLineInfo
  var t = typ.baseClass
  while t != nil:
    t = t.skipTypes(skipPtrs)
-    t.incl tfObjHasKids
+    t.flags.incl tfObjHasKids
    t = t.baseClass

-proc validTupleTypeFields(t: PType): int =
-  # we want to treat tuples with only void fields as empty, so we need to exclude void types here:
-  result = 0
-  for a in t.kids:
-    if not isEmptyType(a): inc result
-
 proc genTupleInfo(m: BModule; typ, origType: PType, name: Rope; info: TLineInfo) =
  genTypeInfoAuxBase(m, typ, typ, name, cIntValue(0), info)
  var expr = getNimNode(m)
-  let nonVoidKids = validTupleTypeFields(typ)
-  if nonVoidKids > 0:
-    var tmp = getTempName(m) & "_" & $nonVoidKids
-    genTNimNodeArray(m, tmp, nonVoidKids)
-    var j = 0
+  if not typ.isEmptyTupleType:
+    var tmp = getTempName(m) & "_" & $typ.kidsLen
+    genTNimNodeArray(m, tmp, typ.kidsLen)
    for i, a in typ.ikids:
-      # Do not produce code for void types
-      if isEmptyType(a): continue
      var tmp2 = getNimNode(m)
      let fieldTypInfo = genTypeInfoV1(m, a, info)
-      m.s[cfsTypeInit3].addSubscriptAssignment(tmp, cIntValue(j), cAddr(tmp2))
+      m.s[cfsTypeInit3].addSubscriptAssignment(tmp, cIntValue(i), cAddr(tmp2))
      m.s[cfsTypeInit3].addFieldAssignment(tmp2, "kind", 1)
      m.s[cfsTypeInit3].addFieldAssignmentWithValue(tmp2, "offset"):
        m.s[cfsTypeInit3].addOffsetof(getTypeDesc(m, origType, dkVar), "Field" & $i)
      m.s[cfsTypeInit3].addFieldAssignment(tmp2, "typ", fieldTypInfo)
      m.s[cfsTypeInit3].addFieldAssignment(tmp2, "name", "\"Field" & $i & "\"")
-      inc j
-    m.s[cfsTypeInit3].addFieldAssignment(expr, "len", nonVoidKids)
+    m.s[cfsTypeInit3].addFieldAssignment(expr, "len", typ.kidsLen)
    m.s[cfsTypeInit3].addFieldAssignment(expr, "kind", 2)
    m.s[cfsTypeInit3].addFieldAssignment(expr, "sons",
      cAddr(subscript(tmp, cIntValue(0))))
  else:
-    m.s[cfsTypeInit3].addFieldAssignment(expr, "len", cIntValue(0))
+    m.s[cfsTypeInit3].addFieldAssignment(expr, "len", typ.kidsLen)
    m.s[cfsTypeInit3].addFieldAssignment(expr, "kind", 2)
  m.s[cfsTypeInit3].addFieldAssignment(tiNameForHcr(m, name), "node", cAddr(expr))

@@ -1690,8 +1642,8 @@ proc generateRttiDestructor(g: ModuleGraph; typ: PType; owner: PSym; kind: TType
  n[bodyPos] = body
  result.ast = n

-  incl result.flagsImpl, sfFromGeneric
-  incl result.flagsImpl, sfGeneratedOp
+  incl result.flags, sfFromGeneric
+  incl result.flags, sfGeneratedOp

 proc genHook(m: BModule; t: PType; info: TLineInfo; op: TTypeAttachedOp; result: var Builder) =
  let theProc = getAttachedOp(m.g.graph, t, op)
@@ -1717,7 +1669,7 @@ proc genHook(m: BModule; t: PType; info: TLineInfo; op: TTypeAttachedOp; result:
        echo "ayclic but has this =trace ", t, " ", theProc.ast
  else:
    when false:
-      if op == attachedTrace and m.config.selectedGC in {gcOrc, gcYrc} and
+      if op == attachedTrace and m.config.selectedGC == gcOrc and
          containsGarbageCollectedRef(t):
        # unfortunately this check is wrong for an object type that only contains
        # .cursor fields like 'Node' inside 'cycleleak'.
@@ -1896,12 +1848,6 @@ proc genTypeInfoV2Impl(m: BModule; t, origType: PType, name: Rope; info: TLineIn
  if t.kind == tyObject and t.baseClass != nil and optEnableDeepCopy in m.config.globalOptions:
    discard genTypeInfoV1(m, t, info)

-proc myModuleOpenForCodegen(m: BModule; idx: FileIndex): bool {.inline.} =
-  if moduleOpenForCodegen(m.g.graph, idx):
-    result = idx.int < m.g.mods.len and m.g.mods[idx.int] != nil
-  else:
-    result = false
-
 proc genTypeInfoV2(m: BModule; t: PType; info: TLineInfo): Rope =
  let origType = t
  # distinct types can have their own destructors
@@ -1930,9 +1876,9 @@ proc genTypeInfoV2(m: BModule; t: PType; info: TLineInfo): Rope =
  m.typeInfoMarkerV2[sig] = result

  let owner = t.skipTypes(typedescPtrs).itemId.module
-  if owner != m.module.position and myModuleOpenForCodegen(m, FileIndex owner):
+  if owner != m.module.position and moduleOpenForCodegen(m.g.graph, FileIndex owner):
    # make sure the type info is created in the owner module
-    discard genTypeInfoV2(m.g.mods[owner], origType, info)
+    discard genTypeInfoV2(m.g.modules[owner], origType, info)
    # reference the type info as extern here
    cgsym(m, "TNimTypeV2")
    declareNimType(m, "TNimTypeV2", result, owner)
@@ -2015,9 +1961,9 @@ proc genTypeInfoV1(m: BModule; t: PType; info: TLineInfo): Rope =
    return prefixTI(result)

  var owner = t.skipTypes(typedescPtrs).itemId.module
-  if owner != m.module.position and myModuleOpenForCodegen(m, FileIndex owner):
+  if owner != m.module.position and moduleOpenForCodegen(m.g.graph, FileIndex owner):
    # make sure the type info is created in the owner module
-    discard genTypeInfoV1(m.g.mods[owner], origType, info)
+    discard genTypeInfoV1(m.g.modules[owner], origType, info)
    # reference the type info as extern here
    cgsym(m, "TNimType")
    cgsym(m, "TNimNode")
@@ -2027,7 +1973,7 @@ proc genTypeInfoV1(m: BModule; t: PType; info: TLineInfo): Rope =
    owner = m.module.position.int32

  m.g.typeInfoMarker[sig] = (str: result, owner: owner)
-  #rememberEmittedTypeInfo(m.g.graph, FileIndex(owner), $result)
+  rememberEmittedTypeInfo(m.g.graph, FileIndex(owner), $result)

  case t.kind
  of tyEmpty, tyVoid: result = cIntValue(0)
@@ -2053,9 +1999,6 @@ proc genTypeInfoV1(m: BModule; t: PType; info: TLineInfo): Rope =
  of tyRef:
    genTypeInfoAux(m, t, t, result, info)
    if m.config.selectedGC in {gcMarkAndSweep, gcRefc, gcGo}:
-      # it may not be used in other places except in `genTraverseProc`,
-      # we have to generate a typedesc for this case, not a weak one
-      discard getTypeDesc(m, origType.last)
      let markerProc = genTraverseProc(m, origType, sig)
      m.s[cfsTypeInit3].addFieldAssignment(tiNameForHcr(m, result), "marker", markerProc)
  of tyPtr, tyRange, tyUncheckedArray: genTypeInfoAux(m, t, t, result, info)
@@ -2094,21 +2037,17 @@ proc genTypeInfo*(config: ConfigRef, m: BModule; t: PType; info: TLineInfo): Rop
  else:
    result = genTypeInfoV1(m, t, info)

-proc retrieveSym(n: PNode): PSym =
-  case n.kind
-  of nkPostfix: result = retrieveSym(n[1])
-  of nkPragmaExpr, nkTypeDef: result = retrieveSym(n[0])
-  of nkSym: result = n.sym
-  else: result = nil
-
 proc genTypeSection(m: BModule, n: PNode) =
  var intSet = initIntSet()
-  let compress = optCompress in m.config.globalOptions
-  for typedef in n:
-    let s = retrieveSym(typedef)
-    if s != nil and ({sfExportc, sfCompilerProc} * s.flags == {sfExportc} or compress) and s.typ != nil and
-        not containsGenericType(s.typ) and
-        s.typ.kind notin {tyVoid, tyNot, tyAnything, tyOr, tyAnd, tyUntyped, tyTyped, tyNone, tyNil, tySink}:
-      discard getTypeDescAux(m, s.typ, intSet, descKindFromSymKind(s.kind))
-      if m.g.generatedHeader != nil:
-        discard getTypeDescAux(m.g.generatedHeader, s.typ, intSet, descKindFromSymKind(s.kind))
+  for i in 0..<n.len:
+    if len(n[i]) == 0: continue
+    if n[i][0].kind != nkPragmaExpr: continue
+    for p in 0..<n[i][0].len:
+      if (n[i][0][p].kind notin {nkSym, nkPostfix}): continue
+      var s = n[i][0][p]
+      if s.kind == nkPostfix:
+        s = n[i][0][p][1]
+      if {sfExportc, sfCompilerProc} * s.sym.flags == {sfExportc}:
+        discard getTypeDescAux(m, s.typ, intSet, descKindFromSymKind(s.sym.kind))
+        if m.g.generatedHeader != nil:
+          discard getTypeDescAux(m.g.generatedHeader, s.typ, intSet, descKindFromSymKind(s.sym.kind))
--- a/compiler/ccgutils.nim
+++ b/compiler/ccgutils.nim
@@ -11,7 +11,7 @@

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

 import std/[hashes, strutils, formatfloat]

@@ -90,6 +90,9 @@ proc ccgIntroducedPtr*(conf: ConfigRef; s: PSym, retType: PType): bool =
    if s.typ.sym != nil and sfForward in s.typ.sym.flags:
      # forwarded objects are *always* passed by pointers for consistency!
      result = true
+    elif s.typ.kind == tySink and conf.selectedGC notin {gcArc, gcAtomicArc, gcOrc, gcHooks}:
+      # bug #23354:
+      result = false
    elif (optByRef in s.options) or (getSize(conf, pt) > conf.target.floatSize * 3):
      result = true           # requested anyway
    elif (tfFinal in pt.flags) and (pt[0] == nil):
@@ -117,14 +120,14 @@ proc makeUnique(m: BModule; s: PSym, name: string = ""): string =
  result.add "_u"
  result.add $s.itemId.item

-proc encodeSym*(m: BModule; s: PSym; makeUnique: bool = false; extra: string = ""): string =
+proc encodeSym*(m: BModule; s: PSym; makeUnique: bool = false): string =
  #Module::Type
-  var name = s.name.s & extra
+  var name = s.name.s
  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 =
+proc encodeType*(m: BModule; t: PType): string =
  result = ""
  var kindName = ($t.kind)[2..^1]
  kindName[0] = toLower($kindName[0])[0]
@@ -135,10 +138,10 @@ proc encodeType*(m: BModule; t: PType; staticLists: var string): string =
    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 encodeType(m, t[i])
    result.add "E"
  of tySequence, tyOpenArray, tyArray, tyVarargs, tyTuple, tyProc, tySet, tyTypeDesc,
-    tyPtr, tyRef, tyVar, tyLent, tySink, tyUncheckedArray, tyOr, tyAnd, tyBuiltInTypeClass:
+    tyPtr, tyRef, tyVar, tyLent, tySink, tyStatic, tyUncheckedArray, tyOr, tyAnd, tyBuiltInTypeClass:
    result =
      case t.kind:
      of tySequence: encodeName("seq")
@@ -147,13 +150,8 @@ proc encodeType*(m: BModule; t: PType; staticLists: var string): string =
    for i in 0..<t.len:
      let s = t[i]
      if s.isNil: continue
-      result.add encodeType(m, s, staticLists)
+      result.add encodeType(m, s)
    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}:
@@ -166,7 +164,7 @@ proc encodeType*(m: BModule; t: PType; staticLists: var string): string =
  of tyString..tyUInt64, tyPointer, tyBool, tyChar, tyVoid, tyAnything, tyNil, tyEmpty:
    result = encodeName(kindName)
  of tyAlias, tyInferred, tyOwned:
-    result = encodeType(m, t.elementType, staticLists)
+    result = encodeType(m, t.elementType)
  else:
    assert false, "encodeType " & $t.kind

--- a/compiler/cgen.nim
+++ b/compiler/cgen.nim
@@ -16,7 +16,7 @@ import
  rodutils, renderer, cgendata, aliases,
  lowerings, lineinfos, pathutils, transf,
  injectdestructors, astmsgs, modulepaths, pushpoppragmas,
-  mangleutils, cbuilderbase, modulegraphs
+  mangleutils, cbuilderbase

 from expanddefaults import caseObjDefaultBranch

@@ -30,6 +30,7 @@ when not defined(leanCompiler):

 import std/strutils except `%`, addf # collides with ropes.`%`

+from ic / ic import ModuleBackendFlag
 import std/[dynlib, math, tables, sets, os, intsets, hashes]

 const
@@ -60,25 +61,14 @@ proc hcrOn(p: BProc): bool = p.module.config.hcrOn
 proc addForwardedProc(m: BModule, prc: PSym) =
  m.g.forwardedProcs.add(prc)

-proc newModule*(g: BModuleList; module: PSym; conf: ConfigRef; idgen: IdGenerator): BModule
-
 proc findPendingModule(m: BModule, s: PSym): BModule =
  # TODO fixme
-  if m.config.symbolFiles == v2Sf or optCompress in m.config.globalOptions:
+  if m.config.symbolFiles == v2Sf:
    let ms = s.itemId.module  #getModule(s)
-    result = m.g.mods[ms]
-  elif m.config.cmd in {cmdNifC, cmdM}:
-    var ms = getModule(s)
-    registerModule m.g.graph, ms
-    if ms.position >= m.g.mods.len:
-      result = newModule(m.g, ms, m.config, idGeneratorFromModule(ms))
-    else:
-      result = m.g.mods[ms.position]
-      if result == nil:
-        result = newModule(m.g, ms, m.config, idGeneratorFromModule(ms))
+    result = m.g.modules[ms]
  else:
    var ms = getModule(s)
-    result = m.g.mods[ms.position]
+    result = m.g.modules[ms.position]

 proc initLoc(k: TLocKind, lode: PNode, s: TStorageLoc, flags: TLocFlags = {}): TLoc =
  result = TLoc(k: k, storage: s, lode: lode,
@@ -107,7 +97,7 @@ proc t(a: TLoc): PType {.inline.} =

 proc lodeTyp(t: PType): PNode =
  result = newNode(nkEmpty)
-  result.typ = t
+  result.typ() = t

 proc isSimpleConst(typ: PType): bool =
  let t = skipTypes(typ, abstractVar)
@@ -132,10 +122,10 @@ proc getModuleDllPath(m: BModule): Rope =
  result = makeCString(dir.string & "/" & filename)

 proc getModuleDllPath(m: BModule, module: int): Rope =
-  result = getModuleDllPath(m.g.mods[module])
+  result = getModuleDllPath(m.g.modules[module])

 proc getModuleDllPath(m: BModule, s: PSym): Rope =
-  result = getModuleDllPath(m.g.mods[s.itemId.module])
+  result = getModuleDllPath(m.g.modules[s.itemId.module])

 import std/macros

@@ -336,10 +326,7 @@ proc genLineDir(p: BProc, t: PNode) =
  let line = t.info.safeLineNm

  if optEmbedOrigSrc in p.config.globalOptions:
-    var code = sourceLine(p.config, t.info)
-    if code.endsWith('\\'):
-      code.add "#"
-    p.s(cpsStmts).add("// " & code & "\L")
+    p.s(cpsStmts).add("//" & sourceLine(p.config, t.info) & "\L")
  let lastFileIndex = p.lastLineInfo.fileIndex
  let freshLine = freshLineInfo(p, t.info)
  if freshLine:
@@ -389,11 +376,7 @@ proc lenField(p: BProc, val: Rope): Rope {.inline.} =

 proc lenExpr(p: BProc; a: TLoc): Rope =
  if optSeqDestructors in p.config.globalOptions:
-    if p.config.isDefined("nimsso") and a.lode != nil and a.t != nil and
-        a.t.skipTypes(abstractInst).kind == tyString:
-      result = cCall(cgsymValue(p.module, "nimStrLen"), rdLoc(a))
-    else:
-      result = dotField(rdLoc(a), "len")
+    result = dotField(rdLoc(a), "len")
  else:
    let ra = rdLoc(a)
    result = cIfExpr(ra, lenField(p, ra), cIntValue(0))
@@ -447,6 +430,7 @@ proc rdCharLoc(a: TLoc): Rope =
 type
  TAssignmentFlag = enum
    needToCopy
+    needToCopySinkParam
    needTempForOpenArray
    needAssignCall
  TAssignmentFlags = set[TAssignmentFlag]
@@ -523,7 +507,7 @@ include ccgreset
 proc resetLoc(p: BProc, loc: var TLoc) =
  let containsGcRef = optSeqDestructors notin p.config.globalOptions and containsGarbageCollectedRef(loc.t)
  let typ = skipTypes(loc.t, abstractVarRange)
-  if isImportedCppType(typ):
+  if isImportedCppType(typ): 
    var didGenTemp = false
    let rl = rdLoc(loc)
    let init = genCppInitializer(p.module, p, typ, didGenTemp)
@@ -534,15 +518,7 @@ proc resetLoc(p: BProc, loc: var TLoc) =

    let atyp = skipTypes(loc.t, abstractInst)
    let rl = rdLoc(loc)
-    if typ.kind == tyString and p.config.isDefined("nimsso"):
-      # SmallString zero state: bytes=0 (slen=0 in low byte, all inline chars zeroed)
-      if atyp.kind in {tyVar, tyLent}:
-        p.s(cpsStmts).addAssignment(derefField(rl, "bytes"), cIntValue(0))
-        p.s(cpsStmts).addAssignment(derefField(rl, "more"), NimNil)
-      else:
-        p.s(cpsStmts).addAssignment(dotField(rl, "bytes"), cIntValue(0))
-        p.s(cpsStmts).addAssignment(dotField(rl, "more"), NimNil)
-    elif atyp.kind in {tyVar, tyLent}:
+    if atyp.kind in {tyVar, tyLent}:
      p.s(cpsStmts).addAssignment(derefField(rl, "len"), cIntValue(0))
      p.s(cpsStmts).addAssignment(derefField(rl, "p"), NimNil)
    else:
@@ -592,13 +568,8 @@ proc constructLoc(p: BProc, loc: var TLoc, isTemp = false) =
  let typ = loc.t
  if optSeqDestructors in p.config.globalOptions and skipTypes(typ, abstractInst + {tyStatic}).kind in {tyString, tySequence}:
    let rl = rdLoc(loc)
-    if skipTypes(typ, abstractInst + {tyStatic}).kind == tyString and p.config.isDefined("nimsso"):
-      # SmallString zero state: bytes=0 (slen=0 in low byte, all inline chars zeroed)
-      p.s(cpsStmts).addFieldAssignment(rl, "bytes", cIntValue(0))
-      p.s(cpsStmts).addFieldAssignment(rl, "more", NimNil)
-    else:
-      p.s(cpsStmts).addFieldAssignment(rl, "len", cIntValue(0))
-      p.s(cpsStmts).addFieldAssignment(rl, "p", NimNil)
+    p.s(cpsStmts).addFieldAssignment(rl, "len", cIntValue(0))
+    p.s(cpsStmts).addFieldAssignment(rl, "p", NimNil)
  elif not isComplexValueType(typ):
    if containsGarbageCollectedRef(loc.t):
      var nilLoc: TLoc = initLoc(locTemp, loc.lode, OnStack)
@@ -630,8 +601,7 @@ proc initLocalVar(p: BProc, v: PSym, immediateAsgn: bool) =
    # ``var v = X()`` gets transformed into ``X(&v)``.
    # Nowadays the logic in ccgcalls deals with this case however.
    if not immediateAsgn:
-      backendEnsureMutable v
-      constructLoc(p, v.locImpl)
+      constructLoc(p, v.loc)

 proc getTemp(p: BProc, t: PType, needsInit=false): TLoc =
  inc(p.labels)
@@ -677,9 +647,8 @@ proc localVarDecl(res: var Builder, p: BProc; n: PNode,
  let s = n.sym
  if s.loc.k == locNone:
    fillLocalName(p, s)
-    backendEnsureMutable s
-    fillLoc(s.locImpl, locLocalVar, n, OnStack)
-    if s.kind == skLet: incl(s, lfNoDeepCopy)
+    fillLoc(s.loc, locLocalVar, n, OnStack)
+    if s.kind == skLet: incl(s.loc.flags, lfNoDeepCopy)

  genCLineDir(res, p, n.info, p.config)

@@ -739,17 +708,15 @@ proc assignGlobalVar(p: BProc, n: PNode; value: Rope) =
  let s = n.sym
  if s.loc.k == locNone:
    fillBackendName(p.module, s)
-    backendEnsureMutable s
-    fillLoc(s.locImpl, locGlobalVar, n, OnHeap)
-    if treatGlobalDifferentlyForHCR(p.module, s): incl(s, lfIndirect)
+    fillLoc(s.loc, locGlobalVar, n, OnHeap)
+    if treatGlobalDifferentlyForHCR(p.module, s): incl(s.loc.flags, lfIndirect)

  if lfDynamicLib in s.loc.flags:
    var q = findPendingModule(p.module, s)
    if q != nil and not containsOrIncl(q.declaredThings, s.id):
      varInDynamicLib(q, s)
    else:
-      backendEnsureMutable s
-      s.locImpl.snippet = mangleDynLibProc(s)
+      s.loc.snippet = mangleDynLibProc(s)
    if value != "":
      internalError(p.config, n.info, ".dynlib variables cannot have a value")
    return
@@ -789,14 +756,12 @@ proc assignGlobalVar(p: BProc, n: PNode; value: Rope) =
      genGlobalVarDecl(p.module.s[cfsVars], p, n, td, initializer = initializer)
  if p.withinLoop > 0 and value == "":
    # fixes tests/run/tzeroarray:
-    backendEnsureMutable s
-    resetLoc(p, s.locImpl)
+    resetLoc(p, s.loc)

 proc callGlobalVarCppCtor(p: BProc; v: PSym; vn, value: PNode; didGenTemp: var bool) =
  let s = vn.sym
  fillBackendName(p.module, s)
-  backendEnsureMutable s
-  fillLoc(s.locImpl, locGlobalVar, vn, OnHeap)
+  fillLoc(s.loc, locGlobalVar, vn, OnHeap)
  let td = getTypeDesc(p.module, vn.sym.typ, dkVar)
  var val = genCppParamsForCtor(p, value, didGenTemp)
  if didGenTemp:  return # generated in the caller
@@ -815,8 +780,7 @@ proc fillProcLoc(m: BModule; n: PNode) =
  let sym = n.sym
  if sym.loc.k == locNone:
    fillBackendName(m, sym)
-    backendEnsureMutable sym
-    fillLoc(sym.locImpl, locProc, n, OnStack)
+    fillLoc(sym.loc, locProc, n, OnStack)

 proc getLabel(p: BProc): TLabel =
  inc(p.labels)
@@ -985,8 +949,7 @@ proc symInDynamicLib(m: BModule, sym: PSym) =
  var extname = sym.loc.snippet
  if not isCall: loadDynamicLib(m, lib)
  var tmp = mangleDynLibProc(sym)
-  backendEnsureMutable sym
-  sym.locImpl.snippet = tmp             # from now on we only need the internal name
+  sym.loc.snippet = tmp             # from now on we only need the internal name
  sym.typ.sym = nil           # generate a new name
  inc(m.labels, 2)
  if isCall:
@@ -1028,10 +991,9 @@ proc varInDynamicLib(m: BModule, sym: PSym) =
  var lib = sym.annex
  var extname = sym.loc.snippet
  loadDynamicLib(m, lib)
-  incl(sym, lfIndirect)
+  incl(sym.loc.flags, lfIndirect)
  var tmp = mangleDynLibProc(sym)
-  backendEnsureMutable sym
-  sym.locImpl.snippet = tmp             # from now on we only need the internal name
+  sym.loc.snippet = tmp             # from now on we only need the internal name
  inc(m.labels, 2)
  let t = ptrType(getTypeDesc(m, sym.typ, dkVar))
  # cgsym has side effects, do it first:
@@ -1044,8 +1006,7 @@ proc varInDynamicLib(m: BModule, sym: PSym) =
  m.s[cfsVars].addVar(name = sym.loc.snippet, typ = t)

 proc symInDynamicLibPartial(m: BModule, sym: PSym) =
-  backendEnsureMutable sym
-  sym.locImpl.snippet = mangleDynLibProc(sym)
+  sym.loc.snippet = mangleDynLibProc(sym)
  sym.typ.sym = nil           # generate a new name

 proc cgsymImpl(m: BModule; sym: PSym) {.inline.} =
@@ -1274,14 +1235,7 @@ proc allPathsAsgnResult(p: BProc; n: PNode): InitResultEnum =
      else:
        allPathsInBranch(n[i].lastSon)
  of nkCallKinds:
-    if canRaiseDisp(p, n[0]) or
-        (n[0].kind == nkSym and sfNoReturn in n[0].sym.flags):
-      # requires initializations when encountering unreachable code
-      result = InitRequired
-    elif n[0].kind == nkSym and
-        n[0].sym.magic in {mUnaryMinusI..mAbsI, mAddI..mPred} and
-          optOverflowCheck in p.config.options:
-      # arithmetic operations may raise exceptions
+    if canRaiseDisp(p, n[0]):
      result = InitRequired
    else:
      for i in 0..<n.safeLen:
@@ -1315,7 +1269,7 @@ proc genProcBody(p: BProc; procBody: PNode) =
    p.blocks[0].sections[cpsInit].addAssignmentWithValue("nimErr_"):
      p.blocks[0].sections[cpsInit].addCall(cgsymValue(p.module, "nimErrorFlag"))

-proc genProcLvl3*(m: BModule, prc: PSym) =
+proc genProcAux*(m: BModule, prc: PSym) =
  var p = newProc(prc, m)
  var header = newBuilder("")
  let isCppMember = m.config.backend == backendCpp and sfCppMember * prc.flags != {}
@@ -1340,7 +1294,7 @@ proc genProcLvl3*(m: BModule, prc: PSym) =
    let resNode = prc.ast[resultPos]
    let res = resNode.sym # get result symbol
    if not isInvalidReturnType(m.config, prc.typ) and sfConstructor notin prc.flags:
-      if sfNoInit in prc.flags: incl(res, sfNoInit)
+      if sfNoInit in prc.flags: incl(res.flags, sfNoInit)
      if sfNoInit in prc.flags and p.module.compileToCpp and (let val = easyResultAsgn(procBody); val != nil):
        var a: TLoc = initLocExprSingleUse(p, val)
        let ra = rdLoc(a)
@@ -1349,7 +1303,7 @@ proc genProcLvl3*(m: BModule, prc: PSym) =
        # declare the result symbol:
        assignLocalVar(p, resNode)
        assert(res.loc.snippet != "")
-        if p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc} and
+        if p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc} and
            allPathsAsgnResult(p, procBody) == InitSkippable:
          # In an ideal world the codegen could rely on injectdestructors doing its job properly
          # and then the analysis step would not be required.
@@ -1361,11 +1315,9 @@ proc genProcLvl3*(m: BModule, prc: PSym) =
      returnBuilder.addReturn(rres)
      returnStmt = extract(returnBuilder)
    elif sfConstructor in prc.flags:
-      resNode.sym.incl lfIndirect
-      backendEnsureMutable resNode.sym
-      fillLoc(resNode.sym.locImpl, locParam, resNode, "this", OnHeap)
-      backendEnsureMutable prc
-      prc.locImpl.snippet = getTypeDesc(m, resNode.sym.locImpl.t, dkVar)
+      resNode.sym.loc.flags.incl lfIndirect
+      fillLoc(resNode.sym.loc, locParam, resNode, "this", OnHeap)
+      prc.loc.snippet = getTypeDesc(m, resNode.sym.loc.t, dkVar)
    else:
      fillResult(p.config, resNode, prc.typ)
      assignParam(p, res, prc.typ.returnType)
@@ -1378,12 +1330,10 @@ proc genProcLvl3*(m: BModule, prc: PSym) =
      if sfNoInit in prc.flags: discard
      elif allPathsAsgnResult(p, procBody) == InitSkippable: discard
      else:
-        backendEnsureMutable res
-        resetLoc(p, res.locImpl)
+        resetLoc(p, res.loc)
      if skipTypes(res.typ, abstractInst).kind == tyArray:
        #incl(res.loc.flags, lfIndirect)
-        backendEnsureMutable res
-        res.locImpl.storage = OnUnknown
+        res.loc.storage = OnUnknown

  for i in 1..<prc.typ.n.len:
    let param = prc.typ.n[i].sym
@@ -1392,8 +1342,7 @@ proc genProcLvl3*(m: BModule, prc: PSym) =
  closureSetup(p, prc)
  genProcBody(p, procBody)

-  # IC: spurious write, seems fine for now:
-  prc.infoImpl = tmpInfo
+  prc.info = tmpInfo

  var generatedProc = newBuilder("")
  generatedProc.genCLineDir prc.info, m.config
@@ -1476,8 +1425,6 @@ proc genProcPrototype(m: BModule, sym: PSym) =
              getModuleDllPath(m, sym),
              '"' & name & '"')
  elif not containsOrIncl(m.declaredProtos, sym.id):
-    if optCompress in m.config.globalOptions:
-      m.queue.add(sym)
    let asPtr = isReloadable(m, sym)
    var header = newBuilder("")
    var visibility: DeclVisibility = None
@@ -1497,9 +1444,8 @@ proc genProcPrototype(m: BModule, sym: PSym) =
          m.s[cfsProcHeaders].add(extract(header))
          m.s[cfsProcHeaders].finishProcHeaderAsProto()

