temp

Cargo.toml

@@ -2,102 +2,39 @@
 resolver = "3"
 members = [
     "fix",
-  "fix-bytecode",
-  "fix-compiler",
+    "fix-builtins",
+    "fix-codegen",
+    "fix-common",
     "fix-error",
-  "fix-lang",
-  "fix-macros",
-  "fix-runtime",
+    "fix-ir",
     "fix-vm",
 ]
 
-[workspace.dependencies]
-bumpalo = {
-  version = "3.20",
-  features = [
-    "allocator-api2",
-    "boxed",
-    "collections",
-  ]
-}
-ere = "0.2"
-ghost-cell = "0.2"
-hashbrown = "0.17"
-num_enum = "0.7"
-rnix = "0.14"
-rowan = "0.16"
-smallvec = { version = "1.15", features = ["const_generics", "const_new"] }
-string-interner = "0.20"
-gc-arena = { version = "0.7", features = ["hashbrown", "smallvec"] }
-
-# https://emschwartz.me/your-clippy-config-should-be-stricter/
-# tombi: format.rules.table-keys-order.disabled = true
-[workspace.lints.clippy]
-# Don't Panic - prevent panics from unwraps and unsafe slicing or indexing
-string_slice = "warn"
-indexing_slicing = "warn"
-unwrap_used = "warn"
-panic = "warn"
-# WIP evaluator: several features are deliberately stubbed with todo!/unimplemented!
-todo = "allow"
-unimplemented = "allow"
-unreachable = "warn"
-get_unwrap = "warn"
-unwrap_in_result = "warn"
-unchecked_time_subtraction = "warn"
-panic_in_result_fn = "warn"
-# Optional - see post for caveats
-# expect_used = "warn"
-# arithmetic_side_effects = "warn"
-
-# Don't Fail Silently - prevent dropped futures and swallowed errors
-let_underscore_future = "warn"
-let_underscore_must_use = "warn"
-unused_result_ok = "warn"
-map_err_ignore = "warn"
-assertions_on_result_states = "warn"
-
-# Don't Do Bad Async Stuff - prevent deadlocks and concurrency bugs
-await_holding_lock = "warn"
-await_holding_refcell_ref = "warn"
-if_let_mutex = "warn"  # only relevant on editions before 2024
-large_futures = "warn"
-
-# Don't Do Unsafe Things with Memory
-mem_forget = "warn"
-undocumented_unsafe_blocks = "warn"
-multiple_unsafe_ops_per_block = "warn"
-unnecessary_safety_doc = "warn"
-unnecessary_safety_comment = "warn"
-
-# Don't Do Potentially Incorrect Things with Numbers
-float_cmp = "warn"
-float_cmp_const = "warn"
-lossy_float_literal = "warn"
-cast_sign_loss = "warn"
-invalid_upcast_comparisons = "warn"
-# Optional - these effectively force you to document numeric invariants
-# cast_possible_wrap = "warn"
-# cast_precision_loss = "warn"
-# cast_possible_truncation = "warn"
-
-# Don't Do Bad Things That are Easy to Avoid
-rc_mutex = "warn"
-debug_assert_with_mut_call = "warn"
-iter_not_returning_iterator = "warn"
-expl_impl_clone_on_copy = "warn"
-infallible_try_from = "warn"
-dbg_macro = "warn"
-
-# Don't `allow` Your Way Around These Lints - every suppression must be
-# a deliberate #[expect(..., reason = "…")] rather than a silent #[allow]
-allow_attributes = "warn"
-allow_attributes_without_reason = "warn"
+[profile.profiling]
+inherits = "release"
+debug = true
 
 [profile.lto]
 inherits = "release"
 lto = true
 
-[profile.profiling]
-inherits = "release"
-debug = true
+[workspace.dependencies]
+bumpalo = { version = "3.20", features = [
+    "allocator-api2",
+    "boxed",
+    "collections",
+] }
+ghost-cell = "0.2"
+hashbrown = "0.16"
+num_enum = "0.7.5"
+smallvec = "1.15"
+ere = "0.2"
+string-interner = "0.19"
+rnix = "0.14"
+rowan = "0.16"
+likely_stable = "0.1"
+
+[workspace.dependencies.gc-arena]
+git = "https://github.com/kyren/gc-arena"
+rev = "75671ae03f53718357b741ed4027560f14e90836"
+features = ["allocator-api2", "hashbrown", "smallvec"]

Justfile

@@ -14,6 +14,22 @@
 @evalr expr:
   cargo run --release -- eval --expr '{{expr}}'
 
+[no-exit-message]
+@repli:
+  cargo run --release --features inspector -- --inspect-brk 127.0.0.1:9229 repl
+
+[no-exit-message]
+@evali expr:
+  cargo run --release --features inspector -- --inspect-brk 127.0.0.1:9229 eval --expr '{{expr}}'
+
+[no-exit-message]
+@replp:
+  cargo run --release --features prof -- repl
+
+[no-exit-message]
+@evalp expr:
+  cargo run --release --features prof -- eval --expr '{{expr}}'
+
 [no-exit-message]
 [positional-arguments]
 @cg *args='':

biome.json

@@ -0,0 +1,70 @@
+{
+  "$schema": "https://biomejs.dev/schemas/2.3.14/schema.json",
+  "vcs": {
+    "enabled": true,
+    "clientKind": "git",
+    "useIgnoreFile": true
+  },
+  "files": {
+    "includes": ["**", "!!**/dist"]
+  },
+  "formatter": {
+    "enabled": true,
+    "formatWithErrors": true,
+    "attributePosition": "auto",
+    "indentStyle": "space",
+    "indentWidth": 2,
+    "lineWidth": 110,
+    "lineEnding": "lf"
+  },
+  "linter": {
+    "rules": {
+      "style": {
+        "useNamingConvention": {
+          "level": "warn",
+          "options": {
+            "strictCase": false,
+            "conventions": [
+              {
+                "selector": { "kind": "objectLiteralProperty" },
+                "formats": ["camelCase", "PascalCase", "CONSTANT_CASE"]
+              },
+              {
+                "selector": { "kind": "typeProperty" },
+                "formats": ["camelCase", "snake_case"]
+              }
+            ]
+          }
+        }
+      }
+    }
+  },
+  "overrides": [
+    {
+      "includes": ["**/global.d.ts"],
+      "linter": {
+        "rules": {
+          "style": {
+            "useNamingConvention": "off"
+          }
+        }
+      }
+    }
+  ],
+  "javascript": {
+    "formatter": {
+      "arrowParentheses": "always",
+      "bracketSameLine": false,
+      "bracketSpacing": true,
+      "jsxQuoteStyle": "double",
+      "quoteProperties": "asNeeded",
+      "semicolons": "always",
+      "trailingCommas": "all"
+    }
+  },
+  "json": {
+    "formatter": {
+      "trailingCommas": "none"
+    }
+  }
+}

clippy.toml

@@ -1,5 +0,0 @@
-allow-indexing-slicing-in-tests = true
-allow-panic-in-tests = true
-allow-unwrap-in-tests = true
-allow-expect-in-tests = true
-allow-dbg-in-tests = true

devShell.nix

@@ -1,24 +0,0 @@
-{ pkgs }:
-pkgs.mkShell {
-  packages = with pkgs; [
-    (fenix.latest.withComponents [
-      "cargo"
-      "clippy"
-      "rust-src"
-      "rustc"
-      "rustfmt"
-      "rust-analyzer"
-    ])
-    cargo-machete
-    cargo-bloat
-    cargo-expand
-    lldb
-    valgrind
-    kdePackages.kcachegrind
-    hyperfine
-    just
-    samply
-    tokei
-    tombi
-  ];
-}

fix-builtins/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "fix-builtins"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+num_enum = { workspace = true }
+gc-arena = { workspace = true }

fix-builtins/src/lib.rs

@@ -0,0 +1,366 @@
+use gc_arena::Collect;
+use num_enum::TryFromPrimitive;
+
+macro_rules! define_builtins {
+    ($(($name:literal, $variant:ident, $arity:expr)),* $(,)?) => {
+        /// Builtin function registry.
+        /// Array index IS the PrimOp id. (name, arity) pairs.
+        pub const BUILTINS: &[(&str, u8)] = &[
+            $(($name, $arity),)*
+        ];
+
+        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, TryFromPrimitive, Collect)]
+        #[repr(u8)]
+        #[collect(require_static)]
+        pub enum BuiltinId {
+            $($variant,)*
+        }
+    };
+}
+
+define_builtins! {
+    ("abort",                    Abort,                    1),
+    ("__add",                      Add,                      2),
+    ("__addErrorContext",          AddErrorContext,           2),
+    ("__all",                      All,                      2),
+    ("__any",                      Any,                      2),
+    ("__appendContext",            AppendContext,             2),
+    ("__attrNames",                AttrNames,                1),
+    ("__attrValues",               AttrValues,               1),
+    ("baseNameOf",               BaseNameOf,               1),
+    ("__bitAnd",                   BitAnd,                   2),
+    ("__bitOr",                    BitOr,                    2),
+    ("__bitXor",                   BitXor,                   2),
+    ("break",                    Break,                    1),
+    ("__catAttrs",                 CatAttrs,                 2),
+    ("__ceil",                     Ceil,                     1),
+    ("__compareVersions",          CompareVersions,          2),
+    ("__concatLists",              ConcatLists,              1),
+    ("__concatMap",                ConcatMap,                2),
+    ("__concatStringsSep",         ConcatStringsSep,         2),
+    ("__convertHash",              ConvertHash,              1),
+    ("__deepSeq",                  DeepSeq,                  2),
+    ("derivation",               Derivation,               1),
+    ("derivationStrict",         DerivationStrict,         1),
+    ("dirOf",                    DirOf,                    1),
+    ("__div",                      Div,                      2),
+    ("__elem",                     Elem,                     2),
+    ("__elemAt",                   ElemAt,                   2),
+    ("fetchGit",                 FetchGit,                 1),
+    ("fetchMercurial",           FetchMercurial,           1),
+    ("fetchTarball",             FetchTarball,             1),
+    ("fetchTree",                FetchTree,                1),
+    ("__fetchurl",                 FetchUrl,                 1),
+    ("__filter",                   Filter,                   2),
+    ("__filterSource",             FilterSource,             2),
+    ("__findFile",                 FindFile,                 2),
+    ("__floor",                    Floor,                    1),
+    ("__foldl'",                   FoldlStrict,              3),
+    ("__fromJSON",                 FromJSON,                 1),
+    ("fromTOML",                 FromTOML,                 1),
+    ("__functionArgs",             FunctionArgs,             1),
+    ("__genList",                  GenList,                  2),
+    ("__genericClosure",           GenericClosure,           1),
+    ("__getAttr",                  GetAttr,                  2),
+    ("__getContext",               GetContext,               1),
+    ("__getEnv",                   GetEnv,                   1),
+    ("__groupBy",                  GroupBy,                  2),
+    ("__hasAttr",                  HasAttr,                  2),
+    ("__hasContext",               HasContext,               1),
+    ("__hashFile",                 HashFile,                 2),
+    ("__hashString",               HashString,               2),
+    ("__head",                     Head,                     1),
+    ("import",                   Import,                   1),
+    ("__intersectAttrs",           IntersectAttrs,           2),
+    ("__isAttrs",                  IsAttrs,                  1),
+    ("__isBool",                   IsBool,                   1),
+    ("__isFloat",                  IsFloat,                  1),
+    ("__isFunction",               IsFunction,               1),
+    ("__isInt",                    IsInt,                    1),
+    ("__isList",                   IsList,                   1),
+    ("isNull",                   IsNull,                   1),
+    ("__isPath",                   IsPath,                   1),
+    ("__isString",                 IsString,                 1),
+    ("__length",                   Length,                   1),
+    ("__lessThan",                 LessThan,                 2),
+    ("__listToAttrs",              ListToAttrs,              1),
+    ("map",                      Map,                      2),
+    ("__mapAttrs",                 MapAttrs,                 2),
+    ("__match",                    Match,                    2),
+    ("__mul",                      Mul,                      2),
+    ("__parseDrvName",             ParseDrvName,             1),
+    ("__partition",                Partition,                2),
+    ("__path",                     Path,                     1),
+    ("__pathExists",               PathExists,               1),
+    ("placeholder",              Placeholder,              1),
+    ("__readDir",                  ReadDir,                  1),
+    ("__readFile",                 ReadFile,                 1),
+    ("__readFileType",             ReadFileType,             1),
+    ("removeAttrs",              RemoveAttrs,              2),
+    ("__replaceStrings",           ReplaceStrings,           3),
+    ("scopedImport",             ScopedImport,             2),
+    ("__seq",                      Seq,                      2),
+    ("__sort",                     Sort,                     2),
+    ("__split",                    Split,                    2),
+    ("__splitVersion",             SplitVersion,             1),
+    ("__storePath",                StorePath,                1),
+    ("__stringLength",             StringLength,             1),
+    ("__sub",                      Sub,                      2),
+    ("__substring",                Substring,                3),
+    ("__tail",                     Tail,                     1),
+    ("throw",                    Throw,                    1),
+    ("__toFile",                   ToFile,                   2),
+    ("__toJSON",                   ToJSON,                   1),
+    ("__toPath",                   ToPath,                   1),
+    ("toString",                 ToString,                 1),
+    ("__toXML",                    ToXML,                    1),
+    ("__trace",                    Trace,                    2),
+    ("__tryEval",                  TryEval,                  1),
+    ("__typeOf",                   TypeOf,                   1),
+    ("__unsafeDiscardStringContext", UnsafeDiscardStringContext, 1),
+    ("__unsafeGetAttrPos",         UnsafeGetAttrPos,         2),
+    ("__warn",                     Warn,                     2),
+    ("__zipAttrsWith",             ZipAttrsWith,             2),
+}
+
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq, TryFromPrimitive)]
+pub enum PrimOpPhase {
+    Abort,
+    Add,
+    AddErrorContext,
+    All,
+    Any,
+    AppendContext,
+    AttrNames,
+    AttrValues,
+    BaseNameOf,
+    BitAnd,
+    BitOr,
+    BitXor,
+    Break,
+    CatAttrs,
+    Ceil,
+    CompareVersions,
+    ConcatLists,
+    ConcatMap,
+    ConcatStringsSep,
+    ConvertHash,
+
+    DeepSeq,
+    DeepSeqPush,
+    DeepSeqLoop,
+
+    Derivation,
+    DerivationStrict,
+    DirOf,
+    Div,
+    Elem,
+    ElemAt,
+    FetchGit,
+    FetchMercurial,
+    FetchTarball,
+    FetchTree,
+    FetchUrl,
+
+    FilterForceList,
+    FilterCallPred,
+    FilterCheck,
+
+    FilterSource,
+    FindFile,
+    Floor,
+    FoldlStrict,
+    FromJSON,
+    FromTOML,
+    FunctionArgs,
+    GenList,
+    GenericClosure,
+    GetAttr,
+    GetContext,
+    GetEnv,
+    GroupBy,
+    HasAttr,
+    HasContext,
+    HashFile,
+    HashString,
+    Head,
+    Import,
+    IntersectAttrs,
+    IsAttrs,
+    IsBool,
+    IsFloat,
+    IsFunction,
+    IsInt,
+    IsList,
+    IsNull,
+    IsPath,
+    IsString,
+    Length,
+    LessThan,
+    ListToAttrs,
+    Map,
+    MapAttrs,
+    Match,
+    Mul,
+    ParseDrvName,
+    Partition,
+    Path,
+    PathExists,
+    Placeholder,
+    ReadDir,
+    ReadFile,
+    ReadFileType,
+    RemoveAttrs,
+    ReplaceStrings,
+    ScopedImport,
+    Seq,
+    Sort,
+    Split,
+    SplitVersion,
+    StorePath,
+    StringLength,
+    Sub,
+    Substring,
+    Tail,
+    Throw,
+    ToFile,
+    ToJSON,
+    ToPath,
+    ToString,
+    ToXML,
+    Trace,
+    TryEval,
+    TypeOf,
+    UnsafeDiscardStringContext,
+    UnsafeGetAttrPos,
+    Warn,
+    ZipAttrsWith,
+
+    ForceResultShallow,
+    ForceResultShallowPush,
+    ForceResultShallowLoop,
+    ForceResultDeepFinish,
+
+    // TODO: split into separate enums
+    CallPattern,
+
+    Illegal,
+}
+
+impl BuiltinId {
+    #[inline(always)]
+    pub fn entry_phase(self) -> PrimOpPhase {
+        use BuiltinId::*;
+        match self {
+            Abort => PrimOpPhase::Abort,
+            Add => PrimOpPhase::Add,
+            AddErrorContext => PrimOpPhase::AddErrorContext,
+            All => PrimOpPhase::All,
+            Any => PrimOpPhase::Any,
+            AppendContext => PrimOpPhase::AppendContext,
+            AttrNames => PrimOpPhase::AttrNames,
+            AttrValues => PrimOpPhase::AttrValues,
+            BaseNameOf => PrimOpPhase::BaseNameOf,
+            BitAnd => PrimOpPhase::BitAnd,
+            BitOr => PrimOpPhase::BitOr,
+            BitXor => PrimOpPhase::BitXor,
+            Break => PrimOpPhase::Break,
+            CatAttrs => PrimOpPhase::CatAttrs,
+            Ceil => PrimOpPhase::Ceil,
+            CompareVersions => PrimOpPhase::CompareVersions,
+            ConcatLists => PrimOpPhase::ConcatLists,
+            ConcatMap => PrimOpPhase::ConcatMap,
+            ConcatStringsSep => PrimOpPhase::ConcatStringsSep,
+            ConvertHash => PrimOpPhase::ConvertHash,
+            DeepSeq => PrimOpPhase::DeepSeq,
+            Derivation => PrimOpPhase::Derivation,
+            DerivationStrict => PrimOpPhase::DerivationStrict,
+            DirOf => PrimOpPhase::DirOf,
+            Div => PrimOpPhase::Div,
+            Elem => PrimOpPhase::Elem,
+            ElemAt => PrimOpPhase::ElemAt,
+            FetchGit => PrimOpPhase::FetchGit,
+            FetchMercurial => PrimOpPhase::FetchMercurial,
+            FetchTarball => PrimOpPhase::FetchTarball,
+            FetchTree => PrimOpPhase::FetchTree,
+            FetchUrl => PrimOpPhase::FetchUrl,
+            Filter => PrimOpPhase::FilterForceList,
+            FilterSource => PrimOpPhase::FilterSource,
+            FindFile => PrimOpPhase::FindFile,
+            Floor => PrimOpPhase::Floor,
+            FoldlStrict => PrimOpPhase::FoldlStrict,
+            FromJSON => PrimOpPhase::FromJSON,
+            FromTOML => PrimOpPhase::FromTOML,
+            FunctionArgs => PrimOpPhase::FunctionArgs,
+            GenList => PrimOpPhase::GenList,
+            GenericClosure => PrimOpPhase::GenericClosure,
+            GetAttr => PrimOpPhase::GetAttr,
+            GetContext => PrimOpPhase::GetContext,
+            GetEnv => PrimOpPhase::GetEnv,
+            GroupBy => PrimOpPhase::GroupBy,
+            HasAttr => PrimOpPhase::HasAttr,
+            HasContext => PrimOpPhase::HasContext,
+            HashFile => PrimOpPhase::HashFile,
+            HashString => PrimOpPhase::HashString,
+            Head => PrimOpPhase::Head,
+            Import => PrimOpPhase::Import,
+            IntersectAttrs => PrimOpPhase::IntersectAttrs,
+            IsAttrs => PrimOpPhase::IsAttrs,
+            IsBool => PrimOpPhase::IsBool,
+            IsFloat => PrimOpPhase::IsFloat,
+            IsFunction => PrimOpPhase::IsFunction,
+            IsInt => PrimOpPhase::IsInt,
+            IsList => PrimOpPhase::IsList,
+            IsNull => PrimOpPhase::IsNull,
+            IsPath => PrimOpPhase::IsPath,
+            IsString => PrimOpPhase::IsString,
+            Length => PrimOpPhase::Length,
+            LessThan => PrimOpPhase::LessThan,
+            ListToAttrs => PrimOpPhase::ListToAttrs,
+            Map => PrimOpPhase::Map,
+            MapAttrs => PrimOpPhase::MapAttrs,
+            Match => PrimOpPhase::Match,
+            Mul => PrimOpPhase::Mul,
+            ParseDrvName => PrimOpPhase::ParseDrvName,
+            Partition => PrimOpPhase::Partition,
+            Path => PrimOpPhase::Path,
+            PathExists => PrimOpPhase::PathExists,
+            Placeholder => PrimOpPhase::Placeholder,
+            ReadDir => PrimOpPhase::ReadDir,
+            ReadFile => PrimOpPhase::ReadFile,
+            ReadFileType => PrimOpPhase::ReadFileType,
+            RemoveAttrs => PrimOpPhase::RemoveAttrs,
+            ReplaceStrings => PrimOpPhase::ReplaceStrings,
+            ScopedImport => PrimOpPhase::ScopedImport,
+            Seq => PrimOpPhase::Seq,
+            Sort => PrimOpPhase::Sort,
+            Split => PrimOpPhase::Split,
+            SplitVersion => PrimOpPhase::SplitVersion,
+            StorePath => PrimOpPhase::StorePath,
+            StringLength => PrimOpPhase::StringLength,
+            Sub => PrimOpPhase::Sub,
+            Substring => PrimOpPhase::Substring,
+            Tail => PrimOpPhase::Tail,
+            Throw => PrimOpPhase::Throw,
+            ToFile => PrimOpPhase::ToFile,
+            ToJSON => PrimOpPhase::ToJSON,
+            ToPath => PrimOpPhase::ToPath,
+            ToString => PrimOpPhase::ToString,
+            ToXML => PrimOpPhase::ToXML,
+            Trace => PrimOpPhase::Trace,
+            TryEval => PrimOpPhase::TryEval,
+            TypeOf => PrimOpPhase::TypeOf,
+            UnsafeDiscardStringContext => PrimOpPhase::UnsafeDiscardStringContext,
+            UnsafeGetAttrPos => PrimOpPhase::UnsafeGetAttrPos,
+            Warn => PrimOpPhase::Warn,
+            ZipAttrsWith => PrimOpPhase::ZipAttrsWith,
+        }
+    }
+}
+
+impl PrimOpPhase {
+    pub fn ip(self) -> u32 {
+        self as u32 * 2
+    }
+}

fix-bytecode/Cargo.toml

@@ -1,14 +0,0 @@
-[package]
-name = "fix-bytecode"
-version = "0.1.0"
-edition = "2024"
-
-[dependencies]
-colored = "3.1.1"
-num_enum = { workspace = true }
-string-interner = { workspace = true }
-
-fix-lang = { path = "../fix-lang" }
-
-[lints]
-workspace = true

fix-bytecode/src/lib.rs

@@ -1,614 +0,0 @@
-#![allow(
-    dead_code,
-    reason = "crate is under active development; some opcodes and helpers are not yet wired up"
-)]
-
-use fix_lang::{BuiltinId, StringId};
-use num_enum::TryFromPrimitive;
-use string_interner::Symbol as _;
-
-pub mod disassembler;
-
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub struct InstructionPtr(pub usize);
-
-#[repr(u8)]
-#[derive(Debug, Clone, Copy)]
-pub enum Op {
-    PushSmi,
-    PushBigInt,
-    PushFloat,
-    PushString,
-    PushNull,
-    PushTrue,
-    PushFalse,
-
-    LoadLocal,
-    LoadOuter,
-    StoreLocal,
-    AllocLocals,
-
-    MakeThunk,
-    MakeClosure,
-    MakePatternClosure,
-
-    Call,
-    DispatchCont,
-
-    MakeAttrs,
-    MakeEmptyAttrs,
-    SelectStatic,
-    SelectDynamic,
-    HasAttrPathStatic,
-    HasAttrPathDynamic,
-    HasAttrStatic,
-    HasAttrDynamic,
-    HasAttrResolve,
-    JumpIfSelectSucceeded,
-    JumpIfSelectFailed,
-
-    MakeList,
-    MakeEmptyList,
-
-    OpAdd,
-    OpSub,
-    OpMul,
-    OpDiv,
-    OpEq,
-    OpNeq,
-    OpLt,
-    OpGt,
-    OpLeq,
-    OpGeq,
-    OpConcat,
-    OpUpdate,
-
-    OpNeg,
-    OpNot,
-
-    JumpIfFalse,
-    JumpIfTrue,
-    Jump,
-
-    CoerceToString,
-
-    ConcatStrings,
-    ResolvePath,
-
-    Assert,
-
-    LookupWith,
-
-    LoadBuiltins,
-    LoadBuiltin,
-
-    LoadReplBinding,
-    LoadScopedBinding,
-
-    Return,
-
-    Illegal,
-}
-
-impl TryFrom<u8> for Op {
-    type Error = u8;
-
-    #[inline(always)]
-    fn try_from(value: u8) -> Result<Self, Self::Error> {
-        if (0..Self::Illegal as u8).contains(&value) {
-            // SAFETY: `value` is in `0..Illegal`, which are exactly the valid
-            // discriminants of this `#[repr(u8)]` enum, so the transmute is sound.
-            Ok(unsafe { std::mem::transmute::<u8, Self>(value) })
-        } else {
-            Err(value)
-        }
-    }
-}
-
-#[repr(u8)]
-#[derive(Debug, Clone, Copy, TryFromPrimitive)]
-pub enum OperandType {
-    Const,
-    BigInt,
-    Local,
-    BuiltinConst,
-    Builtins,
-    ReplBinding,
-    ScopedImportBinding,
-}
-
-pub enum Const {
-    Smi(i32),
-    Float(f64),
-    Bool(bool),
-    String(StringId),
-    Path(StringId),
-    PrimOp(BuiltinId),
-    Null,
-}
-
-#[repr(u8)]
-#[derive(Debug, Clone, Copy, TryFromPrimitive)]
-pub enum AttrKeyType {
-    Static,
-    Dynamic,
-}
-
-pub enum OperandData {
-    Const(u32),
-    BigInt(i64),
-    Local { layer: u8, idx: u32 },
-    BuiltinConst(StringId),
-    Builtins,
-    ReplBinding(StringId),
-    ScopedImportBinding { slot_id: u32, name: StringId },
-}
-
-#[repr(u8)]
-#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
-pub enum Continuation {
-    // primops
-    PAbort,
-    PAdd,
-    PAddErrorContext,
-
-    PAll0,
-    PAll1,
-    PAll2,
-    PAll3,
-
-    PAny0,
-    PAny1,
-    PAny2,
-    PAny3,
-
-    PAppendContext,
-    PAppendContextLoop,
-    PAppendContextEntryForced,
-    PAppendContextOutputsForced,
-    PAppendContextOutputElementLoop,
-    PAppendContextOutputElementForced,
-
-    PAttrNames,
-    PAttrValues,
-    PBaseNameOf,
-    PBitAnd,
-    PBitOr,
-    PBitXor,
-    PBreak,
-    PCatAttrs,
-    PCeil,
-    PCompareVersions,
-    PConcatLists,
-    PConcatMap,
-    PConcatStringsSep,
-    PConvertHash,
-
-    PDeepSeq0,
-    PDeepSeq1,
-    PDeepSeq2,
-    PDeepSeq3,
-    PDeepSeq4,
-    PDeepSeq5,
-
-    PDerivation,
-    PDerivationStrict,
-    PDirOf,
-    PDiv,
-    PElem,
-    PElemAt,
-    PFetchGit,
-    PFetchMercurial,
-    PFetchTarball,
-    PFetchTree,
-    PFetchUrl,
-
-    PFilter0,
-    PFilter1,
-    PFilter2,
-    PFilter3,
-    PFilter4,
-
-    PFilterSource,
-    PFindFile,
-    PFloor,
-    PFoldlStrict0,
-    PFoldlStrict1,
-    PFoldlStrict2,
-    PFoldlStrict3,
-    PFoldlStrict4,
-    PFoldlStrict5,
-    PFromJSON,
-    PFromTOML,
-    PFunctionArgs,
-    PGenList,
-    PGenericClosure,
-    PGetAttr,
-    PGetContext,
-    PGetEnv,
-    PGroupBy,
-    PHasAttr,
-    PHasContext,
-    PHashFile,
-    PHashString,
-    PHead,
-
-    PImport,
-    PImportFinalize,
-    PScopedImport,
-    PScopedImportFinalize,
-
-    PIntersectAttrs,
-    PIsAttrs,
-    PIsBool,
-    PIsFloat,
-    PIsFunction,
-    PIsInt,
-    PIsList,
-    PIsNull,
-    PIsPath,
-    PIsString,
-    PLength,
-    PLessThan,
-    PListToAttrs,
-    PMap,
-    PMapAttrs,
-    PMatch,
-    PMul,
-    PParseDrvName,
-    PPartition,
-    PPath,
-    PPathExists,
-    PPlaceholder,
-    PReadDir,
-    PReadFile,
-    PReadFileType,
-    PRemoveAttrs,
-    PReplaceStrings,
-    PSeq0,
-    PSeq1,
-    PSort,
-    PSplit,
-    PSplitVersion,
-    PStorePath,
-    PStringLength,
-    PSub,
-    PSubstring,
-    PTail,
-    PThrow,
-    PToFile,
-    PToJSON,
-    PToPath,
-    PToString,
-    PToXML,
-    PTrace,
-    PTryEval,
-    PTypeOf,
-    PUnsafeDiscardStringContext,
-    PUnsafeGetAttrPos,
-    PWarn,
-    PZipAttrsWith,
-    PUnsafeDiscardOutputDependency,
-
-    ForceResultShallow,
-    ForceResultShallowPush,
-    ForceResultShallowLoop,
-    ForceResultDeepFinish,
-
-    EqStep,
-    EqForce,
-
-    CallPattern,
-    CallFunctor1,
-    CallFunctor2,
-
-    Illegal,
-}
-
-impl TryFrom<u8> for Continuation {
-    type Error = u8;
-
-    #[inline(always)]
-    fn try_from(value: u8) -> Result<Self, Self::Error> {
-        if (0..Self::Illegal as u8).contains(&value) {
-            // SAFETY: `value` is in `0..Illegal`, which are exactly the valid
-            // discriminants of this `#[repr(u8)]` enum, so the transmute is sound.
-            Ok(unsafe { std::mem::transmute::<u8, Self>(value) })
-        } else {
-            Err(value)
-        }
-    }
-}
-
-impl Continuation {
-    pub const fn entry_for_builtin(id: BuiltinId) -> Self {
-        use BuiltinId::*;
-        match id {
-            Abort => Self::PAbort,
-            Add => Self::PAdd,
-            AddErrorContext => Self::PAddErrorContext,
-            All => Self::PAll0,
-            Any => Self::PAny0,
-            AppendContext => Self::PAppendContext,
-            AttrNames => Self::PAttrNames,
-            AttrValues => Self::PAttrValues,
-            BaseNameOf => Self::PBaseNameOf,
-            BitAnd => Self::PBitAnd,
-            BitOr => Self::PBitOr,
-            BitXor => Self::PBitXor,
-            Break => Self::PBreak,
-            CatAttrs => Self::PCatAttrs,
-            Ceil => Self::PCeil,
-            CompareVersions => Self::PCompareVersions,
-            ConcatLists => Self::PConcatLists,
-            ConcatMap => Self::PConcatMap,
-            ConcatStringsSep => Self::PConcatStringsSep,
-            ConvertHash => Self::PConvertHash,
-            DeepSeq => Self::PDeepSeq0,
-            Derivation => Self::PDerivation,
-            DerivationStrict => Self::PDerivationStrict,
-            DirOf => Self::PDirOf,
-            Div => Self::PDiv,
-            Elem => Self::PElem,
-            ElemAt => Self::PElemAt,
-            FetchGit => Self::PFetchGit,
-            FetchMercurial => Self::PFetchMercurial,
-            FetchTarball => Self::PFetchTarball,
-            FetchTree => Self::PFetchTree,
-            FetchUrl => Self::PFetchUrl,
-            Filter => Self::PFilter0,
-            FilterSource => Self::PFilterSource,
-            FindFile => Self::PFindFile,
-            Floor => Self::PFloor,
-            FoldlStrict => Self::PFoldlStrict0,
-            FromJSON => Self::PFromJSON,
-            FromTOML => Self::PFromTOML,
-            FunctionArgs => Self::PFunctionArgs,
-            GenList => Self::PGenList,
-            GenericClosure => Self::PGenericClosure,
-            GetAttr => Self::PGetAttr,
-            GetContext => Self::PGetContext,
-            GetEnv => Self::PGetEnv,
-            GroupBy => Self::PGroupBy,
-            HasAttr => Self::PHasAttr,
-            HasContext => Self::PHasContext,
-            HashFile => Self::PHashFile,
-            HashString => Self::PHashString,
-            Head => Self::PHead,
-            Import => Self::PImport,
-            IntersectAttrs => Self::PIntersectAttrs,
-            IsAttrs => Self::PIsAttrs,
-            IsBool => Self::PIsBool,
-            IsFloat => Self::PIsFloat,
-            IsFunction => Self::PIsFunction,
-            IsInt => Self::PIsInt,
-            IsList => Self::PIsList,
-            IsNull => Self::PIsNull,
-            IsPath => Self::PIsPath,
-            IsString => Self::PIsString,
-            Length => Self::PLength,
-            LessThan => Self::PLessThan,
-            ListToAttrs => Self::PListToAttrs,
-            Map => Self::PMap,
-            MapAttrs => Self::PMapAttrs,
-            Match => Self::PMatch,
-            Mul => Self::PMul,
-            ParseDrvName => Self::PParseDrvName,
-            Partition => Self::PPartition,
-            Path => Self::PPath,
-            PathExists => Self::PPathExists,
-            Placeholder => Self::PPlaceholder,
-            ReadDir => Self::PReadDir,
-            ReadFile => Self::PReadFile,
-            ReadFileType => Self::PReadFileType,
-            RemoveAttrs => Self::PRemoveAttrs,
-            ReplaceStrings => Self::PReplaceStrings,
-            ScopedImport => Self::PScopedImport,
-            Seq => Self::PSeq0,
-            Sort => Self::PSort,
-            Split => Self::PSplit,
-            SplitVersion => Self::PSplitVersion,
-            StorePath => Self::PStorePath,
-            StringLength => Self::PStringLength,
-            Sub => Self::PSub,
-            Substring => Self::PSubstring,
-            Tail => Self::PTail,
-            Throw => Self::PThrow,
-            ToFile => Self::PToFile,
-            ToJSON => Self::PToJSON,
-            ToPath => Self::PToPath,
-            ToString => Self::PToString,
-            ToXML => Self::PToXML,
-            Trace => Self::PTrace,
-            TryEval => Self::PTryEval,
-            TypeOf => Self::PTypeOf,
-            UnsafeDiscardStringContext => Self::PUnsafeDiscardStringContext,
-            UnsafeDiscardOutputDependency => Self::PUnsafeDiscardOutputDependency,
-            UnsafeGetAttrPos => Self::PUnsafeGetAttrPos,
-            Warn => Self::PWarn,
-            ZipAttrsWith => Self::PZipAttrsWith,
-        }
-    }
-
-    pub const fn ip(self) -> u32 {
-        self as u32 * 2
-    }
-}
-
-pub struct BytecodeReader<'a> {
-    bytecode: &'a [u8],
-    pc: usize,
-    inst_start_pc: usize,
-}
-
-impl std::ops::Deref for BytecodeReader<'_> {
-    type Target = [u8];
-    fn deref(&self) -> &Self::Target {
-        self.bytecode
-    }
-}
-
-pub trait FromBytecode {
-    #[must_use]
-    fn read(reader: &mut BytecodeReader<'_>) -> Self;
-}
-
-impl<const N: usize> FromBytecode for [u8; N] {
-    #[inline(always)]
-    #[expect(
-        clippy::indexing_slicing,
-        reason = "reads well-formed bytecode; an out-of-range PC indicates a codegen bug and should panic loudly"
-    )]
-    fn read(reader: &mut BytecodeReader<'_>) -> Self {
-        let ret = reader.bytecode[reader.pc..reader.pc + N]
-            .try_into()
-            .expect("read_array failed");
-        reader.pc += N;
-        ret
-    }
-}
-
-impl FromBytecode for u8 {
-    #[inline(always)]
-    fn read(reader: &mut BytecodeReader<'_>) -> Self {
-        let [byte] = reader.read();
-        byte
-    }
-}
-
-macro_rules! numbers_impl {
-    ( $($ty:ty),* ) => {
-        $(
-        impl FromBytecode for $ty {
-            #[inline(always)]
-            fn read(reader: &mut BytecodeReader<'_>) -> Self {
-                <$ty>::from_le_bytes(FromBytecode::read(reader))
-            }
-        }
-        )*
-    };
-}
-
-numbers_impl!(u16, u32, i32, i64, f64);
-
-impl FromBytecode for Op {
-    #[inline(always)]
-    #[expect(
-        clippy::panic,
-        reason = "reads well-formed bytecode; an unknown opcode indicates a codegen bug and should panic loudly"
-    )]
-    fn read(reader: &mut BytecodeReader<'_>) -> Self {
-        reader.inst_start_pc = reader.pc;
-        let byte: u8 = reader.read();
-        byte.try_into().unwrap_or_else(|byte| {
-            std::hint::cold_path();
-            panic!("unknown opcode: {byte:#04x}")
-        })
-    }
-}
-
-impl FromBytecode for StringId {
-    #[inline(always)]
-    fn read(reader: &mut BytecodeReader<'_>) -> Self {
-        let raw: u32 = reader.read();
-        StringId(
-            string_interner::symbol::SymbolU32::try_from_usize(raw as usize)
-                .expect("raw is a valid interner symbol index"),
-        )
-    }
-}
-
-impl FromBytecode for OperandData {
-    #[inline(always)]
-    #[expect(
-        clippy::panic,
-        reason = "an unknown operand tag in well-formed bytecode indicates a codegen bug and should panic loudly"
-    )]
-    fn read(reader: &mut BytecodeReader<'_>) -> Self {
-        let tag = reader.read();
-        let ty = OperandType::try_from_primitive(tag).unwrap_or_else(|err| {
-            std::hint::cold_path();
-            panic!("unknown operand tag: {:#04x}", err.number)
-        });
-        match ty {
-            OperandType::Const => OperandData::Const(reader.read()),
-            OperandType::BigInt => OperandData::BigInt(reader.read()),
-            OperandType::Local => {
-                let layer = reader.read();
-                let idx = reader.read();
-                OperandData::Local { layer, idx }
-            }
-            OperandType::BuiltinConst => OperandData::BuiltinConst(reader.read()),
-            OperandType::Builtins => OperandData::Builtins,
-            OperandType::ReplBinding => OperandData::ReplBinding(reader.read()),
-            OperandType::ScopedImportBinding => {
-                let slot_id = reader.read();
-                let name = reader.read();
-                OperandData::ScopedImportBinding { slot_id, name }
-            }
-        }
-    }
-}
-
-macro_rules! read_aliases {
-    { $($alias:ident -> $ty:ty),*$(,)? } => {
-        $(
-        #[inline(always)]
-        #[must_use]
-        pub fn $alias(&mut self) -> $ty {
-            <$ty>::read(self)
-        }
-        )*
-    };
-}
-
-impl<'a> BytecodeReader<'a> {
-    #[must_use]
-    pub fn new(bytecode: &'a [u8], pc: usize) -> Self {
-        Self {
-            bytecode,
-            pc,
-            inst_start_pc: pc,
-        }
-    }
-
-    #[inline(always)]
-    #[must_use]
-    pub fn from_after_op(bytecode: &'a [u8], inst_start_pc: usize) -> Self {
-        Self {
-            bytecode,
-            pc: inst_start_pc + 1,
-            inst_start_pc,
-        }
-    }
-
-    #[inline(always)]
-    #[must_use]
-    pub fn read<T: FromBytecode>(&mut self) -> T {
-        T::read(self)
-    }
-
-    read_aliases! {
-        read_op -> Op,
-        read_u8 -> u8,
-        read_u16 -> u16,
-        read_u32 -> u32,
-        read_i32 -> i32,
-        read_i64 -> i64,
-        read_f64 -> f64,
-        read_string_id -> StringId,
-        read_operand_data -> OperandData,
-    }
-
-    pub fn pc(&self) -> usize {
-        self.pc
-    }
-
-    pub fn set_pc(&mut self, pc: usize) {
-        self.pc = pc;
-    }
-
-    pub fn inst_start_pc(&self) -> usize {
-        self.inst_start_pc
-    }
-}