-include inliner
-
-proc genProcLvl2(m: BModule, prc: PSym) =
+# TODO: figure out how to rename this - it DOES generate a forward declaration
+proc genProcNoForward(m: BModule, prc: PSym) =
  if lfImportCompilerProc in prc.loc.flags:
    fillProcLoc(m, prc.ast[namePos])
    useHeader(m, prc)
@@ -1536,22 +1482,16 @@ proc genProcLvl2(m: BModule, prc: PSym) =
      #if prc.loc.k == locNone:
      # mangle the inline proc based on the module where it is defined -
      # not on the first module that uses it
-      if m.module.itemId.module != prc.itemId.module and optCompress in m.config.globalOptions:
-        let prcCopy = prc # copyInlineProc(prc, m.idgen)
-        fillProcLoc(m, prcCopy.ast[namePos])
-        genProcPrototype(m, prcCopy)
-        genProcLvl3(m, prcCopy)
-      else:
-        let m2 = if m.config.symbolFiles != disabledSf: m
-                else: findPendingModule(m, prc)
-        fillProcLoc(m2, prc.ast[namePos])
-        #elif {sfExportc, sfImportc} * prc.flags == {}:
-        #  # reset name to restore consistency in case of hashing collisions:
-        #  #echo "resetting ", prc.id, " by ", m.module.name.s
-        #  #prc.loc.snippet = nil
-        #  #prc.loc.snippet = mangleName(m, prc)
-        genProcPrototype(m, prc)
-        genProcLvl3(m, prc)
+      let m2 = if m.config.symbolFiles != disabledSf: m
+               else: findPendingModule(m, prc)
+      fillProcLoc(m2, prc.ast[namePos])
+      #elif {sfExportc, sfImportc} * prc.flags == {}:
+      #  # reset name to restore consistency in case of hashing collisions:
+      #  echo "resetting ", prc.id, " by ", m.module.name.s
+      #  prc.loc.snippet = nil
+      #  prc.loc.snippet = mangleName(m, prc)
+      genProcPrototype(m, prc)
+      genProcAux(m, prc)
  elif sfImportc notin prc.flags:
    var q = findPendingModule(m, prc)
    fillProcLoc(q, prc.ast[namePos])
@@ -1559,7 +1499,7 @@ proc genProcLvl2(m: BModule, prc: PSym) =
    # externally-to-the-current-module defined proc, also important
    # to do the declaredProtos check before the call to genProcPrototype
    if isReloadable(m, prc) and prc.id notin m.declaredProtos and
-      q != nil and not sameModules(q.module, m.module):
+      q != nil and q.module.id != m.module.id:
      m.s[cfsDynLibInit].add('\t')
      m.s[cfsDynLibInit].addAssignment(prc.loc.snippet,
        cCast(getProcTypeCast(m, prc),
@@ -1572,7 +1512,7 @@ proc genProcLvl2(m: BModule, prc: PSym) =
      # which will actually become a function pointer
      if isReloadable(m, prc):
        genProcPrototype(q, prc)
-      genProcLvl3(q, prc)
+      genProcAux(q, prc)
  else:
    fillProcLoc(m, prc.ast[namePos])
    useHeader(m, prc)
@@ -1598,26 +1538,25 @@ proc genProc(m: BModule, prc: PSym) =
    addForwardedProc(m, prc)
    fillProcLoc(m, prc.ast[namePos])
  else:
-    genProcLvl2(m, prc)
+    genProcNoForward(m, prc)
    if {sfExportc, sfCompilerProc} * prc.flags == {sfExportc} and
        m.g.generatedHeader != nil and lfNoDecl notin prc.loc.flags:
      genProcPrototype(m.g.generatedHeader, prc)
      if prc.typ.callConv == ccInline:
        if not containsOrIncl(m.g.generatedHeader.declaredThings, prc.id):
-          genProcLvl3(m.g.generatedHeader, prc)
+          genProcAux(m.g.generatedHeader, prc)

 proc genVarPrototype(m: BModule, n: PNode) =
  #assert(sfGlobal in sym.flags)
  let sym = n.sym
  useHeader(m, sym)
  fillBackendName(m, sym)
-  backendEnsureMutable sym
-  fillLoc(sym.locImpl, locGlobalVar, n, OnHeap)
-  if treatGlobalDifferentlyForHCR(m, sym): incl(sym, lfIndirect)
+  fillLoc(sym.loc, locGlobalVar, n, OnHeap)
+  if treatGlobalDifferentlyForHCR(m, sym): incl(sym.loc.flags, lfIndirect)

  if (lfNoDecl in sym.loc.flags) or contains(m.declaredThings, sym.id):
    return
-  if not sameOwners(sym.owner, m.module):
+  if sym.owner.id != m.module.id:
    # else we already have the symbol generated!
    assert(sym.loc.snippet != "")
    incl(m.declaredThings, sym.id)
@@ -1704,7 +1643,7 @@ proc hcrGetProcLoadCode(builder: var Builder, m: BModule, sym, prefix, handle, g
 # prevents inlining of the NimMainInner function and dependent
 # functions, which might otherwise merge their stack frames.
 proc isInnerMainVolatile(m: BModule): bool =
-  m.config.selectedGC notin {gcNone, gcArc, gcAtomicArc, gcOrc, gcYrc}
+  m.config.selectedGC notin {gcNone, gcArc, gcAtomicArc, gcOrc}

 proc genPreMain(m: BModule) =
  m.s[cfsProcs].addDeclWithVisibility(Private):
@@ -1716,6 +1655,8 @@ proc genPreMain(m: BModule) =
      m.s[cfsProcs].addVar(name = "cmdCount", typ = CInt)
    m.s[cfsProcs].addDeclWithVisibility(Private):
      m.s[cfsProcs].addVar(name = "cmdLine", typ = ptrType(ptrType(CChar)))
+    m.s[cfsProcs].addDeclWithVisibility(Private):
+      m.s[cfsProcs].addVar(name = "gEnv", typ = ptrType(ptrType(CChar)))
  m.s[cfsProcs].addDeclWithVisibility(Private):
    m.s[cfsProcs].addProcHeader(m.config.nimMainPrefix & "PreMain", CVoid, cProcParams())
    m.s[cfsProcs].finishProcHeaderWithBody():
@@ -1734,12 +1675,9 @@ proc genMainProcs(m: BModule) =

 proc genMainProcsWithResult(m: BModule) =
  genMainProcs(m)
-  if m.config.cmd != cmdNifC:
-    var res = "nim_program_result"
-    if m.hcrOn: res = cDeref(res)
-    m.s[cfsProcs].addReturn(res)
-  else:
-    m.s[cfsProcs].addReturn(cIntValue(0))
+  var res = "nim_program_result"
+  if m.hcrOn: res = cDeref(res)
+  m.s[cfsProcs].addReturn(res)

 proc genNimMainInner(m: BModule) =
  m.s[cfsProcs].addDeclWithVisibility(Private):
@@ -1749,7 +1687,7 @@ proc genNimMainInner(m: BModule) =
  m.s[cfsProcs].addNewline()

 proc initStackBottom(m: BModule): bool =
-  not (m.config.target.targetOS == osStandalone or m.config.selectedGC in {gcNone, gcArc, gcAtomicArc, gcOrc, gcYrc})
+  not (m.config.target.targetOS == osStandalone or m.config.selectedGC in {gcNone, gcArc, gcAtomicArc, gcOrc})

 proc genNimMainProc(m: BModule, preMainCode: Snippet) =
  m.s[cfsProcs].addProcHeader(ccCDecl, m.config.nimMainPrefix & "NimMain", CVoid, cProcParams())
@@ -1776,10 +1714,12 @@ proc genNimMainBody(m: BModule, preMainCode: Snippet) =
 proc genPosixCMain(m: BModule) =
  m.s[cfsProcs].addProcHeader("main", CInt, cProcParams(
    (name: "argc", typ: CInt),
-    (name: "args", typ: ptrType(ptrType(CChar)))))
+    (name: "args", typ: ptrType(ptrType(CChar))),
+    (name: "env", typ: ptrType(ptrType(CChar)))))
  m.s[cfsProcs].finishProcHeaderWithBody():
    m.s[cfsProcs].addAssignment("cmdLine", "args")
    m.s[cfsProcs].addAssignment("cmdCount", "argc")
+    m.s[cfsProcs].addAssignment("gEnv", "env")
    genMainProcsWithResult(m)
  m.s[cfsProcs].addNewline()

@@ -1877,7 +1817,7 @@ proc genMainProc(m: BModule) =
        builder.addCallStmt(cgsymValue(m, "nimLoadLibraryError"), strLit)

    loadLib(preMainBuilder, "hcr_handle", "hcrGetProc")
-    if m.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc}:
+    if m.config.selectedGC in {gcArc, gcAtomicArc, gcOrc}:
      preMainBuilder.addCallStmt(m.config.nimMainPrefix & "PreMain")
    else:
      preMainBuilder.addVar(name = "rtl_handle", typ = CPointer)
@@ -1938,6 +1878,36 @@ proc genMainProc(m: BModule) =
    if m.config.cppCustomNamespace.len > 0:
      openNamespaceNim(m.config.cppCustomNamespace, m.s[cfsProcs])

+proc registerInitProcs*(g: BModuleList; m: PSym; flags: set[ModuleBackendFlag]) =
+  ## Called from the IC backend.
+  if HasDatInitProc in flags:
+    let datInit = getSomeNameForModule(g.config, g.config.toFullPath(m.info.fileIndex).AbsoluteFile) & "DatInit000"
+    g.mainModProcs.addDeclWithVisibility(Private):
+      g.mainModProcs.addProcHeader(ccNimCall, datInit, CVoid, cProcParams())
+      g.mainModProcs.finishProcHeaderAsProto()
+    g.mainDatInit.addCallStmt(datInit)
+  if HasModuleInitProc in flags:
+    let init = getSomeNameForModule(g.config, g.config.toFullPath(m.info.fileIndex).AbsoluteFile) & "Init000"
+    g.mainModProcs.addDeclWithVisibility(Private):
+      g.mainModProcs.addProcHeader(ccNimCall, init, CVoid, cProcParams())
+      g.mainModProcs.finishProcHeaderAsProto()
+    if sfMainModule in m.flags:
+      g.mainModInit.addCallStmt(init)
+    elif sfSystemModule in m.flags:
+      g.mainDatInit.addCallStmt(init) # systemInit must called right after systemDatInit if any
+    else:
+      g.otherModsInit.addCallStmt(init)
+
+proc whichInitProcs*(m: BModule): set[ModuleBackendFlag] =
+  # called from IC.
+  result = {}
+  if m.hcrOn or m.preInitProc.s(cpsInit).buf.len > 0 or m.preInitProc.s(cpsStmts).buf.len > 0:
+    result.incl HasModuleInitProc
+  for i in cfsTypeInit1..cfsDynLibInit:
+    if m.s[i].buf.len != 0:
+      result.incl HasDatInitProc
+      break
+
 proc registerModuleToMain(g: BModuleList; m: BModule) =
  let
    init = m.getInitName
@@ -1945,7 +1915,7 @@ proc registerModuleToMain(g: BModuleList; m: BModule) =

  if m.hcrOn:
    var hcrModuleMeta = newBuilder("")
-    let systemModulePath = getModuleDllPath(m, g.mods[g.graph.config.m.systemFileIdx.int].module)
+    let systemModulePath = getModuleDllPath(m, g.modules[g.graph.config.m.systemFileIdx.int].module)
    let mainModulePath = getModuleDllPath(m, m.module)
    hcrModuleMeta.addDeclWithVisibility(Private):
      hcrModuleMeta.addArrayVarWithInitializer(kind = Local,
@@ -1962,7 +1932,7 @@ proc registerModuleToMain(g: BModuleList; m: BModule) =
          g.graph.importDeps.withValue(FileIndex(m.module.position), deps):
            for curr in deps[]:
              hcrModuleMeta.addField(modules, ""):
-                hcrModuleMeta.add(getModuleDllPath(m, g.mods[curr.int].module))
+                hcrModuleMeta.add(getModuleDllPath(m, g.modules[curr.int].module))
          hcrModuleMeta.addField(modules, ""):
            hcrModuleMeta.add("\"\"")
    hcrModuleMeta.addDeclWithVisibility(ExportLib):
@@ -2047,7 +2017,7 @@ proc registerModuleToMain(g: BModuleList; m: BModule) =
  if sfSystemModule in m.module.flags:
    if emulatedThreadVars(m.config) and m.config.target.targetOS != osStandalone:
      g.mainDatInit.addCallStmt(cgsymValue(m, "initThreadVarsEmulation"))
-    if m.config.target.targetOS != osStandalone and m.config.selectedGC notin {gcNone, gcArc, gcAtomicArc, gcOrc, gcYrc}:
+    if m.config.target.targetOS != osStandalone and m.config.selectedGC notin {gcNone, gcArc, gcAtomicArc, gcOrc}:
      g.mainDatInit.addCallStmt(cgsymValue(m, "initStackBottomWith"),
        cCast(CPointer, cAddr("inner")))

@@ -2098,8 +2068,7 @@ proc hcrGetProcLoadCode(builder: var Builder, m: BModule, sym, prefix, handle, g

  var extname = prefix & sym
  var tmp = mangleDynLibProc(prc)
-  backendEnsureMutable prc
-  prc.locImpl.snippet = tmp
+  prc.loc.snippet = tmp
  prc.typ.sym = nil

  if not containsOrIncl(m.declaredThings, prc.id):
@@ -2155,8 +2124,6 @@ proc genInitCode(m: BModule) =
      else:
        prcBody.add(extract(m.thing.s(section)))

-  #echo "PRE INIT PROC ", m.module.name.s, " ", m.s[cfsVars].buf.len
-
  if m.preInitProc.s(cpsInit).buf.len > 0 or m.preInitProc.s(cpsStmts).buf.len > 0:
    # Give this small function its own scope
    prcBody.addScope():
@@ -2369,14 +2336,13 @@ proc rawNewModule(g: BModuleList; module: PSym, filename: AbsoluteFile): BModule
 proc rawNewModule(g: BModuleList; module: PSym; conf: ConfigRef): BModule =
  result = rawNewModule(g, module, AbsoluteFile toFullPath(conf, module.position.FileIndex))

-proc newModule(g: BModuleList; module: PSym; conf: ConfigRef; idgen: IdGenerator): BModule =
+proc newModule*(g: BModuleList; module: PSym; conf: ConfigRef): BModule =
  # we should create only one cgen module for each module sym
  result = rawNewModule(g, module, conf)
-  result.idgen = idgen
-  if module.position >= g.mods.len:
-    setLen(g.mods, module.position + 1)
+  if module.position >= g.modules.len:
+    setLen(g.modules, module.position + 1)
  #growCache g.modules, module.position
-  g.mods[module.position] = result
+  g.modules[module.position] = result

 template injectG() {.dirty.} =
  if graph.backend == nil:
@@ -2385,7 +2351,8 @@ template injectG() {.dirty.} =

 proc setupCgen*(graph: ModuleGraph; module: PSym; idgen: IdGenerator): PPassContext =
  injectG()
-  result = newModule(g, module, graph.config, idgen)
+  result = newModule(g, module, graph.config)
+  result.idgen = idgen
  if optGenIndex in graph.config.globalOptions and g.generatedHeader == nil:
    let f = if graph.config.headerFile.len > 0: AbsoluteFile graph.config.headerFile
            else: graph.config.projectFull
@@ -2452,23 +2419,6 @@ proc addHcrInitGuards(p: BProc, n: PNode, inInitGuard: var bool, init: var IfBui

    genStmts(p, n)

-proc handleProcGlobals(m: BModule) =
-  var procGlobals: seq[PNode] = move m.g.graph.procGlobals
-
-  for i in 0..<procGlobals.len:
-    var stmts = newBuilder("")
-
-    # fixes recursive calls #24997
-    swap stmts, m.preInitProc.s(cpsStmts)
-    var transformedN = procGlobals[i]
-    if sfInjectDestructors in m.module.flags:
-      transformedN = injectDestructorCalls(m.g.graph, m.idgen, m.module, transformedN)
-    genStmts(m.preInitProc, transformedN)
-    swap stmts, m.preInitProc.s(cpsStmts)
-
-    handleProcGlobals(m)
-    m.preInitProc.s(cpsStmts).add stmts.extract()
-
 proc genTopLevelStmt*(m: BModule; n: PNode) =
  ## Also called from `ic/cbackend.nim`.
  if pipelineutils.skipCodegen(m.config, n): return
@@ -2484,8 +2434,6 @@ proc genTopLevelStmt*(m: BModule; n: PNode) =
  else:
    genProcBody(m.initProc, transformedN)

-  handleProcGlobals(m)
-
 proc shouldRecompile(m: BModule; code: Rope, cfile: Cfile): bool =
  if optForceFullMake notin m.config.globalOptions:
    if not moduleHasChanged(m.g.graph, m.module):
@@ -2510,15 +2458,16 @@ proc shouldRecompile(m: BModule; code: Rope, cfile: Cfile): bool =
      rawMessage(m.config, errCannotOpenFile, cfile.cname.string)
    result = true

-proc writeModule(m: BModule) =
+# We need 2 different logics here: pending modules (including
+# 'nim__dat') may require file merging for the combination of dead code
+# elimination and incremental compilation! Non pending modules need no
+# such logic and in fact the logic hurts for the main module at least;
+# it would generate multiple 'main' procs, for instance.
+
+proc writeModule(m: BModule, pending: bool) =
  let cfile = getCFile(m)
  if moduleHasChanged(m.g.graph, m.module):
    genInitCode(m)
-
-    while m.queue.len > 0:
-      let sym = m.queue.pop()
-      genProcLvl2(m, sym)
-
    finishTypeDescriptions(m)
    if sfMainModule in m.module.flags:
      # generate main file:
@@ -2553,11 +2502,10 @@ proc generateLibraryDestroyGlobals(graph: ModuleGraph; m: BModule; body: PNode;
  result = newSym(skProc, procname, m.idgen, m.module.owner, m.module.info)
  result.typ = newProcType(m.module.info, m.idgen, m.module.owner)
  result.typ.callConv = ccCDecl
-  backendEnsureMutable result
-  incl result.flagsImpl, sfExportc
-  result.locImpl.snippet = prefixedName
+  incl result.flags, sfExportc
+  result.loc.snippet = prefixedName
  if isDynlib:
-    incl(result.locImpl.flags, lfExportLib)
+    incl(result.loc.flags, lfExportLib)

  let theProc = newNodeI(nkProcDef, m.module.info, bodyPos+1)
  for i in 0..<theProc.len: theProc[i] = newNodeI(nkEmpty, m.module.info)
@@ -2582,7 +2530,7 @@ proc finalCodegenActions*(graph: ModuleGraph; m: BModule; n: PNode) =
        body.add graph.globalDestructors[i]
      body.flags.incl nfTransf # should not be further transformed
      let dtor = generateLibraryDestroyGlobals(graph, m, body, optGenDynLib in m.config.globalOptions)
-      genProcLvl3(m, dtor)
+      genProcAux(m, dtor)
  if pipelineutils.skipCodegen(m.config, n): return
  if moduleHasChanged(graph, m.module):
    # if the module is cached, we don't regenerate the main proc
@@ -2616,7 +2564,7 @@ proc finalCodegenActions*(graph: ModuleGraph; m: BModule; n: PNode) =
        cgsym(m, "rawWrite")

      # raise dependencies on behalf of genMainProc
-      if m.config.target.targetOS != osStandalone and m.config.selectedGC notin {gcNone, gcArc, gcAtomicArc, gcOrc, gcYrc}:
+      if m.config.target.targetOS != osStandalone and m.config.selectedGC notin {gcNone, gcArc, gcAtomicArc, gcOrc}:
        cgsym(m, "initStackBottomWith")
      if emulatedThreadVars(m.config) and m.config.target.targetOS != osStandalone:
        cgsym(m, "initThreadVarsEmulation")
@@ -2624,7 +2572,7 @@ proc finalCodegenActions*(graph: ModuleGraph; m: BModule; n: PNode) =
      if m.g.forwardedProcs.len == 0:
        incl m.flags, objHasKidsValid
      if optMultiMethods in m.g.config.globalOptions or
-          m.g.config.selectedGC notin {gcArc, gcOrc, gcAtomicArc, gcYrc} or
+          m.g.config.selectedGC notin {gcArc, gcOrc, gcAtomicArc} or
          vtables notin m.g.config.features:
        generateIfMethodDispatchers(graph, m.idgen)

@@ -2635,15 +2583,15 @@ proc finalCodegenActions*(graph: ModuleGraph; m: BModule; n: PNode) =
 proc genForwardedProcs(g: BModuleList) =
  # Forward declared proc:s lack bodies when first encountered, so they're given
  # a second pass here
-  # Note: ``genProcLvl2`` may add to ``forwardedProcs``
+  # Note: ``genProcNoForward`` may add to ``forwardedProcs``
  while g.forwardedProcs.len > 0:
    let
      prc = g.forwardedProcs.pop()
-      m = g.mods[prc.itemId.module]
+      m = g.modules[prc.itemId.module]
    if sfForward in prc.flags:
      internalError(m.config, prc.info, "still forwarded: " & prc.name.s)

-    genProcLvl2(m, prc)
+    genProcNoForward(m, prc)

 proc cgenWriteModules*(backend: RootRef, config: ConfigRef) =
  let g = BModuleList(backend)
@@ -2655,6 +2603,6 @@ proc cgenWriteModules*(backend: RootRef, config: ConfigRef) =
  genForwardedProcs(g)

  for m in cgenModules(g):
-    m.writeModule()
+    m.writeModule(pending=true)
  writeMapping(config, g.mapping)
  if g.generatedHeader != nil: writeHeader(g.generatedHeader)
--- a/compiler/cgendata.nim
+++ b/compiler/cgendata.nim
@@ -117,9 +117,9 @@ type
  BModuleList* = ref object of RootObj
    mainModProcs*, mainModInit*, otherModsInit*, mainDatInit*: Builder
    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
@@ -155,7 +155,6 @@ type
    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
@@ -179,9 +178,6 @@ 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
--- a/compiler/cgmeth.nim
+++ b/compiler/cgmeth.nim
@@ -55,7 +55,7 @@ proc methodCall*(n: PNode; conf: ConfigRef): PNode =
  # replace ordinary method by dispatcher method:
  let disp = getDispatcher(result[0].sym)
  if disp != nil:
-    result[0].typ = disp.typ
+    result[0].typ() = disp.typ
    result[0].sym = disp
    # change the arguments to up/downcasts to fit the dispatcher's parameters:
    for i in 1..<result.len:
@@ -123,8 +123,8 @@ 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)
@@ -133,7 +133,7 @@ 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 = ""
+  disp.loc.snippet = ""
  if s.typ.returnType != nil:
    if disp.ast.len > resultPos:
      disp.ast[resultPos].sym = copySym(s.ast[resultPos].sym, idgen)
--- a/compiler/closureiters.nim
+++ b/compiler/closureiters.nim
--- a/compiler/commands.nim
+++ b/compiler/commands.nim
@@ -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 % "-")
@@ -245,7 +245,7 @@ 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"
@@ -266,7 +266,6 @@ 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
@@ -365,7 +364,6 @@ 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 +459,7 @@ template handleStdinOrCmdInput =
    conf.outDir = getNimcacheDir(conf)

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

@@ -475,7 +473,6 @@ proc parseCommand*(command: string): Command =
  of "cpp", "compiletocpp": cmdCompileToCpp
  of "objc", "compiletooc": cmdCompileToOC
  of "js", "compiletojs": cmdCompileToJS
-  of "nif": cmdCompileToNif
  of "r": cmdCrun
  of "m": cmdM
  of "run": cmdTcc
@@ -495,11 +492,10 @@ 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 +507,6 @@ proc setCmd*(conf: ConfigRef, cmd: Command) =
  of cmdCompileToCpp: conf.backend = backendCpp
  of cmdCompileToOC: conf.backend = backendObjc
  of cmdCompileToJS: conf.backend = backendJs
-  of cmdCompileToNif: conf.backend = backendNif
-  of cmdNifC:
-    conf.backend = backendC  # NIF to C compilation
-  of cmdM:
-    # cmdM requires optCompress for proper IC handling (include files, etc.)
-    conf.globalOptions.incl optCompress
  else: discard

 proc setCommandEarly*(conf: ConfigRef, command: string) =
@@ -571,7 +561,6 @@ 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 +594,6 @@ 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 +760,6 @@ 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 +882,11 @@ 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":
@@ -951,7 +918,7 @@ 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)
@@ -968,10 +935,6 @@ 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 +968,7 @@ 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 +1076,6 @@ 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 +1107,9 @@ 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
@@ -13,13 +13,13 @@

 import ast, semdata, lookups, lineinfos, idents, msgs, renderer, types, layeredtable

-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)

@@ -70,89 +70,26 @@ 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
+    concpt: PType

 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 matchType(c: PContext; f, ao: PType; m: var MatchCon): bool

 proc acceptsAllTypes(t: PType): bool=
  result = false
@@ -164,187 +101,84 @@ proc acceptsAllTypes(t: PType): bool=
    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}):
+  for i in start..<f.kidsLen - ord(f.kind == tyGenericInst):
    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, ao: 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.
+  const
+    ignorableForArgType = {tyVar, tySink, tyLent, tyOwned, tyGenericInst, tyAlias, tyInferred}
  
-  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
+  var a = ao
  
-  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)
+  case a.kind
+  of tyGenericParam:
+    let binding = m.existingBinding(a)
+    if binding != nil:
+      a = binding
+  else:
+    discard
  
-  result = false
-
  case f.kind
  of tyAlias:
    result = matchType(c, f.skipModifier, a, m)
  of tyTypeDesc:
    if isSelf(f):
-      let ua = a.skipTypes(asymmetricConceptParamMods)
      if m.magic in {mArrPut, mArrGet}:
+        result = false
        if m.potentialImplementation.reduceToBase.kind in arrPutGetMagicApplies:
-          bindParam(c, m, a, last m.potentialImplementation)
+          m.inferred.add((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)
+        result = matchType(c, a, m.potentialImplementation, m)
    else:
-      if a.kind == tyTypeDesc:
-        if not(a.hasElementType) or a.elementType.kind == tyNone:
-          result = true
-        elif f.hasElementType:
+      if a.kind == tyTypeDesc and f.hasElementType == a.hasElementType:
+        if f.hasElementType:
          result = matchType(c, f.elementType, a.elementType, m)
+        else:
+          result = true # both lack it
+      else:
+        result = false
+  of tyGenericInvocation:
+    result = false
+    if a.kind == tyGenericInst and a.genericHead.kind == tyGenericBody:
+      if sameType(f.genericHead, a.genericHead) and f.kidsLen == a.kidsLen-1:
+        result = matchKids(c, f, a, m, start=FirstGenericParamAt)
+  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.hasElementType and f.elementType.kind != tyNone:
+          # also check the generic's constraints:
+          let oldLen = m.inferred.len
+          result = matchType(c, f.elementType, 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, " ", last ak
+          m.inferred.add((f, last ak))
+          result = true
+        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.
@@ -352,59 +186,91 @@ proc matchType(c: PContext; fo, ao: PType; m: var MatchCon): bool =
      result = matchType(c, f.elementType, a.elementType, 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)
    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:
+       (ak.kind == tyGenericParam and ak.hasElementType and ak.elementType.kind == tyOrdinal)
+  of tyConcept:
+    if a.kind == tyConcept and f.n == a.n:
+      result = true
+    elif m.concpt.size == szIllegalRecursion:
+      result = false
+    else:
+      let oldLen = m.inferred.len
+      let oldPotentialImplementation = m.potentialImplementation
+      m.potentialImplementation = a
+      m.concpt.size = szIllegalRecursion
+      let oldConcept = m.concpt
+      m.concpt = f
+      result = conceptMatchNode(c, f.n.lastSon, m)
+      m.potentialImplementation = oldPotentialImplementation
+      m.concpt = oldConcept
+      m.concpt.size = szUnknownSize
+      if not result:
+        m.inferred.setLen oldLen
+  of tyGenericBody:
+    var ak = a
+    if a.kind == tyGenericBody:
+      ak = last(a)
+    result = matchType(c, last(f), ak, m)
+  of tyCompositeTypeClass:
+    var ak = if a.kind == tyCompositeTypeClass: a.last else: a
+    result = matchType(c, last(f), ak, m)
+  of tyArray, tyTuple, tyVarargs, tyOpenArray, tyRange, tySequence, tyRef, tyPtr,
+     tyGenericInst:
+    # ^ XXX Rewrite this logic, it's more complex than it needs to be.
+    if f.kind == tyArray and f.kidsLen == 3:
      # XXX: this is a work-around!
      # system.nim creates these for the magic array typeclass
      result = true
    else:
+      result = false
      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:
-    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
+      if ak.kind == f.kind and f.kidsLen == ak.kidsLen:
+        result = matchKids(c, f, ak, m)
+  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 f.kids:
+        for aa in a.kids:
+          let oldLenB = m.inferred.len
+          let r = matchType(c, ff, aa, m)
+          if r:
+            inc covered
            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)
+          m.inferred.setLen oldLenB
+
+      result = covered >= a.kidsLen
+      if not result:
+        m.inferred.setLen oldLen
+    else:
+      result = false
+      for ff in f.kids:
+        result = matchType(c, ff, a, m)
+        if result: break # and remember the binding!
+        m.inferred.setLen oldLen
+  of tyNot:
+    if a.kind == tyNot:
+      result = matchType(c, f.elementType, a.elementType, m)
+    else:
+      let oldLen = m.inferred.len
+      result = not matchType(c, f.elementType, a, m)
+      m.inferred.setLen oldLen
+  of tyAnything:
+    result = true
  of tyOrdinal:
    result = isOrdinalType(a, allowEnumWithHoles = false) or a.kind == tyGenericParam
  of tyStatic:
+    result = false
    var scomp = f.base
    if scomp.kind == tyGenericParam:
      if f.base.kidsLen > 0:
@@ -413,75 +279,8 @@ proc matchType(c: PContext; fo, ao: PType; m: var MatchCon): bool =
      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
-  of tyOr:
-    if a.kind == tyOr:
-      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)
-          if r:
-            inc covered
-            break
-          m.bindings.setToPreviousLayer()
-
-      result = covered >= a.kidsLen
-    else:
-      for ff in f.kids:
-        m.bindings = m.bindings.newTypeMapLayer()
-        result = matchType(c, ff, 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)
  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 +290,30 @@ 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.returnType, candidate.typ.returnType, m):
+    m.inferred.setLen oldLen
    return false

  # all other parameters have to be optional parameters:
@@ -530,7 +321,7 @@ 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 +329,13 @@ 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)
  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'
@@ -578,48 +368,7 @@ 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 LayeredIdTable; 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
  ## concept's requirements. If so, we return true and fill the 'bindings' with pairs of
@@ -628,16 +377,28 @@ proc conceptMatch*(c: PContext; concpt, arg: PType; bindings: var LayeredIdTable
  ## `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)
-
-  
+  if arg.containsUnresolvedType:
+    return false
+  var m = MatchCon(inferred: @[], potentialImplementation: arg, concpt: concpt)
+  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.put(a, dest)
+          when logBindings: echo "A bind ", a, " ", dest
+      else:
+        bindings.put(a, b)
+        when logBindings: echo "B bind ", a, " ", b
+    # we have a match, so bind 'arg' itself to 'concpt':
+    bindings.put(concpt, arg)
+    # invocation != nil means we have a non-atomic concept:
+    if invocation != nil and arg.kind == tyGenericInst and invocation.kidsLen == arg.kidsLen-1:
+      # bind even more generic parameters
+      assert invocation.kind == tyGenericInvocation
+      for i in FirstGenericParamAt ..< invocation.kidsLen:
+        bindings.put(invocation[i], arg[i])
--- a/compiler/condsyms.nim
+++ b/compiler/condsyms.nim
@@ -172,8 +172,3 @@ proc initDefines*(symbols: StringTableRef) =
  defineSymbol("nimHasDefaultFloatRoundtrip")
  defineSymbol("nimHasXorSet")

-  defineSymbol("nimHasSetLengthSeqUninitMagic")
-  defineSymbol("nimHasPreviewDuplicateModuleError")
-
-  defineSymbol("nimHasImplicitRangeConversion")
-
--- 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
@@ -439,8 +439,8 @@ 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 +483,7 @@ 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

@@ -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])
@@ -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])
@@ -1180,12 +1176,8 @@ proc genJsonItem(d: PDoc, n, nameNode: PNode, k: TSymKind, nonExports = false):
                   "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:
@@ -1328,7 +1320,7 @@ proc documentEffect(cache: IdentCache; n, x: PNode, effectType: TSpecialWord, id
      if t.startsWith("ref "): t = substr(t, 4)
      effects[i] = newIdentNode(getIdent(cache, t), n.info)
      # set the type so that the following analysis doesn't screw up:
-      effects[i].typ = real[i].typ
+      effects[i].typ() = real[i].typ

    result = newTreeI(nkExprColonExpr, n.info,
      newIdentNode(getIdent(cache, $effectType), n.info), effects)
@@ -1414,19 +1406,16 @@ proc generateDoc*(d: PDoc, n, orig: PNode, config: ConfigRef, docFlags: DocFlags
    for it in n: traceDeps(d, it)
  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
+      # bug #23051; don't generate documentation for exported symbols again
+      if it.kind == nkSym and sfExported notin it.sym.flags:
+        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 +1889,6 @@ 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 +1909,8 @@ 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
@@ -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
@@ -275,7 +275,7 @@ proc unpackObject(conf: ConfigRef, x: pointer, typ: PType, n: PNode): PNode =
  # the nkPar node:
  if n.isNil:
    result = newNode(nkTupleConstr)
-    result.typ = typ
+    result.typ() = typ
    if typ.n.isNil:
      internalError(conf, "cannot unpack unnamed tuple")
    unpackObjectAdd(conf, x, typ.n, result)
@@ -298,7 +298,7 @@ proc unpackObject(conf: ConfigRef, x: pointer, typ: PType, n: PNode): PNode =
 proc unpackArray(conf: ConfigRef, x: pointer, typ: PType, n: PNode): PNode =
  if n.isNil:
    result = newNode(nkBracket)
-    result.typ = typ
+    result.typ() = typ
    newSeq(result.sons, lengthOrd(conf, typ).toInt)
  else:
    result = n
@@ -319,7 +319,7 @@ proc unpack(conf: ConfigRef, x: pointer, typ: PType, n: PNode): PNode =
  template aw(k, v, field: untyped): untyped =
    if n.isNil:
      result = newNode(k)
-      result.typ = typ
+      result.typ() = typ
    else:
      # check we have the right field:
      result = n
@@ -333,12 +333,12 @@ proc unpack(conf: ConfigRef, x: pointer, typ: PType, n: PNode): PNode =
  template setNil() =
    if n.isNil:
      result = newNode(nkNilLit)
-      result.typ = typ
+      result.typ() = typ
    else:
      reset n[]
      result = n
      result[] = TNode(kind: nkNilLit)
-      result.typ = typ
+      result.typ() = typ

  template awi(kind, v: untyped): untyped = aw(kind, v, intVal)
  template awf(kind, v: untyped): untyped = aw(kind, v, floatVal)
@@ -427,7 +427,7 @@ proc fficast*(conf: ConfigRef, x: PNode, destTyp: PType): PNode =
    # cast through a pointer needs a new inner object:
    let y = if x.kind == nkRefTy: newNodeI(nkRefTy, x.info, 1)
            else: x.copyTree
-    y.typ = x.typ
+    y.typ() = x.typ
    result = unpack(conf, a, destTyp, y)
    dealloc a

@@ -481,7 +481,7 @@ proc callForeignFunction*(conf: ConfigRef, fn: PNode, fntyp: PType,
    if aTyp.isNil:
      internalAssert conf, i+1 < fntyp.len
      aTyp = fntyp[i+1]
-      args[i+start].typ = aTyp
+      args[i+start].typ() = aTyp
    sig[i] = mapType(conf, aTyp)
    if sig[i].isNil: globalError(conf, info, "cannot map FFI type")