fix-codegen/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "fix-codegen"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+hashbrown = { workspace = true }
+num_enum = { workspace = true }
+rnix = { workspace = true }
+string-interner = { workspace = true }
+colored = "3.1.1"
+
+fix-builtins = { path = "../fix-builtins" }
+fix-common = { path = "../fix-common" }
+fix-ir = { path = "../fix-ir" }

fix-codegen/src/disassembler.rs

@@ -1,8 +1,9 @@
 use std::fmt::Write;
 
-use colored::Colorize as _;
+use colored::Colorize;
+use num_enum::TryFromPrimitive;
 
-use crate::{BytecodeReader, Continuation, InstructionPtr, Op};
+use crate::{AttrKeyType, InstructionPtr, Op, OperandType};
 
 pub trait DisassemblerContext {
     fn resolve_string(&self, id: u32) -> &str;
@@ -10,15 +11,88 @@ pub trait DisassemblerContext {
 }
 
 pub struct Disassembler<'a, Ctx> {
-    reader: BytecodeReader<'a>,
+    code: &'a [u8],
     ctx: &'a Ctx,
+    pc: usize,
 }
 
 impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
     pub fn new(ip: InstructionPtr, ctx: &'a Ctx) -> Self {
         Self {
-            reader: BytecodeReader::new(ctx.get_code(), ip.0),
+            code: ctx.get_code(),
             ctx,
+            pc: ip.0,
+        }
+    }
+
+    #[inline(always)]
+    fn read_u8(&mut self) -> u8 {
+        let b = self.code[self.pc];
+        self.pc += 1;
+        b
+    }
+
+    #[inline(always)]
+    fn read_u16(&mut self) -> u16 {
+        let bytes = self.code[self.pc..self.pc + 2]
+            .try_into()
+            .expect("no enough bytes");
+        self.pc += 2;
+        u16::from_le_bytes(bytes)
+    }
+
+    #[inline(always)]
+    fn read_u32(&mut self) -> u32 {
+        let bytes = self.code[self.pc..self.pc + 4]
+            .try_into()
+            .expect("no enough bytes");
+        self.pc += 4;
+        u32::from_le_bytes(bytes)
+    }
+
+    #[inline(always)]
+    fn read_i32(&mut self) -> i32 {
+        let bytes = self.code[self.pc..self.pc + 4]
+            .try_into()
+            .expect("no enough bytes");
+        self.pc += 4;
+        i32::from_le_bytes(bytes)
+    }
+
+    #[inline(always)]
+    fn read_i64(&mut self) -> i64 {
+        let bytes = self.code[self.pc..self.pc + 8]
+            .try_into()
+            .expect("no enough bytes");
+        self.pc += 8;
+        i64::from_le_bytes(bytes)
+    }
+
+    #[inline(always)]
+    fn read_f64(&mut self) -> f64 {
+        let bytes = self.code[self.pc..self.pc + 8]
+            .try_into()
+            .expect("no enough bytes");
+        self.pc += 8;
+        f64::from_le_bytes(bytes)
+    }
+
+    #[inline(always)]
+    fn read_operand_data(&mut self) {
+        let tag = self.read_u8();
+        let ty = OperandType::try_from_primitive(tag).expect("invalid operand type");
+        match ty {
+            OperandType::Const => {
+                self.read_u32();
+            }
+            OperandType::Local => {
+                self.read_u8();
+                self.read_u32();
+            }
+            OperandType::Builtins => {}
+            OperandType::BigInt => {
+                self.read_i64();
+            }
         }
     }
 
@@ -30,11 +104,6 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
         self.disassemble_impl(true)
     }
 
-    #[expect(
-        clippy::let_underscore_must_use,
-        clippy::indexing_slicing,
-        reason = "disassembler operates on well-formed bytecode; writes target an in-memory String via fmt::Write, which is infallible"
-    )]
     fn disassemble_impl(&mut self, color: bool) -> String {
         let mut out = String::new();
         if color {
@@ -43,24 +112,24 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
                 out,
                 "{} {}",
                 "Length:".white(),
-                format!("{} bytes", self.reader.len()).cyan()
+                format!("{} bytes", self.code.len()).cyan()
             );
         } else {
             let _ = writeln!(out, "=== Bytecode Disassembly ===");
-            let _ = writeln!(out, "Length: {} bytes", self.reader.len());
+            let _ = writeln!(out, "Length: {} bytes", self.code.len());
         }
 
-        while self.reader.pc() < self.reader.len() {
-            let start_pos = self.reader.pc();
-            let op_byte = self.reader.read_u8();
+        while self.pc < self.code.len() {
+            let start_pos = self.pc;
+            let op_byte = self.read_u8();
             let (mnemonic, args) = self.decode_instruction(op_byte, start_pos);
 
-            let bytes_slice = &self.reader[start_pos + 1..self.reader.pc()];
+            let bytes_slice = &self.code[start_pos + 1..self.pc];
             let mut chunks = bytes_slice.chunks(4);
 
             let first_chunk = chunks.next().unwrap_or(&[]);
             let bytes_str = {
-                let mut temp = format!("{:02x}", self.reader[start_pos]);
+                let mut temp = format!("{:02x}", self.code[start_pos]);
                 for b in first_chunk {
                     let _ = write!(&mut temp, " {:02x}", b);
                 }
@@ -120,36 +189,31 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
         out
     }
 
-    #[expect(
-        clippy::let_underscore_must_use,
-        clippy::cast_sign_loss,
-        reason = "disassembler operates on well-formed bytecode; jump targets are valid non-negative PCs and writes to String are infallible"
-    )]
     fn decode_instruction(&mut self, op_byte: u8, current_pc: usize) -> (&'static str, String) {
-        let op = Op::try_from(op_byte).expect("invalid op code");
+        let op = Op::try_from_primitive(op_byte).expect("invalid op code");
 
         match op {
             Op::PushSmi => {
-                let val = self.reader.read_i32();
+                let val = self.read_i32();
                 ("PushSmi", format!("{}", val))
             }
             Op::PushBigInt => {
-                let val = self.reader.read_i64();
+                let val = self.read_i64();
                 ("PushBigInt", format!("{}", val))
             }
             Op::PushFloat => {
-                let val = self.reader.read_f64();
+                let val = self.read_f64();
                 ("PushFloat", format!("{}", val))
             }
             Op::PushString => {
-                let idx = self.reader.read_u32();
+                let idx = self.read_u32();
                 let s = self.ctx.resolve_string(idx);
                 let len = s.len();
                 let mut s_fmt = format!("{:?}", s);
                 if s_fmt.len() > 60 {
                     s_fmt.truncate(57);
-                    write!(s_fmt, "...\" (total {len} bytes)")
-                        .expect("writing to String is infallible");
+                    #[allow(clippy::unwrap_used)]
+                    write!(s_fmt, "...\" (total {len} bytes)").unwrap();
                 }
                 ("PushString", format!("@{} {}", idx, s_fmt))
             }
@@ -158,38 +222,38 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
             Op::PushFalse => ("PushFalse", String::new()),
 
             Op::LoadLocal => {
-                let idx = self.reader.read_u32();
+                let idx = self.read_u32();
                 ("LoadLocal", format!("[{}]", idx))
             }
             Op::LoadOuter => {
-                let depth = self.reader.read_u8();
-                let idx = self.reader.read_u32();
+                let depth = self.read_u8();
+                let idx = self.read_u32();
                 ("LoadOuter", format!("depth={} [{}]", depth, idx))
             }
             Op::StoreLocal => {
-                let idx = self.reader.read_u32();
+                let idx = self.read_u32();
                 ("StoreLocal", format!("[{}]", idx))
             }
             Op::AllocLocals => {
-                let count = self.reader.read_u32();
+                let count = self.read_u32();
                 ("AllocLocals", format!("count={}", count))
             }
 
             Op::MakeThunk => {
-                let offset = self.reader.read_u32();
+                let offset = self.read_u32();
                 ("MakeThunk", format!("-> {:04x}", offset))
             }
             Op::MakeClosure => {
-                let offset = self.reader.read_u32();
-                let slots = self.reader.read_u32();
+                let offset = self.read_u32();
+                let slots = self.read_u32();
                 ("MakeClosure", format!("-> {:04x} slots={}", offset, slots))
             }
             Op::MakePatternClosure => {
-                let offset = self.reader.read_u32();
-                let slots = self.reader.read_u32();
-                let req_count = self.reader.read_u16();
-                let opt_count = self.reader.read_u16();
-                let ellipsis = self.reader.read_u8() != 0;
+                let offset = self.read_u32();
+                let slots = self.read_u32();
+                let req_count = self.read_u16();
+                let opt_count = self.read_u16();
+                let ellipsis = self.read_u8() != 0;
 
                 let mut arg_str = format!(
                     "-> {:04x} slots={} req={} opt={} ...={})",
@@ -198,18 +262,18 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
 
                 arg_str.push_str(" Args=[");
                 for _ in 0..req_count {
-                    let idx = self.reader.read_u32();
+                    let idx = self.read_u32();
                     arg_str.push_str(&format!("Req({}) ", self.ctx.resolve_string(idx)));
                 }
                 for _ in 0..opt_count {
-                    let idx = self.reader.read_u32();
+                    let idx = self.read_u32();
                     arg_str.push_str(&format!("Opt({}) ", self.ctx.resolve_string(idx)));
                 }
 
                 let total_args = req_count + opt_count;
                 for _ in 0..total_args {
-                    let _name_idx = self.reader.read_u32();
-                    let _span_id = self.reader.read_u32();
+                    let _name_idx = self.read_u32();
+                    let _span_id = self.read_u32();
                 }
                 arg_str.push(']');
 
@@ -217,65 +281,65 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
             }
 
             Op::Call => {
-                let _ = self.reader.read_operand_data();
+                self.read_operand_data();
                 ("Call", "arg=?".into())
-            }
-            Op::DispatchCont => {
-                let phase =
-                    Continuation::try_from(self.reader.read_u8()).expect("invalid primop phase");
-                ("DispatchPrimOp", format!("phase={phase:?}"))
+            },
+            Op::DispatchPrimOp => {
+                todo!();
             }
 
             Op::MakeAttrs => {
-                let static_count = self.reader.read_u32();
-                let dynamic_count = self.reader.read_u32();
-                let mut args = format!("static={} dynamic={}", static_count, dynamic_count);
-
-                for _ in 0..static_count {
-                    let key_id = self.reader.read_u32();
-                    let _ = write!(args, " [{}={}", self.ctx.resolve_string(key_id), key_id);
-                    let _ = self.reader.read_operand_data();
-                    let _span_id = self.reader.read_u32();
-                    args.push(']');
+                let count = self.read_u32();
+                let mut args = format!("size={}", count);
+                for _ in 0..count {
+                    let key_tag = self.read_u8();
+                    let key_ty =
+                        AttrKeyType::try_from_primitive(key_tag).expect("invalid attr key type");
+                    match key_ty {
+                        AttrKeyType::Static => {
+                            let key_id = self.read_u32();
+                            let _ =
+                                write!(args, " [{}={}", self.ctx.resolve_string(key_id), key_id);
                         }
-
-                for _ in 0..dynamic_count {
+                        AttrKeyType::Dynamic => {
                             let _ = write!(args, " [dyn");
-                    let _ = self.reader.read_operand_data();
-                    let _span_id = self.reader.read_u32();
+                            self.read_operand_data();
+                        }
+                    }
+                    self.read_operand_data();
+                    let _span_id = self.read_u32();
                     args.push(']');
                 }
-
                 ("MakeAttrs", args)
             }
             Op::MakeEmptyAttrs => ("MakeEmptyAttrs", String::new()),
 
             Op::SelectStatic => {
-                let span_id = self.reader.read_u32();
-                let key_id = self.reader.read_u32();
+                let span_id = self.read_u32();
+                let key_id = self.read_u32();
                 (
                     "SelectStatic",
                     format!("key={} span={}", self.ctx.resolve_string(key_id), span_id),
                 )
             }
             Op::SelectDynamic => {
-                let span_id = self.reader.read_u32();
+                let span_id = self.read_u32();
                 ("SelectDynamic", format!("span={}", span_id))
             }
             Op::HasAttrPathStatic => {
-                let span_id = self.reader.read_u32();
-                let key_id = self.reader.read_u32();
+                let span_id = self.read_u32();
+                let key_id = self.read_u32();
                 (
                     "HasAttrPathStatic",
                     format!("key={} span={}", self.ctx.resolve_string(key_id), span_id),
                 )
             }
             Op::HasAttrPathDynamic => {
-                let span_id = self.reader.read_u32();
+                let span_id = self.read_u32();
                 ("HasAttrPathDynamic", format!("span={}", span_id))
             }
             Op::HasAttrStatic => {
-                let key_id = self.reader.read_u32();
+                let key_id = self.read_u32();
                 (
                     "HasAttrStatic",
                     format!("key={}", self.ctx.resolve_string(key_id)),
@@ -284,7 +348,7 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
             Op::HasAttrDynamic => ("HasAttrDynamic", String::new()),
             Op::HasAttrResolve => ("HasAttrResolve", String::new()),
             Op::JumpIfSelectSucceeded => {
-                let offset = self.reader.read_i32();
+                let offset = self.read_i32();
                 let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
                 (
                     "JumpIfSelectSucceeded",
@@ -292,7 +356,7 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
                 )
             }
             Op::JumpIfSelectFailed => {
-                let offset = self.reader.read_i32();
+                let offset = self.read_i32();
                 let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
                 (
                     "JumpIfSelectFailed",
@@ -301,9 +365,9 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
             }
 
             Op::MakeList => {
-                let count = self.reader.read_u32();
+                let count = self.read_u32();
                 for _ in 0..count {
-                    let _ = self.reader.read_operand_data();
+                    self.read_operand_data();
                 }
                 ("MakeList", format!("size={}", count))
             }
@@ -325,7 +389,7 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
             Op::OpNot => ("OpNot", String::new()),
 
             Op::JumpIfFalse => {
-                let offset = self.reader.read_i32();
+                let offset = self.read_i32();
                 let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
                 (
                     "JumpIfFalse",
@@ -333,57 +397,54 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
                 )
             }
             Op::JumpIfTrue => {
-                let offset = self.reader.read_i32();
+                let offset = self.read_i32();
                 let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
                 ("JumpIfTrue", format!("-> {:04x} offset={}", target, offset))
             }
             Op::Jump => {
-                let offset = self.reader.read_i32();
+                let offset = self.read_i32();
                 let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
                 ("Jump", format!("-> {:04x} offset={}", target, offset))
             }
 
             Op::ConcatStrings => {
-                let count = self.reader.read_u16();
-                let force = self.reader.read_u8();
+                let count = self.read_u16();
+                let force = self.read_u8();
                 ("ConcatStrings", format!("count={} force={}", count, force))
             }
-            Op::CoerceToString => ("CoerceToString", String::new()),
-            Op::ResolvePath => {
-                let dir_id = self.reader.read_u32();
-                let dir = self.ctx.resolve_string(dir_id);
-                ("ResolvePath", format!("dir={:?}", dir))
-            }
+            Op::ResolvePath => ("ResolvePath", String::new()),
             Op::Assert => {
-                let raw_idx = self.reader.read_u32();
-                let span_id = self.reader.read_u32();
+                let raw_idx = self.read_u32();
+                let span_id = self.read_u32();
                 ("Assert", format!("text_id={} span={}", raw_idx, span_id))
             }
+            Op::PushWith => ("PushWith", String::new()),
+            Op::PopWith => ("PopWith", String::new()),
+            Op::PrepareWith => ("PrepareWith", String::new()),
             Op::LookupWith => {
-                let idx = self.reader.read_u32();
+                let idx = self.read_u32();
                 let name = self.ctx.resolve_string(idx);
-                let n = self.reader.read_u8();
-                for _ in 0..n {
-                    let _ = self.reader.read_operand_data();
-                }
-                ("LookupWith", format!("sym={:?} n={}", name, n))
+                ("LookupWith", format!("{:?}", name))
             }
 
             Op::LoadBuiltins => ("LoadBuiltins", String::new()),
             Op::LoadBuiltin => {
-                let id = self.reader.read_u8();
+                let id = self.read_u8();
                 ("LoadBuiltin", format!("id={}", id))
             }
+            Op::MkPos => {
+                let span_id = self.read_u32();
+                ("MkPos", format!("id={}", span_id))
+            }
             Op::LoadReplBinding => {
-                let idx = self.reader.read_u32();
+                let idx = self.read_u32();
                 let name = self.ctx.resolve_string(idx);
                 ("LoadReplBinding", format!("{:?}", name))
             }
             Op::LoadScopedBinding => {
-                let slot = self.reader.read_u32();
-                let idx = self.reader.read_u32();
+                let idx = self.read_u32();
                 let name = self.ctx.resolve_string(idx);
-                ("LoadScopedBinding", format!("slot={} {:?}", slot, name))
+                ("LoadScopedBinding", format!("{:?}", name))
             }
             Op::Return => ("Return", String::new()),
             Op::Illegal => ("Illegal", String::new()),

fix-codegen/src/lib.rs

@@ -1,14 +1,16 @@
-use fix_bytecode::{Const, InstructionPtr, Op, OperandType};
-use fix_lang::StringId;
+use std::ops::Deref;
+
+use fix_builtins::BuiltinId;
+use fix_common::StringId;
+use fix_ir::{Attr, BinOpKind, Ir, MaybeThunk, Param, RawIrRef, ThunkId, UnOpKind};
 use hashbrown::HashMap;
+use num_enum::TryFromPrimitive;
 use rnix::TextRange;
 use string_interner::Symbol as _;
 
-mod context;
-pub mod ir;
-pub use context::{CodeState, ExtraScope};
-pub use fix_bytecode::disassembler;
-pub use ir::{Attr, BinOpKind, Ir, MaybeThunk, Param, RawIrRef, ThunkId, UnOpKind};
+pub mod disassembler;
+
+pub struct InstructionPtr(pub usize);
 
 pub trait BytecodeContext {
     fn intern_string(&mut self, s: &str) -> StringId;
@@ -16,11 +18,92 @@ pub trait BytecodeContext {
     fn get_code(&self) -> &[u8];
     fn get_code_mut(&mut self) -> &mut Vec<u8>;
     fn add_constant(&mut self, val: Const) -> u32;
-    fn current_source_dir(&mut self) -> StringId;
+}
+
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, TryFromPrimitive)]
+#[allow(clippy::enum_variant_names)]
+pub enum Op {
+    PushSmi,
+    PushBigInt,
+    PushFloat,
+    PushString,
+    PushNull,
+    PushTrue,
+    PushFalse,
+
+    LoadLocal,
+    LoadOuter,
+    StoreLocal,
+    AllocLocals,
+
+    MakeThunk,
+    MakeClosure,
+    MakePatternClosure,
+
+    Call,
+    DispatchPrimOp,
+
+    MakeAttrs,
+    MakeEmptyAttrs,
+    SelectStatic,
+    SelectDynamic,
+    HasAttrPathStatic,
+    HasAttrPathDynamic,
+    HasAttrStatic,
+    HasAttrDynamic,
+    HasAttrResolve,
+    JumpIfSelectSucceeded,
+    JumpIfSelectFailed,
+
+    MakeList,
+    MakeEmptyList,
+
+    OpAdd,
+    OpSub,
+    OpMul,
+    OpDiv,
+    OpEq,
+    OpNeq,
+    OpLt,
+    OpGt,
+    OpLeq,
+    OpGeq,
+    OpConcat,
+    OpUpdate,
+
+    OpNeg,
+    OpNot,
+
+    JumpIfFalse,
+    JumpIfTrue,
+    Jump,
+
+    ConcatStrings,
+    ResolvePath,
+
+    Assert,
+
+    PushWith,
+    PopWith,
+    LookupWith,
+    PrepareWith,
+
+    LoadBuiltins,
+    LoadBuiltin,
+
+    MkPos,
+
+    LoadReplBinding,
+    LoadScopedBinding,
+
+    Return,
+
+    Illegal,
 }
 
 struct ScopeInfo {
-    depth: u8,
+    depth: u16,
     thunk_map: HashMap<ThunkId, u32>,
 }
 
@@ -29,14 +112,40 @@ struct BytecodeEmitter<'a, Ctx: BytecodeContext> {
     scope_stack: Vec<ScopeInfo>,
 }
 
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, TryFromPrimitive)]
+pub enum OperandType {
+    Const,
+    Local,
+    Builtins,
+    BigInt,
+}
+
+pub enum Const {
+    Smi(i32),
+    Float(f64),
+    Bool(bool),
+    String(StringId),
+    PrimOp {
+        id: BuiltinId,
+        arity: u8,
+        dispatch_ip: u32,
+    },
+    Null,
+}
+
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, TryFromPrimitive)]
+pub enum AttrKeyType {
+    Static,
+    Dynamic,
+}
+
 pub enum InlineOperand {
     Const(Const),
-    BigInt(i64),
-    Local { layer: u8, local: u32 },
-    BuiltinConst(StringId),
+    Local { layer: u16, local: u32 },
     Builtins,
-    ReplBinding(StringId),
-    ScopedImportBinding { id: StringId, slot_id: u32 },
+    BigInt(i64),
 }
 
 pub fn compile_bytecode(ir: RawIrRef<'_>, ctx: &mut impl BytecodeContext) -> InstructionPtr {
@@ -54,12 +163,13 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         }
     }
 
-    fn inline_maybe_thunk(&self, val: &MaybeThunk) -> InlineOperand {
+    #[must_use]
+    fn inline_maybe_thunk(&self, val: MaybeThunk) -> InlineOperand {
         use MaybeThunk::*;
-        match *val {
+        match val {
             Int(x) => {
-                if let Ok(x) = x.try_into() {
-                    InlineOperand::Const(Const::Smi(x))
+                if x <= i32::MAX as i64 {
+                    InlineOperand::Const(Const::Smi(x as i32))
                 } else {
                     InlineOperand::BigInt(x)
                 }
@@ -68,55 +178,37 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
             Bool(b) => InlineOperand::Const(Const::Bool(b)),
             Null => InlineOperand::Const(Const::Null),
             Str(id) => InlineOperand::Const(Const::String(id)),
-            Path(id) => InlineOperand::Const(Const::String(id)),
             Thunk(id) => {
                 let (layer, local) = self.resolve_thunk(id);
                 InlineOperand::Local { layer, local }
             }
-            Arg { layer } => InlineOperand::Local { layer, local: 0 },
-            Builtin(id) => InlineOperand::Const(Const::PrimOp(id)),
-            BuiltinConst(id) => InlineOperand::BuiltinConst(id),
-            Builtins => InlineOperand::Builtins,
-            ReplBinding(id) => InlineOperand::ReplBinding(id),
-            ScopedImportBinding { slot_id, sym: id } => {
-                InlineOperand::ScopedImportBinding { slot_id, id }
-            }
+            Arg { layer } => InlineOperand::Local {
+                layer: layer.try_into().expect("scope too deep!"),
+                local: 0,
+            },
+            _ => todo!(),
         }
     }
 
-    fn emit_maybe_thunk(&mut self, val: &MaybeThunk) {
-        use InlineOperand::*;
+    fn emit_maybe_thunk(&mut self, val: MaybeThunk) {
         let operand = self.inline_maybe_thunk(val);
         match operand {
-            Const(val) => {
+            InlineOperand::Const(val) => {
                 let idx = self.ctx.add_constant(val);
                 self.emit_u8(OperandType::Const as u8);
                 self.emit_u32(idx);
             }
-            BigInt(val) => {
-                self.emit_u8(OperandType::BigInt as u8);
-                self.emit_i64(val);
-            }
-            Local { layer, local } => {
+            InlineOperand::Local { layer, local } => {
                 self.emit_u8(OperandType::Local as u8);
-                self.emit_u8(layer);
+                self.emit_u8(layer as u8);
                 self.emit_u32(local);
             }
-            BuiltinConst(id) => {
-                self.emit_u8(OperandType::BuiltinConst as u8);
-                self.emit_str_id(id);
-            }
-            Builtins => {
+            InlineOperand::Builtins => {
                 self.emit_u8(OperandType::Builtins as u8);
             }
-            ReplBinding(id) => {
-                self.emit_u8(OperandType::ReplBinding as u8);
-                self.emit_str_id(id);
-            }
-            ScopedImportBinding { id, slot_id } => {
-                self.emit_u8(OperandType::ScopedImportBinding as u8);
-                self.emit_u32(slot_id);
-                self.emit_str_id(id);
+            InlineOperand::BigInt(val) => {
+                self.emit_u8(OperandType::BigInt as u8);
+                self.emit_i64(val);
             }
         }
     }
@@ -126,11 +218,6 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         self.ctx.get_code_mut().push(op as u8);
     }
 
-    #[inline]
-    fn emit_bool(&mut self, val: bool) {
-        self.emit_u8(u8::from(val));
-    }
-
     #[inline]
     fn emit_u8(&mut self, val: u8) {
         self.ctx.get_code_mut().push(val);
@@ -178,10 +265,6 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         offset
     }
     #[inline]
-    #[expect(
-        clippy::indexing_slicing,
-        reason = "offset addresses a 4-byte i32 placeholder this compiler previously emitted, so it is in bounds"
-    )]
     fn patch_i32(&mut self, offset: usize, val: i32) {
         self.ctx.get_code_mut()[offset..offset + 4].copy_from_slice(&val.to_le_bytes());
     }
@@ -206,15 +289,11 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
             .extend_from_slice(&(id.0.to_usize() as u32).to_le_bytes());
     }
 
-    fn current_depth(&self) -> u8 {
+    fn current_depth(&self) -> u16 {
         self.scope_stack.last().map_or(0, |s| s.depth)
     }
 
-    #[expect(
-        clippy::panic,
-        reason = "a ThunkId must resolve in some enclosing scope; failure indicates a compiler bug"
-    )]
-    fn resolve_thunk(&self, id: ThunkId) -> (u8, u32) {
+    fn resolve_thunk(&self, id: ThunkId) -> (u16, u32) {
         for scope in self.scope_stack.iter().rev() {
             if let Some(&local_idx) = scope.thunk_map.get(&id) {
                 let layer = self.current_depth() - scope.depth;
@@ -224,19 +303,111 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         panic!("ThunkId {:?} not found in any scope", id);
     }
 
-    fn emit_load(&mut self, layer: u8, local: u32) {
+    fn emit_load(&mut self, layer: u16, local: u32) {
         if layer == 0 {
             self.emit_op(Op::LoadLocal);
             self.emit_u32(local);
         } else {
             self.emit_op(Op::LoadOuter);
-            self.emit_u8(layer);
+            self.emit_u8(layer as u8);
             self.emit_u32(local);
         }
     }
 
+    fn count_with_thunks(&self, ir: RawIrRef<'_>) -> usize {
+        match ir.deref() {
+            Ir::With { thunks, body, .. } => thunks.len() + self.count_with_thunks(*body),
+            Ir::TopLevel { thunks, body } => thunks.len() + self.count_with_thunks(*body),
+            Ir::If { cond, consq, alter } => {
+                self.count_with_thunks(*cond)
+                    + self.count_with_thunks(*consq)
+                    + self.count_with_thunks(*alter)
+            }
+            Ir::BinOp { lhs, rhs, .. } => {
+                self.count_with_thunks(*lhs) + self.count_with_thunks(*rhs)
+            }
+            Ir::UnOp { rhs, .. } => self.count_with_thunks(*rhs),
+            Ir::Call { func, .. } => self.count_with_thunks(*func),
+            Ir::Assert {
+                assertion, expr, ..
+            } => self.count_with_thunks(*assertion) + self.count_with_thunks(*expr),
+            Ir::Select { expr, .. } => self.count_with_thunks(*expr),
+            Ir::HasAttr { lhs, .. } => self.count_with_thunks(*lhs),
+            Ir::ConcatStrings { parts, .. } => {
+                parts.iter().map(|p| self.count_with_thunks(*p)).sum()
+            }
+            _ => 0,
+        }
+    }
+
+    fn collect_all_thunks<'ir>(
+        &self,
+        own_thunks: &[(ThunkId, RawIrRef<'ir>)],
+        body: RawIrRef<'ir>,
+    ) -> Vec<(ThunkId, RawIrRef<'ir>)> {
+        let mut all = Vec::from(own_thunks);
+        self.collect_with_thunks_recursive(body, &mut all);
+        let mut i = 0;
+        while i < all.len() {
+            let thunk_body = all[i].1;
+            self.collect_with_thunks_recursive(thunk_body, &mut all);
+            i += 1;
+        }
+        all
+    }
+
+    fn collect_with_thunks_recursive<'ir>(
+        &self,
+        ir: RawIrRef<'ir>,
+        out: &mut Vec<(ThunkId, RawIrRef<'ir>)>,
+    ) {
+        match ir.deref() {
+            Ir::With { thunks, body, .. } => {
+                for &(id, inner) in thunks.iter() {
+                    out.push((id, inner));
+                }
+                self.collect_with_thunks_recursive(*body, out);
+            }
+            Ir::TopLevel { thunks, body } => {
+                for &(id, inner) in thunks.iter() {
+                    out.push((id, inner));
+                }
+                self.collect_with_thunks_recursive(*body, out);
+            }
+            Ir::If { cond, consq, alter } => {
+                self.collect_with_thunks_recursive(*cond, out);
+                self.collect_with_thunks_recursive(*consq, out);
+                self.collect_with_thunks_recursive(*alter, out);
+            }
+            Ir::BinOp { lhs, rhs, .. } => {
+                self.collect_with_thunks_recursive(*lhs, out);
+                self.collect_with_thunks_recursive(*rhs, out);
+            }
+            Ir::UnOp { rhs, .. } => self.collect_with_thunks_recursive(*rhs, out),
+            Ir::Call { func, .. } => {
+                self.collect_with_thunks_recursive(*func, out);
+            }
+            Ir::Assert {
+                assertion, expr, ..
+            } => {
+                self.collect_with_thunks_recursive(*assertion, out);
+                self.collect_with_thunks_recursive(*expr, out);
+            }
+            Ir::Select { expr, .. } => {
+                self.collect_with_thunks_recursive(*expr, out);
+            }
+            Ir::HasAttr { lhs, .. } => self.collect_with_thunks_recursive(*lhs, out),
+            Ir::ConcatStrings { parts, .. } => {
+                for p in parts.iter() {
+                    self.collect_with_thunks_recursive(*p, out);
+                }
+            }
+            _ => (),
+        }
+    }
+
     fn push_scope(&mut self, has_arg: bool, thunk_ids: &[ThunkId]) {
-        let depth = self.scope_stack.len().try_into().expect("scope too deep!");
+        let depth = self.scope_stack.len() as u16;
         let thunk_base = if has_arg { 1u32 } else { 0u32 };
         let thunk_map = thunk_ids
             .iter()
@@ -251,13 +422,19 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
     }
 