--- a/compiler/evaltempl.nim
+++ b/compiler/evaltempl.nim
@@ -182,7 +182,7 @@ proc wrapInComesFrom*(info: TLineInfo; sym: PSym; res: PNode): PNode =
    d.add newSymNode(sym, info)
    result.add d
    result.add res
-    result.typ = res.typ
+    result.typ() = res.typ

 proc evalTemplate*(n: PNode, tmpl, genSymOwner: PSym;
                   conf: ConfigRef;
--- a/compiler/extccomp.nim
+++ b/compiler/extccomp.nim
@@ -257,8 +257,8 @@ 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",
@@ -341,7 +341,7 @@ proc getConfigVar(conf: ConfigRef; c: TSystemCC, suffix: string): string =
  var fullSuffix = suffix
  case conf.backend
  of backendCpp, backendJs, backendObjc: fullSuffix = "." & $conf.backend & suffix
-  of backendC, backendNif: discard
+  of backendC: discard
  of backendInvalid:
    # during parsing of cfg files; we don't know the backend yet, no point in
    # guessing wrong thing
@@ -474,11 +474,6 @@ 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)
@@ -810,59 +805,6 @@ 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 +989,6 @@ 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:
--- a/compiler/guards.nim
+++ b/compiler/guards.nim
@@ -1104,7 +1104,7 @@ proc settype(n: PNode): PType =

 proc buildOf(it, loc: PNode; o: Operators): PNode =
  var s = newNodeI(nkCurly, it.info, it.len-1)
-  s.typ = settype(loc)
+  s.typ() = settype(loc)
  for i in 0..<it.len-1: s[i] = it[i]
  result = newNodeI(nkCall, it.info, 3)
  result[0] = newSymNode(o.opContains)
@@ -1170,7 +1170,7 @@ proc buildProperFieldCheck(access, check: PNode; o: Operators): PNode =
      # set field name to discriminator field name
      a[1] = check[2]
      # set discriminator field type: important for `neg`
-      a.typ = check[2].typ
+      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/iclineinfos.nim
+++ b/compiler/ic/iclineinfos.nim
@@ -0,0 +1,84 @@
+#
+#
+#           The Nim Compiler
+#        (c) Copyright 2024 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+# For the line information we use 32 bits. They are used as follows:
+# Bit 0 (AsideBit): If we have inline line information or not. If not, the
+# remaining 31 bits are used as an index into a seq[(LitId, int, int)].
+#
+# We use 10 bits for the "file ID", this means a program can consist of as much
+# as 1024 different files. (If it uses more files than that, the overflow bit
+# would be set.)
+# This means we have 21 bits left to encode the (line, col) pair. We use 7 bits for the column
+# so 128 is the limit and 14 bits for the line number.
+# The packed representation supports files with up to 16384 lines.
+# Keep in mind that whenever any limit is reached the AsideBit is set and the real line
+# information is kept in a side channel.
+
+import std / assertions
+
+const
+  AsideBit = 1
+  FileBits = 10
+  LineBits = 14
+  ColBits = 7
+  FileMax = (1 shl FileBits) - 1
+  LineMax = (1 shl LineBits) - 1
+  ColMax = (1 shl ColBits) - 1
+
+static:
+  assert AsideBit + FileBits + LineBits + ColBits == 32
+
+import .. / ic / [bitabs, rodfiles] # for LitId
+
+type
+  PackedLineInfo* = distinct uint32
+
+  LineInfoManager* = object
+    aside: seq[(LitId, int32, int32)]
+
+const
+  NoLineInfo* = PackedLineInfo(0'u32)
+
+proc pack*(m: var LineInfoManager; file: LitId; line, col: int32): PackedLineInfo =
+  if file.uint32 <= FileMax.uint32 and line <= LineMax and col <= ColMax:
+    let col = if col < 0'i32: 0'u32 else: col.uint32
+    let line = if line < 0'i32: 0'u32 else: line.uint32
+    # use inline representation:
+    result = PackedLineInfo((file.uint32 shl 1'u32) or (line shl uint32(AsideBit + FileBits)) or
+      (col shl uint32(AsideBit + FileBits + LineBits)))
+  else:
+    result = PackedLineInfo((m.aside.len shl 1) or AsideBit)
+    m.aside.add (file, line, col)
+
+proc unpack*(m: LineInfoManager; i: PackedLineInfo): (LitId, int32, int32) =
+  let i = i.uint32
+  if (i and 1'u32) == 0'u32:
+    # inline representation:
+    result = (LitId((i shr 1'u32) and FileMax.uint32),
+      int32((i shr uint32(AsideBit + FileBits)) and LineMax.uint32),
+      int32((i shr uint32(AsideBit + FileBits + LineBits)) and ColMax.uint32))
+  else:
+    result = m.aside[int(i shr 1'u32)]
+
+proc getFileId*(m: LineInfoManager; i: PackedLineInfo): LitId =
+  result = unpack(m, i)[0]
+
+proc store*(r: var RodFile; m: LineInfoManager) = storeSeq(r, m.aside)
+proc load*(r: var RodFile; m: var LineInfoManager) = loadSeq(r, m.aside)
+
+when isMainModule:
+  var m = LineInfoManager(aside: @[])
+  for i in 0'i32..<16388'i32:
+    for col in 0'i32..<100'i32:
+      let packed = pack(m, LitId(1023), i, col)
+      let u = unpack(m, packed)
+      assert u[0] == LitId(1023)
+      assert u[1] == i
+      assert u[2] == col
+  echo m.aside.len
--- 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, tables]
+
+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 _, v in pairs(m.syms):
+    checkLocalSym c, v.id
+
+  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, tables]
+
+from std/os import nil
+from std/private/miscdollars import toLocation
+
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
+import ".." / [ast, modulegraphs, msgs, options]
+import iclineinfos
+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 +1,367 @@
+#
+#
+#           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 iclineinfos
+
+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
+    id*: int32
+    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
+    id*: int32
+    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 = PackedTree(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 +1,283 @@
+#
+#
+#           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]
+
+import std / tables
+
+## 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 storeOrderedTable*[K, T](f: var RodFile; s: OrderedTable[K, T]) =
+  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 _, v in s:
+      storePrim(f, v)
+
+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 loadOrderedTable*[K, T](f: var RodFile; s: var OrderedTable[K, 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 = initOrderedTable[K, T](lenPrefix)
+    for i in 0..<lenPrefix:
+      var x = default T
+      loadPrim(f, x)
+      s[x.id] = x
+
+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))

@@ -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)
@@ -242,8 +245,7 @@ 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
+    result.options.incl optImportHidden
  let moduleIdent = if n.kind in {nkInfix, nkImportAs}: n[^1] else: n
  result.info = moduleIdent.info
  if trackUnusedImport:
@@ -289,8 +291,9 @@ proc myImportModule(c: PContext, n: var PNode, importStmtResult: PNode): PSym =
      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)
+    realModule = c.graph.importModuleCallback(c.graph, c.module, f)
    result = importModuleAs(c, n, realModule, transf.importHidden, trackUnusedImport)
    popOptionEntry(c)

--- 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 +162,13 @@ 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
+  # bug #23354; an object type could have a non-trival assignements when it is passed to a sink parameter
+  if not hasDestructor(c, n.typ) and (n.typ.kind != tyObject or isTrival(getAttachedOp(c.graph, n.typ, attachedAsgn))): 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 +185,10 @@ 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 +197,7 @@ 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 '\''
@@ -255,12 +247,7 @@ 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 +275,7 @@ 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 +291,7 @@ 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:
@@ -331,21 +318,21 @@ 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:
+  if c.graph.config.selectedGC == gcOrc 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})
    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:
        result.add callCodegenProc(c.graph, "nimMarkCyclic", dest.info, dest)
      else:
        let xenv = genBuiltin(c.graph, c.idgen, mAccessEnv, "accessEnv", dest)
-        xenv.typ = getSysType(c.graph, dest.info, tyPointer)
+        xenv.typ() = getSysType(c.graph, dest.info, tyPointer)
        result.add callCodegenProc(c.graph, "nimMarkCyclic", dest.info, xenv)

 proc genCopyNoCheck(c: var Con; dest, ri: PNode; a: TTypeAttachedOp): PNode =
@@ -373,7 +360,7 @@ 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 +400,7 @@ 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 & ")")
@@ -421,7 +408,7 @@ proc genWasMoved(c: var Con, n: PNode): PNode =
 proc genDefaultCall(t: PType; c: Con; info: TLineInfo): PNode =
  result = newNodeI(nkCall, info)
  result.add(newSymNode(createMagic(c.graph, c.idgen, "default", mDefault)))
-  result.typ = t
+  result.typ() = t

 proc destructiveMoveVar(n: PNode; c: var Con; s: var Scope): PNode =
  # generate: (let tmp = v; reset(v); tmp)
@@ -459,50 +446,49 @@ proc isCapturedVar(n: PNode): bool =
  else: result = false

 proc passCopyToSink(n: PNode; c: var Con; s: var Scope): PNode =
+  result = newNodeIT(nkStmtListExpr, n.info, n.typ)
  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}:
+  let tmp = c.getTemp(s, nTyp, n.info)
+  if hasDestructor(c, nTyp):
+    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 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 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)
+  else:
+    if c.graph.config.selectedGC in {gcArc, gcOrc, 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 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 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)
+    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
@@ -533,7 +519,7 @@ 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 +559,7 @@ 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))
@@ -612,7 +598,7 @@ 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}:
@@ -773,7 +759,7 @@ 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)
@@ -828,9 +814,9 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing
          n[1].typ.skipTypes(abstractInst-{tyOwned}).kind == tyOwned:
        # allow conversions from owned to unowned via this little hack:
        let nTyp = n[1].typ
-        n[1].typ = n.typ
+        n[1].typ() = n.typ
        result[1] = p(n[1], c, s, sinkArg)
-        result[1].typ = nTyp
+        result[1].typ() = nTyp
      else:
        result[1] = p(n[1], c, s, sinkArg)
    elif n.kind in {nkObjDownConv, nkObjUpConv}:
@@ -929,7 +915,7 @@ 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:
@@ -949,9 +935,6 @@ 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 +950,7 @@ 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 +979,6 @@ 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)
@@ -1046,9 +1014,9 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode; tmpFlags = {sfSing
          n[1].typ.skipTypes(abstractInst-{tyOwned}).kind == tyOwned:
        # allow conversions from owned to unowned via this little hack:
        let nTyp = n[1].typ
-        n[1].typ = n.typ
+        n[1].typ() = n.typ
        result[1] = p(n[1], c, s, mode)
-        result[1].typ = nTyp
+        result[1].typ() = nTyp
      else:
        result[1] = p(n[1], c, s, mode)

@@ -1154,25 +1122,6 @@ 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 +1148,7 @@ 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):
@@ -1248,22 +1197,15 @@ proc moveOrCopy(dest, ri: PNode; c: var Con; s: var Scope, flags: set[MoveOrCopy
        result.add p(ri, c, s, consumed)
        c.finishCopy(result, dest, flags, 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)
@@ -1302,55 +1244,6 @@ 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 +1257,15 @@ 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
@@ -6,7 +6,7 @@ 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;loongarch64
  macosx: i386;amd64;powerpc64;arm64
  solaris: i386;amd64;sparc;sparc64
  freebsd: i386;amd64;powerpc64;arm;arm64;riscv64;sparc64;mips;mipsel;mips64;mips64el;powerpc;powerpc64el
@@ -80,7 +80,6 @@ Files: "lib"
 Files: "examples"
 Files: "dist/nimble"
 Files: "dist/checksums"
-Files: "dist/nimony"

 Files: "tests"

--- a/compiler/int128.nim
+++ b/compiler/int128.nim
@@ -460,9 +460,7 @@ 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

--- a/compiler/jsgen.nim
+++ b/compiler/jsgen.nim
@@ -277,8 +277,7 @@ proc mangleName(m: BModule, s: PSym): Rope =
      else:
        result.add("_")
        result.add(rope(s.id))
-    ensureMutable s
-    s.locImpl.snippet = result
+    s.loc.snippet = result

 proc escapeJSString(s: string): string =
  result = newStringOfCap(s.len + s.len shr 2)
@@ -729,47 +728,44 @@ proc arithAux(p: PProc, n: PNode, r: var TCompRes, op: TMagic) =
  of mShrI:
    let typ = n[1].typ.skipTypes(abstractVarRange)
    if typ.kind == tyInt64 and optJsBigInt64 in p.config.globalOptions:
-      applyFormat("BigInt.asIntN(64, BigInt.asUintN(64, $1) >> (BigInt($2) & 63n))")
+      applyFormat("BigInt.asIntN(64, BigInt.asUintN(64, $1) >> BigInt($2))")
    elif typ.kind == tyUInt64 and optJsBigInt64 in p.config.globalOptions:
-      applyFormat("($1 >> (BigInt($2) & 63n))")
+      applyFormat("($1 >> BigInt($2))")
    else:
-      let bitmask = typ.size * 8 - 1
      if typ.kind in {tyInt..tyInt32}:
        let trimmerU = unsignedTrimmer(typ.size)
        let trimmerS = signedTrimmer(typ.size)
-        r.res = "((($1 $2) >>> ($3 & $5)) $4)" % [xLoc, trimmerU, yLoc, trimmerS, $bitmask]
+        r.res = "((($1 $2) >>> $3) $4)" % [xLoc, trimmerU, yLoc, trimmerS]
      else:
-        r.res = "($1 >>> ($2 & $3))" % [xLoc, yLoc, $bitmask]
+        applyFormat("($1 >>> $2)")
  of mShlI:
    let typ = n[1].typ.skipTypes(abstractVarRange)
    if typ.size == 8:
      if typ.kind == tyInt64 and optJsBigInt64 in p.config.globalOptions:
-        applyFormat("BigInt.asIntN(64, $1 << (BigInt($2) & 63n))")
+        applyFormat("BigInt.asIntN(64, $1 << BigInt($2))")
      elif typ.kind == tyUInt64 and optJsBigInt64 in p.config.globalOptions:
-        applyFormat("BigInt.asUintN(64, $1 << (BigInt($2) & 63n))")
+        applyFormat("BigInt.asUintN(64, $1 << BigInt($2))")
      else:
-        applyFormat("($1 * Math.pow(2, ($2 & 63)))")
+        applyFormat("($1 * Math.pow(2, $2))")
    else:
-      let bitmask = typ.size * 8 - 1
      if typ.kind in {tyUInt..tyUInt32}:
        let trimmer = unsignedTrimmer(typ.size)
-        r.res = "(($1 << ($2 & $4)) $3)" % [xLoc, yLoc, trimmer, $bitmask]
+        r.res = "(($1 << $2) $3)" % [xLoc, yLoc, trimmer]
      else:
        let trimmer = signedTrimmer(typ.size)
-        r.res = "(($1 << ($2 & $4)) $3)" % [xLoc, yLoc, trimmer, $bitmask]
+        r.res = "(($1 << $2) $3)" % [xLoc, yLoc, trimmer]
  of mAshrI:
    let typ = n[1].typ.skipTypes(abstractVarRange)
    if typ.size == 8:
      if optJsBigInt64 in p.config.globalOptions:
-        applyFormat("($1 >> (BigInt($2) & 63n))")
+        applyFormat("($1 >> BigInt($2))")
      else:
-        applyFormat("Math.floor($1 / Math.pow(2, ($2 & 63)))")
+        applyFormat("Math.floor($1 / Math.pow(2, $2))")
    else:
-      let bitmask = typ.size * 8 - 1
      if typ.kind in {tyUInt..tyUInt32}:
-        r.res = "($1 >>> ($2 & $3)))" % [xLoc, yLoc, $bitmask]
+        applyFormat("($1 >>> $2)")
      else:
-        r.res = "($1 >> ($2 & $3))" % [xLoc, yLoc, $bitmask]
+        applyFormat("($1 >> $2)")
  of mBitandI: bitwiseExpr("&")
  of mBitorI: bitwiseExpr("|")
  of mBitxorI: bitwiseExpr("^")
@@ -1006,8 +1002,7 @@ proc genTry(p: PProc, n: PNode, r: var TCompRes) =
      # If some branch requires a local alias introduce it here. This is needed
      # since JS cannot do ``catch x as y``.
      if excAlias != nil:
-        ensureMutable excAlias.sym
-        excAlias.sym.locImpl.snippet = mangleName(p.module, excAlias.sym)
+        excAlias.sym.loc.snippet = mangleName(p.module, excAlias.sym)
        lineF(p, "var $1 = lastJSError;$n", excAlias.sym.loc.snippet)
      gen(p, n[i][^1], a)
      moveInto(p, a, r)
@@ -1140,8 +1135,7 @@ proc genBlock(p: PProc, n: PNode, r: var TCompRes) =
    # named block?
    if (n[0].kind != nkSym): internalError(p.config, n.info, "genBlock")
    var sym = n[0].sym
-    ensureMutable sym
-    sym.locImpl.k = locOther
+    sym.loc.k = locOther
    sym.position = idx+1
  let labl = p.unique
  lineF(p, "Label$1: {$n", [labl.rope])
@@ -1240,8 +1234,7 @@ proc generateHeader(p: PProc, prc: PSym): Rope =
      # to keep it simple
      let env = prc.ast[paramsPos].lastSon
      assert env.kind == nkSym, "env is missing"
-      ensureMutable env.sym
-      env.sym.locImpl.snippet = "this"
+      env.sym.loc.snippet = "this"

  for i in 1..<typ.n.len:
    assert(typ.n[i].kind == nkSym)
@@ -1378,15 +1371,12 @@ proc genFieldAddr(p: PProc, n: PNode, r: var TCompRes) =
  r.typ = etyBaseIndex
  let b = if n.kind == nkHiddenAddr: n[0] else: n
  gen(p, b[0], a)
-  if skipTypes(b[0].typ, abstractVarRange + tyTypeClasses).kind == tyTuple:
-    # ref #25227 about `+ tyTypeClasses`
+  if skipTypes(b[0].typ, abstractVarRange).kind == tyTuple:
    r.res = makeJSString("Field" & $getFieldPosition(p, b[1]))
  else:
    if b[1].kind != nkSym: internalError(p.config, b[1].info, "genFieldAddr")
    var f = b[1].sym
-    if f.loc.snippet == "": 
-      ensureMutable f
-      f.locImpl.snippet = mangleName(p.module, f)
+    if f.loc.snippet == "": f.loc.snippet = mangleName(p.module, f)
    r.res = makeJSString($f.loc.snippet)
  internalAssert p.config, a.typ != etyBaseIndex
  r.address = a.res
@@ -1414,9 +1404,7 @@ proc genFieldAccess(p: PProc, n: PNode, r: var TCompRes) =
  else:
    if n[1].kind != nkSym: internalError(p.config, n[1].info, "genFieldAccess")
    var f = n[1].sym
-    if f.loc.snippet == "": 
-      ensureMutable f
-      f.locImpl.snippet = mangleName(p.module, f)
+    if f.loc.snippet == "": f.loc.snippet = mangleName(p.module, f)
    r.res = "$1.$2" % [r.res, f.loc.snippet]
    mkTemp(1)
  r.kind = resExpr
@@ -1437,15 +1425,11 @@ proc genCheckedFieldOp(p: PProc, n: PNode, addrTyp: PType, r: var TCompRes) =
  # Field symbol
  var field = accessExpr[1].sym
  internalAssert p.config, field.kind == skField
-  if field.loc.snippet == "": 
-    ensureMutable field
-    field.locImpl.snippet = mangleName(p.module, field)
+  if field.loc.snippet == "": field.loc.snippet = mangleName(p.module, field)
  # Discriminant symbol
  let disc = checkExpr[2].sym
  internalAssert p.config, disc.kind == skField
-  if disc.loc.snippet == "": 
-    ensureMutable disc
-    disc.locImpl.snippet = mangleName(p.module, disc)
+  if disc.loc.snippet == "": disc.loc.snippet = mangleName(p.module, disc)

  var setx: TCompRes = default(TCompRes)
  gen(p, checkExpr[1], setx)
@@ -1602,11 +1586,7 @@ proc genAddr(p: PProc, n: PNode, r: var TCompRes) =
    of nkObjDownConv:
      gen(p, n[0], r)
    of nkHiddenDeref, nkDerefExpr:
-      if n.kind in {nkAddr, nkHiddenAddr}:
-        # addr ( deref ( x )) --> x
-        gen(p, n[0][0], r)
-      else:
-        gen(p, n[0], r)
+      gen(p, n[0], r)
    of nkHiddenAddr:
      gen(p, n[0], r)
    of nkConv:
@@ -1857,9 +1837,7 @@ proc genPatternCall(p: PProc; n: PNode; pat: string; typ: PType;
 proc genInfixCall(p: PProc, n: PNode, r: var TCompRes) =
  # don't call '$' here for efficiency:
  let f = n[0].sym
-  if f.loc.snippet == "": 
-    ensureMutable f
-    f.locImpl.snippet = mangleName(p.module, f)
+  if f.loc.snippet == "": f.loc.snippet = mangleName(p.module, f)
  if sfInfixCall in f.flags:
    let pat = $n[0].sym.loc.snippet
    internalAssert p.config, pat.len > 0
@@ -2018,12 +1996,8 @@ proc createVar(p: PProc, typ: PType, indirect: bool): Rope =
    if indirect: result = "[$1]" % [result]
  of tyTuple:
    result = rope("{")
-    var first = true
    for i in 0..<t.len:
-      # Do not produce code for void types
-      if isEmptyType(t[i]): continue
-      if not first: result.add(", ")
-      first = false
+      if i > 0: result.add(", ")
      result.addf("Field$1: $2", [i.rope,
            createVar(p, t[i], false)])
    result.add("}")
@@ -2355,8 +2329,8 @@ proc genMagic(p: PProc, n: PNode, r: var TCompRes) =
      r.res = "if (null != $1) { if (null == $2) $2 = $3; else $2 += $3; }" %
        [b, lhs.rdLoc, tmp]
    else:
-      useMagic(p, "nimAddStrStr")
-      r.res = "nimAddStrStr($1, $2);" % [lhs.rdLoc, rhs.rdLoc]
+      let (a, tmp) = maybeMakeTemp(p, n[1], lhs)
+      r.res = "$1.push.apply($3, $2);" % [a, rhs.rdLoc, tmp]
    r.kind = resExpr
  of mAppendSeqElem:
    var x, y: TCompRes = default(TCompRes)
@@ -2460,7 +2434,7 @@ proc genMagic(p: PProc, n: PNode, r: var TCompRes) =
    binaryExpr(p, n, r, "mnewString",
      """if ($1.length < $2) { for (var i = $3.length; i < $4; ++i) $3.push(0); }
         else {$3.length = $4; }""")
-  of mSetLengthSeq, mSetLengthSeqUninit:
+  of mSetLengthSeq:
    var x, y: TCompRes = default(TCompRes)
    gen(p, n[1], x)
    gen(p, n[2], y)
@@ -2599,9 +2573,7 @@ proc genObjConstr(p: PProc, n: PNode, r: var TCompRes) =
    let val = it[1]
    gen(p, val, a)
    var f = it[0].sym
-    if f.loc.snippet == "": 
-      ensureMutable f
-      f.locImpl.snippet = mangleName(p.module, f)
+    if f.loc.snippet == "": f.loc.snippet = mangleName(p.module, f)
    fieldIDs.incl(lookupFieldAgain(n.typ.skipTypes({tyDistinct}), f).id)

    let typ = val.typ.skipTypes(abstractInst)
@@ -2903,8 +2875,6 @@ proc genCast(p: PProc, n: PNode, r: var TCompRes) =
  elif dest.kind in tyFloat..tyFloat64:
    if src.kind in {tyInt64, tyUInt64} and optJsBigInt64 in p.config.globalOptions:
      r.res = "Number($1)" % [r.res]
-  elif dest.kind == tyChar and (fromInt or fromUint):
-    r.res = "($1 & 255)" % [r.res]
  elif (src.kind == tyPtr and mapType(p, src) == etyObject) and dest.kind == tyPointer:
    r.address = r.res
    r.res = "null"
--- a/compiler/jstypes.nim
+++ b/compiler/jstypes.nim
@@ -122,7 +122,7 @@ proc genEnumInfo(p: PProc, typ: PType, name: Rope) =
         [name, genTypeInfo(p, typ.baseClass)])

 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
--- a/compiler/lambdalifting.nim
+++ b/compiler/lambdalifting.nim
@@ -150,7 +150,6 @@ template isIterator*(owner: PSym): bool =

 proc createEnvObj(g: ModuleGraph; idgen: IdGenerator; owner: PSym; info: TLineInfo): PType =
  result = createObj(g, idgen, owner, info, final=false)
-  result.incl tfFinal
  if owner.isIterator:
    rawAddField(result, createStateField(g, owner, idgen))

@@ -161,7 +160,7 @@ proc getClosureIterResult*(g: ModuleGraph; iter: PSym; idgen: IdGenerator): PSym
    # XXX a bit hacky:
    result = newSym(skResult, getIdent(g.cache, ":result"), idgen, iter, iter.info, {})
    result.typ = iter.typ.returnType
-    incl(result.flagsImpl, sfUsed)
+    incl(result.flags, sfUsed)
    iter.ast.add newSymNode(result)

 proc addHiddenParam(routine: PSym, param: PSym) =
@@ -200,7 +199,7 @@ 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 +215,6 @@ 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))
@@ -232,7 +227,7 @@ 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 =
  ## lambda lifting can be harmful for JS-like code generators.
@@ -244,7 +239,7 @@ proc createTypeBoundOpsLL(g: ModuleGraph; refType: PType; info: TLineInfo; idgen
    createTypeBoundOps(g, nil, refType.elementType, 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)
@@ -294,7 +289,7 @@ proc markAsClosure(g: ModuleGraph; owner: PSym; n: PNode) =
  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

@@ -340,7 +335,7 @@ 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
@@ -412,29 +407,17 @@ 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 =
@@ -626,7 +609,7 @@ proc rawClosureCreation(owner: PSym;
      let unowned = c.unownedEnvVars[owner.id]
      assert unowned != nil
      let env2 = copyTree(env)
-      env2.typ = unowned.typ
+      env2.typ() = unowned.typ
      result.add newAsgnStmt(unowned, env2, env.info)
      createTypeBoundOpsLL(d.graph, unowned.typ, env.info, d.idgen, owner)

@@ -640,7 +623,7 @@ 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:
@@ -682,7 +665,7 @@ proc closureCreationForIter(owner: PSym, iter: 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)
+  incl(v.flags, sfShadowed)
  v.typ = asOwnedRef(d, getHiddenParam(d.graph, iter.sym).typ)
  var vnode: PNode
  if iterOwner.isIterator:
@@ -803,7 +786,7 @@ proc liftCapturedVars(n: PNode; owner: PSym; d: var DetectionPass;
      let oldInContainer = c.inContainer
      c.inContainer = 0
      let m = newSymNode(n[namePos].sym)
-      m.typ = n.typ
+      m.typ() = n.typ
      result = liftCapturedVars(m, owner, d, c)
      c.inContainer = oldInContainer
  of nkHiddenStdConv:
@@ -991,20 +974,6 @@ 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))
--- a/compiler/layeredtable.nim
+++ b/compiler/layeredtable.nim
@@ -1,4 +1,5 @@
-import ast, astalgo
+import std/tables
+import ast

 type
  LayeredIdTableObj* {.acyclic.} = object
@@ -27,15 +28,14 @@ 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
+  pt.previousLen + pt.topLayer.len

 proc newTypeMapLayer*(pt: LayeredIdTable): LayeredIdTable =
-  result = LayeredIdTable(topLayer: initTypeMapping(), previousLen: pt.currentLen)
+  result = LayeredIdTable(topLayer: initTable[ItemId, PType](), previousLen: pt.currentLen)
  when useRef:
    result.nextLayer = pt
  else:
@@ -46,20 +46,12 @@ 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
+    when defined(gcDestructors):
+      pt = pt.nextLayer[]
+    else:
+      # workaround refc
+      let tmp = pt.nextLayer[]
+      pt = tmp

 proc lookup(typeMap: ref LayeredIdTableObj, key: ItemId): PType =
  result = nil
--- a/compiler/lexer.nim
+++ b/compiler/lexer.nim
@@ -316,28 +316,6 @@ 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 +491,6 @@ 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 +896,7 @@ 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
@@ -40,7 +40,7 @@ template asink*(t: PType): PSym = getAttachedOp(c.g, t, attachedSink)

 proc fillBody(c: var TLiftCtx; t: PType; body, x, y: PNode)
 proc produceSym(g: ModuleGraph; c: PContext; typ: PType; kind: TTypeAttachedOp;
-              info: TLineInfo; idgen: IdGenerator): PSym
+              info: TLineInfo; idgen: IdGenerator; isDistinct = false): PSym

 proc createTypeBoundOps*(g: ModuleGraph; c: PContext; orig: PType; info: TLineInfo;
                         idgen: IdGenerator)
@@ -49,7 +49,7 @@ proc at(a, i: PNode, elemType: PType): PNode =
  result = newNodeI(nkBracketExpr, a.info, 2)
  result[0] = a
  result[1] = i
-  result.typ = elemType
+  result.typ() = elemType

 proc destructorOverridden(g: ModuleGraph; t: PType): bool =
  let op = getAttachedOp(g, t, attachedDestructor)
@@ -68,7 +68,7 @@ proc dotField(x: PNode, f: PSym): PNode =
  else:
    result[0] = x
  result[1] = newSymNode(f, x.info)
-  result.typ = f.typ
+  result.typ() = f.typ

 proc newAsgnStmt(le, ri: PNode): PNode =
  result = newNodeI(nkAsgn, le.info, 2)
@@ -88,10 +88,10 @@ proc defaultOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    body.add newAsgnStmt(x, y)
  elif c.kind == attachedDestructor and c.addMemReset:
    let call = genBuiltin(c, mDefault, "default", x)
-    call.typ = t
+    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:
@@ -105,7 +105,7 @@ proc genWhileLoop(c: var TLiftCtx; i, dest: PNode): PNode =
  result = newNodeI(nkWhileStmt, c.info, 2)
  let cmp = genBuiltin(c, mLtI, "<", i)
  cmp.add genLen(c.g, dest)
-  cmp.typ = getSysType(c.g, c.info, tyBool)
+  cmp.typ() = getSysType(c.g, c.info, tyBool)
  result[0] = cmp
  result[1] = newNodeI(nkStmtList, c.info)

@@ -127,10 +127,10 @@ proc genContainerOf(c: var TLiftCtx; objType: PType, field, x: PSym): PNode =
  dotExpr.add newSymNode(field)

  let offsetOf = genBuiltin(c, mOffsetOf, "offsetof", dotExpr)
-  offsetOf.typ = intType
+  offsetOf.typ() = intType

  let minusExpr = genBuiltin(c, mSubI, "-", castExpr1)
-  minusExpr.typ = intType
+  minusExpr.typ() = intType
  minusExpr.add offsetOf

  let objPtr = makePtrType(objType.owner, objType, c.idgen)
@@ -148,7 +148,7 @@ proc destructorCall(c: var TLiftCtx; op: PSym; x: PNode): PNode =
  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

@@ -163,12 +163,12 @@ proc fillBodyObj(c: var TLiftCtx; n, body, x, y: PNode; enforceDefaultOp: bool,
    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))
+        body.add genBuiltin(c, mWasMoved, "`=wasMoved`", x.dotField(f))
      fillBody(c, f.typ, body, x.dotField(f), b)
  of nkNilLit: discard
  of nkRecCase:
@@ -218,38 +218,23 @@ 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, enforceWasMoved)
  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
+  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()
+    fillBody(c, skipTypes(t.baseClass, abstractPtrs), body, dest, src)
+  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)
@@ -280,11 +265,11 @@ proc fillBodyObjT(c: var TLiftCtx; t: PType, body, x, y: PNode) =
      # because the wasMoved(dest) call would zero out src, if dest aliases src.
      var cond = newTree(nkCall, newSymNode(c.g.getSysMagic(c.info, "==", mEqRef)),
        newTreeIT(nkAddr, c.info, makePtrType(c.fn, x.typ, c.idgen), x), newTreeIT(nkAddr, c.info, makePtrType(c.fn, y.typ, c.idgen), y))
-      cond.typ = getSysType(c.g, x.info, tyBool)
+      cond.typ() = getSysType(c.g, x.info, tyBool)
      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 +277,7 @@ 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

@@ -312,7 +296,7 @@ proc fillBodyObjT(c: var TLiftCtx; t: PType, body, x, y: PNode) =

 proc boolLit*(g: ModuleGraph; info: TLineInfo; value: bool): PNode =
  result = newIntLit(g, info, ord value)
-  result.typ = getSysType(g, info, tyBool)
+  result.typ() = getSysType(g, info, tyBool)

 proc getCycleParam(c: TLiftCtx): PNode =
  assert c.kind in {attachedAsgn, attachedDup}
@@ -380,10 +364,6 @@ 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 +377,7 @@ 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 +403,7 @@ 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 +519,7 @@ 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 +529,13 @@ 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)
@@ -583,18 +545,18 @@ proc newSeqCall(c: var TLiftCtx; x, y: PNode): PNode =
  # don't call genAddr(c, x) here:
  result = genBuiltin(c, mNewSeq, "newSeq", x)
  let lenCall = genBuiltin(c, mLengthSeq, "len", y)
-  lenCall.typ = getSysType(c.g, x.info, tyInt)
+  lenCall.typ() = getSysType(c.g, x.info, tyInt)
  result.add lenCall

 proc setLenStrCall(c: var TLiftCtx; x, y: PNode): PNode =
  let lenCall = genBuiltin(c, mLengthStr, "len", y)
-  lenCall.typ = getSysType(c.g, x.info, tyInt)
+  lenCall.typ() = getSysType(c.g, x.info, tyInt)
  result = genBuiltin(c, mSetLengthStr, "setLen", x) # genAddr(g, x))
  result.add lenCall

 proc setLenSeqCall(c: var TLiftCtx; t: PType; x, y: PNode): PNode =
  let lenCall = genBuiltin(c, mLengthSeq, "len", y)
-  lenCall.typ = getSysType(c.g, x.info, tyInt)
+  lenCall.typ() = getSysType(c.g, x.info, tyInt)
  var op = getSysMagic(c.g, x.info, "setLen", mSetLengthSeq)
  op = instantiateGeneric(c, op, t, t)
  result = newTree(nkCall, newSymNode(op, x.info), x, lenCall)
@@ -617,37 +579,14 @@ proc checkSelfAssignment(c: var TLiftCtx; t: PType; body, x, y: PNode) =
      newTreeIT(nkAddr, c.info, makePtrType(c.fn, x.typ, c.idgen), x),
      newTreeIT(nkAddr, c.info, makePtrType(c.fn, y.typ, c.idgen), y)
      )
-  cond.typ = getSysType(c.g, c.info, tyBool)
+  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 +595,9 @@ 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 +612,7 @@ 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 +650,7 @@ 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)
@@ -728,23 +663,16 @@ 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
@@ -771,43 +699,14 @@ 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