     fn emit_toplevel(&mut self, ir: RawIrRef<'_>) {
-        match ir {
+        match ir.deref() {
             &Ir::TopLevel { body, ref thunks } => {
-                let thunk_ids: Vec<ThunkId> = thunks.iter().map(|&(id, _)| id).collect();
+                let with_thunk_count = self.count_with_thunks(body);
+                let total_slots = thunks.len() + with_thunk_count;
+
+                let all_thunks = self.collect_all_thunks(thunks, body);
+                let thunk_ids: Vec<ThunkId> = all_thunks.iter().map(|&(id, _)| id).collect();
+
                 self.push_scope(false, &thunk_ids);
-                if !thunks.is_empty() {
+
+                if total_slots > 0 {
                     self.emit_op(Op::AllocLocals);
-                    self.emit_u32(thunks.len().try_into().expect("too many thunks"));
+                    self.emit_u32(total_slots as u32);
                 }
 
                 self.emit_scope_thunks(thunks);
@@ -291,11 +468,11 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
     }
 
     fn emit_expr(&mut self, ir: RawIrRef<'_>) {
-        match ir {
+        match ir.deref() {
             &Ir::Int(x) => {
-                if let Ok(x) = x.try_into() {
+                if x <= i32::MAX as i64 {
                     self.emit_op(Op::PushSmi);
-                    self.emit_i32(x);
+                    self.emit_i32(x as i32);
                 } else {
                     self.emit_op(Op::PushBigInt);
                     self.emit_i64(x);
@@ -315,8 +492,6 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
             &Ir::Path(p) => {
                 self.emit_expr(p);
                 self.emit_op(Op::ResolvePath);
-                let dir_id = self.ctx.current_source_dir();
-                self.emit_str_id(dir_id);
             }
             &Ir::If { cond, consq, alter } => {
                 self.emit_expr(cond);
@@ -379,7 +554,7 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                 self.emit_maybe_thunk(arg);
             }
             &Ir::Arg { layer } => {
-                self.emit_load(layer, 0);
+                self.emit_load(layer.try_into().expect("scope too deep!"), 0);
             }
             &Ir::TopLevel { body, ref thunks } => {
                 self.emit_toplevel_inner(body, thunks);
@@ -392,6 +567,10 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
             } => {
                 self.emit_select(expr, attrpath, default, span);
             }
+            &Ir::Thunk(id) => {
+                let (layer, local) = self.resolve_thunk(id);
+                self.emit_load(layer, local);
+            }
             Ir::Builtins => {
                 self.emit_op(Op::LoadBuiltins);
             }
@@ -401,23 +580,24 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
             }
             &Ir::BuiltinConst(id) => {
                 self.emit_select(
-                    &Ir::Builtins,
+                    RawIrRef(&Ir::Builtins),
                     &[Attr::Str(id, TextRange::default())],
                     None,
                     TextRange::default(),
                 );
             }
             &Ir::ConcatStrings {
-                ref parts,
-                force_string,
+                parts: _,
+                force_string: _,
             } => {
-                for &part in parts.iter() {
-                    self.emit_expr(part);
-                    self.emit_op(Op::CoerceToString);
-                }
-                self.emit_op(Op::ConcatStrings);
-                self.emit_u16(parts.len() as u16);
-                self.emit_bool(force_string);
+                todo!("redesign ConcatStrings");
+                // self.emit_op(Op::ConcatStrings);
+                // self.emit_u16(parts.len() as u16);
+                // self.emit_u8(if force_string { 1 } else { 0 });
+                // for &part in parts.iter() {
+                //     let operand = self.inline_maybe_thunk(part);
+                //     self.emit_inline_operand(operand);
+                // }
             }
             &Ir::HasAttr { lhs, ref rhs } => {
                 self.emit_has_attr(lhs, rhs);
@@ -431,99 +611,40 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                 let raw_idx = self.ctx.intern_string(assertion_raw);
                 let span_id = self.ctx.register_span(*span);
                 self.emit_expr(*assertion);
+                self.emit_expr(*expr);
                 self.emit_op(Op::Assert);
                 self.emit_str_id(raw_idx);
                 self.emit_u32(span_id);
-                self.emit_expr(*expr);
+            }
+            &Ir::CurPos(span) => {
+                let span_id = self.ctx.register_span(span);
+                self.emit_op(Op::MkPos);
+                self.emit_u32(span_id);
             }
             &Ir::ReplBinding(name) => {
                 self.emit_op(Op::LoadReplBinding);
                 self.emit_str_id(name);
             }
-            &Ir::ScopedImportBinding { sym, slot_id } => {
+            &Ir::ScopedImportBinding(name) => {
                 self.emit_op(Op::LoadScopedBinding);
-                self.emit_u32(slot_id);
-                self.emit_str_id(sym);
-            }
-            Ir::WithLookup { sym, namespaces } => {
-                // counter
-                self.emit_expr(&Ir::Int(0));
-                self.emit_op(Op::LookupWith);
-                self.emit_str_id(*sym);
-                self.emit_u8(
-                    namespaces
-                        .len()
-                        .try_into()
-                        .expect("too many `with` namespaces"),
-                );
-                for namespace in namespaces {
-                    self.emit_maybe_thunk(namespace);
-                }
-            }
-            &Ir::MaybeThunk(thunk) => {
-                use MaybeThunk::*;
-                match *thunk {
-                    Int(x) => {
-                        if let Ok(x) = x.try_into() {
-                            self.emit_op(Op::PushSmi);
-                            self.emit_i32(x);
-                        } else {
-                            self.emit_op(Op::PushBigInt);
-                            self.emit_i64(x);
-                        }
-                    }
-                    Float(x) => {
-                        self.emit_op(Op::PushFloat);
-                        self.emit_f64(x);
-                    }
-                    Bool(true) => self.emit_op(Op::PushTrue),
-                    Bool(false) => self.emit_op(Op::PushFalse),
-                    Null => self.emit_op(Op::PushNull),
-                    Str(id) => {
-                        self.emit_op(Op::PushString);
-                        self.emit_str_id(id);
-                    }
-                    Path(id) => {
-                        self.emit_op(Op::PushString);
-                        self.emit_str_id(id);
-                        self.emit_op(Op::ResolvePath);
-                        let dir_id = self.ctx.current_source_dir();
-                        self.emit_str_id(dir_id);
-                    }
-                    Thunk(id) => {
-                        let (layer, local) = self.resolve_thunk(id);
-                        self.emit_load(layer, local);
-                    }
-                    Arg { layer } => self.emit_load(layer, 0),
-                    Builtin(id) => {
-                        self.emit_op(Op::LoadBuiltin);
-                        self.emit_u8(id as u8);
-                    }
-                    BuiltinConst(id) => self.emit_select(
-                        &Ir::Builtins,
-                        &[Attr::Str(id, TextRange::default())],
-                        None,
-                        TextRange::default(),
-                    ),
-                    Builtins => self.emit_op(Op::LoadBuiltins),
-                    ReplBinding(name) => {
-                        self.emit_op(Op::LoadReplBinding);
                 self.emit_str_id(name);
             }
-                    ScopedImportBinding { slot_id, sym } => {
-                        self.emit_op(Op::LoadScopedBinding);
-                        self.emit_u32(slot_id);
-                        self.emit_str_id(sym);
-                    }
+            &Ir::With {
+                namespace,
+                body,
+                ref thunks,
+            } => {
+                self.emit_with(namespace, body, thunks);
             }
+            &Ir::WithLookup(name) => {
+                // TODO: specialize shallow with lookups
+                self.emit_op(Op::PrepareWith);
+                self.emit_op(Op::LookupWith);
+                self.emit_str_id(name);
             }
         }
     }
 
-    #[expect(
-        clippy::unreachable,
-        reason = "the outer match only reaches this arm for the binary operator kinds enumerated above"
-    )]
     fn emit_binop(&mut self, lhs: RawIrRef<'_>, rhs: RawIrRef<'_>, kind: BinOpKind) {
         use BinOpKind::*;
         match kind {
@@ -584,6 +705,18 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                 let end_offset = (self.ctx.get_code_mut().len() as i32) - (after_jump as i32);
                 self.patch_i32(end_placeholder, end_offset);
             }
+            PipeL => {
+                todo!("new call");
+                // self.emit_expr(rhs);
+                // self.emit_expr(lhs);
+                // self.emit_op(Op::Call);
+            }
+            PipeR => {
+                todo!("new call");
+                // self.emit_expr(lhs);
+                // self.emit_expr(rhs);
+                // self.emit_op(Op::Call);
+            }
             _ => {
                 self.emit_expr(lhs);
                 self.emit_expr(rhs);
@@ -606,13 +739,17 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         }
     }
 
-    fn emit_func<'ir>(
+    fn emit_func(
         &mut self,
-        thunks: &[(ThunkId, RawIrRef<'ir>)],
-        param: &Option<Param<'ir>>,
-        body: RawIrRef<'ir>,
+        thunks: &[(ThunkId, RawIrRef<'_>)],
+        param: &Option<Param<'_>>,
+        body: RawIrRef<'_>,
     ) {
-        let thunk_ids: Vec<ThunkId> = thunks.iter().map(|&(id, _)| id).collect();
+        let with_thunk_count = self.count_with_thunks(body);
+        let total_slots = thunks.len() + with_thunk_count;
+
+        let all_thunks = self.collect_all_thunks(thunks, body);
+        let thunk_ids: Vec<ThunkId> = all_thunks.iter().map(|&(id, _)| id).collect();
 
         let skip_patch = self.emit_jump_placeholder();
         let entry_point = self.ctx.get_code().len() as u32;
@@ -631,10 +768,10 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         {
             self.emit_op(Op::MakePatternClosure);
             self.emit_u32(entry_point);
-            self.emit_u32(thunks.len().try_into().expect("too many thunks"));
+            self.emit_u32(total_slots as u32);
             self.emit_u16(required.len() as u16);
             self.emit_u16(optional.len() as u16);
-            self.emit_bool(*ellipsis);
+            self.emit_u8(if *ellipsis { 1 } else { 0 });
 
             for &(sym, _) in required.iter() {
                 self.emit_str_id(sym);
@@ -650,36 +787,33 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         } else {
             self.emit_op(Op::MakeClosure);
             self.emit_u32(entry_point);
-            self.emit_u32(thunks.len().try_into().expect("too many thunks"));
+            self.emit_u32(total_slots as u32);
         }
     }
 
     fn emit_attrset(
         &mut self,
-        stcs: &ir::HashMap<'_, StringId, (&MaybeThunk, TextRange)>,
-        dyns: &[(RawIrRef<'_>, &MaybeThunk, TextRange)],
+        stcs: &fix_ir::HashMap<'_, StringId, (MaybeThunk, TextRange)>,
+        dyns: &[(RawIrRef<'_>, MaybeThunk, TextRange)],
     ) {
         if stcs.is_empty() && dyns.is_empty() {
             self.emit_op(Op::MakeEmptyAttrs);
             return;
         }
 
-        for &(key_expr, _val, _span) in dyns.iter() {
-            self.emit_expr(key_expr);
-        }
-
+        let total = stcs.len() + dyns.len();
         self.emit_op(Op::MakeAttrs);
-        self.emit_u32(stcs.len() as u32);
-        self.emit_u32(dyns.len() as u32);
+        self.emit_u32(total as u32);
 
         for (&sym, &(val, span)) in stcs.iter() {
+            self.emit_u8(AttrKeyType::Static as u8);
             self.emit_str_id(sym);
             self.emit_maybe_thunk(val);
             let span_id = self.ctx.register_span(span);
             self.emit_u32(span_id);
         }
-
         for &(_key, val, span) in dyns.iter() {
+            self.emit_u8(AttrKeyType::Dynamic as u8);
             self.emit_maybe_thunk(val);
             let span_id = self.ctx.register_span(span);
             self.emit_u32(span_id);
@@ -716,25 +850,14 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         }
 
         if let Some(default) = default {
-            // FIXME: i32???
-            let before: i32 = self
-                .ctx
-                .get_code()
-                .len()
-                .try_into()
-                .expect("emitted code length fits in i32");
+            let before: i32 = self.ctx.get_code().len().try_into().unwrap();
             for patch in dynamic_patches {
                 self.patch_jump_target(patch);
             }
             self.emit_op(Op::JumpIfSelectSucceeded);
             let placeholder = self.emit_i32_placeholder();
             self.emit_expr(default);
-            let after: i32 = self
-                .ctx
-                .get_code()
-                .len()
-                .try_into()
-                .expect("emitted code length fits in i32");
+            let after: i32 = self.ctx.get_code().len().try_into().unwrap();
             // Offset is relative to after the placeholder, so subtract the
             // size of JumpIfSelectSucceeded (1) + placeholder (4).
             self.patch_i32(placeholder, after - before - 5);
@@ -745,10 +868,6 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         }
     }
 
-    #[expect(
-        clippy::panic,
-        reason = "a hasAttr attrpath always has at least one attr by construction of the AST"
-    )]
     fn emit_has_attr(&mut self, lhs: RawIrRef<'_>, rhs: &[Attr<RawIrRef<'_>>]) {
         self.emit_expr(lhs);
 
@@ -792,6 +911,19 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         self.emit_op(Op::HasAttrResolve);
     }
 
+    fn emit_with(
+        &mut self,
+        namespace: MaybeThunk,
+        body: RawIrRef<'_>,
+        thunks: &[(ThunkId, RawIrRef<'_>)],
+    ) {
+        self.emit_op(Op::PushWith);
+        self.emit_maybe_thunk(namespace);
+        self.emit_scope_thunks(thunks);
+        self.emit_expr(body);
+        self.emit_op(Op::PopWith);
+    }
+
     fn emit_toplevel_inner(&mut self, body: RawIrRef<'_>, thunks: &[(ThunkId, RawIrRef<'_>)]) {
         self.emit_scope_thunks(thunks);
         self.emit_expr(body);

fix-common/Cargo.toml

@@ -1,13 +1,9 @@
 [package]
-name = "fix-lang"
+name = "fix-common"
 version = "0.1.0"
 edition = "2024"
 
 [dependencies]
-ere = { workspace = true }
 gc-arena = { workspace = true }
-num_enum = { workspace = true }
 string-interner = { workspace = true }
-
-[lints]
-workspace = true
+ere = { workspace = true }

fix-common/src/lib.rs

@@ -4,162 +4,6 @@ use std::fmt::{Debug, Display, Formatter, Result as FmtResult};
 use std::ops::{Deref, DerefMut};
 