  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
@@ -821,7 +720,7 @@ proc atomicRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  if isFinal(elemType):
    addDestructorCall(c, elemType, actions, genDeref(tmp, nkDerefExpr))
    var alignOf = genBuiltin(c, mAlignOf, "alignof", newNodeIT(nkType, c.info, elemType))
-    alignOf.typ = getSysType(c.g, c.info, tyInt)
+    alignOf.typ() = getSysType(c.g, c.info, tyInt)
    actions.add callCodegenProc(c.g, "nimRawDispose", c.info, tmp, alignOf)
  else:
    addDestructorCall(c, elemType, newNodeI(nkStmtList, c.info), genDeref(tmp, nkDerefExpr))
@@ -831,7 +730,7 @@ proc atomicRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  if isCyclic:
    if isFinal(elemType):
      let typInfo = genBuiltin(c, mGetTypeInfoV2, "getTypeInfoV2", newNodeIT(nkType, x.info, elemType))
-      typInfo.typ = getSysType(c.g, c.info, tyPointer)
+      typInfo.typ() = getSysType(c.g, c.info, tyPointer)
      cond = callCodegenProc(c.g, "nimDecRefIsLastCyclicStatic", c.info, tmp, typInfo)
    else:
      cond = callCodegenProc(c.g, "nimDecRefIsLastCyclicDyn", c.info, tmp)
@@ -839,7 +738,7 @@ proc atomicRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    cond = callCodegenProc(c.g, "nimDecRefIsLastDyn", c.info, x)
  else:
    cond = callCodegenProc(c.g, "nimDecRefIsLast", c.info, x)
-  cond.typ = getSysType(c.g, x.info, tyBool)
+  cond.typ() = getSysType(c.g, x.info, tyBool)

  case c.kind
  of attachedSink:
@@ -866,13 +765,13 @@ proc atomicRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    if isCyclic:
      if isFinal(elemType):
        let typInfo = genBuiltin(c, mGetTypeInfoV2, "getTypeInfoV2", newNodeIT(nkType, x.info, elemType))
-        typInfo.typ = getSysType(c.g, c.info, tyPointer)
+        typInfo.typ() = getSysType(c.g, c.info, tyPointer)
        body.add callCodegenProc(c.g, "nimTraceRef", c.info, genAddrOf(x, c.idgen), typInfo, y)
      else:
        # 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)
@@ -887,28 +786,9 @@ proc atomicClosureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  ## Closures are really like refs except they always use a virtual destructor
  ## and we need to do the refcounting only on the ref field which we call 'xenv':
  let xenv = genBuiltin(c, mAccessEnv, "accessEnv", x)
-  xenv.typ = getSysType(c.g, c.info, tyPointer)
+  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)
@@ -922,7 +802,7 @@ proc atomicClosureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
    if isCyclic: "nimDecRefIsLastCyclicDyn"
    else: "nimDecRefIsLast"
  let cond = callCodegenProc(c.g, decRefProc, c.info, tmp)
-  cond.typ = getSysType(c.g, x.info, tyBool)
+  cond.typ() = getSysType(c.g, x.info, tyBool)

  case c.kind
  of attachedSink:
@@ -934,18 +814,19 @@ proc atomicClosureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
      body.add newAsgnStmt(x, y)
  of attachedAsgn:
    let yenv = genBuiltin(c, mAccessEnv, "accessEnv", y)
-    yenv.typ = getSysType(c.g, c.info, tyPointer)
+    yenv.typ() = getSysType(c.g, c.info, tyPointer)
    if isCyclic:
      body.add genIf(c, yenv, callCodegenProc(c.g, "nimIncRefCyclic", c.info, yenv, getCycleParam(c)))
      body.add newAsgnStmt(x, y)
      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:
    let yenv = genBuiltin(c, mAccessEnv, "accessEnv", y)
-    yenv.typ = getSysType(c.g, c.info, tyPointer)
+    yenv.typ() = getSysType(c.g, c.info, tyPointer)
    if isCyclic:
      body.add newAsgnStmt(x, y)
      body.add genIf(c, yenv, callCodegenProc(c.g, "nimIncRefCyclic", c.info, yenv, getCycleParam(c)))
@@ -957,7 +838,7 @@ 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
@@ -985,7 +866,7 @@ 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)
@@ -997,7 +878,7 @@ proc ownedRefOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
  if isFinal(elemType):
    addDestructorCall(c, elemType, actions, genDeref(x, nkDerefExpr))
    var alignOf = genBuiltin(c, mAlignOf, "alignof", newNodeIT(nkType, c.info, elemType))
-    alignOf.typ = getSysType(c.g, c.info, tyInt)
+    alignOf.typ() = getSysType(c.g, c.info, tyInt)
    actions.add callCodegenProc(c.g, "nimRawDispose", c.info, x, alignOf)
  else:
    addDestructorCall(c, elemType, newNodeI(nkStmtList, c.info), genDeref(x, nkDerefExpr))
@@ -1013,21 +894,21 @@ 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:
    # a big problem is that we don't know the environment's type here, so we
    # have to go through some indirection; we delegate this to the codegen:
    let call = newNodeI(nkCall, c.info, 2)
-    call.typ = t
+    call.typ() = t
    call[0] = newSymNode(createMagic(c.g, c.idgen, "deepCopy", mDeepCopy))
    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)
+    xx.typ() = getSysType(c.g, c.info, tyPointer)
    case c.kind
    of attachedSink:
      # we 'nil' y out afterwards so we *need* to take over its reference
@@ -1036,13 +917,13 @@ proc closureOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
      body.add newAsgnStmt(x, y)
    of attachedAsgn:
      let yy = genBuiltin(c, mAccessEnv, "accessEnv", y)
-      yy.typ = getSysType(c.g, c.info, tyPointer)
+      yy.typ() = getSysType(c.g, c.info, tyPointer)
      body.add genIf(c, yy, callCodegenProc(c.g, "nimIncRef", c.info, yy))
      body.add genIf(c, xx, callCodegenProc(c.g, "nimDecWeakRef", c.info, xx))
      body.add newAsgnStmt(x, y)
    of attachedDup:
      let yy = genBuiltin(c, mAccessEnv, "accessEnv", y)
-      yy.typ = getSysType(c.g, c.info, tyPointer)
+      yy.typ() = getSysType(c.g, c.info, tyPointer)
      body.add newAsgnStmt(x, y)
      body.add genIf(c, yy, callCodegenProc(c.g, "nimIncRef", c.info, yy))
    of attachedDestructor:
@@ -1053,11 +934,11 @@ 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)
-  xx.typ = getSysType(c.g, c.info, tyPointer)
+  xx.typ() = getSysType(c.g, c.info, tyPointer)
  var actions = newNodeI(nkStmtList, c.info)
  #discard addDestructorCall(c, elemType, newNodeI(nkStmtList, c.info), genDeref(xx))
  actions.add callCodegenProc(c.g, "nimDestroyAndDispose", c.info, xx)
@@ -1071,7 +952,7 @@ 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 +961,7 @@ 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 +970,7 @@ 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 +1002,9 @@ 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 +1021,23 @@ 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.elementType, body, x, y)
  of tyTuple:
    fillBodyTup(c, t, body, x, y)
  of tyVarargs, tyOpenArray:
@@ -1181,7 +1063,9 @@ proc produceSymDistinctType(g: ModuleGraph; c: PContext; typ: PType;
  assert typ.kind == tyDistinct
  let baseType = typ.elementType
  if getAttachedOp(g, baseType, kind) == nil:
-    discard produceSym(g, c, baseType, kind, info, idgen)
+    # TODO: fixme `isDistinct` is a fix for #23552; remove it after
+    # `-d:nimPreviewNonVarDestructor` becomes the default
+    discard produceSym(g, c, baseType, kind, info, idgen, isDistinct = true)
  result = getAttachedOp(g, baseType, kind)
  setAttachedOp(g, idgen.module, typ, kind, result)

@@ -1202,7 +1086,7 @@ 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)
@@ -1216,10 +1100,11 @@ proc symDupPrototype(g: ModuleGraph; typ: PType; owner: PSym; kind: TTypeAttache
  n[bodyPos] = newNodeI(nkStmtList, info)
  n[resultPos] = newSymNode(res)
  result.ast = n
-  incl result.flagsImpl, {sfFromGeneric, sfGeneratedOp}
+  incl result.flags, sfFromGeneric
+  incl result.flags, sfGeneratedOp

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

@@ -1229,8 +1114,8 @@ 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} and not isDistinct)):
    dest.typ = typ
  else:
    dest.typ = makeVarType(typ.owner, typ, idgen)
@@ -1245,7 +1130,7 @@ 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)
@@ -1258,37 +1143,27 @@ 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)
  let yy = genBuiltin(c, mAccessTypeField, "accessTypeField", y)
-  xx.typ = getSysType(c.g, c.info, tyPointer)
-  yy.typ = xx.typ
+  xx.typ() = getSysType(c.g, c.info, tyPointer)
+  yy.typ() = xx.typ
  body.add newAsgnStmt(xx, yy)

 proc produceSym(g: ModuleGraph; c: PContext; typ: PType; kind: TTypeAttachedOp;
-              info: TLineInfo; idgen: IdGenerator): PSym =
+              info: TLineInfo; idgen: IdGenerator; isDistinct = false): 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:
-    result = symPrototype(g, typ, typ.owner, kind, info, idgen)
+    result = symPrototype(g, typ, typ.owner, kind, info, idgen, isDistinct = isDistinct)

  var a = TLiftCtx(info: info, g: g, kind: kind, c: c, asgnForType: typ, idgen: idgen,
                   fn: result)
@@ -1305,48 +1180,35 @@ proc produceSym(g: ModuleGraph; c: PContext; typ: PType; kind: TTypeAttachedOp;

  if kind == attachedSink and destructorOverridden(g, typ):
    ## compiler can use a combination of `=destroy` and memCopy for sink op
-    ensureMutable dest
-    dest.flagsImpl.incl sfCursor
+    dest.flags.incl sfCursor
    let op = getAttachedOp(g, typ, attachedDestructor)
    result.ast[bodyPos].add newOpCall(a, op, if op.typ.firstParamType.kind == tyVar: d[0] else: d)
    result.ast[bodyPos].add 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
+    incl result.flags, 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
+    incl result.options, optQuirky
  completePartialOp(g, idgen.module, typ, kind, result)


@@ -1371,9 +1233,7 @@ 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 +1268,7 @@ 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 +1277,11 @@ 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
+  incl orig.flags, tfCheckedForDestructor
  # for user defined generic destructors:
  let origRoot = genericRoot(orig)
  if origRoot != nil:
-    # IC: review this solution again later
-    incl origRoot.flagsImpl, tfGenericHasDestructor
+    incl origRoot.flags, tfGenericHasDestructor

  let skipped = orig.skipTypes({tyGenericInst, tyAlias, tySink})
  if isEmptyContainer(skipped) or skipped.kind == tyStatic: return
@@ -1443,13 +1301,13 @@ 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 +1323,8 @@ proc createTypeBoundOps(g: ModuleGraph; c: PContext; orig: PType; info: TLineInf
    if canon != orig:
      setAttachedOp(g, idgen.module, orig, k, getAttachedOp(g, canon, k))

-  if not isTrivial(getAttachedOp(g, orig, attachedDestructor)):
-    #or not isTrivial(orig.assignment) or
-    # not isTrivial(orig.sink):
-    # IC: review this solution again later
-    orig.flagsImpl.incl tfHasAsgn
+  if not isTrival(getAttachedOp(g, orig, attachedDestructor)):
+    #or not isTrival(orig.assignment) or
+    # not isTrival(orig.sink):
+    orig.flags.incl tfHasAsgn
    # ^ XXX Breaks IC!
--- a/compiler/liftlocals.nim
+++ b/compiler/liftlocals.nim
@@ -32,12 +32,12 @@ proc interestingVar(s: PSym): bool {.inline.} =
 proc lookupOrAdd(c: var Ctx; s: PSym; info: TLineInfo): PNode =
  let field = addUniqueField(c.objType, s, c.cache, c.idgen)
  var deref = newNodeI(nkHiddenDeref, info)
-  deref.typ = c.objType
+  deref.typ() = c.objType
  deref.add(newSymNode(c.partialParam, info))
  result = newNodeI(nkDotExpr, info)
  result.add(deref)
  result.add(newSymNode(field))
-  result.typ = field.typ
+  result.typ() = field.typ

 proc liftLocals(n: PNode; i: int; c: var Ctx) =
  let it = n[i]
--- a/compiler/lineinfos.nim
+++ b/compiler/lineinfos.nim
@@ -93,13 +93,10 @@ type
    warnBareExcept = "BareExcept",
    warnImplicitDefaultValue = "ImplicitDefaultValue",
    warnIgnoredSymbolInjection = "IgnoredSymbolInjection",
-    warnStdPrefix = "StdPrefix",
-    warnUnknownNotes = "UnknownNotes",
-    warnLongLiterals = "LongLiterals",
+    warnStdPrefix = "StdPrefix"
+    warnUnknownNotes = "UnknownNotes"
    warnUser = "User",
    warnGlobalVarConstructorTemporary = "GlobalVarConstructorTemporary",
-    warnImplicitRangeConversion = "ImplicitRangeConversion",
-    warnSystemRangeConversion = "SystemRangeConversion",
    # hints
    hintSuccess = "Success", hintSuccessX = "SuccessX",
    hintCC = "CC",
@@ -113,7 +110,6 @@ 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

@@ -205,11 +201,8 @@ const
    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",
@@ -243,7 +236,6 @@ 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"
  ]
@@ -264,9 +256,9 @@ 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,
@@ -279,10 +271,6 @@ const
  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 +289,6 @@ 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
@@ -95,7 +95,7 @@ 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
     optStyleUsages notin ctx.config.globalOptions and # ignore if requested to only check name usage
@@ -136,7 +136,7 @@ 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
     sym.kind != skTemp and # 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
    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

@@ -86,47 +86,6 @@ 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 +93,7 @@ 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 +109,7 @@ 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 +117,7 @@ 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 +127,7 @@ 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
@@ -58,11 +58,13 @@ 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:
      handleError(n, origin)
+  of nkOpenSym:
+    result = considerQuotedIdent(c, n[0], origin)
  else:
    handleError(n, origin)

@@ -75,13 +77,10 @@ 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) =
@@ -311,7 +310,7 @@ 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)
+  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)
@@ -388,7 +387,7 @@ 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 +411,8 @@ 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 +421,8 @@ 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
--- a/compiler/lowerings.nim
+++ b/compiler/lowerings.nim
@@ -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

@@ -174,12 +174,12 @@ proc rawIndirectAccess*(a: PNode; field: PSym; info: TLineInfo): PNode =
  # returns a[].field as a node
  assert field.kind == skField
  var deref = newNodeI(nkHiddenDeref, info)
-  deref.typ = a.typ.skipTypes(abstractInst)[0]
+  deref.typ() = a.typ.skipTypes(abstractInst)[0]
  deref.add a
  result = newNodeI(nkDotExpr, info)
  result.add deref
  result.add newSymNode(field)
-  result.typ = field.typ
+  result.typ() = field.typ

 proc rawDirectAccess*(obj, field: PSym): PNode =
  # returns a.field as a node
@@ -187,7 +187,7 @@ proc rawDirectAccess*(obj, field: PSym): PNode =
  result = newNodeI(nkDotExpr, field.info)
  result.add newSymNode(obj)
  result.add newSymNode(field)
-  result.typ = field.typ
+  result.typ() = field.typ

 proc lookupInRecord(n: PNode, id: ItemId): PSym =
  result = nil
@@ -250,12 +250,12 @@ proc newDotExpr*(obj, b: PSym): PNode =
  assert field != nil, b.name.s
  result.add newSymNode(obj)
  result.add newSymNode(field)
-  result.typ = field.typ
+  result.typ() = field.typ

 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).elementType
  var t = deref.typ.skipTypes(abstractInst)
  var field: PSym
  while true:
@@ -273,12 +273,12 @@ proc indirectAccess*(a: PNode, b: ItemId, info: TLineInfo): PNode =
  result = newNodeI(nkDotExpr, info)
  result.add deref
  result.add newSymNode(field)
-  result.typ = field.typ
+  result.typ() = field.typ

 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).elementType
  var t = deref.typ.skipTypes(abstractInst)
  var field: PSym
  let bb = getIdent(cache, b)
@@ -297,7 +297,7 @@ proc indirectAccess*(a: PNode, b: string, info: TLineInfo; cache: IdentCache): P
  result = newNodeI(nkDotExpr, info)
  result.add deref
  result.add newSymNode(field)
-  result.typ = field.typ
+  result.typ() = field.typ

 proc getFieldFromObj*(t: PType; v: PSym): PSym =
  assert v.kind != skField
@@ -320,7 +320,7 @@ proc indirectAccess*(a, b: PSym, info: TLineInfo): PNode =
 proc genAddrOf*(n: PNode; idgen: IdGenerator; typeKind = tyPtr): PNode =
  result = newNodeI(nkAddr, n.info, 1)
  result[0] = n
-  result.typ = newType(typeKind, idgen, n.typ.owner)
+  result.typ() = newType(typeKind, idgen, n.typ.owner)
  result.typ.rawAddSon(n.typ)

 proc genDeref*(n: PNode; k = nkHiddenDeref): PNode =
@@ -344,18 +344,18 @@ 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.returnType

 proc newIntLit*(g: ModuleGraph; info: TLineInfo; value: BiggestInt): PNode =
  result = nkIntLit.newIntNode(value)
-  result.typ = getSysType(g, info, tyInt)
+  result.typ() = getSysType(g, info, tyInt)

 proc genHigh*(g: ModuleGraph; n: PNode): PNode =
  if skipTypes(n.typ, abstractVar).kind == tyArray:
    result = newIntLit(g, n.info, toInt64(lastOrd(g.config, skipTypes(n.typ, abstractVar))))
  else:
    result = newNodeI(nkCall, n.info, 2)
-    result.typ = getSysType(g, n.info, tyInt)
+    result.typ() = getSysType(g, n.info, tyInt)
    result[0] = newSymNode(getSysMagic(g, n.info, "high", mHigh))
    result[1] = n

@@ -364,7 +364,7 @@ proc genLen*(g: ModuleGraph; n: PNode): PNode =
    result = newIntLit(g, n.info, toInt64(lastOrd(g.config, skipTypes(n.typ, abstractVar)) + 1))
  else:
    result = newNodeI(nkCall, n.info, 2)
-    result.typ = getSysType(g, n.info, tyInt)
+    result.typ() = getSysType(g, n.info, tyInt)
    result[0] = newSymNode(getSysMagic(g, n.info, "len", mLengthSeq))
    result[1] = n

--- 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

@@ -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
@@ -26,14 +26,12 @@ import
 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

@@ -97,6 +95,14 @@ 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 +117,6 @@ 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)
@@ -163,7 +137,15 @@ 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
@@ -202,7 +184,7 @@ proc commandInteractive(graph: ModuleGraph) =
    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)
@@ -223,6 +205,10 @@ 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 +257,7 @@ 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
@@ -289,7 +275,6 @@ proc mainCommand*(graph: ModuleGraph) =
    of backendCpp: commandCompileToC(graph)
    of backendObjc: commandCompileToC(graph)
    of backendJs: commandCompileToJS(graph)
-    of backendNif: commandCompileToNif(graph)
    of backendInvalid: raiseAssert "unreachable"

  template docLikeCmd(body) =
@@ -320,6 +305,8 @@ proc mainCommand*(graph: ModuleGraph) =
  case conf.cmd
  of cmdBackends:
    compileToBackend()
+    when BenchIC:
+      echoTimes graph.packed
  of cmdTcc:
    when hasTinyCBackend:
      extccomp.setCC(conf, "tcc", unknownLineInfo)
@@ -416,27 +403,16 @@ 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 cmdRod:
+    wantMainModule(conf)
+    commandView(graph)
+    #msgWriteln(conf, "Beware: Indentation tokens depend on the parser's state!")
  of cmdInteractive: commandInteractive(graph)
  of cmdNimscript:
    if conf.projectIsCmd or conf.projectIsStdin: discard
--- 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, strtabs, algorithm, os, strutils, parseutils]
 import ../dist/checksums/src/checksums/md5
 import ast, astalgo, options, lineinfos,idents, btrees, ropes, msgs, pathutils, packages, suggestsymdb
+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
@@ -41,12 +41,25 @@ 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
+
  PipelinePass* = enum
    NonePass
    SemPass
    JSgenPass
    CgenPass
-    NifgenPass
    EvalPass
    InterpreterPass
    GenDependPass
@@ -56,19 +69,19 @@ 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
@@ -94,8 +107,8 @@ type
    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]
@@ -123,10 +136,6 @@ type

    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 +157,8 @@ 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 = [
@@ -209,43 +214,85 @@ 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 = default(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)
+  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 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 = nil
+    for s in interfaceSymbols(g.config, g.cache, g.packed, FileIndex(m.position), name, importHidden):
+      if result == nil:
+        # set result to the first symbol
+        result = s
+      else:
+        # another symbol found
+        amb = true
+        break
+  else:
+    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

 proc systemModuleSym*(g: ModuleGraph; name: PIdent): PSym =
  result = someSym(g, g.systemModule, name)
@@ -257,113 +304,109 @@ iterator systemModuleSyms*(g: ModuleGraph; name: PIdent): PSym =
    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 +420,21 @@ 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 +454,10 @@ 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

@@ -489,13 +522,15 @@ 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, m)))
+  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.
@@ -542,14 +577,12 @@ proc initModuleGraphFields(result: ModuleGraph) =
  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 +598,49 @@ 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 +678,13 @@ proc markDirty*(g: ModuleGraph; fileIdx: FileIndex) =
  if m != nil:
    g.suggestSymbols.del(fileIdx)
    g.suggestErrors.del(fileIdx)
-    incl m.flagsImpl, sfDirty
+    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 +724,23 @@ 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) =
+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:
@@ -728,7 +761,7 @@ 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

--- a/compiler/modulepaths.nim
+++ b/compiler/modulepaths.nim
@@ -79,10 +79,6 @@ 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 +87,9 @@ 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
@@ -32,9 +32,9 @@ 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.")
--- 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:
@@ -59,12 +60,12 @@ proc makeCString*(s: string): Rope =
    toCChar(s[i], result)
  result.add('\"')

-proc newFileInfo(fullPath: AbsoluteFile, projPath: RelativeFile; kind = fikSource): TFileInfo =
+proc newFileInfo(fullPath: AbsoluteFile, projPath: RelativeFile): TFileInfo =
  result = TFileInfo(fullPath: fullPath, projPath: projPath,
                    shortName: fullPath.extractFilename,
                    quotedFullName: fullPath.string.makeCString,
-                    lines: @[],
-                    kind: kind)
+                    lines: @[]
+  )
  result.quotedName = result.shortName.makeCString
  when defined(nimpretty):
    if not result.fullPath.isEmpty:
@@ -132,23 +133,6 @@ proc fileInfoIdx*(conf: ConfigRef; filename: RelativeFile): FileIndex =
  var dummy: bool = false
  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)
  if line < int high(uint16):
@@ -240,7 +224,7 @@ 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 +232,7 @@ 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)
@@ -664,9 +648,7 @@ 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 =
--- 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
@@ -919,7 +919,7 @@ proc infix(ctx: NilCheckerContext, l: PNode, r: PNode, magic: TMagic): PNode =
    newSymNode(op, r.info),
    l,
    r)
-  result.typ = newType(tyBool, ctx.idgen, nil)
+  result.typ() = newType(tyBool, ctx.idgen, nil)

 proc prefixNot(ctx: NilCheckerContext, node: PNode): PNode =
  var cache = newIdentCache()
@@ -929,7 +929,7 @@ proc prefixNot(ctx: NilCheckerContext, node: PNode): PNode =
  result = nkPrefix.newTree(
    newSymNode(op, node.info),
    node)
-  result.typ = newType(tyBool, ctx.idgen, nil)
+  result.typ() = newType(tyBool, ctx.idgen, nil)

 proc infixEq(ctx: NilCheckerContext, l: PNode, r: PNode): PNode =
  infix(ctx, l, r, mEqRef)
--- a/compiler/nim.cfg
+++ b/compiler/nim.cfg
@@ -11,9 +11,6 @@ define:nimPreviewRangeDefault
 define:nimPreviewNonVarDestructor
 define:nimPreviewCheckedClose
 define:nimPreviewAsmSemSymbol
-define:nimPreviewCStringComparisons
-define:nimPreviewDuplicateModuleError
-
 threads:off

 #import:"$projectpath/testability"
@@ -65,7 +62,3 @@ define:useStdoutAsStdmsg
@if nimHasVtables:
  experimental:vtables
@end
-
-@if nimHasImplicitRangeConversion:
-  warning[ImplicitRangeConversion]:off
-@end
--- a/compiler/nim.nim
+++ b/compiler/nim.nim
@@ -118,7 +118,7 @@ proc handleCmdLine(cache: IdentCache; conf: ConfigRef) =
  if conf.selectedGC == gcUnselected:
    if conf.backend in {backendC, backendCpp, backendObjc} or
        (conf.cmd in cmdDocLike and conf.backend != backendJs) or
-        conf.cmd in {cmdGendepend, cmdNifC, cmdIc, cmdM}:
+        conf.cmd == cmdGendepend:
      initOrcDefines(conf)

  mainCommand(graph)
--- a/compiler/nimconf.nim
+++ b/compiler/nimconf.nim
@@ -207,6 +207,7 @@ proc parseAssignment(L: var Lexer, tok: var Token;
      checkSymbol(L, tok)
      val.add($tok)
      confTok(L, tok, config, condStack)
+  config.currentConfigDir = parentDir(filename.string)
  if percent:
    processSwitch(s, strtabs.`%`(val, config.configVars,
                                {useEnvironment, useEmpty}), passPP, info, config)
@@ -248,8 +249,6 @@ proc loadConfigs*(cfg: RelativeFile; cache: IdentCache; conf: ConfigRef; idgen:
  setDefaultLibpath(conf)
  template readConfigFile(path) =
    let configPath = path
-    conf.currentConfigDir = configPath.splitFile.dir.string
-    setConfigVar(conf, "selfDir", conf.currentConfigDir)
    if readConfigFile(configPath, cache, conf):
      conf.configFiles.add(configPath)

--- a/compiler/nimeval.nim
+++ b/compiler/nimeval.nim
@@ -128,7 +128,7 @@ proc createInterpreter*(scriptName: string;
    if conf.libpath.isEmpty: conf.libpath = AbsoluteDir p

  var m = graph.makeModule(scriptName)
-  incl(m, sfMainModule)
+  incl(m.flags, sfMainModule)
  var idgen = idGeneratorFromModule(m)
  var vm = newCtx(m, cache, graph, idgen)
  vm.mode = emRepl
@@ -168,7 +168,7 @@ proc runRepl*(r: TLLRepl;
  if supportNimscript: defineSymbol(conf.symbols, "nimconfig")
  when hasFFI: defineSymbol(graph.config.symbols, "nimffi")
  var m = graph.makeStdinModule()
-  incl(m, sfMainModule)
+  incl(m.flags, sfMainModule)
  var idgen = idGeneratorFromModule(m)

  if supportNimscript: graph.vm = setupVM(m, cache, "stdin", graph, idgen)
--- a/compiler/nimsets.nim
+++ b/compiler/nimsets.nim
@@ -84,7 +84,7 @@ proc toTreeSet*(conf: ConfigRef; s: TBitSet, settype: PType, info: TLineInfo): P
  elemType = settype[0]
  first = firstOrd(conf, elemType).toInt64
  result = newNodeI(nkCurly, info)
-  result.typ = settype
+  result.typ() = settype
  result.info = info
  e = 0
  while e < s.len * ElemSize:
@@ -101,7 +101,7 @@ proc toTreeSet*(conf: ConfigRef; s: TBitSet, settype: PType, info: TLineInfo): P
        result.add aa
      else:
        n = newNodeI(nkRange, info)
-        n.typ = elemType
+        n.typ() = elemType
        n.add aa
        let bb = newIntTypeNode(b + first, elemType)
        bb.info = info
--- a/compiler/optimizer.nim
+++ b/compiler/optimizer.nim
@@ -28,14 +28,11 @@ type
    hasReturn, hasBreak: bool
    label: PSym # can be nil
    parent: ptr BasicBlock
-    symToDel: seq[PNode]

  Con = object
    somethingTodo: bool
    inFinally: int

-proc invalidateWasMoved(c: var BasicBlock; x: PNode)
-
 proc nestedBlock(parent: var BasicBlock; kind: TNodeKind): BasicBlock =
  BasicBlock(wasMovedLocs: @[], kind: kind, hasReturn: false, hasBreak: false,
    label: nil, parent: addr(parent))
@@ -65,10 +62,6 @@ proc mergeBasicBlockInfo(parent: var BasicBlock; this: BasicBlock) {.inline.} =
  if this.hasReturn:
    parent.wasMovedLocs.setLen 0
    parent.hasReturn = true
-  elif this.symToDel.len > 0:
-    parent.symToDel = this.symToDel
-    for i in this.symToDel:
-      invalidateWasMoved(parent, i)

 proc wasMovedTarget(matches: var IntSet; branch: seq[PNode]; moveTarget: PNode): bool =
  result = false
@@ -156,7 +149,6 @@ proc analyse(c: var Con; b: var BasicBlock; n: PNode) =
    # any usage of the location before destruction implies we
    # cannot elide the 'wasMoved(x)':
    b.invalidateWasMoved n
-    b.symToDel.add n

  of nkNone..pred(nkSym), succ(nkSym)..nkNilLit, nkTypeSection, nkProcDef, nkConverterDef,
      nkMethodDef, nkIteratorDef, nkMacroDef, nkTemplateDef, nkLambda, nkDo,
--- a/compiler/options.nim
+++ b/compiler/options.nim
@@ -25,7 +25,7 @@ const
  useEffectSystem* = true
  useWriteTracking* = false
  hasFFI* = defined(nimHasLibFFI)
-  copyrightYear* = "2026"
+  copyrightYear* = "2025"

  nimEnableCovariance* = defined(nimEnableCovariance)

@@ -68,7 +68,6 @@ type                          # please make sure we have under 32 options
    optUseNimcache,           # save artifacts (including binary) in $nimcache
    optStyleHint,             # check that the names adhere to NEP-1
    optStyleError,            # enforce that the names adhere to NEP-1
-    optStyleWarning,          # emit style checks as warnings
    optStyleUsages,           # only enforce consistent **usages** of the symbol
    optSkipSystemConfigFile,  # skip the system's cfg/nims config file
    optSkipProjConfigFile,    # skip the project's cfg/nims config file
@@ -111,10 +110,6 @@ type                          # please make sure we have under 32 options
    optEnableDeepCopy         # ORC specific: enable 'deepcopy' for all types.
    optShowNonExportedFields  # for documentation: show fields that are not exported
    optJsBigInt64             # use bigints for 64-bit integers in JS
-    optDocRaw                 # for documentation: Don't render markdown for JSON output
-    optItaniumMangle          # mangling follows the Itanium spec
-    optCompress               # turn on AST compression by converting it to NIF
-    optWithinConfigSystem     # we still compile within the configuration system

  TGlobalOptions* = set[TGlobalOption]

@@ -144,7 +139,6 @@ type
    backendCpp = "cpp"
    backendJs = "js"
    backendObjc = "objc"
-    backendNif = "nif"
    # backendNimscript = "nimscript" # this could actually work
    # backendLlvm = "llvm" # probably not well supported; was cmdCompileToLLVM

@@ -157,6 +151,7 @@ type
    cmdCheck # semantic checking for whole project
    cmdM     # only compile a single
    cmdParse # parse a single file (for debugging)
+    cmdRod # .rod to some text representation (for debugging)
    cmdIdeTools # ide tools (e.g. nimsuggest)
    cmdNimscript # evaluate nimscript
    cmdDoc0
@@ -176,13 +171,10 @@ type
    cmdNop
    cmdJsonscript # compile a .json build file
    # old unused: cmdInterpret, cmdDef: def feature (find definition for IDEs)
-    cmdCompileToNif
-    cmdNifC  # generate C code from NIF files
-    cmdIc  # generate .build.nif for nifmake

 const
  cmdBackends* = {cmdCompileToC, cmdCompileToCpp, cmdCompileToOC,
-                  cmdCompileToJS, cmdCrun, cmdCompileToNif}
+                  cmdCompileToJS, cmdCrun}
  cmdDocLike* = {cmdDoc0, cmdDoc, cmdDoc2tex, cmdJsondoc0, cmdJsondoc,
                 cmdCtags, cmdBuildindex}

@@ -195,7 +187,6 @@ type
    gcRegions = "regions"
    gcArc = "arc"
    gcOrc = "orc"
-    gcYrc = "yrc"       # thread-safe ORC (concurrent cycle collector)
    gcAtomicArc = "atomicArc"
    gcMarkAndSweep = "markAndSweep"
    gcHooks = "hooks"
@@ -257,8 +248,6 @@ type
      ## Useful for libraries that rely on local passC
    jsNoLambdaLifting
      ## Old transformation for closures in JS backend
-    noPanicOnExcept
-      ## don't panic on bare except