 use gc_arena::Collect;
-use num_enum::TryFromPrimitive;
-
-macro_rules! define_builtins {
-    ($(($name:literal, $variant:ident, $arity:expr)),* $(,)?) => {
-        const BUILTINS: &[(&str, u8)] = &[
-            $(($name, $arity),)*
-        ];
-
-        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, TryFromPrimitive, Collect)]
-        #[repr(u8)]
-        #[collect(require_static)]
-        pub enum BuiltinId {
-            $($variant,)*
-        }
-
-        impl BuiltinId {
-            pub const ALL: [Self; BUILTINS.len()] = [$(Self::$variant,)*];
-        }
-    };
-}
-
-define_builtins! {
-    ("abort",                    Abort,                    1),
-    ("__add",                      Add,                      2),
-    ("__addErrorContext",          AddErrorContext,           2),
-    ("__all",                      All,                      2),
-    ("__any",                      Any,                      2),
-    ("__appendContext",            AppendContext,             2),
-    ("__attrNames",                AttrNames,                1),
-    ("__attrValues",               AttrValues,               1),
-    ("baseNameOf",               BaseNameOf,               1),
-    ("__bitAnd",                   BitAnd,                   2),
-    ("__bitOr",                    BitOr,                    2),
-    ("__bitXor",                   BitXor,                   2),
-    ("break",                    Break,                    1),
-    ("__catAttrs",                 CatAttrs,                 2),
-    ("__ceil",                     Ceil,                     1),
-    ("__compareVersions",          CompareVersions,          2),
-    ("__concatLists",              ConcatLists,              1),
-    ("__concatMap",                ConcatMap,                2),
-    ("__concatStringsSep",         ConcatStringsSep,         2),
-    ("__convertHash",              ConvertHash,              1),
-    ("__deepSeq",                  DeepSeq,                  2),
-    ("derivation",               Derivation,               1),
-    ("derivationStrict",         DerivationStrict,         1),
-    ("dirOf",                    DirOf,                    1),
-    ("__div",                      Div,                      2),
-    ("__elem",                     Elem,                     2),
-    ("__elemAt",                   ElemAt,                   2),
-    ("fetchGit",                 FetchGit,                 1),
-    ("fetchMercurial",           FetchMercurial,           1),
-    ("fetchTarball",             FetchTarball,             1),
-    ("fetchTree",                FetchTree,                1),
-    ("__fetchurl",                 FetchUrl,                 1),
-    ("__filter",                   Filter,                   2),
-    ("__filterSource",             FilterSource,             2),
-    ("__findFile",                 FindFile,                 2),
-    ("__floor",                    Floor,                    1),
-    ("__foldl'",                   FoldlStrict,              3),
-    ("__fromJSON",                 FromJSON,                 1),
-    ("fromTOML",                 FromTOML,                 1),
-    ("__functionArgs",             FunctionArgs,             1),
-    ("__genList",                  GenList,                  2),
-    ("__genericClosure",           GenericClosure,           1),
-    ("__getAttr",                  GetAttr,                  2),
-    ("__getContext",               GetContext,               1),
-    ("__getEnv",                   GetEnv,                   1),
-    ("__groupBy",                  GroupBy,                  2),
-    ("__hasAttr",                  HasAttr,                  2),
-    ("__hasContext",               HasContext,               1),
-    ("__hashFile",                 HashFile,                 2),
-    ("__hashString",               HashString,               2),
-    ("__head",                     Head,                     1),
-    ("import",                   Import,                   1),
-    ("__intersectAttrs",           IntersectAttrs,           2),
-    ("__isAttrs",                  IsAttrs,                  1),
-    ("__isBool",                   IsBool,                   1),
-    ("__isFloat",                  IsFloat,                  1),
-    ("__isFunction",               IsFunction,               1),
-    ("__isInt",                    IsInt,                    1),
-    ("__isList",                   IsList,                   1),
-    ("isNull",                   IsNull,                   1),
-    ("__isPath",                   IsPath,                   1),
-    ("__isString",                 IsString,                 1),
-    ("__length",                   Length,                   1),
-    ("__lessThan",                 LessThan,                 2),
-    ("__listToAttrs",              ListToAttrs,              1),
-    ("map",                      Map,                      2),
-    ("__mapAttrs",                 MapAttrs,                 2),
-    ("__match",                    Match,                    2),
-    ("__mul",                      Mul,                      2),
-    ("__parseDrvName",             ParseDrvName,             1),
-    ("__partition",                Partition,                2),
-    ("__path",                     Path,                     1),
-    ("__pathExists",               PathExists,               1),
-    ("placeholder",              Placeholder,              1),
-    ("__readDir",                  ReadDir,                  1),
-    ("__readFile",                 ReadFile,                 1),
-    ("__readFileType",             ReadFileType,             1),
-    ("removeAttrs",              RemoveAttrs,              2),
-    ("__replaceStrings",           ReplaceStrings,           3),
-    ("scopedImport",             ScopedImport,             2),
-    ("__seq",                      Seq,                      2),
-    ("__sort",                     Sort,                     2),
-    ("__split",                    Split,                    2),
-    ("__splitVersion",             SplitVersion,             1),
-    ("__storePath",                StorePath,                1),
-    ("__stringLength",             StringLength,             1),
-    ("__sub",                      Sub,                      2),
-    ("__substring",                Substring,                3),
-    ("__tail",                     Tail,                     1),
-    ("throw",                    Throw,                    1),
-    ("__toFile",                   ToFile,                   2),
-    ("__toJSON",                   ToJSON,                   1),
-    ("__toPath",                   ToPath,                   1),
-    ("toString",                 ToString,                 1),
-    ("__toXML",                    ToXML,                    1),
-    ("__trace",                    Trace,                    2),
-    ("__tryEval",                  TryEval,                  1),
-    ("__typeOf",                   TypeOf,                   1),
-    ("__unsafeDiscardStringContext", UnsafeDiscardStringContext, 1),
-    ("__unsafeDiscardOutputDependency", UnsafeDiscardOutputDependency, 1),
-    ("__unsafeGetAttrPos",         UnsafeGetAttrPos,         2),
-    ("__warn",                     Warn,                     2),
-    ("__zipAttrsWith",             ZipAttrsWith,             2),
-}
-
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub struct BuiltinInfo {
-    pub name: &'static str,
-    pub global_name: &'static str,
-    pub global: bool,
-    pub arity: u8,
-}
-
-impl BuiltinId {
-    pub const TOTAL: usize = BUILTINS.len();
-
-    #[expect(
-        clippy::indexing_slicing,
-        reason = "a `BuiltinId` discriminant is always a valid index into the `BUILTINS` table"
-    )]
-    #[inline(always)]
-    pub fn info(self) -> BuiltinInfo {
-        let (global_name, arity) = BUILTINS[self as usize];
-        let (name, global) = global_name
-            .strip_prefix("__")
-            .map_or((global_name, true), |name| (name, false));
-        BuiltinInfo {
-            name,
-            global_name,
-            global,
-            arity,
-        }
-    }
-}
 
 #[repr(transparent)]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Collect)]
@@ -461,10 +305,6 @@ fn fmt_nix_float(f: &mut Formatter<'_>, x: f64) -> FmtResult {
     let precision: i32 = 6;
     let exp = x.abs().log10().floor() as i32;
 
-    #[expect(
-        clippy::cast_sign_loss,
-        reason = "this branch runs only when exp < precision, so precision-1-exp and precision-1 are non-negative"
-    )]
     let formatted = if exp >= -4 && exp < precision {
         let decimal_places = (precision - 1 - exp) as usize;
         format!("{x:.decimal_places$}")
@@ -489,9 +329,11 @@ fn fmt_nix_float(f: &mut Formatter<'_>, x: f64) -> FmtResult {
     };
 
     if formatted.contains('.') {
-        if let Some((head, tail)) = formatted.split_once('e') {
-            let trimmed = head.trim_end_matches('0').trim_end_matches('.');
-            write!(f, "{trimmed}e{tail}")
+        if let Some(e_pos) = formatted.find('e') {
+            let trimmed = formatted[..e_pos]
+                .trim_end_matches('0')
+                .trim_end_matches('.');
+            write!(f, "{}{}", trimmed, &formatted[e_pos..])
         } else {
             let trimmed = formatted.trim_end_matches('0').trim_end_matches('.');
             write!(f, "{trimmed}")

fix-compiler/src/context.rs

@@ -1,570 +0,0 @@
-use bumpalo::Bump;
-use fix_bytecode::{Const, Continuation, InstructionPtr, Op};
-use fix_error::{Error, Result, Source};
-use fix_lang::{StringId, Symbol};
-use fix_runtime::{StaticValue, VmCode, VmRuntimeCtx};
-use ghost_cell::{GhostCell, GhostToken};
-use hashbrown::{HashMap, HashSet};
-use string_interner::DefaultStringInterner;
-
-use crate::BytecodeContext;
-use crate::ir::downgrade::{Downgrade as _, DowngradeContext};
-use crate::ir::{
-    GhostMaybeThunkRef, GhostRoIrRef, GhostRoMaybeThunkRef, GhostRoRef, Ir, MaybeThunk, RawIrRef,
-    ThunkId,
-};
-
-pub struct CodeState {
-    pub bytecode: Vec<u8>,
-    pub sources: Vec<Source>,
-    pub spans: Vec<(usize, rnix::TextRange)>,
-    pub thunk_count: usize,
-    pub global_env: HashMap<StringId, MaybeThunk>,
-}
-
-impl CodeState {
-    pub fn new(strings: &mut DefaultStringInterner) -> Self {
-        let global_env = crate::ir::new_global_env(strings);
-        let mut bytecode = Vec::with_capacity(Continuation::Illegal as usize * 2);
-        for phase in 0..=Continuation::Illegal as u8 {
-            bytecode.push(Op::DispatchCont as u8);
-            bytecode.push(phase);
-        }
-        Self {
-            sources: Vec::new(),
-            spans: Vec::new(),
-            thunk_count: 0,
-            bytecode,
-            global_env,
-        }
-    }
-
-    pub fn compile_bytecode<'ctx>(
-        &'ctx mut self,
-        source: Source,
-        extra_scope: Option<ExtraScope<'ctx>>,
-        runtime: &'ctx mut impl VmRuntimeCtx,
-    ) -> Result<InstructionPtr> {
-        let mut compiler = CompilerCtx {
-            code: self,
-            runtime,
-        };
-        compiler.compile_bytecode(source, extra_scope)
-    }
-}
-
-impl VmCode for CodeState {
-    fn bytecode(&self) -> &[u8] {
-        &self.bytecode
-    }
-
-    fn compile_with_scope(
-        &mut self,
-        source: Source,
-        extra_scope: Option<fix_runtime::ExtraScope>,
-        runtime: &mut impl VmRuntimeCtx,
-    ) -> Result<InstructionPtr> {
-        let extra = extra_scope.map(|s| match s {
-            fix_runtime::ExtraScope::ScopedImport { keys, slot_id } => {
-                ExtraScope::ScopedImport { keys, slot_id }
-            }
-        });
-        CodeState::compile_bytecode(self, source, extra, runtime)
-    }
-}
-
-struct CompilerCtx<'a, R: VmRuntimeCtx> {
-    code: &'a mut CodeState,
-    runtime: &'a mut R,
-}
-
-impl<'a, R: VmRuntimeCtx> CompilerCtx<'a, R> {
-    fn compile_bytecode(
-        &mut self,
-        source: Source,
-        extra_scope: Option<ExtraScope>,
-    ) -> Result<InstructionPtr> {
-        let root = self.downgrade(source, extra_scope)?;
-        let ip = crate::compile_bytecode(root.as_ref(), self);
-        Ok(ip)
-    }
-
-    fn downgrade(&mut self, source: Source, extra_scope: Option<ExtraScope>) -> Result<OwnedIr> {
-        tracing::debug!("Parsing Nix expression");
-
-        self.code.sources.push(source.clone());
-
-        let root = rnix::Root::parse(&source.src);
-        handle_parse_error(root.errors(), source.clone()).map_or(Ok(()), Err)?;
-
-        tracing::debug!("Downgrading Nix expression");
-        let expr = root
-            .tree()
-            .expr()
-            .ok_or_else(|| Error::parse_error("unexpected EOF".into()))?;
-        let bump = Bump::new();
-        GhostToken::new(|token| {
-            let downgrade_ctx = DowngradeCtx::new(
-                &bump,
-                token,
-                self.runtime,
-                &self.code.global_env,
-                extra_scope.map(Into::into),
-                &mut self.code.thunk_count,
-                source,
-            );
-            let ir = downgrade_ctx.downgrade_toplevel(expr)?;
-            // SAFETY: `ir` borrows from `bump`, which is moved into the returned
-            // `OwnedIr` alongside the reference. The `'static` lifetime is a
-            // storage token that is re-narrowed to the `OwnedIr`'s own borrow in
-            // `as_ref`, so no reference ever outlives the arena backing it.
-            let ir = unsafe { std::mem::transmute::<RawIrRef<'_>, RawIrRef<'static>>(ir) };
-            // SAFETY: `ir` borrows from `bump`
-            Ok(unsafe { OwnedIr::new(bump, ir) })
-        })
-    }
-}
-
-impl<'a, R: VmRuntimeCtx> BytecodeContext for CompilerCtx<'a, R> {
-    fn intern_string(&mut self, s: &str) -> StringId {
-        self.runtime.intern_string(s)
-    }
-
-    fn register_span(&mut self, range: rnix::TextRange) -> u32 {
-        let id = self.code.spans.len();
-        let source_id = self
-            .code
-            .sources
-            .len()
-            .checked_sub(1)
-            .expect("current_source not set");
-        self.code.spans.push((source_id, range));
-        id as u32
-    }
-
-    fn get_code(&self) -> &[u8] {
-        &self.code.bytecode
-    }
-
-    fn get_code_mut(&mut self) -> &mut Vec<u8> {
-        &mut self.code.bytecode
-    }
-
-    fn add_constant(&mut self, val: Const) -> u32 {
-        use Const::*;
-        let val = match val {
-            Smi(x) => StaticValue::new(x),
-            Float(x) => StaticValue::new(x),
-            Bool(x) => StaticValue::new(x),
-            String(x) => StaticValue::new(x),
-            Path(x) => StaticValue::new(fix_runtime::Path(x)),
-            PrimOp(id) => StaticValue::new(fix_runtime::PrimOp::from(id)),
-            Null => StaticValue::default(),
-        };
-        self.runtime.add_const(val)
-    }
-
-    fn current_source_dir(&mut self) -> StringId {
-        let dir = self
-            .code
-            .sources
-            .last()
-            .expect("current_source not set")
-            .get_dir()
-            .to_string_lossy()
-            .into_owned();
-        self.runtime.intern_string(dir)
-    }
-}
-
-fn parse_error_span(error: &rnix::ParseError) -> Option<rnix::TextRange> {
-    use rnix::ParseError::*;
-    match error {
-        Unexpected(range)
-        | UnexpectedExtra(range)
-        | UnexpectedWanted(_, range, _)
-        | UnexpectedDoubleBind(range)
-        | DuplicatedArgs(range, _) => Some(*range),
-        _ => None,
-    }
-}
-
-fn handle_parse_error<'a>(
-    errors: impl IntoIterator<Item = &'a rnix::ParseError>,
-    source: Source,
-) -> Option<Box<Error>> {
-    for err in errors {
-        if let Some(span) = parse_error_span(err) {
-            return Some(
-                Error::parse_error(err.to_string())
-                    .with_source(source)
-                    .with_span(span),
-            );
-        }
-    }
-    None
-}
-
-struct DowngradeCtx<'ctx, 'id, 'ir, R: VmRuntimeCtx> {
-    bump: &'ir Bump,
-    token: GhostToken<'id>,
-    runtime: &'ctx mut R,
-    source: Source,
-    scopes: Vec<Scope<'ctx, 'id, 'ir>>,
-    with_stack: Vec<GhostRoMaybeThunkRef<'id, 'ir>>,
-    thunk_count: &'ctx mut usize,
-    thunk_scopes: Vec<ThunkScope<'id, 'ir>>,
-}
-
-impl<'ctx, 'id, 'ir, R: VmRuntimeCtx> DowngradeCtx<'ctx, 'id, 'ir, R> {
-    fn new(
-        bump: &'ir Bump,
-        token: GhostToken<'id>,
-        runtime: &'ctx mut R,
-        global: &'ctx HashMap<StringId, MaybeThunk>,
-        extra_scope: Option<Scope<'ctx, 'id, 'ir>>,
-        thunk_count: &'ctx mut usize,
-        source: Source,
-    ) -> Self {
-        Self {
-            bump,
-            token,
-            runtime,
-            source,
-            scopes: std::iter::once(Scope::Global(global))
-                .chain(extra_scope)
-                .collect(),
-            thunk_count,
-            with_stack: Vec::new(),
-            thunk_scopes: vec![ThunkScope::new_in(bump)],
-        }
-    }
-}
-
-impl<'ctx: 'ir, 'id, 'ir, R: VmRuntimeCtx> DowngradeContext<'id, 'ir>
-    for DowngradeCtx<'ctx, 'id, 'ir, R>
-{
-    fn new_expr(&self, expr: Ir<'ir, GhostRoRef<'id, 'ir>>) -> GhostRoIrRef<'id, 'ir> {
-        self.bump.alloc(GhostCell::new(expr).into())
-    }
-
-    fn maybe_thunk(&mut self, ir: GhostRoIrRef<'id, 'ir>) -> GhostRoMaybeThunkRef<'id, 'ir> {
-        use MaybeThunk::*;
-        let expr = (|| {
-            let expr = match *ir.borrow(&self.token) {
-                Ir::Builtin(x) => Builtin(x),
-                Ir::Int(x) => Int(x),
-                Ir::Float(x) => Float(x),
-                Ir::Bool(x) => Bool(x),
-                Ir::Str(x) => Str(x),
-                Ir::Arg { layer } => Arg { layer },
-                Ir::Builtins => Builtins,
-                Ir::Null => Null,
-                Ir::MaybeThunk(thunk) => return Some(thunk),
-                _ => return None,
-            };
-            Some(self.bump.alloc(GhostCell::new(expr).into()))
-        })();
-        if let Some(thunk) = expr {
-            return thunk;
-        }
-        let id = ThunkId(*self.thunk_count);
-        *self.thunk_count = self.thunk_count.checked_add(1).expect("thunk id overflow");
-        self.thunk_scopes
-            .last_mut()
-            .expect("no active cache scope")
-            .add_binding(id, ir);
-        self.bump.alloc(GhostCell::new(Thunk(id)).into())
-    }
-
-    fn intern_string(&mut self, sym: impl AsRef<str>) -> StringId {
-        self.runtime.intern_string(sym)
-    }
-
-    fn resolve_sym(&self, id: StringId) -> Symbol<'_> {
-        self.runtime.resolve_string(id).into()
-    }
-
-    #[expect(
-        clippy::unwrap_in_result,
-        reason = "exceeding u8::MAX thunk scope layers is a compiler invariant violation, not a user-facing error"
-    )]
-    fn lookup(
-        &mut self,
-        sym: StringId,
-        span: rnix::TextRange,
-    ) -> Result<GhostRoMaybeThunkRef<'id, 'ir>> {
-        for scope in self.scopes.iter().rev() {
-            match scope {
-                &Scope::Global(global_scope) => {
-                    if let Some(expr) = global_scope.get(&sym) {
-                        return Ok(expr.into());
-                    }
-                }
-                &Scope::Repl(repl_bindings) => {
-                    if repl_bindings.contains(&sym) {
-                        return Ok(self
-                            .bump
-                            .alloc(GhostCell::new(MaybeThunk::ReplBinding(sym)).into()));
-                    }
-                }
-                &Scope::ScopedImport { ref keys, slot_id } => {
-                    if keys.contains(&sym) {
-                        return Ok(self.bump.alloc(
-                            GhostCell::new(MaybeThunk::ScopedImportBinding { sym, slot_id }).into(),
-                        ));
-                    }
-                }
-                Scope::Let(let_scope) => {
-                    if let Some(&expr) = let_scope.get(&sym) {
-                        return Ok(expr.into());
-                    }
-                }
-                &Scope::Param {
-                    sym: param_sym,
-                    abs_layer,
-                } => {
-                    if param_sym == sym {
-                        let layers: u8 =
-                            self.thunk_scopes.len().try_into().expect("scope too deep!");
-                        let layer = layers - abs_layer;
-                        return Ok(self
-                            .bump
-                            .alloc(GhostCell::new(MaybeThunk::Arg { layer }).into()));
-                    }
-                }
-            }
-        }
-
-        if !self.with_stack.is_empty() {
-            let id = ThunkId(*self.thunk_count);
-            *self.thunk_count = self.thunk_count.checked_add(1).expect("thunk id overflow");
-            let mut namespaces =
-                bumpalo::collections::Vec::with_capacity_in(self.with_stack.len(), self.bump);
-            namespaces.extend(self.with_stack.iter().rev().copied());
-            let body = self
-                .bump
-                .alloc(GhostCell::new(Ir::WithLookup { sym, namespaces }).into());
-            self.thunk_scopes
-                .last_mut()
-                .expect("no active thunk scope")
-                .add_binding(id, body);
-            Ok(self
-                .bump
-                .alloc(GhostCell::new(MaybeThunk::Thunk(id)).into()))
-        } else {
-            Err(Error::downgrade_error(
-                format!("'{}' not found", self.resolve_sym(sym)),
-                self.get_current_source(),
-                span,
-            ))
-        }
-    }
-
-    fn get_current_source(&self) -> Source {
-        self.source.clone()
-    }
-
-    #[expect(
-        clippy::panic_in_result_fn,
-        reason = "assert_eq guards an internal invariant (bindings and values have equal length); a mismatch is a compiler bug, not a user error"
-    )]
-    fn with_let_scope<F, Ret>(&mut self, keys: &[StringId], f: F) -> Result<Ret>
-    where
-        F: FnOnce(
-            &mut Self,
-        ) -> Result<(
-            bumpalo::collections::Vec<'ir, GhostRoMaybeThunkRef<'id, 'ir>>,
-            Ret,
-        )>,
-    {
-        let base = *self.thunk_count;
-        *self.thunk_count = self
-            .thunk_count
-            .checked_add(keys.len())
-            .expect("thunk id overflow");
-        let handles = (base..base + keys.len())
-            .map(|id| {
-                &*self
-                    .bump
-                    .alloc(GhostCell::new(MaybeThunk::Thunk(ThunkId(id))))
-            })
-            .collect::<Vec<_>>();
-        let scope = keys.iter().copied().zip(handles.iter().copied()).collect();
-        self.scopes.push(Scope::Let(scope));
-        let (vals, ret) = { f(self)? };
-        self.scopes.pop();
-        assert_eq!(keys.len(), vals.len());
-        let scope = self.thunk_scopes.last_mut().expect("no active thunk scope");
-        for (i, (val, handle)) in vals.into_iter().zip(handles).enumerate() {
-            let thunk = *val.borrow(&self.token);
-            *handle.borrow_mut(&mut self.token) = thunk;
-            let id = ThunkId(base + i);
-            let ir_ref = self
-                .bump
-                .alloc(GhostCell::new(Ir::MaybeThunk(handle.into())).into());
-            scope.add_binding(id, ir_ref);
-        }
-        Ok(ret)
-    }
-
-    fn with_param_scope<F, Ret>(&mut self, sym: StringId, f: F) -> Ret
-    where
-        F: FnOnce(&mut Self) -> Ret,
-    {
-        self.scopes.push(Scope::Param {
-            sym,
-            abs_layer: self.thunk_scopes.len().try_into().expect("scope too deep!"),
-        });
-        let mut guard = ScopeGuard { ctx: self };
-        f(guard.as_ctx())
-    }
-
-    fn with_with_scope<F, Ret>(&mut self, namespace: GhostRoMaybeThunkRef<'id, 'ir>, f: F) -> Ret
-    where
-        F: FnOnce(&mut Self) -> Ret,
-    {
-        self.with_stack.push(namespace);
-        let ret = f(self);
-        self.with_stack.pop();
-        ret
-    }
-
-    #[expect(
-        clippy::panic,
-        reason = "exceeding u8::MAX thunk scope layers is a compiler invariant violation, not a user-facing error"
-    )]
-    fn with_thunk_scope<F, Ret>(
-        &mut self,
-        f: F,
-    ) -> (
-        Ret,
-        bumpalo::collections::Vec<'ir, (ThunkId, GhostRoIrRef<'id, 'ir>)>,
-    )
-    where
-        F: FnOnce(&mut Self) -> Ret,
-    {
-        if self.thunk_scopes.len() == u8::MAX as usize {
-            panic!("scope too deep!");
-        }
-        self.thunk_scopes.push(ThunkScope::new_in(self.bump));
-        let ret = f(self);
-        (
-            ret,
-            self.thunk_scopes
-                .pop()
-                .expect("no thunk scope left???")
-                .bindings,
-        )
-    }
-
-    fn bump(&self) -> &'ir bumpalo::Bump {
-        self.bump
-    }
-}
-
-impl<'id, 'ir, 'ctx: 'ir, R: VmRuntimeCtx> DowngradeCtx<'ctx, 'id, 'ir, R> {
-    fn downgrade_toplevel(mut self, root: rnix::ast::Expr) -> Result<RawIrRef<'ir>> {
-        let body = root.downgrade(&mut self)?;
-        let thunks = self
-            .thunk_scopes
-            .pop()
-            .expect("no thunk scope left???")
-            .bindings;
-        Ok(Ir::freeze(
-            self.new_expr(Ir::TopLevel { body, thunks }),
-            self.token,
-        ))
-    }
-}
-
-struct ThunkScope<'id, 'ir> {
-    bindings: bumpalo::collections::Vec<'ir, (ThunkId, GhostRoIrRef<'id, 'ir>)>,
-}
-
-impl<'id, 'ir> ThunkScope<'id, 'ir> {
-    fn new_in(bump: &'ir Bump) -> Self {
-        Self {
-            bindings: bumpalo::collections::Vec::new_in(bump),
-        }
-    }
-
-    fn add_binding(&mut self, id: ThunkId, ir: GhostRoIrRef<'id, 'ir>) {
-        self.bindings.push((id, ir));
-    }
-}
-
-enum Scope<'ctx, 'id, 'ir> {
-    Global(&'ctx HashMap<StringId, MaybeThunk>),
-    Repl(&'ctx HashSet<StringId>),
-    ScopedImport {
-        keys: HashSet<StringId>,
-        slot_id: u32,
-    },
-    Let(HashMap<StringId, GhostMaybeThunkRef<'id, 'ir>>),
-    Param {
-        sym: StringId,
-        abs_layer: u8,
-    },
-}
-
-pub enum ExtraScope<'ctx> {
-    Repl(&'ctx HashSet<StringId>),
-    ScopedImport {
-        keys: HashSet<StringId>,
-        slot_id: u32,
-    },
-}
-
-impl<'ctx> From<ExtraScope<'ctx>> for Scope<'ctx, '_, '_> {
-    fn from(value: ExtraScope<'ctx>) -> Self {
-        use ExtraScope::*;
-        match value {
-            ScopedImport { keys, slot_id } => Scope::ScopedImport { keys, slot_id },
-            Repl(scope) => Scope::Repl(scope),
-        }
-    }
-}
-
-struct ScopeGuard<'a, 'ctx, 'id, 'ir, R: VmRuntimeCtx> {
-    ctx: &'a mut DowngradeCtx<'ctx, 'id, 'ir, R>,
-}
-
-impl<'a, 'ctx, 'id, 'ir, R: VmRuntimeCtx> Drop for ScopeGuard<'a, 'ctx, 'id, 'ir, R> {
-    fn drop(&mut self) {
-        self.ctx.scopes.pop();
-    }
-}
-
-impl<'a, 'ctx, 'id, 'ir, R: VmRuntimeCtx> ScopeGuard<'a, 'ctx, 'id, 'ir, R> {
-    fn as_ctx(&mut self) -> &mut DowngradeCtx<'ctx, 'id, 'ir, R> {
-        self.ctx
-    }
-}
-
-mod sealed {
-    use super::*;
-
-    pub struct OwnedIr {
-        _bump: Bump,
-        ir: RawIrRef<'static>,
-    }
-
-    impl OwnedIr {
-        /// # Safety
-        /// `ir` must borrows from `bump`
-        pub unsafe fn new(bump: Bump, ir: RawIrRef<'static>) -> Self {
-            Self { _bump: bump, ir }
-        }
-
-        pub fn as_ref<'ir>(&'ir self) -> RawIrRef<'ir> {
-            // SAFETY: `self.ir`'s `'static` lifetime is a storage token; the IR is
-            // backed by `self._bump`, which lives as long as `self`. Narrowing to
-            // `'ir` (tied to `&self`) hands out a reference that cannot outlive the
-            // arena.
-            unsafe { std::mem::transmute::<RawIrRef<'static>, RawIrRef<'ir>>(self.ir) }
-        }
-    }
-}
-
-pub use sealed::OwnedIr;