  SymbolFilesOption* = enum
    disabledSf, writeOnlySf, readOnlySf, v2Sf, stressTest
@@ -371,7 +360,6 @@ type
    numberOfProcessors*: int   # number of processors
    lastCmdTime*: float        # when caas is enabled, we measure each command
    symbolFiles*: SymbolFilesOption
-    ic*: bool # whether ic is enabled
    spellSuggestMax*: int # max number of spelling suggestions for typos

    cppDefines*: HashSet[string] # (*)
@@ -414,7 +402,6 @@ type
    projectPath*: AbsoluteDir # holds a path like /home/alice/projects/nim/compiler/
    projectFull*: AbsoluteFile # projectPath/projectName
    projectIsStdin*: bool # whether we're compiling from stdin
-    stdinFile*: AbsoluteFile # Filename to use in messages for stdin
    lastMsgWasDot*: set[StdOrrKind] # the last compiler message was a single '.'
    projectMainIdx*: FileIndex # the canonical path id of the main module
    projectMainIdx2*: FileIndex # consider merging with projectMainIdx
@@ -516,7 +503,7 @@ const
    optHints, optStackTrace, optLineTrace, # consider adding `optStackTraceMsgs`
    optTrMacros, optStyleCheck, optCursorInference}
  DefaultGlobalOptions* = {optThreadAnalysis, optExcessiveStackTrace,
-    optJsBigInt64, optItaniumMangle}
+    optJsBigInt64}

 proc getSrcTimestamp(): DateTime =
  try:
@@ -591,7 +578,6 @@ proc newConfigRef*(): ConfigRef =
    projectPath: AbsoluteDir"", # holds a path like /home/alice/projects/nim/compiler/
    projectFull: AbsoluteFile"", # projectPath/projectName
    projectIsStdin: false, # whether we're compiling from stdin
-    stdinFile: AbsoluteFile"stdinfile",
    projectMainIdx: FileIndex(0'i32), # the canonical path id of the main module
    command: "", # the main command (e.g. cc, check, scan, etc)
    commandArgs: @[], # any arguments after the main command
@@ -1048,9 +1034,6 @@ proc isDynlibOverride*(conf: ConfigRef; lib: string): bool =
 proc showNonExportedFields*(conf: ConfigRef) =
  incl(conf.globalOptions, optShowNonExportedFields)

-proc docRawOutput*(conf: ConfigRef) =
-  incl(conf.globalOptions, optDocRaw)
-
 proc expandDone*(conf: ConfigRef): bool =
  result = conf.ideCmd == ideExpand and conf.expandLevels == 0 and conf.expandProgress

--- a/compiler/packages.nim
+++ b/compiler/packages.nim
@@ -33,7 +33,7 @@ proc getPackage*(conf: ConfigRef; cache: IdentCache; fileIdx: FileIndex): PSym =
    pkgIdent = getIdent(cache, pkgName)
  newSym(skPackage, pkgIdent, idGeneratorForPackage(int32(fileIdx)), nil, info)

-proc getPackageSymbol*(sym: PSym): PSym =
+func getPackageSymbol*(sym: PSym): PSym =
  ## Return the owning package symbol.
  assert sym != nil
  result = sym
@@ -41,18 +41,18 @@ proc getPackageSymbol*(sym: PSym): PSym =
    result = result.owner
    assert result != nil, repr(sym.info)

-proc getPackageId*(sym: PSym): int =
+func getPackageId*(sym: PSym): int =
  ## Return the owning package ID.
  sym.getPackageSymbol.id

-proc belongsToProjectPackage*(conf: ConfigRef, sym: PSym): bool =
+func belongsToProjectPackage*(conf: ConfigRef, sym: PSym): bool =
  ## Return whether the symbol belongs to the project's package.
  ##
  ## See Also:
  ## * `modulegraphs.belongsToStdlib`
  conf.mainPackageId == sym.getPackageId

-proc belongsToProjectPackageMaybeNil*(conf: ConfigRef, sym: PSym): bool =
+func belongsToProjectPackageMaybeNil*(conf: ConfigRef, sym: PSym): bool =
  ## Return whether the symbol belongs to the project's package.
  ## Returns `false` if `sym` is nil.
  ##
--- a/compiler/parampatterns.nim
+++ b/compiler/parampatterns.nim
@@ -13,7 +13,7 @@
 import ast, types, msgs, idents, renderer, wordrecg, trees,
  options

-import std/[strutils, assertions]
+import std/strutils

 # we precompile the pattern here for efficiency into some internal
 # stack based VM :-) Why? Because it's fun; I did no benchmarks to see if that
@@ -216,11 +216,6 @@ proc exprRoot*(n: PNode; allowCalls = true): PSym =
    else:
      break

-proc isAssignable*(owner: PSym, n: PNode): TAssignableResult
-
-proc isLentableBranch(owner: PSym, n: PNode): bool =
-  result = isAssignable(owner, n) in {arLentValue, arAddressableConst, arLentValue}
-
 proc isAssignable*(owner: PSym, n: PNode): TAssignableResult =
  ## 'owner' can be nil!
  result = arNone
@@ -313,35 +308,6 @@ proc isAssignable*(owner: PSym, n: PNode): TAssignableResult =
    # nkVarTy denotes an lvalue, but the example above is the only
    # possible code which will get us here
    result = arLValue
-  of nkIfExpr, nkIfStmt:
-    # allow 'if' expressions to be lent if all branches are lentable
-    for branch in n:
-      if branch.len == 2:
-        if not isLentableBranch(owner, branch[1]):
-          return
-      elif branch.len == 1:
-        if not isLentableBranch(owner, branch[0]):
-          return
-      else:
-        raiseAssert "Malformed `if` statement in isAssignable"
-    result = arLentValue
-  of nkCaseStmt:
-    # allow 'case' expressions to be lent if all branches are lentable
-    for i in 1 ..< n.len:
-      let branch = n[i]
-      case branch.kind
-      of nkOfBranch:
-        if not isLentableBranch(owner, branch[^1]):
-          return
-      of nkElifBranch:
-        if not isLentableBranch(owner, branch[1]):
-          return
-      of nkElse:
-        if not isLentableBranch(owner, branch[0]):
-          return
-      else:
-        raiseAssert "Malformed `case` statement in isAssignable"
-    result = arLentValue
  else:
    discard

--- a/compiler/parser.nim
+++ b/compiler/parser.nim
@@ -638,9 +638,8 @@ proc semiStmtList(p: var Parser, result: PNode) =
        getTok(p)
      if p.tok.tokType == tkParRi:
        break
-      # ignore indent:
-      #elif not (sameOrNoInd(p) or realInd(p)):
-      #  parMessage(p, errInvalidIndentation)
+      elif not (sameInd(p) or realInd(p)):
+        parMessage(p, errInvalidIndentation)
      let a = complexOrSimpleStmt(p)
      if a.kind == nkEmpty:
        parMessage(p, errExprExpected, p.tok)
@@ -700,12 +699,10 @@ proc parsePar(p: var Parser): PNode =
      asgn.add b
      result.add(asgn)
      if p.tok.tokType == tkSemiColon:
-        getTok(p)
        semiStmtList(p, result)
    elif p.tok.tokType == tkSemiColon:
      # stmt context:
      result.add(a)
-      getTok(p)
      semiStmtList(p, result)
    else:
      a = colonOrEquals(p, a)
@@ -1156,10 +1153,7 @@ proc parseParamList(p: var Parser, retColon = true): PNode =
        parMessage(p, errGenerated, "the syntax is 'parameter: var T', not 'var parameter: T'")
        break
      else:
-        if p.tok.tokType in tokKeywordLow..tokKeywordHigh:
-          parMessage(p, errGenerated, "'" & $p.tok.ident.s & "' is a keyword and cannot be used as a parameter name")
-        else:
-          parMessage(p, "expected closing ')'")
+        parMessage(p, "expected closing ')'")
        break
      result.add(a)
      if p.tok.tokType notin {tkComma, tkSemiColon}: break
@@ -2113,28 +2107,12 @@ proc parseObjectCase(p: var Parser): PNode =
  #| objectBranches = objectBranch (IND{=} objectBranch)*
  #|                       (IND{=} 'elif' expr colcom objectPart)*
  #|                       (IND{=} 'else' colcom objectPart)?
-  #| objectCase = 'case' (declColonEquals / pragma)? ':'? COMMENT?
+  #| objectCase = 'case' declColonEquals ':'? COMMENT?
  #|             (IND{>} objectBranches DED
  #|             | IND{=} objectBranches)
  result = newNodeP(nkRecCase, p)
-  getTok(p)
-  if p.tok.tokType != tkOf:
-    # of case will be handled later
-    if p.tok.indent >= 0: parMessage(p, errInvalidIndentation)
-  var a: PNode
-  if p.tok.tokType in {tkSymbol, tkAccent}:
-    a = parseIdentColonEquals(p, {withPragma})
-  else:
-    a = newNodeP(nkIdentDefs, p)
-    if p.tok.tokType == tkCurlyDotLe:
-      var prag = newNodeP(nkPragmaExpr, p)
-      prag.add(p.emptyNode)
-      prag.add(parsePragma(p))
-      a.add(prag)
-    else:
-      a.add(p.emptyNode)
-    a.add(p.emptyNode)
-    a.add(p.emptyNode)
+  getTokNoInd(p)
+  var a = parseIdentColonEquals(p, {withPragma})
  result.add(a)
  if p.tok.tokType == tkColon: getTok(p)
  flexComment(p, result)
--- a/compiler/passes.nim
+++ b/compiler/passes.nim
@@ -148,6 +148,11 @@ proc processModule*(graph: ModuleGraph; module: PSym; idgen: IdGenerator;
    closeParser(p)
    if s.kind != llsStdIn: break
  closePasses(graph, a)
+  if graph.config.backend notin {backendC, backendCpp, backendObjc}:
+    # We only write rod files here if no C-like backend is active.
+    # The C-like backends have been patched to support the IC mechanism.
+    # They are responsible for closing the rod files. See `cbackend.nim`.
+    closeRodFile(graph, module)
  result = true

 proc compileModule*(graph: ModuleGraph; fileIdx: FileIndex; flags: TSymFlags, fromModule: PSym = nil): PSym =
@@ -163,12 +168,24 @@ proc compileModule*(graph: ModuleGraph; fileIdx: FileIndex; flags: TSymFlags, fr
      elif graph.config.projectIsCmd: s = llStreamOpen(graph.config.cmdInput)
    discard processModule(graph, result, idGeneratorFromModule(result), s)
  if result == nil:
-    result = newModule(graph, fileIdx)
-    result.incl flags
-    registerModule(graph, result)
-    processModuleAux("import")
+    var cachedModules: seq[FileIndex] = @[]
+    result = moduleFromRodFile(graph, fileIdx, cachedModules)
+    let filename = AbsoluteFile toFullPath(graph.config, fileIdx)
+    if result == nil:
+      result = newModule(graph, fileIdx)
+      result.flags.incl flags
+      registerModule(graph, result)
+      processModuleAux("import")
+    else:
+      if sfSystemModule in flags:
+        graph.systemModule = result
+      partialInitModule(result, graph, fileIdx, filename)
+    for m in cachedModules:
+      registerModuleById(graph, m)
+      replayStateChanges(graph.packed.pm[m.int].module, graph)
+      replayGenericCacheInformation(graph, m.int)
  elif graph.isDirty(result):
-    result.excl sfDirty
+    result.flags.excl sfDirty
    # reset module fields:
    initStrTables(graph, result)
    result.ast = nil
--- a/compiler/patterns.nim
+++ b/compiler/patterns.nim
@@ -77,7 +77,7 @@ proc inSymChoice(sc, x: PNode): bool =
    result = false
    for i in 0..<sc.len:
      if sc[i].sym == x.sym: return true
-  elif sc.kind in {nkOpenSymChoice, nkOpenSym}:
+  elif sc.kind == nkOpenSymChoice:
    # same name suffices for open sym choices!
    result = sc[0].sym.name.id == x.sym.name.id
  else:
--- a/compiler/pipelines.nim
+++ b/compiler/pipelines.nim
@@ -1,12 +1,7 @@
 import sem, cgen, modulegraphs, ast, llstream, parser, msgs,
       lineinfos, reorder, options, semdata, cgendata, modules, pathutils,
       packages, syntaxes, depends, vm, pragmas, idents, lookups, wordrecg,
-       liftdestructors, nifgen
-
-when not defined(nimKochBootstrap):
-  import vmdef
-  import ast2nif
-  import "../dist/nimony/src/lib" / [nifstreams, bitabs]
+       liftdestructors

 import pipelineutils

@@ -28,10 +23,6 @@ proc processPipeline(graph: ModuleGraph; semNode: PNode; bModule: PPassContext):
    result = semNode
    if bModule != nil:
      genTopLevelStmt(BModule(bModule), result)
-  of NifgenPass:
-    result = semNode
-    if bModule != nil:
-      genTopLevelNif(bModule, result)
  of JSgenPass:
    when not defined(leanCompiler):
      result = processJSCodeGen(bModule, semNode)
@@ -40,12 +31,7 @@ proc processPipeline(graph: ModuleGraph; semNode: PNode; bModule: PPassContext):
  of GenDependPass:
    result = addDotDependency(bModule, semNode)
  of SemPass:
-    # Return the semantic node for cmdM (NIF generation needs it)
-    # For regular check, we don't need the result
-    if graph.config.cmd == cmdM:
-      result = semNode
-    else:
-      result = graph.emptyNode
+    result = graph.emptyNode
  of Docgen2Pass, Docgen2TexPass:
    when not defined(leanCompiler):
      result = processNode(bModule, semNode)
@@ -62,8 +48,7 @@ proc processPipeline(graph: ModuleGraph; semNode: PNode; bModule: PPassContext):
    raiseAssert "use setPipeLinePass to set a proper PipelinePass"

 proc processImplicitImports*(graph: ModuleGraph; implicits: seq[string], nodeKind: TNodeKind,
-                             m: PSym, ctx: PContext, bModule: PPassContext, idgen: IdGenerator;
-                             topLevelStmts: PNode) =
+                             m: PSym, ctx: PContext, bModule: PPassContext, idgen: IdGenerator) =
  # XXX fixme this should actually be relative to the config file!
  let relativeTo = toFullPath(graph.config, m.info)
  for module in items(implicits):
@@ -75,13 +60,8 @@ proc processImplicitImports*(graph: ModuleGraph; implicits: seq[string], nodeKin
      importStmt.add str
      message(graph.config, importStmt.info, hintProcessingStmt, $idgen[])
      let semNode = semWithPContext(ctx, importStmt)
-      if semNode == nil:
+      if semNode == nil or processPipeline(graph, semNode, bModule) == nil:
        break
-      let top = processPipeline(graph, semNode, bModule)
-      if top == nil:
-        break
-      if topLevelStmts != nil:
-        topLevelStmts.add top

 proc prePass*(c: PContext; n: PNode) =
  for son in n:
@@ -103,7 +83,7 @@ proc prePass*(c: PContext; n: PNode) =
                let feature = parseEnum[Feature](name.strVal)
                if feature == codeReordering:
                  c.features.incl feature
-                  c.module.incl sfReorder
+                  c.module.flags.incl sfReorder
              except ValueError:
                discard
            else:
@@ -151,8 +131,6 @@ proc processPipelineModule*(graph: ModuleGraph; module: PSym; idgen: IdGenerator
        nil
    of SemPass:
      nil
-    of NifgenPass:
-      setupNifgen(graph, module, idgen)
    of NonePass:
      raiseAssert "use setPipeLinePass to set a proper PipelinePass"

@@ -166,11 +144,6 @@ proc processPipelineModule*(graph: ModuleGraph; module: PSym; idgen: IdGenerator
  else:
    s = stream
    graph.interactive = stream.kind == llsStdIn
-  var topLevelStmts =
-    if optCompress in graph.config.globalOptions or graph.config.cmd == cmdM:
-      newNodeI(nkStmtList, module.info)
-    else:
-      nil
  while true:
    syntaxes.openParser(p, fileIdx, s, graph.cache, graph.config)

@@ -180,8 +153,8 @@ proc processPipelineModule*(graph: ModuleGraph; module: PSym; idgen: IdGenerator
      # in ROD files. I think we should enable this feature only
      # for the interactive mode.
      if module.name.s != "nimscriptapi":
-        processImplicitImports graph, graph.config.implicitImports, nkImportStmt, module, ctx, bModule, idgen, topLevelStmts
-        processImplicitImports graph, graph.config.implicitIncludes, nkIncludeStmt, module, ctx, bModule, idgen, topLevelStmts
+        processImplicitImports graph, graph.config.implicitImports, nkImportStmt, module, ctx, bModule, idgen
+        processImplicitImports graph, graph.config.implicitIncludes, nkIncludeStmt, module, ctx, bModule, idgen

    checkFirstLineIndentation(p)
    block processCode:
@@ -202,9 +175,7 @@ proc processPipelineModule*(graph: ModuleGraph; module: PSym; idgen: IdGenerator
      if graph.pipelinePass != EvalPass:
        message(graph.config, sl.info, hintProcessingStmt, $idgen[])
      var semNode = semWithPContext(ctx, sl)
-      let top = processPipeline(graph, semNode, bModule)
-      if top != nil and topLevelStmts != nil:
-        topLevelStmts.add top
+      discard processPipeline(graph, semNode, bModule)

    closeParser(p)
    if s.kind != llsStdIn: break
@@ -221,7 +192,7 @@ proc processPipelineModule*(graph: ModuleGraph; module: PSym; idgen: IdGenerator
          if retTyp != nil:
            # TODO: properly semcheck the code of dispatcher?
            createTypeBoundOps(graph, ctx, retTyp, disp.ast.info, idgen)
-          genProcLvl3(m, disp)
+          genProcAux(m, disp)
        discard closePContext(graph, ctx, nil)
  of JSgenPass:
    when not defined(leanCompiler):
@@ -236,31 +207,14 @@ proc processPipelineModule*(graph: ModuleGraph; module: PSym; idgen: IdGenerator
  of Docgen2JsonPass:
    when not defined(leanCompiler):
      discard closeJson(graph, bModule, finalNode)
-  of NifgenPass:
-    closeNif(graph, bModule, finalNode)
  of NonePass:
    raiseAssert "use setPipeLinePass to set a proper PipelinePass"

-  when not defined(nimKochBootstrap):
-    # For cmdM: only write NIF for the main module, not for imported modules
-    # (imported modules should be loaded from existing NIF files)
-    let shouldWriteNif = (optCompress in graph.config.globalOptions) or
-                         (graph.config.cmd == cmdM and sfMainModule in module.flags)
-    if shouldWriteNif and not graph.config.isDefined("nimscript"):
-      topLevelStmts.add finalNode
-      # Collect replay actions from both pragma computations and VM state diff
-      var replayActions: seq[PNode] = @[]
-      # Get pragma-recorded replay actions (compile, link, passC, passL, etc.)
-      if graph.nifReplayActions.hasKey(module.position.int32):
-        replayActions.add graph.nifReplayActions[module.position.int32]
-      # Also get VM state diff (macro cache operations)
-      if graph.vm != nil:
-        for (m, n) in PCtx(graph.vm).vmstateDiff:
-          if m == module:
-            replayActions.add n
-
-      writeNifModule(graph.config, module.position.int32, topLevelStmts, graph.opsLog, replayActions)
-
+  if graph.config.backend notin {backendC, backendCpp, backendObjc}:
+    # We only write rod files here if no C-like backend is active.
+    # The C-like backends have been patched to support the IC mechanism.
+    # They are responsible for closing the rod files. See `cbackend.nim`.
+    closeRodFile(graph, module)
  result = true

 proc compilePipelineModule*(graph: ModuleGraph; fileIdx: FileIndex; flags: TSymFlags; fromModule: PSym = nil): PSym =
@@ -276,50 +230,34 @@ proc compilePipelineModule*(graph: ModuleGraph; fileIdx: FileIndex; flags: TSymF
      elif graph.config.projectIsCmd: s = llStreamOpen(graph.config.cmdInput)
    discard processPipelineModule(graph, result, idGeneratorFromModule(result), s)
  if result == nil:
-    when not defined(nimKochBootstrap):
-      # For cmdM: load imports from NIF files (but compile the main module from source)
-      # Skip when withinSystem is true (compiling system.nim itself)
-      if graph.config.cmd == cmdM and
-         sfMainModule notin flags and
-         not graph.withinSystem and
-         not graph.config.isDefined("nimscript"):
-        let precomp = moduleFromNifFile(graph, fileIdx)
-        if precomp.module == nil:
-          let nifPath = toNifFilename(graph.config, fileIdx)
-          globalError(graph.config, unknownLineInfo,
-            "nim m requires precompiled NIF for import: " & toFullPath(graph.config, fileIdx) &
-            " (expected: " & nifPath & ")")
-          return nil  # Don't fall through to compile from source
-        else:
-          # Module successfully loaded from NIF file - use it and skip processing
-          result = precomp.module
-          if sfSystemModule in flags:
-            graph.systemModule = result
-          partialInitModule(result, graph, fileIdx, AbsoluteFile(toFullPath(graph.config, fileIdx)))
-          # Replay state changes from the loaded NIF module
-          if result.ast != nil:
-            replayStateChanges(result, graph)
-          return result  # Return early, don't process from source
+    var cachedModules: seq[FileIndex] = @[]
+    result = moduleFromRodFile(graph, fileIdx, cachedModules)
    let path = toFullPath(graph.config, fileIdx)
    let filename = AbsoluteFile path
-    # it could be a stdinfile/cmdfile
-    if fileExists(filename) and not graph.config.projectIsStdin:
+    if fileExists(filename): # it could be a stdinfile
      graph.cachedFiles[path] = $secureHashFile(path)
    if result == nil:
      result = newModule(graph, fileIdx)
-      result.incl flags
+      result.flags.incl flags
      registerModule(graph, result)
      processModuleAux("import")
    else:
      if sfSystemModule in flags:
        graph.systemModule = result
      if sfMainModule in flags and graph.config.cmd == cmdM:
-        result.incl flags
+        result.flags.incl flags
        registerModule(graph, result)
        processModuleAux("import")
      partialInitModule(result, graph, fileIdx, filename)
+    for m in cachedModules:
+      registerModuleById(graph, m)
+      if sfMainModule in flags and graph.config.cmd == cmdM:
+        discard
+      else:
+        replayStateChanges(graph.packed.pm[m.int].module, graph)
+        replayGenericCacheInformation(graph, m.int)
  elif graph.isDirty(result):
-    result.excl sfDirty
+    result.flags.excl sfDirty
    # reset module fields:
    initStrTables(graph, result)
    result.ast = nil
@@ -347,12 +285,10 @@ proc connectPipelineCallbacks*(graph: ModuleGraph) =

 proc compilePipelineSystemModule*(graph: ModuleGraph) =
  if graph.systemModule == nil:
-    graph.withinSystem = true
    connectPipelineCallbacks(graph)
    graph.config.m.systemFileIdx = fileInfoIdx(graph.config,
        graph.config.libpath / RelativeFile"system.nim")
    discard graph.compilePipelineModule(graph.config.m.systemFileIdx, {sfSystemModule})
-    graph.withinSystem = false

 proc compilePipelineProject*(graph: ModuleGraph; projectFileIdx = InvalidFileIdx) =
  connectPipelineCallbacks(graph)
@@ -369,23 +305,7 @@ proc compilePipelineProject*(graph: ModuleGraph; projectFileIdx = InvalidFileIdx
  graph.importStack.add projectFile

  if projectFile == systemFileIdx:
-    graph.withinSystem = true
    discard graph.compilePipelineModule(projectFile, {sfMainModule, sfSystemModule})
-    graph.withinSystem = false
-  elif graph.config.cmd == cmdM:
-    # For cmdM: load system.nim from NIF first, then compile the main module
-    connectPipelineCallbacks(graph)
-    graph.config.m.systemFileIdx = fileInfoIdx(graph.config,
-        graph.config.libpath / RelativeFile"system.nim")
-    when not defined(nimKochBootstrap):
-      let precomp = moduleFromNifFile(graph, graph.config.m.systemFileIdx)
-      graph.systemModule = precomp.module
-      if graph.systemModule == nil:
-        let nifPath = toNifFilename(graph.config, graph.config.m.systemFileIdx)
-        localError(graph.config, unknownLineInfo,
-          "nim m requires precompiled NIF for system module (expected: " & nifPath & ")")
-        return
-    discard graph.compilePipelineModule(projectFile, {sfMainModule})
  else:
    graph.compilePipelineSystemModule()
    discard graph.compilePipelineModule(projectFile, {sfMainModule})
--- a/compiler/platform.nim
+++ b/compiler/platform.nim
@@ -210,8 +210,8 @@ type
    cpuNone, cpuI386, cpuM68k, cpuAlpha, cpuPowerpc, cpuPowerpc64,
    cpuPowerpc64el, cpuSparc, cpuVm, cpuHppa, cpuIa64, cpuAmd64, cpuMips,
    cpuMipsel, cpuArm, cpuArm64, cpuJS, cpuNimVM, cpuAVR, cpuMSP430,
-    cpuSparc64, cpuS390x, cpuMips64, cpuMips64el, cpuRiscV32, cpuRiscV64,
-    cpuEsp, cpuWasm32, cpuE2k, cpuLoongArch64
+    cpuSparc64, cpuMips64, cpuMips64el, cpuRiscV32, cpuRiscV64, cpuEsp, cpuWasm32,
+    cpuE2k, cpuLoongArch64

 type
  TInfoCPU* = tuple[name: string, intSize: int, endian: Endianness,
@@ -241,7 +241,6 @@ const
    (name: "avr", intSize: 16, endian: littleEndian, floatSize: 32, bit: 16),
    (name: "msp430", intSize: 16, endian: littleEndian, floatSize: 32, bit: 16),
    (name: "sparc64", intSize: 64, endian: bigEndian, floatSize: 64, bit: 64),
-    (name: "s390x", intSize: 64, endian: bigEndian, floatSize: 64, bit: 64),
    (name: "mips64", intSize: 64, endian: bigEndian, floatSize: 64, bit: 64),
    (name: "mips64el", intSize: 64, endian: littleEndian, floatSize: 64, bit: 64),
    (name: "riscv32", intSize: 32, endian: littleEndian, floatSize: 64, bit: 32),
--- a/compiler/plugins/itersgen.nim
+++ b/compiler/plugins/itersgen.nim
@@ -33,7 +33,7 @@ proc iterToProcImpl*(c: PContext, n: PNode): PNode =

  let prc = newSym(skProc, n[3].ident, c.idgen, iter.sym.owner, iter.sym.info)
  prc.typ = copyType(iter.sym.typ, c.idgen, prc)
-  excl prc.typ, tfCapturesEnv
+  excl prc.typ.flags, tfCapturesEnv
  prc.typ.n.add newSymNode(getEnvParam(iter.sym))
  prc.typ.rawAddSon t
  let orig = iter.sym.ast
--- a/compiler/pragmas.nim
+++ b/compiler/pragmas.nim
@@ -21,6 +21,8 @@ import std/[os, math, strutils]
 when defined(nimPreviewSlimSystem):
  import std/assertions

+from ic / ic import addCompilerProc
+
 const
  FirstCallConv* = wNimcall
  LastCallConv* = wNoconv
@@ -105,7 +107,7 @@ proc getPragmaVal*(procAst: PNode; name: TSpecialWord): PNode =
      return it[1]

 proc pragma*(c: PContext, sym: PSym, n: PNode, validPragmas: TSpecialWords;
-            isStatement: bool = false; comesFromPush = false)
+            isStatement: bool = false)

 proc recordPragma(c: PContext; n: PNode; args: varargs[string]) =
  var recorded = newNodeI(nkReplayAction, n.info)
@@ -146,7 +148,7 @@ proc pragmaEnsures(c: PContext, n: PNode) =
    if o.kind in routineKinds and o.typ != nil and o.typ.returnType != nil:
      var s = newSym(skResult, getIdent(c.cache, "result"), c.idgen, o, n.info)
      s.typ = o.typ.returnType
-      incl(s.flagsImpl, sfUsed)
+      incl(s.flags, sfUsed)
      addDecl(c, s)
    n[1] = c.semExpr(c, n[1])
    closeScope(c)
@@ -154,12 +156,12 @@ proc pragmaEnsures(c: PContext, n: PNode) =
 proc setExternName(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  # special cases to improve performance:
  if extname == "$1":
-    s.setSnippet(rope(s.name.s))
+    s.loc.snippet = rope(s.name.s)
  elif '$' notin extname:
-    s.setSnippet(rope(extname))
+    s.loc.snippet = rope(extname)
  else:
    try:
-      s.setSnippet(rope(extname % s.name.s))
+      s.loc.snippet = rope(extname % s.name.s)
    except ValueError:
      localError(c.config, info, "invalid extern name: '" & extname & "'. (Forgot to escape '$'?)")
  when hasFFI:
@@ -168,36 +170,36 @@ proc setExternName(c: PContext; s: PSym, extname: string, info: TLineInfo) =

 proc makeExternImport(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  setExternName(c, s, extname, info)
-  s.incl(sfImportc)
-  s.excl(sfForward)
+  incl(s.flags, sfImportc)
+  excl(s.flags, sfForward)

 proc makeExternExport(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  setExternName(c, s, extname, info)
-  s.incl(sfExportc)
+  incl(s.flags, sfExportc)

 proc processImportCompilerProc(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  setExternName(c, s, extname, info)
-  s.incl(sfImportc)
-  s.excl(sfForward)
-  incl(s.locImpl.flags, lfImportCompilerProc)
+  incl(s.flags, sfImportc)
+  excl(s.flags, sfForward)
+  incl(s.loc.flags, lfImportCompilerProc)

 proc processImportCpp(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  setExternName(c, s, extname, info)
-  s.incl(sfImportc)
-  incl(s.flagsImpl, sfInfixCall)
-  excl(s.flagsImpl, sfForward)
+  incl(s.flags, sfImportc)
+  incl(s.flags, sfInfixCall)
+  excl(s.flags, sfForward)
  if c.config.backend == backendC:
    let m = s.getModule()
-    incl(m.flagsImpl, sfCompileToCpp)
+    incl(m.flags, sfCompileToCpp)
  incl c.config.globalOptions, optMixedMode

 proc processImportObjC(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  setExternName(c, s, extname, info)
-  s.incl(sfImportc)
-  incl(s.flagsImpl, sfNamedParamCall)
-  excl(s.flagsImpl, sfForward)
+  incl(s.flags, sfImportc)
+  incl(s.flags, sfNamedParamCall)
+  excl(s.flags, sfForward)
  let m = s.getModule()
-  m.incl(sfCompileToObjc)
+  incl(m.flags, sfCompileToObjc)

 proc newEmptyStrNode(c: PContext; n: PNode, strVal: string = ""): PNode {.noinline.} =
  result = newNodeIT(nkStrLit, n.info, getSysType(c.graph, n.info, tyString))
@@ -237,14 +239,14 @@ proc getOptionalStr(c: PContext, n: PNode, defaultStr: string): string =
 proc processVirtual(c: PContext, n: PNode, s: PSym, flag: TSymFlag) =
  s.constraint = newEmptyStrNode(c, n, getOptionalStr(c, n, "$1"))
  s.constraint.strVal = s.constraint.strVal % s.name.s
-  s.flagsImpl.incl {flag, sfInfixCall, sfExportc, sfMangleCpp}
+  s.flags.incl {flag, sfInfixCall, sfExportc, sfMangleCpp}

  s.typ.callConv = ccMember
  incl c.config.globalOptions, optMixedMode

 proc processCodegenDecl(c: PContext, n: PNode, sym: PSym) =
  sym.constraint = getStrLitNode(c, n)
-  sym.flagsImpl.incl sfCodegenDecl
+  sym.flags.incl sfCodegenDecl

 proc processMagic(c: PContext, n: PNode, s: PSym) =
  #if sfSystemModule notin c.module.flags:
@@ -280,10 +282,10 @@ proc onOff(c: PContext, n: PNode, op: TOptions, resOptions: var TOptions) =

 proc pragmaNoForward*(c: PContext, n: PNode; flag=sfNoForward) =
  if isTurnedOn(c, n):
-    incl(c.module.flagsImpl, flag)
+    incl(c.module.flags, flag)
    c.features.incl codeReordering
  else:
-    excl(c.module.flagsImpl, flag)
+    excl(c.module.flags, flag)
    # c.features.excl codeReordering

  # deprecated as of 0.18.1
@@ -355,9 +357,9 @@ proc processDynLib(c: PContext, n: PNode, sym: PSym) =
      var lib = getLib(c, libDynamic, expectDynlibNode(c, n))
      if not lib.isOverridden:
        addToLib(lib, sym)
-        sym.incl(lfDynamicLib)
+        incl(sym.loc.flags, lfDynamicLib)
    else:
-      sym.incl(lfExportLib)
+      incl(sym.loc.flags, lfExportLib)
    # since we'll be loading the dynlib symbols dynamically, we must use
    # a calling convention that doesn't introduce custom name mangling
    # cdecl is the default - the user can override this explicitly
@@ -433,7 +435,7 @@ proc processExperimental(c: PContext; n: PNode) =
          if not isTopLevel(c):
              localError(c.config, n.info,
                         "Code reordering experimental pragma only valid at toplevel")
-          c.module.flagsImpl.incl sfReorder
+          c.module.flags.incl sfReorder
      except ValueError:
        localError(c.config, n[1].info, "unknown experimental feature")
    else:
@@ -567,7 +569,7 @@ proc processCompile(c: PContext, n: PNode) =
    n[i] = c.semConstExpr(c, n[i])
    case n[i].kind
    of nkStrLit, nkRStrLit, nkTripleStrLit:
-      when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc) or defined(gcYrc):
+      when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc):
        result = n[i].strVal
      else:
        shallowCopy(result, n[i].strVal)
@@ -634,7 +636,7 @@ proc semAsmOrEmit*(con: PContext, n: PNode, marker: char): PNode =
        var e = searchInScopes(con, getIdent(con.cache, sub), amb)
        # XXX what to do here if 'amb' is true?
        if e != nil:
-          incl(e.flagsImpl, sfUsed)
+          incl(e.flags, sfUsed)
          if isDefined(con.config, "nimPreviewAsmSemSymbol"):
            result.add con.semExprWithType(con, newSymNode(e), {efTypeAllowed})
          else:
@@ -723,12 +725,12 @@ proc processPragma(c: PContext, n: PNode, i: int) =
 proc pragmaRaisesOrTags(c: PContext, n: PNode) =
  proc processExc(c: PContext, x: PNode) =
    if c.hasUnresolvedArgs(c, x):
-      x.typ = makeTypeFromExpr(c, x)
+      x.typ() = makeTypeFromExpr(c, x)
    else:
      var t = skipTypes(c.semTypeNode(c, x, nil), skipPtrs)
      if t.kind notin {tyObject, tyOr}:
        localError(c.config, x.info, errGenerated, "invalid type for raises/tags list")
-      x.typ = t
+      x.typ() = t

  if n.kind in nkPragmaCallKinds and n.len == 2:
    let it = n[1]
@@ -755,21 +757,23 @@ proc typeBorrow(c: PContext; sym: PSym, n: PNode) =
    let it = n[1]
    if it.kind != nkAccQuoted:
      localError(c.config, n.info, "a type can only borrow `.` for now")
-  incl(sym.typ, tfBorrowDot)
+  incl(sym.typ.flags, tfBorrowDot)

 proc markCompilerProc(c: PContext; s: PSym) =
  # minor hack ahead: FlowVar is the only generic .compilerproc type which
  # should not have an external name set:
  if s.kind != skType or s.name.s != "FlowVar":
    makeExternExport(c, s, "$1", s.info)
-  incl(s, sfCompilerProc)
-  incl(s.flagsImpl, sfUsed)
+  incl(s.flags, sfCompilerProc)
+  incl(s.flags, sfUsed)
  registerCompilerProc(c.graph, s)
+  if c.config.symbolFiles != disabledSf:
+    addCompilerProc(c.encoder, c.packedRepr, s)

 proc deprecatedStmt(c: PContext; outerPragma: PNode) =
  let pragma = outerPragma[1]
  if pragma.kind in {nkStrLit..nkTripleStrLit}:
-    incl(c.module, sfDeprecated)
+    incl(c.module.flags, sfDeprecated)
    c.module.constraint = getStrLitNode(c, outerPragma)
    return
  if pragma.kind != nkBracket:
@@ -838,7 +842,7 @@ proc processEffectsOf(c: PContext, n: PNode; owner: PSym) =
    let r = c.semExpr(c, n)
    if r.kind == nkSym and r.sym.kind == skParam:
      if r.sym.owner == owner:
-        incl r.sym, sfEffectsDelayed
+        incl r.sym.flags, sfEffectsDelayed
      else:
        localError(c.config, n.info, errGenerated, "parameter cannot be declared as .effectsOf")
    else:
@@ -889,7 +893,7 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
    if keyDeep:
      localError(c.config, it.info, "user pragma cannot have arguments")

-    pragma(c, sym, userPragma.ast, validPragmas, isStatement, comesFromPush)
+    pragma(c, sym, userPragma.ast, validPragmas, isStatement)
    n.sons[i..i] = userPragma.ast.sons # expand user pragma with its content
    i.inc(userPragma.ast.len - 1) # inc by -1 is ok, user pragmas was empty
  else:
@@ -903,8 +907,8 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
          if c.config.backend != backendCpp:
            localError(c.config, it.info, "exportcpp requires `cpp` backend, got: " & $c.config.backend)
          else:
-            incl(sym, sfMangleCpp)
-        incl(sym.flagsImpl, sfUsed) # avoid wrong hints
+            incl(sym.flags, sfMangleCpp)
+        incl(sym.flags, sfUsed) # avoid wrong hints
      of wImportc:
        let name = getOptionalStr(c, it, "$1")
        cppDefine(c.config, name)
@@ -917,24 +921,24 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
        processImportCompilerProc(c, sym, name, it.info)
      of wExtern: setExternName(c, sym, expectStrLit(c, it), it.info)
      of wDirty:
-        if sym.kind == skTemplate: incl(sym, sfDirty)
+        if sym.kind == skTemplate: incl(sym.flags, sfDirty)
        else: invalidPragma(c, it)
      of wRedefine:
-        if sym.kind == skTemplate: incl(sym, sfTemplateRedefinition)
+        if sym.kind == skTemplate: incl(sym.flags, sfTemplateRedefinition)
        else: invalidPragma(c, it)
      of wCallsite:
-        if sym.kind == skTemplate: incl(sym, sfCallsite)
+        if sym.kind == skTemplate: incl(sym.flags, sfCallsite)
        else: invalidPragma(c, it)
      of wImportCpp:
        processImportCpp(c, sym, getOptionalStr(c, it, "$1"), it.info)
      of wCppNonPod:
-        incl(sym, sfCppNonPod)
+        incl(sym.flags, sfCppNonPod)
      of wImportJs:
        if c.config.backend != backendJs:
          localError(c.config, it.info, "`importjs` pragma requires the JavaScript target")
        let name = getOptionalStr(c, it, "$1")
-        incl(sym, sfImportc)
-        incl(sym.flagsImpl, sfInfixCall)
+        incl(sym.flags, sfImportc)
+        incl(sym.flags, sfInfixCall)
        if sym.kind in skProcKinds and {'(', '#', '@'} notin name:
          localError(c.config, n.info, "`importjs` for routines requires a pattern")
        setExternName(c, sym, name, it.info)
@@ -943,19 +947,15 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
      of wSize:
        if sym.typ == nil: invalidPragma(c, it)
        var size = expectIntLit(c, it)
-        if sfImportc in sym.flags:
-          # no restrictions on size for imported types
-          setImportedTypeSize(c.config, sym.typ, size)
+        case size
+        of 1, 2, 4:
+          sym.typ.size = size
+          sym.typ.align = int16 size
+        of 8:
+          sym.typ.size = 8
+          sym.typ.align = floatInt64Align(c.config)
        else:
-          case size
-          of 1, 2, 4:
-            sym.typ.size = size
-            sym.typ.align = int16 size
-          of 8:
-            sym.typ.size = 8
-            sym.typ.align = floatInt64Align(c.config)
-          else:
-            localError(c.config, it.info, "size may only be 1, 2, 4 or 8")
+          localError(c.config, it.info, "size may only be 1, 2, 4 or 8")
      of wAlign:
        let alignment = expectIntLit(c, it)
        if isPowerOfTwo(alignment) and alignment > 0:
@@ -964,29 +964,29 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
          localError(c.config, it.info, "power of two expected")
      of wNodecl:
        noVal(c, it)
-        sym.incl(lfNoDecl)
+        incl(sym.loc.flags, lfNoDecl)
      of wPure, wAsmNoStackFrame:
        noVal(c, it)
        if sym != nil:
          if k == wPure and sym.kind in routineKinds: invalidPragma(c, it)
-          else: incl(sym, sfPure)
+          else: incl(sym.flags, sfPure)
      of wVolatile:
        noVal(c, it)
-        incl(sym, sfVolatile)
+        incl(sym.flags, sfVolatile)
      of wCursor:
        noVal(c, it)
-        incl(sym, sfCursor)
+        incl(sym.flags, sfCursor)
      of wRegister:
        noVal(c, it)
-        incl(sym, sfRegister)
+        incl(sym.flags, sfRegister)
      of wNoalias:
        noVal(c, it)
-        incl(sym, sfNoalias)
+        incl(sym.flags, sfNoalias)
      of wEffectsOf:
        processEffectsOf(c, it, sym)
      of wThreadVar:
        noVal(c, it)
-        incl(sym, {sfThread, sfGlobal})
+        incl(sym.flags, {sfThread, sfGlobal})
      of wDeadCodeElimUnused:
        warningDeprecated(c.config, n.info, "'{.deadcodeelim: on.}' is deprecated, now a noop")  # deprecated, dead code elim always on
      of wNoForward: pragmaNoForward(c, it)
@@ -996,50 +996,51 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
        noVal(c, it)
        if comesFromPush:
          if sym.kind in {skProc, skFunc}:
-            incl(sym, sfCompileTime)
+            incl(sym.flags, sfCompileTime)
        else:
-          incl(sym, sfCompileTime)
+          incl(sym.flags, sfCompileTime)
        #incl(sym.loc.flags, lfNoDecl)
      of wGlobal:
        noVal(c, it)
-        incl(sym, {sfGlobal, sfPure})
+        incl(sym.flags, sfGlobal)
+        incl(sym.flags, sfPure)
      of wConstructor:
-        incl(sym, sfConstructor)
+        incl(sym.flags, sfConstructor)
        if sfImportc notin sym.flags:
          sym.constraint = newEmptyStrNode(c, it, getOptionalStr(c, it, ""))
          sym.constraint.strVal = sym.constraint.strVal
-          sym.flagsImpl.incl {sfExportc, sfMangleCpp}
+          sym.flags.incl {sfExportc, sfMangleCpp}
          sym.typ.callConv = ccNoConvention
      of wHeader:
        var lib = getLib(c, libHeader, getStrLitNode(c, it))
        addToLib(lib, sym)
-        incl(sym, sfImportc)
-        incl(sym.locImpl.flags, lfHeader)
-        incl(sym.locImpl.flags, lfNoDecl)
+        incl(sym.flags, sfImportc)
+        incl(sym.loc.flags, lfHeader)
+        incl(sym.loc.flags, lfNoDecl)
        # implies nodecl, because otherwise header would not make sense
-        if sym.locImpl.snippet == "": sym.locImpl.snippet = rope(sym.name.s)
+        if sym.loc.snippet == "": sym.loc.snippet = rope(sym.name.s)
      of wNoSideEffect:
        noVal(c, it)
        if sym != nil:
-          incl(sym, sfNoSideEffect)
-          if sym.typ != nil: incl(sym.typ, tfNoSideEffect)
+          incl(sym.flags, sfNoSideEffect)
+          if sym.typ != nil: incl(sym.typ.flags, tfNoSideEffect)
      of wSideEffect:
        noVal(c, it)
-        incl(sym, sfSideEffect)
+        incl(sym.flags, sfSideEffect)
      of wNoreturn:
        noVal(c, it)
        # Disable the 'noreturn' annotation when in the "Quirky Exceptions" mode!
        if c.config.exc != excQuirky:
-          incl(sym, sfNoReturn)
+          incl(sym.flags, sfNoReturn)
        if sym.typ.returnType != nil:
          localError(c.config, sym.ast[paramsPos][0].info,
            ".noreturn with return type not allowed")
      of wNoDestroy:
        noVal(c, it)
-        incl(sym, sfGeneratedOp)
+        incl(sym.flags, sfGeneratedOp)
      of wNosinks:
        noVal(c, it)
-        incl(sym, sfWasForwarded)
+        incl(sym.flags, sfWasForwarded)
      of wDynlib:
        processDynLib(c, it, sym)
      of wCompilerProc, wCore:
@@ -1048,79 +1049,79 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
        recordPragma(c, it, "cppdefine", sym.name.s)
        if sfFromGeneric notin sym.flags: markCompilerProc(c, sym)
      of wNonReloadable:
-        sym.incl sfNonReloadable
+        sym.flags.incl sfNonReloadable
      of wProcVar:
        # old procvar annotation, no longer needed
        noVal(c, it)
      of wExplain:
-        sym.incl sfExplain
+        sym.flags.incl sfExplain
      of wDeprecated:
        if sym != nil and sym.kind in routineKinds + {skType, skVar, skLet, skConst}:
          if it.kind in nkPragmaCallKinds: discard getStrLitNode(c, it)
-          incl(sym, sfDeprecated)
+          incl(sym.flags, sfDeprecated)
        elif sym != nil and sym.kind != skModule:
          # We don't support the extra annotation field
          if it.kind in nkPragmaCallKinds:
            localError(c.config, it.info, "annotation to deprecated not supported here")
-          incl(sym, sfDeprecated)
+          incl(sym.flags, sfDeprecated)
        # At this point we're quite sure this is a statement and applies to the
        # whole module
        elif it.kind in nkPragmaCallKinds: deprecatedStmt(c, it)
-        else: incl(c.module, sfDeprecated)
+        else: incl(c.module.flags, sfDeprecated)
      of wVarargs:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
-        else: incl(sym.typ, tfVarargs)
+        else: incl(sym.typ.flags, tfVarargs)
      of wBorrow:
        if sym.kind == skType:
          typeBorrow(c, sym, it)
        else:
          noVal(c, it)
-          incl(sym, sfBorrow)
+          incl(sym.flags, sfBorrow)
      of wFinal:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
-        else: incl(sym.typ, tfFinal)
+        else: incl(sym.typ.flags, tfFinal)
      of wInheritable:
        noVal(c, it)
        if sym.typ == nil or tfFinal in sym.typ.flags: invalidPragma(c, it)
-        else: incl(sym.typ, tfInheritable)
+        else: incl(sym.typ.flags, tfInheritable)
      of wPackage:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
-        else: incl(sym, sfForward)
+        else: incl(sym.flags, sfForward)
      of wAcyclic:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
-        else: incl(sym.typ, tfAcyclic)
+        else: incl(sym.typ.flags, tfAcyclic)
      of wShallow:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
-        else: incl(sym.typ, tfShallow)
+        else: incl(sym.typ.flags, tfShallow)
      of wThread:
        noVal(c, it)
-        incl(sym, sfThread)
+        incl(sym.flags, sfThread)
        if sym.typ != nil:
-          incl(sym.typ, tfThread)
+          incl(sym.typ.flags, tfThread)
          if sym.typ.callConv == ccClosure: sym.typ.callConv = ccNimCall
      of wSendable:
        noVal(c, it)
        if sym != nil and sym.typ != nil:
-          incl(sym.typ, tfSendable)
+          incl(sym.typ.flags, tfSendable)
        else:
          invalidPragma(c, it)
      of wGcSafe:
        noVal(c, it)
        if sym != nil:
-          if sym.kind != skType: incl(sym, sfThread)
-          if sym.typ != nil: incl(sym.typ, tfGcSafe)
+          if sym.kind != skType: incl(sym.flags, sfThread)
+          if sym.typ != nil: incl(sym.typ.flags, tfGcSafe)
          else: invalidPragma(c, it)
        else:
          discard "no checking if used as a code block"
      of wPacked:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
-        else: incl(sym.typ, tfPacked)
+        else: incl(sym.typ.flags, tfPacked)
      of wHint:
        let s = expectStrLit(c, it)
        recordPragma(c, it, "hint", s)
@@ -1136,8 +1137,8 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
          # distinguish properly between
          # ``proc p() {.error}`` and ``proc p() = {.error: "msg".}``
          if it.kind in nkPragmaCallKinds: discard getStrLitNode(c, it)
-          incl(sym, sfError)
-          excl(sym, sfForward)
+          incl(sym.flags, sfError)
+          excl(sym.flags, sfForward)
        else:
          let s = expectStrLit(c, it)
          recordPragma(c, it, "error", s)
@@ -1147,18 +1148,18 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
      of wUndef: processUndef(c, it)
      of wCompile:
        let m = sym.getModule()
-        incl(m.flagsImpl, sfUsed)
+        incl(m.flags, sfUsed)
        processCompile(c, it)
      of wLink: processLink(c, it)
      of wPassl:
        let m = sym.getModule()
-        incl(m.flagsImpl, sfUsed)
+        incl(m.flags, sfUsed)
        let s = expectStrLit(c, it)
        extccomp.addLinkOption(c.config, s)
        recordPragma(c, it, "passl", s)
      of wPassc:
        let m = sym.getModule()
-        incl(m.flagsImpl, sfUsed)
+        incl(m.flags, sfUsed)
        let s = expectStrLit(c, it)
        extccomp.addCompileOption(c.config, s)
        recordPragma(c, it, "passc", s)
@@ -1176,16 +1177,16 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
        result = true
      of wPragma:
        if not sym.isNil and sym.kind == skTemplate:
-          sym.incl sfCustomPragma
+          sym.flags.incl sfCustomPragma
        else:
          processPragma(c, n, i)
          result = true
      of wDiscardable:
        noVal(c, it)
-        if sym != nil: incl(sym, sfDiscardable)
+        if sym != nil: incl(sym.flags, sfDiscardable)
      of wNoInit:
        noVal(c, it)
-        if sym != nil: incl(sym, sfNoInit)
+        if sym != nil: incl(sym.flags, sfNoInit)
      of wCodegenDecl: processCodegenDecl(c, it, sym)
      of wChecks, wObjChecks, wFieldChecks, wRangeChecks, wBoundChecks,
         wOverflowChecks, wNilChecks, wAssertions, wWarnings, wHints,
@@ -1195,8 +1196,7 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
        processOption(c, it, c.config.options)
      of wStackTrace, wLineTrace:
        if sym.kind in {skProc, skMethod, skConverter}:
-          ensureMutable sym
-          processOption(c, it, sym.optionsImpl)
+          processOption(c, it, sym.options)
        else:
          processOption(c, it, c.config.options)
      of FirstCallConv..LastCallConv:
@@ -1204,7 +1204,7 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
        if sym.typ == nil: invalidPragma(c, it)
        else:
          sym.typ.callConv = wordToCallConv(k)
-          sym.typ.incl tfExplicitCallConv
+          sym.typ.flags.incl tfExplicitCallConv
      of wEmit: pragmaEmit(c, it)
      of wUnroll: pragmaUnroll(c, it)
      of wLinearScanEnd, wComputedGoto: noVal(c, it)
@@ -1214,11 +1214,11 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
      of wIncompleteStruct:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
-        else: incl(sym.typ, tfIncompleteStruct)
+        else: incl(sym.typ.flags, tfIncompleteStruct)
      of wCompleteStruct:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
-        else: incl(sym.typ, tfCompleteStruct)
+        else: incl(sym.typ.flags, tfCompleteStruct)
      of wUnchecked:
        noVal(c, it)
        if sym.typ == nil or sym.typ.kind notin {tyArray, tyUncheckedArray}:
@@ -1231,35 +1231,34 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
        else:
          noVal(c, it)
          if sym.typ == nil: invalidPragma(c, it)
-          else: incl(sym.typ, tfUnion)
+          else: incl(sym.typ.flags, tfUnion)
      of wRequiresInit:
        noVal(c, it)
        if sym.kind == skField:
-          sym.incl sfRequiresInit
+          sym.flags.incl sfRequiresInit
        elif sym.typ != nil:
-          incl(sym.typ, tfNeedsFullInit)
+          incl(sym.typ.flags, tfNeedsFullInit)
        else:
          invalidPragma(c, it)
      of wByRef:
        noVal(c, it)
        if sym != nil and sym.kind == skParam:
-          ensureMutable sym
-          sym.optionsImpl.incl optByRef
+          sym.options.incl optByRef
        elif sym == nil or sym.typ == nil:
          processOption(c, it, c.config.options)
        else:
-          incl(sym.typ, tfByRef)
+          incl(sym.typ.flags, tfByRef)
      of wByCopy:
        noVal(c, it)
        if sym.kind == skParam:
-          incl(sym, sfByCopy)
+          incl(sym.flags, sfByCopy)
        elif sym.kind != skType or sym.typ == nil: invalidPragma(c, it)
-        else: incl(sym.typ, tfByCopy)
+        else: incl(sym.typ.flags, tfByCopy)
      of wPartial:
        noVal(c, it)
        if sym.kind != skType or sym.typ == nil: invalidPragma(c, it)
        else:
-          incl(sym.typ, tfPartial)
+          incl(sym.typ.flags, tfPartial)
      of wInject, wGensym:
        # We check for errors, but do nothing with these pragmas otherwise
        # as they are handled directly in 'evalTemplate'.
@@ -1287,7 +1286,7 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
        if sym == nil or sym.kind notin {skVar, skLet}:
          invalidPragma(c, it)
        else:
-          sym.incl sfGoto
+          sym.flags.incl sfGoto
      of wExportNims:
        if sym == nil: invalidPragma(c, it)
        else: magicsys.registerNimScriptSymbol(c.graph, sym)
@@ -1302,7 +1301,7 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
        noVal(c, it)
      of wBase:
        noVal(c, it)
-        sym.incl sfBase
+        sym.flags.incl sfBase
      of wIntDefine:
        processDefineConst(c, n, sym, mIntDefine)
      of wStrDefine:
@@ -1312,22 +1311,21 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
      of wUsed:
        noVal(c, it)
        if sym == nil: invalidPragma(c, it)
-        else: sym.incl sfUsed
+        else: sym.flags.incl sfUsed
      of wLiftLocals:
-        sym.incl(sfForceLift)
+        sym.flags.incl(sfForceLift)
      of wRequires, wInvariant, wAssume, wAssert:
        pragmaProposition(c, it)
      of wEnsures:
        pragmaEnsures(c, it)
      of wEnforceNoRaises:
-        sym.incl sfNeverRaises
+        sym.flags.incl sfNeverRaises
      of wQuirky:
-        sym.incl sfNeverRaises
+        sym.flags.incl sfNeverRaises
        if sym.kind in {skProc, skMethod, skConverter, skFunc, skIterator}:
-          ensureMutable sym
-          sym.optionsImpl.incl optQuirky
+          sym.options.incl optQuirky
      of wSystemRaisesDefect:
-        sym.incl sfSystemRaisesDefect
+        sym.flags.incl sfSystemRaisesDefect
      of wVirtual:
        processVirtual(c, it, sym, sfVirtual)
      of wMember:
@@ -1384,9 +1382,9 @@ proc implicitPragmas*(c: PContext, sym: PSym, info: TLineInfo,
    var lib = c.optionStack[^1].dynlib
    if {lfDynamicLib, lfHeader} * sym.loc.flags == {} and
        sfImportc in sym.flags and lib != nil:
-      incl(sym, lfDynamicLib)
+      incl(sym.loc.flags, lfDynamicLib)
      addToLib(lib, sym)
-      if sym.locImpl.snippet == "": sym.locImpl.snippet = rope(sym.name.s)
+      if sym.loc.snippet == "": sym.loc.snippet = rope(sym.name.s)

 proc hasPragma*(n: PNode, pragma: TSpecialWord): bool =
  if n == nil: return false
@@ -1407,12 +1405,11 @@ proc pragmaRec(c: PContext, sym: PSym, n: PNode, validPragmas: TSpecialWords;
    inc i

 proc pragma(c: PContext, sym: PSym, n: PNode, validPragmas: TSpecialWords;
-            isStatement: bool; comesFromPush = false) =
+            isStatement: bool) =
  if n == nil: return
  pragmaRec(c, sym, n, validPragmas, isStatement)
  # XXX: in the case of a callable def, this should use its info
-  if not comesFromPush:
-    implicitPragmas(c, sym, n.info, validPragmas)
+  implicitPragmas(c, sym, n.info, validPragmas)

 proc pragmaCallable*(c: PContext, sym: PSym, n: PNode, validPragmas: TSpecialWords,
                    isStatement: bool = false) =
--- a/compiler/renderer.nim
+++ b/compiler/renderer.nim
@@ -14,7 +14,7 @@
 {.used.}

 import
-  lexer, options, idents, ast, msgs, lineinfos, wordrecg, trees
+  lexer, options, idents, ast, msgs, lineinfos, wordrecg

 import std/[strutils]

@@ -30,7 +30,7 @@ type
  TRenderFlags* = set[TRenderFlag]
  TRenderTok* = object
    kind*: TokType
-    length*: int32
+    length*: int16
    sym*: PSym

  Section = enum
@@ -66,359 +66,6 @@ proc renderTree*(n: PNode, renderFlags: TRenderFlags = {}): string
 # determines how long the subtree will likely be, the second
 # phase appends to a buffer that will be the output.

-type
-  TPreferedDesc* = enum
-    preferName, # default
-    preferDesc, # probably should become what preferResolved is
-    preferExported,
-    preferModuleInfo, # fully qualified
-    preferGenericArg,
-    preferTypeName,
-    preferResolved, # fully resolved symbols
-    preferMixed,
-      # most useful, shows: symbol + resolved symbols if it differs, e.g.:
-      # tuple[a: MyInt{int}, b: float]
-    preferInlayHint,
-    preferInferredEffects,
-
-proc typeToString*(typ: PType; prefer: TPreferedDesc = preferName): string
-template `$`*(typ: PType): string = typeToString(typ)
-
-proc valueToString(a: PNode): string =
-  case a.kind
-  of nkCharLit, nkUIntLit..nkUInt64Lit:
-    result = $cast[uint64](a.intVal)
-  of nkIntLit..nkInt64Lit:
-    result = $a.intVal
-  of nkFloatLit..nkFloat128Lit: result = $a.floatVal
-  of nkStrLit..nkTripleStrLit: result = a.strVal
-  of nkStaticExpr: result = "static(" & a[0].renderTree & ")"
-  else: result = "<invalid value>"
-
-proc rangeToStr(n: PNode): string =
-  assert(n.kind == nkRange)
-  result = valueToString(n[0]) & ".." & valueToString(n[1])
-
-const preferToResolveSymbols = {preferName, preferTypeName, preferModuleInfo,
-  preferGenericArg, preferResolved, preferMixed, preferInlayHint, preferInferredEffects}
-
-
-const
-  typeToStr: array[TTypeKind, string] = ["None", "bool", "char", "empty",
-    "Alias", "typeof(nil)", "untyped", "typed", "typeDesc",
-    # xxx typeDesc=>typedesc: typedesc is declared as such, and is 10x more common.
-    "GenericInvocation", "GenericBody", "GenericInst", "GenericParam",
-    "distinct $1", "enum", "ordinal[$1]", "array[$1, $2]", "object", "tuple",
-    "set[$1]", "range[$1]", "ptr ", "ref ", "var ", "seq[$1]", "proc",
-    "pointer", "OpenArray[$1]", "string", "cstring", "Forward",
-    "int", "int8", "int16", "int32", "int64",
-    "float", "float32", "float64", "float128",
-    "uint", "uint8", "uint16", "uint32", "uint64",
-    "owned", "sink",
-    "lent ", "varargs[$1]", "UncheckedArray[$1]", "Error Type",
-    "BuiltInTypeClass", "UserTypeClass",
-    "UserTypeClassInst", "CompositeTypeClass", "inferred",
-    "and", "or", "not", "any", "static", "TypeFromExpr", "concept", # xxx bugfix
-    "void", "iterable"]
-
-proc addTypeFlags(name: var string, typ: PType) {.inline.} =
-  if tfNotNil in typ.flags: name.add(" not nil")
-
-proc isIntLit*(t: PType): bool {.inline.} =
-  result = t.kind == tyInt and t.n != nil and t.n.kind == nkIntLit
-
-proc isFloatLit*(t: PType): bool {.inline.} =
-  result = t.kind == tyFloat and t.n != nil and t.n.kind == nkFloatLit
-
-# TODO: It would be a good idea to kill the special state of a resolved
-# concept by switching to tyAlias within the instantiated procs.
-# Currently, tyAlias is always skipped with skipModifier, which means that
-# we can store information about the matched concept in another position.
-# Then builtInFieldAccess can be modified to properly read the derived
-# consts and types stored within the concept.
-template isResolvedUserTypeClass*(t: PType): bool =
-  tfResolved in t.flags
-
-proc typeToString(typ: PType, prefer: TPreferedDesc = preferName): string =
-  let preferToplevel = prefer
-  proc getPrefer(prefer: TPreferedDesc): TPreferedDesc =
-    if preferToplevel in {preferResolved, preferMixed}:
-      preferToplevel # sticky option
-    else:
-      prefer
-
-  proc typeToString(typ: PType, prefer: TPreferedDesc = preferName): string =
-    result = ""
-    let prefer = getPrefer(prefer)
-    let t = typ
-    if t == nil: return
-    if prefer in preferToResolveSymbols and t.sym != nil and
-         sfAnon notin t.sym.flags and t.kind notin {tySequence, tyInferred}:
-      if t.kind == tyInt and isIntLit(t):
-        if prefer == preferInlayHint:
-          result = t.sym.name.s
-        else:
-          result = t.sym.name.s & " literal(" & $t.n.intVal & ")"
-      elif t.kind == tyAlias and t.elementType.kind != tyAlias:
-        result = typeToString(t.elementType)
-      elif prefer in {preferResolved, preferMixed}:
-        case t.kind
-        of IntegralTypes + {tyFloat..tyFloat128} + {tyString, tyCstring}:
-          result = typeToStr[t.kind]
-        of tyGenericBody:
-          result = typeToString(t.last)
-        of tyCompositeTypeClass:
-          # avoids showing `A[any]` in `proc fun(a: A)` with `A = object[T]`
-          result = typeToString(t.last.last)
-        else:
-          result = t.sym.name.s
-        if prefer == preferMixed and result != t.sym.name.s:
-          result = t.sym.name.s & "{" & result & "}"
-      elif prefer in {preferName, preferTypeName, preferInlayHint, preferInferredEffects} or t.sym.owner.isNil:
-        # note: should probably be: {preferName, preferTypeName, preferGenericArg}
-        result = t.sym.name.s
-        if t.kind == tyGenericParam and t.genericParamHasConstraints:
-          result.add ": "
-          result.add t.elementType.typeToString
-      else:
-        result = t.sym.owner.name.s & '.' & t.sym.name.s
-      result.addTypeFlags(t)
-      return
-    case t.kind
-    of tyInt:
-      if not isIntLit(t) or prefer == preferExported:
-        result = typeToStr[t.kind]
-      else:
-        case prefer:
-        of preferGenericArg:
-          result = $t.n.intVal
-        of preferInlayHint:
-          result = "int"
-        else:
-          result = "int literal(" & $t.n.intVal & ")"
-    of tyGenericInst:
-      result = typeToString(t.genericHead) & '['
-      for needsComma, a in t.genericInstParams:
-        if needsComma: result.add(", ")
-        result.add(typeToString(a, preferGenericArg))
-      result.add(']')
-    of tyGenericInvocation:
-      result = typeToString(t.genericHead) & '['
-      for needsComma, a in t.genericInvocationParams:
-        if needsComma: result.add(", ")
-        result.add(typeToString(a, preferGenericArg))
-      result.add(']')
-    of tyGenericBody:
-      result = typeToString(t.typeBodyImpl) & '['
-      for i, a in t.genericBodyParams:
-        if i > 0: result.add(", ")
-        result.add(typeToString(a, preferTypeName))
-      result.add(']')
-    of tyTypeDesc:
-      if t.elementType.kind == tyNone: result = "typedesc"
-      else: result = "typedesc[" & typeToString(t.elementType) & "]"
-    of tyStatic:
-      if prefer == preferGenericArg and t.n != nil:
-        result = t.n.renderTree
-      else:
-        result = "static[" & (if t.hasElementType: typeToString(t.skipModifier) else: "") & "]"
-        if t.n != nil: result.add "(" & renderTree(t.n) & ")"
-    of tyUserTypeClass:
-      if t.sym != nil and t.sym.owner != nil:
-        if t.isResolvedUserTypeClass: return typeToString(t.last)
-        return t.sym.owner.name.s
-      else:
-        result = "<invalid tyUserTypeClass>"
-    of tyBuiltInTypeClass:
-      result =
-        case t.base.kind
-        of tyVar: "var"
-        of tyRef: "ref"
-        of tyPtr: "ptr"
-        of tySequence: "seq"
-        of tyArray: "array"
-        of tySet: "set"
-        of tyRange: "range"
-        of tyDistinct: "distinct"
-        of tyProc: "proc"
-        of tyObject: "object"
-        of tyTuple: "tuple"
-        of tyOpenArray: "openArray"
-        else: typeToStr[t.base.kind]
-    of tyInferred:
-      let concrete = t.previouslyInferred
-      if concrete != nil: result = typeToString(concrete)
-      else: result = "inferred[" & typeToString(t.base) & "]"
-    of tyUserTypeClassInst:
-      let body = t.base
-      result = body.sym.name.s & "["
-      for needsComma, a in t.userTypeClassInstParams:
-        if needsComma: result.add(", ")
-        result.add(typeToString(a))
-      result.add "]"
-    of tyAnd:
-      for i, son in t.ikids:
-        if i > 0: result.add(" and ")
-        result.add(typeToString(son))
-    of tyOr:
-      for i, son in t.ikids:
-        if i > 0: result.add(" or ")
-        result.add(typeToString(son))
-    of tyNot:
-      result = "not " & typeToString(t.elementType)
-    of tyUntyped:
-      #internalAssert t.len == 0
-      result = "untyped"
-    of tyFromExpr:
-      if t.n == nil:
-        result = "unknown"
-      else:
-        result = "typeof(" & renderTree(t.n) & ")"
-    of tyArray:
-      result = "array"
-      if t.hasElementType:
-        if t.indexType.kind == tyRange:
-          result &= "[" & rangeToStr(t.indexType.n) & ", " &
-              typeToString(t.elementType) & ']'
-        else:
-          result &= "[" & typeToString(t.indexType) & ", " &
-              typeToString(t.elementType) & ']'
-    of tyUncheckedArray:
-      result = "UncheckedArray"
-      if t.hasElementType:
-        result &= "[" & typeToString(t.elementType) & ']'
-    of tySequence:
-      if t.sym != nil and prefer != preferResolved:
-        result = t.sym.name.s
-      else:
-        result = "seq"
-        if t.hasElementType:
-          result &= "[" & typeToString(t.elementType) & ']'
-    of tyOrdinal:
-      result = "ordinal"
-      if t.hasElementType:
-        result &= "[" & typeToString(t.skipModifier) & ']'
-    of tySet:
-      result = "set"
-      if t.hasElementType:
-        result &= "[" & typeToString(t.elementType) & ']'
-    of tyOpenArray:
-      result = "openArray"
-      if t.hasElementType:
-        result &= "[" & typeToString(t.elementType) & ']'
-    of tyDistinct:
-      result = "distinct " & typeToString(t.elementType,
-        if prefer == preferModuleInfo: preferModuleInfo else: preferTypeName)
-    of tyIterable:
-      # xxx factor this pattern
-      result = "iterable"
-      if t.hasElementType:
-        result &= "[" & typeToString(t.skipModifier) & ']'
-    of tyTuple:
-      # we iterate over t.sons here, because t.n may be nil
-      if t.n != nil:
-        result = "tuple["
-        for i in 0..<t.n.len:
-          assert(t.n[i].kind == nkSym)
-          result.add(t.n[i].sym.name.s & ": " & typeToString(t.n[i].sym.typ))
-          if i < t.n.len - 1: result.add(", ")
-        result.add(']')
-      elif t.isEmptyTupleType:
-        result = "tuple[]"
-      elif t.isSingletonTupleType:
-        result = "("
-        for son in t.kids:
-          result.add(typeToString(son))
-        result.add(",)")
-      else:
-        result = "("
-        for i, son in t.ikids:
-          if i > 0: result.add ", "
-          result.add(typeToString(son))
-        result.add(')')
-    of tyPtr, tyRef, tyVar, tyLent:
-      result = if isOutParam(t): "out " else: typeToStr[t.kind]
-      result.add typeToString(t.elementType)
-    of tyRange:
-      result = "range "
-      if t.n != nil and t.n.kind == nkRange:
-        result.add rangeToStr(t.n)
-      if prefer != preferExported:
-        result.add("(" & typeToString(t.elementType) & ")")
-    of tyProc:
-      result = if tfIterator in t.flags: "iterator "
-               elif t.owner != nil:
-                 case t.owner.kind
-                 of skTemplate: "template "
-                 of skMacro: "macro "
-                 of skConverter: "converter "
-                 else: "proc "
-              else:
-                "proc "
-      if tfUnresolved in t.flags: result.add "[*missing parameters*]"
-      result.add "("
-      for i, a in t.paramTypes:
-        if i > FirstParamAt: result.add(", ")
-        let j = paramTypeToNodeIndex(i)
-        if t.n != nil and j < t.n.len and t.n[j].kind == nkSym:
-          result.add(t.n[j].sym.name.s)
-          result.add(": ")
-        result.add(typeToString(a))
-      result.add(')')
-      if t.returnType != nil: result.add(": " & typeToString(t.returnType))
-      var prag = if t.callConv == ccNimCall and tfExplicitCallConv notin t.flags: "" else: $t.callConv
-      var hasImplicitRaises = false
-      if not isNil(t.owner) and not isNil(t.owner.ast) and (t.owner.ast.len - 1) >= pragmasPos:
-        let pragmasNode = t.owner.ast[pragmasPos]
-        let raisesSpec = effectSpec(pragmasNode, wRaises)
-        if not isNil(raisesSpec):
-          addSep(prag)
-          prag.add("raises: ")
-          prag.add(renderTree raisesSpec)
-          hasImplicitRaises = true
-      if tfNoSideEffect in t.flags:
-        addSep(prag)
-        prag.add("noSideEffect")
-      if tfThread in t.flags:
-        addSep(prag)
-        prag.add("gcsafe")
-      var effectsOfStr = ""
-      for i, a in t.paramTypes:
-        let j = paramTypeToNodeIndex(i)
-        if t.n != nil and j < t.n.len and t.n[j].kind == nkSym and t.n[j].sym.kind == skParam and sfEffectsDelayed in t.n[j].sym.flags:
-          addSep(effectsOfStr)
-          effectsOfStr.add(t.n[j].sym.name.s)
-      if effectsOfStr != "":
-        addSep(prag)
-        prag.add("effectsOf: ")
-        prag.add(effectsOfStr)
-      if not hasImplicitRaises and prefer == preferInferredEffects and not isNil(t.owner) and not isNil(t.owner.typ) and not isNil(t.owner.typ.n) and (t.owner.typ.n.len > 0):
-        let effects = t.n[0]
-        if effects.kind == nkEffectList and effects.len == effectListLen:
-          var inferredRaisesStr = ""
-          let effs = effects[exceptionEffects]
-          if not isNil(effs):
-            for eff in items(effs):
-              if not isNil(eff):
-                addSep(inferredRaisesStr)
-                inferredRaisesStr.add($eff.typ)
-          addSep(prag)
-          prag.add("raises: <inferred> [")
-          prag.add(inferredRaisesStr)
-          prag.add("]")
-      if prag.len != 0: result.add("{." & prag & ".}")
-    of tyVarargs:
-      result = typeToStr[t.kind] % typeToString(t.elementType)
-    of tySink:
-      result = "sink " & typeToString(t.skipModifier)
-    of tyOwned:
-      result = "owned " & typeToString(t.elementType)
-    else:
-      result = typeToStr[t.kind]
-    result.addTypeFlags(t)
-  result = typeToString(typ, prefer)
-
-
 proc disamb(g: var TSrcGen; s: PSym): int =
  # we group by 's.name.s' to compute the stable name ID.
  result = 0
@@ -507,7 +154,7 @@ proc initSrcGen(renderFlags: TRenderFlags; config: ConfigRef): TSrcGen =
                   )