fix-compiler/src/ir.rs

@@ -1,327 +0,0 @@
-use std::hash::Hash;
-use std::marker::PhantomData;
-
-use bumpalo::Bump;
-use bumpalo::collections::Vec;
-use fix_lang::{BuiltinId, StringId};
-use ghost_cell::{GhostCell, GhostToken};
-use rnix::{TextRange, ast};
-use string_interner::DefaultStringInterner;
-
-pub mod downgrade;
-
-pub type HashMap<'ir, K, V> = hashbrown::HashMap<K, V, hashbrown::DefaultHashBuilder, &'ir Bump>;
-
-pub type GhostIrRef<'id, 'ir> = <GhostRef<'id, 'ir> as RefExt<'ir>>::IrRef;
-pub type GhostRoIrRef<'id, 'ir> = <GhostRoRef<'id, 'ir> as RefExt<'ir>>::IrRef;
-pub type RawIrRef<'ir> = <RawRef<'ir> as RefExt<'ir>>::IrRef;
-pub type GhostMaybeThunkRef<'id, 'ir> = <GhostRef<'id, 'ir> as RefExt<'ir>>::MaybeThunkRef;
-pub type GhostRoMaybeThunkRef<'id, 'ir> = <GhostRoRef<'id, 'ir> as RefExt<'ir>>::MaybeThunkRef;
-
-impl<'id, 'ir> Ir<'ir, GhostRoRef<'id, 'ir>> {
-    /// Freeze a mutable IR reference into a read-only one, consuming the
-    /// `GhostToken` to prevent any further mutation.
-    pub fn freeze(this: GhostRoIrRef<'id, 'ir>, _: GhostToken<'id>) -> RawIrRef<'ir> {
-        // SAFETY: The transmute is sound because:
-        // - `GhostCell<'id, T>` is `#[repr(transparent)]` over `T`, so
-        //   `&'ir GhostCell<'id, T>` and `&'ir T` have identical layout.
-        // - `Ir<'ir, R>` is `#[repr(C)]`, and for every field that depends on
-        //   `R`, instantiating `R = GhostRef<'id, 'ir>` vs `R = RawRef<'ir>`
-        //   produces types of identical layout:
-        //     - `R::IrRef` becomes `&'ir GhostCell<'id, Ir<...>>` vs `&'ir Ir<...>`
-        //     - `R::MaybeThunkRef` becomes `&'ir GhostCell<'id, MaybeThunk>`
-        //       vs `&'ir MaybeThunk`
-        //     - `R::Ref<Ir<'ir, R>>` (used in `ConcatStrings::parts`) reduces
-        //       to the same case as `R::IrRef`
-        // - Therefore `IrRef<'id, 'ir>` and `RawIrRef<'ir>` are both
-        //   pointer-sized references with the same layout.
-        //
-        // Consuming the `GhostToken` guarantees no `borrow_mut` calls can
-        // occur afterwards, so the shared `&Ir` references reachable from a
-        // `RawIrRef<'ir>` can never alias with mutable references.
-        unsafe { std::mem::transmute::<GhostRoIrRef<'id, 'ir>, RawIrRef<'ir>>(this) }
-    }
-}
-
-#[repr(transparent)]
-pub struct GhostRoCell<'id, T: ?Sized>(GhostCell<'id, T>);
-
-impl<'id, T> From<GhostCell<'id, T>> for GhostRoCell<'id, T> {
-    fn from(value: GhostCell<'id, T>) -> Self {
-        Self(value)
-    }
-}
-
-impl<'id, T: ?Sized> From<&GhostCell<'id, T>> for &GhostRoCell<'id, T> {
-    fn from(value: &GhostCell<'id, T>) -> Self {
-        // SAFETY: `GhostRoCell` is `#[repr(transparent)]` over `GhostCell`
-        // TODO: document mutability
-        unsafe { std::mem::transmute(value) }
-    }
-}
-
-impl<'id, T: ?Sized> From<&T> for &GhostRoCell<'id, T> {
-    fn from(value: &T) -> Self {
-        // SAFETY: `GhostRoCell` is `#[repr(transparent)]` over `GhostCell`,
-        //         which is `#[repr(transparent)]` over `T`
-        // TODO: document mutability
-        unsafe { std::mem::transmute(value) }
-    }
-}
-
-impl<'id, T: ?Sized> GhostRoCell<'id, T> {
-    pub fn borrow<'a>(&'a self, token: &'a GhostToken<'id>) -> &'a T {
-        self.0.borrow(token)
-    }
-}
-
-#[repr(C)]
-#[derive(Debug, Clone, Copy)]
-pub enum MaybeThunk {
-    Int(i64),
-    Float(f64),
-    Bool(bool),
-    Null,
-    Str(StringId),
-    Path(StringId),
-    Thunk(ThunkId),
-    Arg { layer: u8 },
-    Builtin(BuiltinId),
-    BuiltinConst(StringId),
-    Builtins,
-    ReplBinding(StringId),
-    ScopedImportBinding { slot_id: u32, sym: StringId },
-}
-
-pub trait Ref<'ir> {
-    type Ref<T>
-    where
-        T: 'ir;
-}
-
-pub trait RefExt<'ir>: Ref<'ir> {
-    type Ir;
-    type IrRef;
-    type MaybeThunkRef;
-}
-impl<'ir, T: Ref<'ir> + 'ir> RefExt<'ir> for T {
-    type Ir = Ir<'ir, Self>;
-    type IrRef = Self::Ref<Self::Ir>;
-    type MaybeThunkRef = Self::Ref<MaybeThunk>;
-}
-
-pub struct GhostRef<'id, 'ir>(PhantomData<&'ir GhostCell<'id, ()>>);
-pub struct GhostRoRef<'id, 'ir>(PhantomData<&'ir GhostRoCell<'id, ()>>);
-pub struct RawRef<'ir>(PhantomData<&'ir ()>);
-
-impl<'id, 'ir> Ref<'ir> for GhostRef<'id, 'ir> {
-    type Ref<T: 'ir> = &'ir GhostCell<'id, T>;
-}
-impl<'id, 'ir> Ref<'ir> for GhostRoRef<'id, 'ir> {
-    type Ref<T: 'ir> = &'ir GhostRoCell<'id, T>;
-}
-impl<'ir> Ref<'ir> for RawRef<'ir> {
-    type Ref<T: 'ir> = &'ir T;
-}
-
-#[repr(C)]
-#[derive(Debug)]
-pub enum Ir<'ir, R: RefExt<'ir> + ?Sized + 'ir> {
-    Int(i64),
-    Float(f64),
-    Bool(bool),
-    Null,
-    Str(StringId),
-    Path(R::IrRef),
-    AttrSet {
-        stcs: HashMap<'ir, StringId, (R::MaybeThunkRef, TextRange)>,
-        dyns: Vec<'ir, (R::IrRef, R::MaybeThunkRef, TextRange)>,
-    },
-    List {
-        items: Vec<'ir, R::MaybeThunkRef>,
-    },
-    ConcatStrings {
-        parts: Vec<'ir, R::Ref<Ir<'ir, R>>>,
-        force_string: bool,
-    },
-
-    // OPs
-    UnOp {
-        rhs: R::IrRef,
-        kind: UnOpKind,
-    },
-    BinOp {
-        lhs: R::IrRef,
-        rhs: R::IrRef,
-        kind: BinOpKind,
-    },
-    HasAttr {
-        lhs: R::IrRef,
-        rhs: Vec<'ir, Attr<R::IrRef>>,
-    },
-    Select {
-        expr: R::IrRef,
-        attrpath: Vec<'ir, Attr<R::IrRef>>,
-        default: Option<R::IrRef>,
-        span: TextRange,
-    },
-
-    // Conditionals
-    If {
-        cond: R::IrRef,
-        consq: R::IrRef,
-        alter: R::IrRef,
-    },
-    Assert {
-        assertion: R::IrRef,
-        expr: R::IrRef,
-        assertion_raw: String,
-        span: TextRange,
-    },
-
-    WithLookup {
-        sym: StringId,
-        namespaces: Vec<'ir, R::MaybeThunkRef>,
-    },
-
-    // Function related
-    Func {
-        body: R::IrRef,
-        param: Option<Param<'ir>>,
-        thunks: Vec<'ir, (ThunkId, R::IrRef)>,
-    },
-    Arg {
-        layer: u8,
-    },
-    Call {
-        func: R::IrRef,
-        arg: R::MaybeThunkRef,
-        span: TextRange,
-    },
-
-    // Builtins
-    Builtins,
-    Builtin(BuiltinId),
-    BuiltinConst(StringId),
-
-    // Misc
-    TopLevel {
-        body: R::IrRef,
-        thunks: Vec<'ir, (ThunkId, R::IrRef)>,
-    },
-    MaybeThunk(R::MaybeThunkRef),
-    ReplBinding(StringId),
-    ScopedImportBinding {
-        sym: StringId,
-        slot_id: u32,
-    },
-}
-
-#[repr(transparent)]
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
-pub struct ThunkId(pub usize);
-
-/// Represents a key in an attribute path.
-#[derive(Debug)]
-pub enum Attr<Ref> {
-    /// A dynamic attribute key, which is an expression that must evaluate to a string.
-    /// Example: `attrs.${key}`
-    Dynamic(Ref, TextRange),
-    /// A static attribute key.
-    /// Example: `attrs.key`
-    Str(StringId, TextRange),
-}
-
-/// The kinds of binary operations supported in Nix.
-#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
-pub enum BinOpKind {
-    // Arithmetic
-    Add,
-    Sub,
-    Div,
-    Mul,
-
-    // Comparison
-    Eq,
-    Neq,
-    Lt,
-    Gt,
-    Leq,
-    Geq,
-
-    // Logical
-    And,
-    Or,
-    Impl,
-
-    // Set/String/Path operations
-    Con, // List concatenation (`++`)
-    Upd, // AttrSet update (`//`)
-}
-
-/// The kinds of unary operations.
-#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
-pub enum UnOpKind {
-    Neg, // Negation (`-`)
-    Not, // Logical not (`!`)
-}
-
-impl From<ast::UnaryOpKind> for UnOpKind {
-    fn from(value: ast::UnaryOpKind) -> Self {
-        match value {
-            ast::UnaryOpKind::Invert => UnOpKind::Not,
-            ast::UnaryOpKind::Negate => UnOpKind::Neg,
-        }
-    }
-}
-
-/// Describes the parameters of a function.
-#[derive(Debug)]
-pub struct Param<'ir> {
-    pub required: Vec<'ir, (StringId, TextRange)>,
-    pub optional: Vec<'ir, (StringId, TextRange)>,
-    pub ellipsis: bool,
-}
-
-pub fn new_global_env(
-    strings: &mut DefaultStringInterner,
-) -> hashbrown::HashMap<StringId, MaybeThunk> {
-    let mut global_env = hashbrown::HashMap::new();
-    let builtins_sym = StringId(strings.get_or_intern("builtins"));
-    global_env.insert(builtins_sym, MaybeThunk::Builtins);
-
-    for id in BuiltinId::ALL {
-        let name = StringId(strings.get_or_intern(id.info().global_name));
-        global_env.insert(name, MaybeThunk::Builtin(id));
-    }
-
-    let consts = [
-        (
-            "__currentSystem",
-            MaybeThunk::BuiltinConst(StringId(strings.get_or_intern("currentSystem"))),
-        ),
-        ("__langVersion", MaybeThunk::Int(6)),
-        (
-            "__nixVersion",
-            MaybeThunk::BuiltinConst(StringId(strings.get_or_intern("nixVersion"))),
-        ),
-        (
-            "__storeDir",
-            MaybeThunk::BuiltinConst(StringId(strings.get_or_intern("storeDir"))),
-        ),
-        (
-            "__nixPath",
-            MaybeThunk::BuiltinConst(StringId(strings.get_or_intern("nixPath"))),
-        ),
-        ("null", MaybeThunk::Null),
-        ("true", MaybeThunk::Bool(true)),
-        ("false", MaybeThunk::Bool(false)),
-    ];
-
-    for (name, ir) in consts {
-        let name = StringId(strings.get_or_intern(name));
-        global_env.insert(name, ir);
-    }
-
-    global_env
-}

fix-error/Cargo.toml

@@ -5,8 +5,5 @@ edition = "2024"
 