 proc addTok(g: var TSrcGen, kind: TokType, s: string; sym: PSym = nil) =
-  g.tokens.add TRenderTok(kind: kind, length: int32(s.len), sym: sym)
+  g.tokens.add TRenderTok(kind: kind, length: int16(s.len), sym: sym)
  g.buf.add(s)
  if kind != tkSpaces:
    inc g.col, s.len
@@ -680,10 +327,6 @@ proc pushCom(g: var TSrcGen, n: PNode) =
  setLen(g.comStack, g.comStack.len + 1)
  g.comStack[^1] = n

-proc popCom(g: var TSrcGen): PNode =
-  result = g.comStack[^1]
-  setLen(g.comStack, g.comStack.len - 1)
-
 proc popAllComs(g: var TSrcGen) =
  setLen(g.comStack, 0)

@@ -767,7 +410,7 @@ proc atom(g: TSrcGen; n: PNode): string =
  of nkEmpty: result = ""
  of nkIdent: result = n.ident.s
  of nkSym: result = n.sym.name.s
-  of nkClosedSymChoice, nkOpenSymChoice, nkOpenSym: result = n[0].sym.name.s
+  of nkClosedSymChoice, nkOpenSymChoice: result = n[0].sym.name.s
  of nkStrLit: result = ""; result.addQuoted(n.strVal)
  of nkRStrLit: result = "r\"" & replace(n.strVal, "\"", "\"\"") & '\"'
  of nkTripleStrLit: result = "\"\"\"" & n.strVal & "\"\"\""
@@ -922,16 +565,8 @@ proc lsub(g: TSrcGen; n: PNode): int =
  of nkIfExpr:
    result = lsub(g, n[0][0]) + lsub(g, n[0][1]) + lsons(g, n, 1) +
        len("if_:_")
-  of nkElifExpr, nkElifBranch:
-    if isEmptyType(n[1].typ):
-      result = lsons(g, n) + len("elif_:_")
-    else:
-      result = lsons(g, n) + len("_elif_:_")
-  of nkElseExpr, nkElse:
-    if isEmptyType(n[0].typ):
-      result = lsub(g, n[0]) + len("else:_")
-    else:
-      result = lsub(g, n[0]) + len("_else:_") # type descriptions
+  of nkElifExpr: result = lsons(g, n) + len("_elif_:_")
+  of nkElseExpr: result = lsub(g, n[0]) + len("_else:_") # type descriptions
  of nkTypeOfExpr: result = (if n.len > 0: lsub(g, n[0]) else: 0)+len("typeof()")
  of nkRefTy: result = (if n.len > 0: lsub(g, n[0])+1 else: 0) + len("ref")
  of nkPtrTy: result = (if n.len > 0: lsub(g, n[0])+1 else: 0) + len("ptr")
@@ -974,6 +609,8 @@ proc lsub(g: TSrcGen; n: PNode): int =
  of nkCommentStmt: result = n.comment.len
  of nkOfBranch: result = lcomma(g, n, 0, - 2) + lsub(g, lastSon(n)) + len("of_:_")
  of nkImportAs: result = lsub(g, n[0]) + len("_as_") + lsub(g, n[1])
+  of nkElifBranch: result = lsons(g, n) + len("elif_:_")
+  of nkElse: result = lsub(g, n[0]) + len("else:_")
  of nkFinally: result = lsub(g, n[0]) + len("finally:_")
  of nkGenericParams: result = lcomma(g, n) + 2
  of nkFormalParams:
@@ -1215,28 +852,10 @@ proc genSymSuffix(result: var string, s: PSym) {.inline.} =
    result.add '_'
    result.addInt s.id

-proc gsemmedParams(g: var TSrcGen, n: PNode) =
-  put(g, tkParLe, "(")
-  for i in 1..<n.len:
-    if i > 1:
-      putWithSpace(g, tkComma, ";")
-    let x {.cursor.} = n[i]
-    if x.kind == nkSym:
-      put g, tkSymbol, renderDefinitionName(x.sym)
-      putWithSpace(g, tkColon, ":")
-      put g, tkSymbol, typeToString(x.sym.typ)
-    else:
-      gsub(g, x)
-  put(g, tkParRi, ")")
-  if not isEmptyType(n[0].typ):
-    putWithSpace(g, tkColon, ":")
-    gsub(g, n[0])
-
 proc gproc(g: var TSrcGen, n: PNode) =
  var c: TContext = initContext()
-  var s: PSym = nil
  if n[namePos].kind == nkSym:
-    s = n[namePos].sym
+    let s = n[namePos].sym
    var ret = renderDefinitionName(s)
    ret.genSymSuffix(s)
    put(g, tkSymbol, ret)
@@ -1251,10 +870,7 @@ proc gproc(g: var TSrcGen, n: PNode) =
      gsub(g, n[miscPos][1])
    else:
      gsub(g, n[genericParamsPos])
-  if n[paramsPos].len == 0 and s != nil and s.typ != nil and s.typ.n != nil:
-    gsemmedParams(g, s.typ.n)
-  else:
-    gsub(g, n[paramsPos])
+  gsub(g, n[paramsPos])
  if renderNoPragmas notin g.flags:
    gsub(g, n[pragmasPos])
  if renderNoBody notin g.flags:
@@ -1386,7 +1002,7 @@ type
 proc bracketKind*(g: TSrcGen, n: PNode): BracketKind =
  if renderIds notin g.flags:
    case n.kind
-    of nkClosedSymChoice, nkOpenSymChoice, nkOpenSym:
+    of nkClosedSymChoice, nkOpenSymChoice:
      if n.len > 0: result = bracketKind(g, n[0])
      else: result = bkNone
    of nkSym:
@@ -1731,10 +1347,6 @@ proc gsub(g: var TSrcGen, n: PNode, c: TContext, fromStmtList = false) =
      if not n[0].isExported() and renderNonExportedFields notin g.flags:
        # Skip if this is a property in a type and its not exported
        # (While also not allowing rendering of non exported fields)
-        if shouldRenderComment(g, n):
-          # `shouldRenderComment` indicts that we have comments to render
-          # but it's a non-exported field, so we just pop without rendering any comment
-          discard popCom(g)
        return
      # render postfix for object fields:
      exclFlags = g.flags * {renderNoPostfix}
@@ -1803,7 +1415,10 @@ proc gsub(g: var TSrcGen, n: PNode, c: TContext, fromStmtList = false) =
  of nkPrefix:
    gsub(g, n, 0)
    if n.len > 1:
-      let opr = getPIdent(n[0])
+      let opr = if n[0].kind == nkIdent: n[0].ident
+                elif n[0].kind == nkSym: n[0].sym.name
+                elif n[0].kind in {nkOpenSymChoice, nkClosedSymChoice}: n[0][0].sym.name
+                else: nil
      let nNext = skipHiddenNodes(n[1])
      if nNext.kind == nkPrefix or (opr != nil and renderer.isKeyword(opr)):
        put(g, tkSpaces, Space)
@@ -1854,30 +1469,15 @@ proc gsub(g: var TSrcGen, n: PNode, c: TContext, fromStmtList = false) =
    putWithSpace(g, tkColon, ":")
    if n.len > 0: gsub(g, n[0], 1)
    gsons(g, n, emptyContext, 1)
-  of nkElifExpr, nkElifBranch:
-    if isEmptyType(n[1].typ):
-      optNL(g)
-      putWithSpace(g, tkElif, "elif")
-      gsub(g, n, 0)
-      putWithSpace(g, tkColon, ":")
-      gcoms(g)
-      gstmts(g, n[1], c)
-    else:
-      putWithSpace(g, tkElif, " elif")
-      gcond(g, n[0])
-      putWithSpace(g, tkColon, ":")
-      gsub(g, n, 1)
-  of nkElseExpr, nkElse:
-    if isEmptyType(n[0].typ):
-      optNL(g)
-      put(g, tkElse, "else")
-      putWithSpace(g, tkColon, ":")
-      gcoms(g)
-      gstmts(g, n[0], c)
-    else:
-      put(g, tkElse, " else")
-      putWithSpace(g, tkColon, ":")
-      gsub(g, n, 0)
+  of nkElifExpr:
+    putWithSpace(g, tkElif, " elif")
+    gcond(g, n[0])
+    putWithSpace(g, tkColon, ":")
+    gsub(g, n, 1)
+  of nkElseExpr:
+    put(g, tkElse, " else")
+    putWithSpace(g, tkColon, ":")
+    gsub(g, n, 0)
  of nkTypeOfExpr:
    put(g, tkType, "typeof")
    put(g, tkParLe, "(")
@@ -2139,6 +1739,19 @@ proc gsub(g: var TSrcGen, n: PNode, c: TContext, fromStmtList = false) =
  of nkMixinStmt:
    putWithSpace(g, tkMixin, "mixin")
    gcomma(g, n, c)
+  of nkElifBranch:
+    optNL(g)
+    putWithSpace(g, tkElif, "elif")
+    gsub(g, n, 0)
+    putWithSpace(g, tkColon, ":")
+    gcoms(g)
+    gstmts(g, n[1], c)
+  of nkElse:
+    optNL(g)
+    put(g, tkElse, "else")
+    putWithSpace(g, tkColon, ":")
+    gcoms(g)
+    gstmts(g, n[0], c)
  of nkFinally, nkDefer:
    optNL(g)
    if n.kind == nkFinally:
@@ -2210,9 +1823,6 @@ proc gsub(g: var TSrcGen, n: PNode, c: TContext, fromStmtList = false) =
    putWithSpace(g, tkSymbol, "error")
    #gcomma(g, n, c)
    gsub(g, n[0], c)
-  of nkReplayAction:
-    put(g, tkSymbol, "replayaction")
-    #gsons(g, n, c, 0)
  else:
    #nkNone, nkExplicitTypeListCall:
    internalError(g.config, n.info, "renderer.gsub(" & $n.kind & ')')
--- a/compiler/reorder.nim
+++ b/compiler/reorder.nim
@@ -93,7 +93,7 @@ proc computeDeps(cache: IdentCache; n: PNode, declares, uses: var IntSet; topLev
  of nkIdent: uses.incl n.ident.id
  of nkSym: uses.incl n.sym.name.id
  of nkAccQuoted: uses.incl accQuoted(cache, n).id
-  of nkOpenSymChoice, nkClosedSymChoice, nkOpenSym:
+  of nkOpenSymChoice, nkClosedSymChoice:
    uses.incl n[0].sym.name.id
  of nkStmtList, nkStmtListExpr, nkWhenStmt, nkElifBranch, nkElse, nkStaticStmt:
    for i in 0..<n.len: computeDeps(cache, n[i], declares, uses, topLevel)
--- a/compiler/scriptconfig.nim
+++ b/compiler/scriptconfig.nim
@@ -213,10 +213,9 @@ proc runNimScript*(cache: IdentCache; scriptName: AbsoluteFile;
  unregisterArcOrc(conf)
  conf.globalOptions.excl optOwnedRefs
  conf.selectedGC = gcUnselected
-  conf.globalOptions.incl optWithinConfigSystem

  var m = graph.makeModule(scriptName)
-  incl(m, sfMainModule)
+  incl(m.flags, sfMainModule)
  var vm = setupVM(m, cache, scriptName.string, graph, idgen)
  graph.vm = vm

@@ -231,7 +230,7 @@ proc runNimScript*(cache: IdentCache; scriptName: AbsoluteFile;
  if optOwnedRefs in oldGlobalOptions:
    conf.globalOptions.incl {optTinyRtti, optOwnedRefs, optSeqDestructors}
    defineSymbol(conf.symbols, "nimv2")
-  if conf.selectedGC in {gcArc, gcOrc, gcYrc, gcAtomicArc}:
+  if conf.selectedGC in {gcArc, gcOrc, gcAtomicArc}:
    conf.globalOptions.incl {optTinyRtti, optSeqDestructors}
    defineSymbol(conf.symbols, "nimv2")
    defineSymbol(conf.symbols, "gcdestructors")
@@ -241,8 +240,6 @@ proc runNimScript*(cache: IdentCache; scriptName: AbsoluteFile;
      defineSymbol(conf.symbols, "gcarc")
    of gcOrc:
      defineSymbol(conf.symbols, "gcorc")
-    of gcYrc:
-      defineSymbol(conf.symbols, "gcyrc")
    of gcAtomicArc:
      defineSymbol(conf.symbols, "gcatomicarc")
    else:
@@ -254,5 +251,4 @@ proc runNimScript*(cache: IdentCache; scriptName: AbsoluteFile;
  #initDefines()
  undefSymbol(conf.symbols, "nimscript")
  undefSymbol(conf.symbols, "nimconfig")
-  conf.globalOptions.excl optWithinConfigSystem
  conf.symbolFiles = oldSymbolFiles
--- a/compiler/sem.nim
+++ b/compiler/sem.nim
@@ -102,7 +102,7 @@ proc fitNode(c: PContext, formal: PType, arg: PNode; info: TLineInfo): PNode =
               renderTree(arg, {renderNoComments}))
    # error correction:
    result = copyTree(arg)
-    result.typ = formal
+    result.typ() = formal
  elif arg.kind in nkSymChoices and formal.skipTypes(abstractInst).kind == tyEnum:
    # Pick the right 'sym' from the sym choice by looking at 'formal' type:
    result = nil
@@ -116,7 +116,7 @@ proc fitNode(c: PContext, formal: PType, arg: PNode; info: TLineInfo): PNode =
      typeMismatch(c.config, info, formal, arg.typ, arg)
      # error correction:
      result = copyTree(arg)
-      result.typ = formal
+      result.typ() = formal
    else:
      result = fitNodePostMatch(c, formal, result)

@@ -126,7 +126,7 @@ proc fitNodeConsiderViewType(c: PContext, formal: PType, arg: PNode; info: TLine
    #classifyViewType(formal) != noView:
    result = newNodeIT(nkHiddenAddr, a.info, formal)
    result.add a
-    formal.incl tfVarIsPtr
+    formal.flags.incl tfVarIsPtr
  else:
   result = a

@@ -260,7 +260,7 @@ proc newSymG*(kind: TSymKind, n: PNode, c: PContext): PSym =
  else:
    result = newSym(kind, considerQuotedIdent(c, n), c.idgen, getCurrOwner(c), n.info)
    if find(result.name.s, '`') >= 0:
-      result.flagsImpl.incl sfWasGenSym
+      result.flags.incl sfWasGenSym
  #if kind in {skForVar, skLet, skVar} and result.owner.kind == skModule:
  #  incl(result.flags, sfGlobal)
  when defined(nimsuggest):
@@ -321,7 +321,7 @@ proc hasCycle(n: PNode): bool =
      break
  excl n.flags, nfNone

-proc fixupTypeAfterEval(c: PContext, evaluated, eOrig: PNode; producedClosure: var bool): PNode =
+proc fixupTypeAfterEval(c: PContext, evaluated, eOrig: PNode): PNode =
  # recompute the types as 'eval' isn't guaranteed to construct types nor
  # that the types are sound:
  when true:
@@ -333,7 +333,7 @@ proc fixupTypeAfterEval(c: PContext, evaluated, eOrig: PNode; producedClosure: v
      if hasCycle(result):
        result = localErrorNode(c, eOrig, "the resulting AST is cyclic and cannot be processed further")
      else:
-        semmacrosanity.annotateType(result, expectedType, c.config, producedClosure)
+        semmacrosanity.annotateType(result, expectedType, c.config)
  else:
    result = semExprWithType(c, evaluated)
    #result = fitNode(c, e.typ, result) inlined with special case:
@@ -346,19 +346,6 @@ proc fixupTypeAfterEval(c: PContext, evaluated, eOrig: PNode; producedClosure: v
         isArrayConstr(arg):
        arg.typ = eOrig.typ

-proc resetEvalPosition(n: PNode) =
-  # resets the eval position of variables because `tryConstExpr` may be
-  # called multiple times on the same node
-  case n.kind
-  of {nkNone..nkNilLit}-{nkSym}:
-    discard
-  of nkSym:
-    if n.sym.kind in {skVar, skLet} and sfGlobal notin n.sym.flags:
-      n.sym.position = 0
-  else:
-    for i in 0..<n.safeLen:
-      resetEvalPosition(n[i])
-
 proc tryConstExpr(c: PContext, n: PNode; expectedType: PType = nil): PNode =
  var e = semExprWithType(c, n, expectedType = expectedType)
  if e == nil: return
@@ -383,10 +370,7 @@ proc tryConstExpr(c: PContext, n: PNode; expectedType: PType = nil): PNode =
    if result == nil or result.kind == nkEmpty:
      result = nil
    else:
-      var producedClosure = false
-      result = fixupTypeAfterEval(c, result, e, producedClosure)
-      if producedClosure:
-        result = nil
+      result = fixupTypeAfterEval(c, result, e)

  except ERecoverableError:
    result = nil
@@ -395,8 +379,6 @@ proc tryConstExpr(c: PContext, n: PNode; expectedType: PType = nil): PNode =
    # Restore the error hook
    c.graph.config.structuredErrorHook = tempHook

-  resetEvalPosition(n)
-
  c.config.errorCounter = oldErrorCount
  c.config.errorMax = oldErrorMax
  c.config.m.errorOutputs = oldErrorOutputs
@@ -425,10 +407,7 @@ proc semConstExpr(c: PContext, n: PNode; expectedType: PType = nil): PNode =
      # error correction:
      result = e
    else:
-      var producedClosure = false
-      result = fixupTypeAfterEval(c, result, e, producedClosure)
-      if producedClosure:
-        result = nil
+      result = fixupTypeAfterEval(c, result, e)

 proc semExprFlagDispatched(c: PContext, n: PNode, flags: TExprFlags; expectedType: PType = nil): PNode =
  if efNeedStatic in flags:
@@ -491,7 +470,7 @@ proc semAfterMacroCall(c: PContext, call, macroResult: PNode,
                   renderTree(result, {renderNoComments}))
        result = newSymNode(errorSym(c, result))
      else:
-        result.typ = makeTypeDesc(c, typ)
+        result.typ() = makeTypeDesc(c, typ)
      #result = symNodeFromType(c, typ, n.info)
    else:
      if s.ast[genericParamsPos] != nil and retType.isMetaType:
@@ -650,7 +629,7 @@ proc defaultFieldsForTuple(c: PContext, recNode: PNode, hasDefault: var bool, ch
                      newNodeIT(nkType, recNode.info, asgnType)
                    )
      asgnExpr.flags.incl nfSkipFieldChecking
-      asgnExpr.typ = recNode.typ
+      asgnExpr.typ() = recNode.typ
      result.add newTree(nkExprColonExpr, recNode, asgnExpr)
  else:
    raiseAssert "unreachable"
@@ -672,7 +651,7 @@ proc defaultFieldsForTheUninitialized(c: PContext, recNode: PNode, checkDefault:
      if checkDefault: # don't add defaults when checking whether a case branch has default fields
        return
      defaultValue = newIntNode(nkIntLit#[c.graph]#, 0)
-      defaultValue.typ = discriminator.typ
+      defaultValue.typ() = discriminator.typ
    selectedBranch = recNode.pickCaseBranchIndex defaultValue
    defaultValue.flags.incl nfSkipFieldChecking
    result.add newTree(nkExprColonExpr, discriminator, defaultValue)
@@ -685,7 +664,7 @@ proc defaultFieldsForTheUninitialized(c: PContext, recNode: PNode, checkDefault:
    elif recType.kind in {tyObject, tyArray, tyTuple}:
      let asgnExpr = defaultNodeField(c, recNode, recNode.typ, checkDefault)
      if asgnExpr != nil:
-        asgnExpr.typ = recNode.typ
+        asgnExpr.typ() = recNode.typ
        asgnExpr.flags.incl nfSkipFieldChecking
        result.add newTree(nkExprColonExpr, recNode, asgnExpr)
  else:
@@ -698,7 +677,7 @@ proc defaultNodeField(c: PContext, a: PNode, aTyp: PType, checkDefault: bool): P
    let child = defaultFieldsForTheUninitialized(c, aTypSkip.n, checkDefault)
    if child.len > 0:
      var asgnExpr = newTree(nkObjConstr, newNodeIT(nkType, a.info, aTyp))
-      asgnExpr.typ = aTyp
+      asgnExpr.typ() = aTyp
      asgnExpr.sons.add child
      result = semExpr(c, asgnExpr)
    else:
@@ -710,11 +689,11 @@ proc defaultNodeField(c: PContext, a: PNode, aTyp: PType, checkDefault: bool): P
      let node = newNode(nkIntLit)
      node.intVal = toInt64(lengthOrd(c.graph.config, aTypSkip))
      let typeNode = newNode(nkType)
-      typeNode.typ = makeTypeDesc(c, aTypSkip[1])
+      typeNode.typ() = makeTypeDesc(c, aTypSkip[1])
      result = semExpr(c, newTree(nkCall, newTree(nkBracketExpr, newSymNode(getSysSym(c.graph, a.info, "arrayWithDefault"), a.info), typeNode),
              node
                ))
-      result.typ = aTyp
+      result.typ() = aTyp
    else:
      result = nil
  of tyTuple:
@@ -723,7 +702,7 @@ proc defaultNodeField(c: PContext, a: PNode, aTyp: PType, checkDefault: bool): P
      let children = defaultFieldsForTuple(c, aTypSkip.n, hasDefault, checkDefault)
      if hasDefault and children.len > 0:
        result = newNodeI(nkTupleConstr, a.info)
-        result.typ = aTyp
+        result.typ() = aTyp
        result.sons.add children
        result = semExpr(c, result)
      else:
@@ -776,7 +755,6 @@ proc preparePContext*(graph: ModuleGraph; module: PSym; idgen: IdGenerator): PCo
  result.semTypeNode = semTypeNode
  result.instTypeBoundOp = sigmatch.instTypeBoundOp
  result.hasUnresolvedArgs = hasUnresolvedArgs
-  result.semAsgnOpr = semAsgnOpr
  result.templInstCounter = new int

  pushProcCon(result, module)
@@ -855,7 +833,7 @@ proc semStmtAndGenerateGenerics(c: PContext, n: PNode): PNode =
    appendToModule(c.module, result)
  trackStmt(c, c.module, result, isTopLevel = true)
  if optMultiMethods notin c.config.globalOptions and
-      c.config.selectedGC in {gcArc, gcOrc, gcAtomicArc, gcYrc} and
+      c.config.selectedGC in {gcArc, gcOrc, gcAtomicArc} and
      Feature.vtables in c.config.features:
    sortVTableDispatchers(c.graph)

@@ -889,6 +867,8 @@ proc semWithPContext*(c: PContext, n: PNode): PNode =
      else:
        result = newNodeI(nkEmpty, n.info)
      #if c.config.cmd == cmdIdeTools: findSuggest(c, n)
+  storeRodNode(c, result)
+

 proc reportUnusedModules(c: PContext) =
  if c.config.cmd == cmdM: return
--- a/compiler/semcall.nim
+++ b/compiler/semcall.nim
@@ -144,6 +144,7 @@ proc pickBestCandidate(c: PContext, headSymbol: PNode,
  while true:
    determineType(c, sym)
    z = initCandidate(c, sym, initialBinding, scope, diagnosticsFlag)
+
    # this is kinda backwards as without a check here the described
    # problems in recalc would not happen, but instead it 100%
    # does check forever in some cases
@@ -160,13 +161,9 @@ proc pickBestCandidate(c: PContext, headSymbol: PNode,
          addTypeBoundSymbols(c.graph, arg.typ, name, filter, symMarker, syms)

      if z.state == csMatch:
-        # Iterator preference is heuristic in iterator-admitting contexts.
-        # The dedicated iterable path uses `iteratorPreference`, other
-        # context use exact-match bump
+        # little hack so that iterators are preferred over everything else:
        if sym.kind == skIterator:
-          if efPreferIteratorForIterable in flags:
-            inc(z.iteratorPreference)
-          elif not (efWantIterator notin flags and efWantIterable in flags):
+          if not (efWantIterator notin flags and efWantIterable in flags):
            inc(z.exactMatches, 200)
          else:
            dec(z.exactMatches, 200)
@@ -187,7 +184,7 @@ proc pickBestCandidate(c: PContext, headSymbol: PNode,
      # 1) new symbols are discovered but the loop ends before we recalc
      # 2) new symbols are discovered and resemmed forever
      # not 100% sure if these are possible though as they would rely
-      # on somehow introducing a new overload during overload resolution
+      #  on somehow introducing a new overload during overload resolution

      # Symbol table has been modified. Restart and pre-calculate all syms
      # before any further candidate init and compare. SLOW, but rare case.
@@ -248,6 +245,14 @@ proc effectProblem(f, a: PType; result: var string; c: PContext) =
        if not c.graph.compatibleProps(c.graph, f, a):
          result.add "\n  The `.requires` or `.ensures` properties are incompatible."

+proc renderNotLValue(n: PNode): string =
+  result = $n
+  let n = if n.kind == nkHiddenDeref: n[0] else: n
+  if n.kind == nkHiddenCallConv and n.len > 1:
+    result = $n[0] & "(" & result & ")"
+  elif n.kind in {nkHiddenStdConv, nkHiddenSubConv} and n.len == 2:
+    result = typeToString(n.typ.skipTypes(abstractVar)) & "(" & result & ")"
+
 proc presentFailedCandidates(c: PContext, n: PNode, errors: CandidateErrors):
                            (TPreferedDesc, string) =
  var prefer = preferName
@@ -585,7 +590,7 @@ proc resolveOverloads(c: PContext, n, orig: PNode,
  let overloadsState = result.state
  if overloadsState != csMatch:
    if nfDotField in n.flags:
-      internalAssert c.config, f.kind in nkIdentKinds and n.len >= 2
+      internalAssert c.config, f.kind == nkIdent and n.len >= 2

      # leave the op head symbol empty,
      # we are going to try multiple variants
@@ -675,7 +680,7 @@ proc bracketNotFoundError(c: PContext; n: PNode; flags: TExprFlags) =
  # copied from semOverloadedCallAnalyzeEffects, might be overkill:
  const baseFilter = {skProc, skFunc, skMethod, skConverter, skMacro, skTemplate}
  let filter =
-    if flags*{efInTypeof, efWantIterator, efWantIterable, efPreferIteratorForIterable} != {}:
+    if flags*{efInTypeof, efWantIterator, efWantIterable} != {}:
      baseFilter + {skIterator}
    else: baseFilter
  # this will add the errors:
@@ -690,16 +695,9 @@ proc instGenericConvertersArg*(c: PContext, a: PNode, x: TCandidate) =
  if a.kind == nkHiddenCallConv and a[0].kind == nkSym:
    let s = a[0].sym
    if s.isGenericRoutineStrict:
-      var src = s.typ.firstParamType
-      var convMatch = newCandidate(c, src)
-      var arg = a[1]
-      if arg.kind in {nkHiddenAddr, nkHiddenSubConv}: arg = arg[^1]
-      let srca = typeRel(convMatch, src, arg.typ)
-      if srca notin {isEqual, isGeneric, isSubtype}:
-        internalError(c.config, a.info, "generic converter failed rematch")
-      let finalCallee = generateInstance(c, s, convMatch.bindings, a.info)
+      let finalCallee = generateInstance(c, s, x.bindings, a.info)
      a[0].sym = finalCallee
-      a[0].typ = finalCallee.typ
+      a[0].typ() = finalCallee.typ
      #a.typ = finalCallee.typ.returnType

 proc instGenericConvertersSons*(c: PContext, n: PNode, x: TCandidate) =
@@ -734,13 +732,13 @@ proc inferWithMetatype(c: PContext, formal: PType,
    # This almost exactly replicates the steps taken by the compiler during
    # param matching. It performs an embarrassing amount of back-and-forth
    # type jugling, but it's the price to pay for consistency and correctness
-    result.typ = generateTypeInstance(c, m.bindings, arg.info,
+    result.typ() = generateTypeInstance(c, m.bindings, arg.info,
                                      formal.skipTypes({tyCompositeTypeClass}))
  else:
    typeMismatch(c.config, arg.info, formal, arg.typ, arg)
    # error correction:
    result = copyTree(arg)
-    result.typ = formal
+    result.typ() = formal

 proc updateDefaultParams(c: PContext, call: PNode) =
  # In generic procs, the default parameter may be unique for each
@@ -763,7 +761,7 @@ proc updateDefaultParams(c: PContext, call: PNode) =
        pushInfoContext(c.config, call.info, call[0].sym.detailedInfo)
        typeMismatch(c.config, def.info, formal.typ, def.typ, formal.ast)
        popInfoContext(c.config)
-        def.typ = errorType(c)
+        def.typ() = errorType(c)
      call[i] = def

 proc getCallLineInfo(n: PNode): TLineInfo =
@@ -834,39 +832,21 @@ proc inheritBindings(c: PContext, x: var TCandidate, expectedType: PType) =
  for i in 0 ..< flatUnbound.len():
    x.bindings.put(flatUnbound[i], flatBound[i])

-proc compactVoidArgs(n: PNode): PNode =
-  # deletes void args from the argument list, which are created by `setSon`
-  var hasNil = false
-  for i in 0..<n.len:
-    if n[i] == nil:
-      hasNil = true
-      break
-  if not hasNil:
-    result = n
-  else:
-    result = copyNode(n)
-    for i in 0..<n.len:
-      if n[i] != nil:
-        result.add n[i]
-
 proc semResolvedCall(c: PContext, x: var TCandidate,
                     n: PNode, flags: TExprFlags;
                     expectedType: PType = nil): PNode =
  assert x.state == csMatch
  var finalCallee = x.calleeSym
  let info = getCallLineInfo(n)
-  markUsed(c, info, finalCallee, isGenericInstance = false)
-  onUse(info, finalCallee, isGenericInstance = false)
+  markUsed(c, info, finalCallee)
+  onUse(info, finalCallee)
  assert finalCallee.ast != nil
-  if x.matchedErrorType:
-    markUsed(c, info, finalCallee, isGenericInstance = true)
-    onUse(info, finalCallee, isGenericInstance = true)
  if x.matchedErrorType:
    result = x.call
    result[0] = newSymNode(finalCallee, getCallLineInfo(result[0]))
    if containsGenericType(result.typ):
-      result.typ = newTypeS(tyError, c)
-      incl result.typ, tfCheckedForDestructor
+      result.typ() = newTypeS(tyError, c)
+      incl result.typ.flags, tfCheckedForDestructor
    return
  let gp = finalCallee.ast[genericParamsPos]
  if gp.isGenericParams:
@@ -892,19 +872,17 @@ proc semResolvedCall(c: PContext, x: var TCandidate,
          # this node will be used in template substitution,
          # pretend this is an untyped node and let regular sem handle the type
          # to prevent problems where a generic parameter is treated as a value
-          tn.typ = nil
+          tn.typ() = nil
          x.call.add tn
        else:
          internalAssert c.config, false
-  markUsed(c, info, finalCallee, isGenericInstance = true)
-  onUse(info, finalCallee, isGenericInstance = true)

-  result = compactVoidArgs(x.call)
+  result = x.call
  instGenericConvertersSons(c, result, x)
  markConvertersUsed(c, result)
  result[0] = newSymNode(finalCallee, getCallLineInfo(result[0]))
  if finalCallee.magic notin {mArrGet, mArrPut}:
-    result.typ = finalCallee.typ.returnType
+    result.typ() = finalCallee.typ.returnType
  updateDefaultParams(c, result)

 proc canDeref(n: PNode): bool {.inline.} =
@@ -913,7 +891,7 @@ proc canDeref(n: PNode): bool {.inline.} =

 proc tryDeref(n: PNode): PNode =
  result = newNodeI(nkHiddenDeref, n.info)
-  result.typ = n.typ.skipTypes(abstractInst)[0]
+  result.typ() = n.typ.skipTypes(abstractInst)[0]
  result.add n

 proc semOverloadedCall(c: PContext, n, nOrig: PNode,
@@ -932,16 +910,16 @@ proc semOverloadedCall(c: PContext, n, nOrig: PNode,
  else:
    if c.inGenericContext > 0 and c.matchedConcept == nil:
      result = semGenericStmt(c, n)
-      result.typ = makeTypeFromExpr(c, result.copyTree)
-    elif efNoUndeclared in flags:
-      result = nil
+      result.typ() = makeTypeFromExpr(c, result.copyTree)
    elif efExplain notin flags:
      # repeat the overload resolution,
      # this time enabling all the diagnostic output (this should fail again)
      result = semOverloadedCall(c, n, nOrig, filter, flags + {efExplain})
-    else:
+    elif efNoUndeclared notin flags:
      result = nil
      notFoundError(c, n, errors)
+    else:
+      result = nil

 proc explicitGenericInstError(c: PContext; n: PNode): PNode =
  localError(c.config, getCallLineInfo(n), errCannotInstantiateX % renderTree(n))
@@ -964,12 +942,10 @@ proc explicitGenericSym(c: PContext, n: PNode, s: PSym, errors: var CandidateErr
        diagnostics: m.diagnostics))
    return nil
  var newInst = generateInstance(c, s, m.bindings, n.info)
-  newInst.typ.excl tfUnresolved
+  newInst.typ.flags.excl tfUnresolved
  let info = getCallLineInfo(n)
-  markUsed(c, info, s, isGenericInstance = false)
-  onUse(info, s, isGenericInstance = false)
-  markUsed(c, info, newInst, isGenericInstance = true)
-  onUse(info, newInst, isGenericInstance = true)
+  markUsed(c, info, s)
+  onUse(info, s)
  result = newSymNode(newInst, info)

 proc setGenericParams(c: PContext, n, expectedParams: PNode) =
@@ -983,9 +959,9 @@ proc setGenericParams(c: PContext, n, expectedParams: PNode) =
          nil
      e = semExprWithType(c, n[i], expectedType = constraint)
    if e.typ == nil:
-      n[i].typ = errorType(c)
+      n[i].typ() = errorType(c)
    else:
-      n[i].typ = e.typ
+      n[i].typ() = e.typ.skipTypes({tyTypeDesc})

 proc explicitGenericInstantiation(c: PContext, n: PNode, s: PSym, doError: bool): PNode =
  assert n.kind == nkBracketExpr
@@ -1002,7 +978,7 @@ proc explicitGenericInstantiation(c: PContext, n: PNode, s: PSym, doError: bool)
        # same as in semOverloadedCall, make expression untyped,
        # may have failed match due to unresolved types
        result = semGenericStmt(c, n)
-        result.typ = makeTypeFromExpr(c, result.copyTree)
+        result.typ() = makeTypeFromExpr(c, result.copyTree)
      elif doError:
        notFoundError(c, n, errors)
  elif a.kind in {nkClosedSymChoice, nkOpenSymChoice}:
@@ -1020,7 +996,7 @@ proc explicitGenericInstantiation(c: PContext, n: PNode, s: PSym, doError: bool)
          # any failing match stops building the symchoice for correctness,
          # can also make it untyped from the start
          result = semGenericStmt(c, n)
-          result.typ = makeTypeFromExpr(c, result.copyTree)
+          result.typ() = makeTypeFromExpr(c, result.copyTree)
          return
    # get rid of nkClosedSymChoice if not ambiguous:
    if result.len == 0:
--- a/compiler/semdata.nim
+++ b/compiler/semdata.nim
@@ -9,15 +9,16 @@

 ## This module contains the data structures for the semantic checking phase.

-import std/[tables, intsets, sets, strutils]
+import std/[tables, intsets, sets]

 when defined(nimPreviewSlimSystem):
  import std/assertions

 import
  options, ast, msgs, idents, renderer,
-  magicsys, vmdef, modulegraphs, lineinfos, pathutils, layeredtable,
-  types, lowerings, trees, parampatterns, astalgo
+  magicsys, vmdef, modulegraphs, lineinfos, pathutils, layeredtable
+
+import ic / ic

 type
  TOptionEntry* = object      # entries to put on a stack for pragma parsing
@@ -40,7 +41,7 @@ type
    breakInLoop*: bool        # whether we are in a loop without block
    next*: PProcCon           # used for stacking procedure contexts
    mappingExists*: bool
-    mapping*: SymMapping
+    mapping*: Table[ItemId, PSym]
    caseContext*: seq[tuple[n: PNode, idx: int]]
    localBindStmts*: seq[PNode]

@@ -54,18 +55,7 @@ type
    inst*: PInstantiation

  TExprFlag* = enum
-    efLValue,
-      # The expression is used as an assignable location.
-    efWantIterator,
-      # Admit iterator candidates and prefer them during overload resolution.
-    efWantIterable,
-      # Admit iterator candidates for expressions that may feed iterable-style
-      # chaining.
-    efPreferIteratorForIterable,
-      # Prefer iterator candidates for `iterable[T]` matching and wrap a
-      # successful iterator call as `tyIterable`.
-    efInTypeof,
-      # The expression is being semchecked under `typeof`.
+    efLValue, efWantIterator, efWantIterable, efInTypeof,
    efNeedStatic,
      # Use this in contexts where a static value is mandatory
    efPreferStatic,
@@ -162,6 +152,7 @@ type
    generics*: seq[TInstantiationPair] # pending list of instantiated generics to compile
    topStmts*: int # counts the number of encountered top level statements
    lastGenericIdx*: int      # used for the generics stack
+    hloLoopDetector*: int     # used to prevent endless loops in the HLO
    inParallelStmt*: int
    instTypeBoundOp*: proc (c: PContext; dc: PSym; t: PType; info: TLineInfo;
                            op: TTypeAttachedOp; col: int): PSym {.nimcall.}
@@ -180,13 +171,8 @@ type
    sideEffects*: Table[int, seq[(TLineInfo, PSym)]] # symbol.id index
    inUncheckedAssignSection*: int
    importModuleLookup*: Table[int, seq[int]] # (module.ident.id, [module.id])
-    forwardTypeUpdates*: seq[(PType, PNode)]
-      # types that need to be updated in a type section
-      # due to containing forward types, and their corresponding nodes
+    skipTypes*: seq[PNode] # used to skip types between passes in type section. So far only used for inheritance, sets and generic bodies.
    inTypeofContext*: int
-
-    semAsgnOpr*: proc (c: PContext; n: PNode; k: TNodeKind): PNode {.nimcall.}
-
  TBorrowState* = enum
    bsNone, bsReturnNotMatch, bsNoDistinct, bsGeneric, bsNotSupported, bsMatch

@@ -210,29 +196,29 @@ proc getIntLitType*(c: PContext; literal: PNode): PType =
 proc setIntLitType*(c: PContext; result: PNode) =
  let i = result.intVal
  case c.config.target.intSize
-  of 8: result.typ = getIntLitType(c, result)
+  of 8: result.typ() = getIntLitType(c, result)
  of 4:
    if i >= low(int32) and i <= high(int32):
-      result.typ = getIntLitType(c, result)
+      result.typ() = getIntLitType(c, result)
    else:
-      result.typ = getSysType(c.graph, result.info, tyInt64)
+      result.typ() = getSysType(c.graph, result.info, tyInt64)
  of 2:
    if i >= low(int16) and i <= high(int16):
-      result.typ = getIntLitType(c, result)
+      result.typ() = getIntLitType(c, result)
    elif i >= low(int32) and i <= high(int32):
-      result.typ = getSysType(c.graph, result.info, tyInt32)
+      result.typ() = getSysType(c.graph, result.info, tyInt32)
    else:
-      result.typ = getSysType(c.graph, result.info, tyInt64)
+      result.typ() = getSysType(c.graph, result.info, tyInt64)
  of 1:
    # 8 bit CPUs are insane ...
    if i >= low(int8) and i <= high(int8):
-      result.typ = getIntLitType(c, result)
+      result.typ() = getIntLitType(c, result)
    elif i >= low(int16) and i <= high(int16):
-      result.typ = getSysType(c.graph, result.info, tyInt16)
+      result.typ() = getSysType(c.graph, result.info, tyInt16)
    elif i >= low(int32) and i <= high(int32):
-      result.typ = getSysType(c.graph, result.info, tyInt32)
+      result.typ() = getSysType(c.graph, result.info, tyInt32)
    else:
-      result.typ = getSysType(c.graph, result.info, tyInt64)
+      result.typ() = getSysType(c.graph, result.info, tyInt64)
  else:
    internalError(c.config, result.info, "invalid int size")

@@ -268,7 +254,7 @@ proc popProcCon*(c: PContext) {.inline.} = c.p = c.p.next

 proc put*(p: PProcCon; key, val: PSym) =
  if not p.mappingExists:
-    p.mapping = initSymMapping()
+    p.mapping = initTable[ItemId, PSym]()
    p.mappingExists = true
  #echo "put into table ", key.info
  p.mapping[key.itemId] = val
@@ -300,24 +286,22 @@ proc considerGenSyms*(c: PContext; n: PNode) =
      considerGenSyms(c, n[i])

 proc newOptionEntry*(conf: ConfigRef): POptionEntry =
-  result = POptionEntry(
-    options: conf.options,
-    defaultCC: ccNimCall,
-    dynlib: nil,
-    notes: conf.notes,
-    warningAsErrors: conf.warningAsErrors
-  )
+  new(result)
+  result.options = conf.options
+  result.defaultCC = ccNimCall
+  result.dynlib = nil
+  result.notes = conf.notes
+  result.warningAsErrors = conf.warningAsErrors

 proc pushOptionEntry*(c: PContext): POptionEntry =
-  let prev = c.optionStack[^1]
-  result = POptionEntry(
-    options: c.config.options,
-    defaultCC: prev.defaultCC,
-    dynlib: prev.dynlib,
-    notes: c.config.notes,
-    warningAsErrors: c.config.warningAsErrors,
-    features: c.features
-  )
+  new(result)
+  var prev = c.optionStack[^1]
+  result.options = c.config.options
+  result.defaultCC = prev.defaultCC
+  result.dynlib = prev.dynlib
+  result.notes = c.config.notes
+  result.warningAsErrors = c.config.warningAsErrors
+  result.features = c.features
  c.optionStack.add(result)

 proc popOptionEntry*(c: PContext) =
@@ -328,34 +312,44 @@ proc popOptionEntry*(c: PContext) =
  c.optionStack.setLen(c.optionStack.len - 1)

 proc newContext*(graph: ModuleGraph; module: PSym): PContext =
-  result = PContext(
-    optionStack: @[newOptionEntry(graph.config)],
-    libs: @[],
-    module: module,
-    friendModules: @[module],
-    converters: @[],
-    patterns: @[],
-    includedFiles: initIntSet(),
-    pureEnumFields: initStrTable(),
-    userPragmas: initStrTable(),
-    generics: @[],
-    unknownIdents: initIntSet(),
-    cache: graph.cache,
-    graph: graph,
-    signatures: initStrTable(),
-    features: graph.config.features
-  )
+  new(result)
+  result.optionStack = @[newOptionEntry(graph.config)]
+  result.libs = @[]
+  result.module = module
+  result.friendModules = @[module]
+  result.converters = @[]
+  result.patterns = @[]
+  result.includedFiles = initIntSet()
+  result.pureEnumFields = initStrTable()
+  result.userPragmas = initStrTable()
+  result.generics = @[]
+  result.unknownIdents = initIntSet()
+  result.cache = graph.cache
+  result.graph = graph
+  result.signatures = initStrTable()
+  result.features = graph.config.features
+  if graph.config.symbolFiles != disabledSf:
+    let id = module.position
+    if graph.config.cmd != cmdM:
+      assert graph.packed[id].status in {undefined, outdated}
+    graph.packed[id].status = storing
+    graph.packed[id].module = module
+    initEncoder graph, module
+
+template packedRepr*(c): untyped = c.graph.packed[c.module.position].fromDisk
+template encoder*(c): untyped = c.graph.encoders[c.module.position]

 proc addIncludeFileDep*(c: PContext; f: FileIndex) =
-  discard
+  if c.config.symbolFiles != disabledSf:
+    addIncludeFileDep(c.encoder, c.packedRepr, f)

 proc addImportFileDep*(c: PContext; f: FileIndex) =
-  discard
+  if c.config.symbolFiles != disabledSf:
+    addImportFileDep(c.encoder, c.packedRepr, f)

 proc addPragmaComputation*(c: PContext; n: PNode) =
-  # Also store for NIF-based IC (cmdM mode or optCompress)
-  if optCompress in c.config.globalOptions or c.config.cmd == cmdM:
-    addNifReplayAction(c.graph, c.module.position.int32, n)
+  if c.config.symbolFiles != disabledSf:
+    addPragmaComputation(c.encoder, c.packedRepr, n)

 proc inclSym(sq: var seq[PSym], s: PSym): bool =
  for i in 0..<sq.len:
@@ -363,31 +357,42 @@ proc inclSym(sq: var seq[PSym], s: PSym): bool =
  sq.add s
  result = true

-proc addConverter*(c: PContext, conv: PSym) =
-  assert conv != nil
-  if inclSym(c.converters, conv):
+proc addConverter*(c: PContext, conv: LazySym) =
+  assert conv.sym != nil
+  if inclSym(c.converters, conv.sym):
    add(c.graph.ifaces[c.module.position].converters, conv)

-proc addConverterDef*(c: PContext, conv: PSym) =
+proc addConverterDef*(c: PContext, conv: LazySym) =
  addConverter(c, conv)
+  if c.config.symbolFiles != disabledSf:
+    addConverter(c.encoder, c.packedRepr, conv.sym)

-proc addPureEnum*(c: PContext, e: PSym) =
-  assert e != nil
+proc addPureEnum*(c: PContext, e: LazySym) =
+  assert e.sym != nil
  add(c.graph.ifaces[c.module.position].pureEnums, e)
+  if c.config.symbolFiles != disabledSf:
+    addPureEnum(c.encoder, c.packedRepr, e.sym)

-proc addPattern*(c: PContext, p: PSym) =
-  assert p != nil
-  if inclSym(c.patterns, p):
+proc addPattern*(c: PContext, p: LazySym) =
+  assert p.sym != nil
+  if inclSym(c.patterns, p.sym):
    add(c.graph.ifaces[c.module.position].patterns, p)
+  if c.config.symbolFiles != disabledSf:
+    addTrmacro(c.encoder, c.packedRepr, p.sym)

 proc exportSym*(c: PContext; s: PSym) =
  strTableAdds(c.graph, c.module, s)
+  if c.config.symbolFiles != disabledSf:
+    addExported(c.encoder, c.packedRepr, s)

 proc reexportSym*(c: PContext; s: PSym) =
  strTableAdds(c.graph, c.module, s)
+  if c.config.symbolFiles != disabledSf:
+    addReexport(c.encoder, c.packedRepr, s)

 proc newLib*(kind: TLibKind): PLib =
-  result = PLib(kind: kind)   #result.syms = initObjectSet()
+  new(result)
+  result.kind = kind          #result.syms = initObjectSet()

 proc addToLib*(lib: PLib, sym: PSym) =
  #if sym.annex != nil and not isGenericRoutine(sym):
@@ -421,7 +426,7 @@ proc makeVarType*(c: PContext, baseType: PType; kind = tyVar): PType =

 proc makeTypeSymNode*(c: PContext, typ: PType, info: TLineInfo): PNode =
  let typedesc = newTypeS(tyTypeDesc, c)
-  incl typedesc.flagsImpl, tfCheckedForDestructor
+  incl typedesc.flags, tfCheckedForDestructor
  internalAssert(c.config, typ != nil)
  typedesc.addSonSkipIntLit(typ, c.idgen)
  let sym = newSym(skType, c.cache.idAnon, c.idgen, getCurrOwner(c), info,
@@ -445,7 +450,7 @@ when false:
 proc makeStaticExpr*(c: PContext, n: PNode): PNode =
  result = newNodeI(nkStaticExpr, n.info)
  result.sons = @[n]
-  result.typ = if n.typ != nil and n.typ.kind == tyStatic: n.typ
+  result.typ() = if n.typ != nil and n.typ.kind == tyStatic: n.typ
               else: newTypeS(tyStatic, c, n.typ)

 proc makeAndType*(c: PContext, t1, t2: PType): PType =
@@ -454,8 +459,8 @@ proc makeAndType*(c: PContext, t1, t2: PType): PType =
  result.rawAddSon t2
  propagateToOwner(result, t1)
  propagateToOwner(result, t2)
-  result.flagsImpl.incl((t1.flags + t2.flags) * {tfHasStatic})
-  result.flagsImpl.incl tfHasMeta
+  result.flags.incl((t1.flags + t2.flags) * {tfHasStatic})
+  result.flags.incl tfHasMeta

 proc makeOrType*(c: PContext, t1, t2: PType): PType =
  if t1.kind != tyOr and t2.kind != tyOr:
@@ -473,14 +478,14 @@ proc makeOrType*(c: PContext, t1, t2: PType): PType =
    addOr(t2)
  propagateToOwner(result, t1)
  propagateToOwner(result, t2)
-  result.incl((t1.flags + t2.flags) * {tfHasStatic})
-  result.incl tfHasMeta
+  result.flags.incl((t1.flags + t2.flags) * {tfHasStatic})
+  result.flags.incl tfHasMeta

 proc makeNotType*(c: PContext, t1: PType): PType =
  result = newTypeS(tyNot, c, son = t1)
  propagateToOwner(result, t1)
-  result.flagsImpl.incl(t1.flags * {tfHasStatic})
-  result.flagsImpl.incl tfHasMeta
+  result.flags.incl(t1.flags * {tfHasStatic})
+  result.flags.incl tfHasMeta

 proc nMinusOne(c: PContext; n: PNode): PNode =
  result = newTreeI(nkCall, n.info, newSymNode(getSysMagic(c.graph, n.info, "pred", mPred)), n)
@@ -490,7 +495,7 @@ proc makeRangeWithStaticExpr*(c: PContext, n: PNode): PType =
  let intType = getSysType(c.graph, n.info, tyInt)
  result = newTypeS(tyRange, c, son = intType)
  if n.typ != nil and n.typ.n == nil:
-    result.incl tfUnresolved
+    result.flags.incl tfUnresolved
  result.n = newTreeI(nkRange, n.info, newIntTypeNode(0, intType),
    makeStaticExpr(c, nMinusOne(c, n)))

@@ -500,11 +505,11 @@ template rangeHasUnresolvedStatic*(t: PType): bool =
 proc errorType*(c: PContext): PType =
  ## creates a type representing an error state
  result = newTypeS(tyError, c)
-  result.flagsImpl.incl tfCheckedForDestructor
+  result.flags.incl tfCheckedForDestructor

 proc errorNode*(c: PContext, n: PNode): PNode =
  result = newNodeI(nkEmpty, n.info)
-  result.typ = errorType(c)
+  result.typ() = errorType(c)

 # These mimic localError
 template localErrorNode*(c: PContext, n: PNode, info: TLineInfo, msg: TMsgKind, arg: string): PNode =
@@ -550,21 +555,21 @@ proc makeTypeDesc*(c: PContext, typ: PType): PType =
    result = typ
  else:
    result = newTypeS(tyTypeDesc, c, skipIntLit(typ, c.idgen))
-    incl result, tfCheckedForDestructor
+    incl result.flags, tfCheckedForDestructor

 proc symFromType*(c: PContext; t: PType, info: TLineInfo): PSym =
  if t.sym != nil: return t.sym
  result = newSym(skType, getIdent(c.cache, "AnonType"), c.idgen, t.owner, info)
-  result.flagsImpl.incl sfAnon
+  result.flags.incl sfAnon
  result.typ = t

 proc symNodeFromType*(c: PContext, t: PType, info: TLineInfo): PNode =
  result = newSymNode(symFromType(c, t, info), info)
-  result.typ = makeTypeDesc(c, t)
+  result.typ() = makeTypeDesc(c, t)

 proc markIndirect*(c: PContext, s: PSym) {.inline.} =
  if s.kind in {skProc, skFunc, skConverter, skMethod, skIterator}:
-    incl(s.flagsImpl, sfAddrTaken)
+    incl(s.flags, sfAddrTaken)
    # XXX add to 'c' for global analysis

 proc illFormedAst*(n: PNode; conf: ConfigRef) =
@@ -599,11 +604,19 @@ template addExport*(c: PContext; s: PSym) =
  ## convenience to export a symbol from the current module
  addExport(c.graph, c.module, s)

+proc storeRodNode*(c: PContext, n: PNode) =
+  if c.config.symbolFiles != disabledSf:
+    toPackedNodeTopLevel(n, c.encoder, c.packedRepr)
+
 proc addToGenericProcCache*(c: PContext; s: PSym; inst: PInstantiation) =
-  c.graph.procInstCache.mgetOrPut(s.itemId, @[]).add inst
+  c.graph.procInstCache.mgetOrPut(s.itemId, @[]).add LazyInstantiation(module: c.module.position, inst: inst)
+  if c.config.symbolFiles != disabledSf:
+    storeInstantiation(c.encoder, c.packedRepr, s, inst)

 proc addToGenericCache*(c: PContext; s: PSym; inst: PType) =
-  c.graph.typeInstCache.mgetOrPut(s.itemId, @[]).add inst
+  c.graph.typeInstCache.mgetOrPut(s.itemId, @[]).add LazyType(typ: inst)
+  if c.config.symbolFiles != disabledSf:
+    storeTypeInst(c.encoder, c.packedRepr, s, inst)

 proc sealRodFile*(c: PContext) =
  if c.config.symbolFiles != disabledSf:
@@ -619,168 +632,6 @@ proc rememberExpansion*(c: PContext; info: TLineInfo; expandedSym: PSym) =
  ## in the sem'checked AST. This is very bad for IDE-like tooling
  ## ("find all usages of this template" would not work). We need special
  ## logic to remember macro/template expansions. This is done here and
-  ## delegated to the "NIF" file mechanism.
-  discard "XXX To implement"
-
-const
-  errVarForOutParamNeededX = "for a 'var' type a variable needs to be passed; but '$1' is immutable"
-  errXStackEscape = "address of '$1' may not escape its stack frame"
-
-proc renderNotLValue*(n: PNode): string =
-  result = $n
-  let n = if n.kind == nkHiddenDeref: n[0] else: n
-  if n.kind == nkHiddenCallConv and n.len > 1:
-    result = $n[0] & "(" & result & ")"
-  elif n.kind in {nkHiddenStdConv, nkHiddenSubConv} and n.len == 2:
-    result = typeToString(n.typ.skipTypes(abstractVar)) & "(" & result & ")"
-
-proc isAssignable(c: PContext, n: PNode): TAssignableResult =
-  result = parampatterns.isAssignable(c.p.owner, n)
-
-proc newHiddenAddrTaken(c: PContext, n: PNode, isOutParam: bool): PNode =
-  if n.kind == nkHiddenDeref and not (c.config.backend == backendCpp or
-                                      sfCompileToCpp in c.module.flags):
-    checkSonsLen(n, 1, c.config)
-    result = n[0]
-  else:
-    result = newNodeIT(nkHiddenAddr, n.info, makeVarType(c, n.typ))
-    result.add n
-    let aa = isAssignable(c, n)
-    let sym = getRoot(n)
-    if aa notin {arLValue, arLocalLValue}:
-      if aa == arDiscriminant and c.inUncheckedAssignSection > 0:
-        discard "allow access within a cast(unsafeAssign) section"
-      elif strictDefs in c.features and aa == arAddressableConst and
-              sym != nil and sym.kind == skLet and isOutParam:
-        discard "allow let varaibles to be passed to out parameters"
-      else:
-        localError(c.config, n.info, errVarForOutParamNeededX % renderNotLValue(n))
-
-proc analyseIfAddressTaken(c: PContext, n: PNode, isOutParam: bool): PNode =
-  result = n
-  case n.kind
-  of nkSym:
-    # n.sym.typ can be nil in 'check' mode ...
-    if n.sym.typ != nil and
-        skipTypes(n.sym.typ, abstractInst-{tyTypeDesc}).kind notin {tyVar, tyLent}:
-      incl(n.sym.flagsImpl, sfAddrTaken)
-      result = newHiddenAddrTaken(c, n, isOutParam)
-  of nkDotExpr:
-    checkSonsLen(n, 2, c.config)
-    if n[1].kind != nkSym:
-      internalError(c.config, n.info, "analyseIfAddressTaken")
-      return
-    if skipTypes(n[1].sym.typ, abstractInst-{tyTypeDesc}).kind notin {tyVar, tyLent}:
-      incl(n[1].sym.flagsImpl, sfAddrTaken)
-      result = newHiddenAddrTaken(c, n, isOutParam)
-  of nkBracketExpr:
-    checkMinSonsLen(n, 1, c.config)
-    if skipTypes(n[0].typ, abstractInst-{tyTypeDesc}).kind notin {tyVar, tyLent}:
-      if n[0].kind == nkSym: incl(n[0].sym.flagsImpl, sfAddrTaken)
-      result = newHiddenAddrTaken(c, n, isOutParam)
-  else:
-    result = newHiddenAddrTaken(c, n, isOutParam)
-
-proc analyseIfAddressTakenInCall*(c: PContext, n: PNode, isConverter = false) =
-  checkMinSonsLen(n, 1, c.config)
-  if n[0].typ == nil:
-    # n[0] might be erroring node in nimsuggest
-    return
-  const
-    FakeVarParams = {mNew, mNewFinalize, mInc, ast.mDec, mIncl, mExcl,
-      mSetLengthStr, mSetLengthSeq, mSetLengthSeqUninit, mAppendStrCh, mAppendStrStr, mSwap,
-      mAppendSeqElem, mNewSeq, mShallowCopy, mDeepCopy, mMove, mWasMoved}
-
-  template checkIfConverterCalled(c: PContext, n: PNode) =
-    ## Checks if there is a converter call which wouldn't be checked otherwise
-    # Call can sometimes be wrapped in a deref
-    let node = if n.kind == nkHiddenDeref: n[0] else: n
-    if node.kind == nkHiddenCallConv:
-      analyseIfAddressTakenInCall(c, node, true)
-  # get the real type of the callee
-  # it may be a proc var with a generic alias type, so we skip over them
-  var t = n[0].typ.skipTypes({tyGenericInst, tyAlias, tySink})
-  if n[0].kind == nkSym and n[0].sym.magic in FakeVarParams:
-    # BUGFIX: check for L-Value still needs to be done for the arguments!
-    # note sometimes this is eval'ed twice so we check for nkHiddenAddr here:
-    for i in 1..<n.len:
-      if i < t.len and t[i] != nil and
-          skipTypes(t[i], abstractInst-{tyTypeDesc}).kind in {tyVar}:
-        let it = n[i]
-        let aa = isAssignable(c, it)
-        if aa notin {arLValue, arLocalLValue}:
-          if it.kind != nkHiddenAddr:
-            if aa == arDiscriminant and c.inUncheckedAssignSection > 0:
-              discard "allow access within a cast(unsafeAssign) section"
-            else:
-              localError(c.config, it.info, errVarForOutParamNeededX % $it)
-        # Make sure to still check arguments for converters
-        c.checkIfConverterCalled(n[i])
-    # bug #5113: disallow newSeq(result) where result is a 'var T':
-    if n[0].sym.magic in {mNew, mNewFinalize, mNewSeq}:
-      var arg = n[1] #.skipAddr
-      if arg.kind == nkHiddenDeref: arg = arg[0]
-      if arg.kind == nkSym and arg.sym.kind == skResult and
-          arg.typ.skipTypes(abstractInst).kind in {tyVar, tyLent}:
-        localError(c.config, n.info, errXStackEscape % renderTree(n[1], {renderNoComments}))
-
-    return
-  for i in 1..<n.len:
-    let n = if n.kind == nkHiddenDeref: n[0] else: n
-    c.checkIfConverterCalled(n[i])
-    if i < t.len and
-        skipTypes(t[i], abstractInst-{tyTypeDesc}).kind in {tyVar}:
-      # Converters wrap var parameters in nkHiddenAddr but they haven't been analysed yet.
-      # So we need to make sure we are checking them still when in a converter call
-      if n[i].kind != nkHiddenAddr or isConverter:
-        n[i] = analyseIfAddressTaken(c, n[i].skipAddr(), isOutParam(skipTypes(t[i], abstractInst-{tyTypeDesc})))
-
-
-proc replaceHookMagic*(c: PContext, n: PNode, kind: TTypeAttachedOp): PNode =
-  ## Replaces builtin generic hooks with lifted hooks.
-  case kind
-  of attachedDestructor:
-    result = n
-    let t = n[1].typ.skipTypes({tyAlias, tyVar, tySink})
-    let op = getAttachedOp(c.graph, t, attachedDestructor)
-    if op != nil:
-      result[0] = newSymNode(op)
-      if op.typ != nil and op.typ.len == 2 and op.typ.firstParamType.kind != tyVar:
-        if n[1].kind == nkSym and n[1].sym.kind == skParam and
-            n[1].typ.kind == tyVar:
-          result[1] = genDeref(n[1])
-        else:
-          result[1] = skipAddr(n[1])
-  of attachedTrace:
-    result = n
-    let t = n[1].typ.skipTypes({tyAlias, tyVar, tySink})
-    let op = getAttachedOp(c.graph, t, attachedTrace)
-    if op != nil:
-      result[0] = newSymNode(op)
-  of attachedDup:
-    result = n
-    let t = n[1].typ.skipTypes({tyAlias, tyVar, tySink})
-    let op = getAttachedOp(c.graph, t, attachedDup)
-    if op != nil:
-      result[0] = newSymNode(op)
-      if op.typ.len == 3:
-        let boolLit = newIntLit(c.graph, n.info, 1)
-        boolLit.typ = getSysType(c.graph, n.info, tyBool)
-        result.add boolLit
-  of attachedWasMoved:
-    result = n
-    let t = n[1].typ.skipTypes({tyAlias, tyVar, tySink})
-    let op = getAttachedOp(c.graph, t, attachedWasMoved)
-    if op != nil:
-      result[0] = newSymNode(op)
-      analyseIfAddressTakenInCall(c, result, false)
-  of attachedSink:
-    result = c.semAsgnOpr(c, n, nkSinkAsgn)
-  of attachedAsgn:
-    result = c.semAsgnOpr(c, n, nkAsgn)
-  of attachedDeepCopy:
-    result = n
-    let t = n[1].typ.skipTypes({tyAlias, tyVar, tySink})
-    let op = getAttachedOp(c.graph, t, kind)
-    if op != nil:
-      result[0] = newSymNode(op)
+  ## delegated to the "rod" file mechanism.
+  if c.config.symbolFiles != disabledSf:
+    storeExpansion(c.encoder, c.packedRepr, info, expandedSym)
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
ringabout	86688cbcb0	fixes #24721 ; Table add missing sink	2025-02-25 20:26:37 +08:00
ringabout	c08f9311bf	fixes #24720 ; std lib iterators unnecessarily require value copies	2025-02-25 20:14:13 +08:00