 [dependencies]
 miette = { version = "7.6", features = ["fancy"] }
-rnix = { workspace = true }
 thiserror = "2.0"
-
-[lints]
-workspace = true
+rnix = { workspace = true }

fix-error/src/lib.rs

@@ -4,7 +4,7 @@ use std::sync::Arc;
 use miette::{Diagnostic, NamedSource, SourceSpan};
 use thiserror::Error;
 
-pub type Result<T, E = Box<Error>> = core::result::Result<T, E>;
+pub type Result<T> = core::result::Result<T, Box<Error>>;
 
 #[derive(Clone, Debug)]
 pub enum SourceType {

fix-ir/Cargo.toml

@@ -1,22 +1,17 @@
 [package]
-name = "fix-compiler"
+name = "fix-ir"
 version = "0.1.0"
 edition = "2024"
 
 [dependencies]
 bumpalo = { workspace = true }
-colored = "3.1.1"
 ghost-cell = { workspace = true }
-hashbrown = { workspace = true }
 rnix = { workspace = true }
 rowan = { workspace = true }
 string-interner = { workspace = true }
+hashbrown = { workspace = true }
+num_enum = { workspace = true }
 
-fix-bytecode = { path = "../fix-bytecode" }
+fix-builtins = { path = "../fix-builtins" }
+fix-common = { path = "../fix-common" }
 fix-error = { path = "../fix-error" }
-fix-lang = { path = "../fix-lang" }
-fix-runtime = { path = "../fix-runtime" }
-tracing = "0.1"
-
-[lints]
-workspace = true

fix-ir/src/downgrade.rs

@@ -1,6 +1,7 @@
 use bumpalo::collections::{CollectIn, Vec};
+use fix_builtins::BuiltinId;
+use fix_common::Symbol;
 use fix_error::{Error, Result, Source};
-use fix_lang::{BuiltinId, Symbol};
 use hashbrown::HashSet;
 use hashbrown::hash_map::Entry;
 use rnix::TextRange;
@@ -38,12 +39,12 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>, T, E: std::fmt::Display>
 }
 
 pub trait DowngradeContext<'id: 'ir, 'ir> {
-    fn new_expr(&self, expr: Ir<'ir, GhostRoRef<'id, 'ir>>) -> GhostRoIrRef<'id, 'ir>;
-    fn maybe_thunk(&mut self, ir: GhostRoIrRef<'id, 'ir>) -> GhostRoMaybeThunkRef<'id, 'ir>;
+    fn new_expr(&self, expr: Ir<'ir, IrRef<'id, 'ir>>) -> IrRef<'id, 'ir>;
+    fn maybe_thunk(&mut self, ir: IrRef<'id, 'ir>) -> MaybeThunk;
 
     fn intern_string(&mut self, sym: impl AsRef<str>) -> StringId;
     fn resolve_sym(&self, id: StringId) -> Symbol<'_>;
-    fn lookup(&mut self, sym: StringId, span: TextRange) -> Result<GhostRoMaybeThunkRef<'id, 'ir>>;
+    fn lookup(&self, sym: StringId, span: TextRange) -> Result<MaybeThunk>;
 
     fn get_current_source(&self) -> Source;
 
@@ -52,11 +53,11 @@ pub trait DowngradeContext<'id: 'ir, 'ir> {
         F: FnOnce(&mut Self) -> R;
     fn with_let_scope<F, R>(&mut self, bindings: &[StringId], f: F) -> Result<R>
     where
-        F: FnOnce(&mut Self) -> Result<(Vec<'ir, GhostRoMaybeThunkRef<'id, 'ir>>, R)>;
-    fn with_with_scope<F, R>(&mut self, namespace: GhostRoMaybeThunkRef<'id, 'ir>, f: F) -> R
+        F: FnOnce(&mut Self) -> Result<(Vec<'ir, IrRef<'id, 'ir>>, R)>;
+    fn with_with_scope<F, R>(&mut self, f: F) -> R
     where
         F: FnOnce(&mut Self) -> R;
-    fn with_thunk_scope<F, R>(&mut self, f: F) -> (R, Vec<'ir, (ThunkId, GhostRoIrRef<'id, 'ir>)>)
+    fn with_thunk_scope<F, R>(&mut self, f: F) -> (R, Vec<'ir, (ThunkId, IrRef<'id, 'ir>)>)
     where
         F: FnOnce(&mut Self) -> R;
 
@@ -64,11 +65,11 @@ pub trait DowngradeContext<'id: 'ir, 'ir> {
 }
 
 pub trait Downgrade<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>>;
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>>;
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for Expr {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         use Expr::*;
         match self {
             Apply(apply) => apply.downgrade(ctx),
@@ -97,7 +98,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
             AttrSet(attrs) => attrs.downgrade(ctx),
             UnaryOp(op) => op.downgrade(ctx),
             Ident(ident) => ident.downgrade(ctx),
-            CurPos(curpos) => curpos.downgrade(ctx),
+            CurPos(curpos) => Ok(ctx.new_expr(Ir::CurPos(curpos.syntax().text_range()))),
             With(with) => with.downgrade(ctx),
             HasAttr(has) => has.downgrade(ctx),
             Paren(paren) => paren
@@ -113,7 +114,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::Assert {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let assertion = self.condition().require(ctx, span)?;
         let assertion_raw = assertion.to_string();
@@ -129,7 +130,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::IfElse {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let cond = self.condition().require(ctx, span)?.downgrade(ctx)?;
         let consq = self.body().require(ctx, span)?.downgrade(ctx)?;
@@ -141,7 +142,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 macro_rules! path {
     ($ty:ident) => {
         impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::$ty {
-            fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+            fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
                 downgrade_path(self.parts(), ctx)
             }
         }
@@ -151,15 +152,11 @@ path!(PathAbs);
 path!(PathRel);
 path!(PathHome);
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::PathSearch {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let path = {
             let temp = self.content().require(ctx, span)?;
             let text = temp.text();
-            #[expect(
-                clippy::string_slice,
-                reason = "PathSearch text is <...> wrapped in ASCII angle brackets, so byte indices 1 and len-1 are char boundaries"
-            )]
             let id = ctx.intern_string(&text[1..text.len() - 1]);
             let expr = ctx.new_expr(Ir::Str(id));
             ctx.maybe_thunk(expr)
@@ -183,7 +180,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::Str {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let normalized = self.normalized_parts();
         let is_single_literal = normalized.len() == 1
             && matches!(normalized.first(), Some(ast::InterpolPart::Literal(_)));
@@ -213,7 +210,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::Literal {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let expr = match self.kind() {
             ast::LiteralKind::Integer(int) => Ir::Int(int.value().require(ctx, span)?),
@@ -228,73 +225,16 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::Ident {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let text = self.ident_token().require(ctx, span)?.to_string();
         let sym = ctx.intern_string(text);
-        ctx.lookup(sym, span)
-            .map(|thunk| ctx.new_expr(Ir::MaybeThunk(thunk)))
-    }
-}
-
-impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::CurPos {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
-        fn byte_offset_to_line_col(content: &str, offset: usize) -> (u32, u32) {
-            let mut line = 1u32;
-            let mut col = 1u32;
-
-            for (idx, ch) in content.char_indices() {
-                if idx >= offset {
-                    break;
-                }
-                if ch == '\n' {
-                    line += 1;
-                    col = 1;
-                } else {
-                    col += 1;
-                }
-            }
-
-            (line, col)
-        }
-
-        let span = self.syntax().text_range();
-        let source = ctx.get_current_source();
-        let (line, column) = byte_offset_to_line_col(&source.src, span.start().into());
-
-        let file_sym = ctx.intern_string("file");
-        let line_sym = ctx.intern_string("line");
-        let column_sym = ctx.intern_string("column");
-
-        let file: GhostRoMaybeThunkRef = ctx
-            .bump()
-            .alloc(GhostCell::new(MaybeThunk::Str(ctx.intern_string(source.get_name()))).into());
-        let line = ctx
-            .bump()
-            .alloc(GhostCell::new(MaybeThunk::Int(i64::from(line))).into());
-        let column = ctx
-            .bump()
-            .alloc(GhostCell::new(MaybeThunk::Int(i64::from(column))).into());
-
-        let map = {
-            let mut map = HashMap::new_in(ctx.bump());
-
-            map.insert(file_sym, (file, TextRange::default()));
-            map.insert(line_sym, (line, TextRange::default()));
-            map.insert(column_sym, (column, TextRange::default()));
-
-            map
-        };
-
-        Ok(ctx.new_expr(Ir::AttrSet {
-            stcs: map,
-            dyns: Vec::new_in(ctx.bump()),
-        }))
+        ctx.lookup(sym, span).map(|thunk| thunk.to_ir(ctx))
     }
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::AttrSet {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let rec = self.rec_token().is_some();
         if !rec {
             let attrs = downgrade_attrs(self, ctx)?;
@@ -310,7 +250,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::List {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let bump = ctx.bump();
         let items = self
             .items()
@@ -324,52 +264,17 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::BinOp {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
-        use BinOpKind::*;
-        use ast::BinOpKind as Kind;
-
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let lhs = self.lhs().require(ctx, span)?.downgrade(ctx)?;
         let rhs = self.rhs().require(ctx, span)?.downgrade(ctx)?;
-        let kind = match self.operator().require(ctx, span)? {
-            Kind::Concat => Con,
-            Kind::Update => Upd,
-            Kind::Add => Add,
-            Kind::Sub => Sub,
-            Kind::Mul => Mul,
-            Kind::Div => Div,
-            Kind::And => And,
-            Kind::Equal => Eq,
-            Kind::Implication => Impl,
-            Kind::Less => Lt,
-            Kind::LessOrEq => Leq,
-            Kind::More => Gt,
-            Kind::MoreOrEq => Geq,
-            Kind::NotEqual => Neq,
-            Kind::Or => Or,
-            Kind::PipeLeft => {
-                let arg = ctx.maybe_thunk(rhs);
-                return Ok(ctx.new_expr(Ir::Call {
-                    func: lhs,
-                    arg,
-                    span,
-                }));
-            }
-            Kind::PipeRight => {
-                let arg = ctx.maybe_thunk(lhs);
-                return Ok(ctx.new_expr(Ir::Call {
-                    func: rhs,
-                    arg,
-                    span,
-                }));
-            }
-        };
+        let kind = self.operator().require(ctx, span)?.into();
         Ok(ctx.new_expr(Ir::BinOp { lhs, rhs, kind }))
     }
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::HasAttr {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let lhs = self.expr().require(ctx, span)?.downgrade(ctx)?;
         let rhs = downgrade_attrpath(self.attrpath().require(ctx, span)?, ctx)?;
@@ -378,7 +283,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::UnaryOp {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let rhs = self.expr().require(ctx, span)?.downgrade(ctx)?;
         let kind = self.operator().require(ctx, span)?.into();
@@ -387,7 +292,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::Select {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let expr = self.expr().require(ctx, span)?.downgrade(ctx)?;
         let attrpath = downgrade_attrpath(self.attrpath().require(ctx, span)?, ctx)?;
@@ -406,7 +311,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::LegacyLet {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let entries: Vec<'ir, _> = self.entries().collect_in(ctx.bump());
         let attrset_expr = downgrade_let_bindings(entries, ctx, |ctx, binding_keys| {
@@ -435,7 +340,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::LetIn {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let entries: Vec<'ir, _> = self.entries().collect_in(ctx.bump());
         let span = self.syntax().text_range();
         let body_expr = self.body().require(ctx, span)?;
@@ -445,35 +350,45 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::With {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let namespace = self.namespace().require(ctx, span)?.downgrade(ctx)?;
         let namespace = ctx.maybe_thunk(namespace);
 
         let body_expr = self.body().require(ctx, span)?;
-        ctx.with_with_scope(namespace, |ctx| body_expr.downgrade(ctx))
+        let (body, thunks) =
+            ctx.with_thunk_scope(|ctx| ctx.with_with_scope(|ctx| body_expr.downgrade(ctx)));
+        let body = body?;
+
+        Ok(ctx.new_expr(Ir::With {
+            namespace,
+            body,
+            thunks,
+        }))
     }
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::Lambda {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let raw_param = self.param().require(ctx, span)?;
         let body_ast = self.body().require(ctx, span)?;
 
         struct Ret<'id, 'ir> {
             param: Option<Param<'ir>>,
-            body: GhostRoIrRef<'id, 'ir>,
+            body: IrRef<'id, 'ir>,
         }
 
-        let (ret, thunks) = ctx.with_thunk_scope(|ctx| -> Result<Ret> {
-            let (param, body) = match raw_param {
+        let (ret, thunks) = ctx.with_thunk_scope(|ctx| {
+            let param;
+            let body;
+
+            match raw_param {
                 ast::Param::IdentParam(id) => {
                     let param_sym = ctx.intern_string(id.to_string());
-                    (
-                        None,
-                        ctx.with_param_scope(param_sym, |ctx| body_ast.downgrade(ctx))?,
-                    )
+                    param = None;
+
+                    body = ctx.with_param_scope(param_sym, |ctx| body_ast.downgrade(ctx))?;
                 }
                 ast::Param::Pattern(pattern) => {
                     let alias = pattern
@@ -495,18 +410,17 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
                         body_ast.clone().downgrade(ctx)
                     })?;
 
-                    (
-                        Some(Param {
+                    param = Some(Param {
                         required,
                         optional,
                         ellipsis,
-                        }),
-                        inner_body,
-                    )
-                }
-            };
+                    });
 
-            Ok(Ret { param, body })
+                    body = inner_body;
+                }
+            }
+
+            Result::Ok(Ret { param, body })
         });
         let Ret { param, body } = ret?;
 
@@ -519,7 +433,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 }
 
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::Apply {
-    fn downgrade(self, ctx: &mut Ctx) -> Result<GhostRoIrRef<'id, 'ir>> {
+    fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let func = self.lambda().require(ctx, span)?.downgrade(ctx)?;
         let arg = self.argument().require(ctx, span)?.downgrade(ctx)?;
@@ -553,10 +467,6 @@ impl<'id: 'ir, 'ir> PendingAttrSet<'ir> {
         }
     }
 
-    #[expect(
-        clippy::indexing_slicing,
-        reason = "path is non-empty here: path.first() was just unwrapped above, so path[1..] is in bounds"
-    )]
     fn insert(
         &mut self,
         path: &[ast::Attr],
@@ -658,10 +568,6 @@ impl<'id: 'ir, 'ir> PendingAttrSet<'ir> {
     ) -> Result<()> {
         if !path.is_empty() {
             let mut nested = PendingAttrSet::new_in(ctx.bump());
-            #[expect(
-                clippy::indexing_slicing,
-                reason = "path is non-empty in this branch, so path[0] and path[1..] are in bounds"
-            )]
             nested.insert_dynamic(
                 path[0].clone(),
                 path[0].syntax().text_range(),
@@ -676,10 +582,6 @@ impl<'id: 'ir, 'ir> PendingAttrSet<'ir> {
         Ok(())
     }
 
-    #[expect(
-        clippy::unreachable,
-        reason = "value was just reassigned to PendingValue::Set on the line above, so the re-match always hits the Set arm"
-    )]
     fn ensure_pending_set<'a>(
         value: &'a mut PendingValue<'ir>,
         ctx: &mut impl DowngradeContext<'id, 'ir>,
@@ -933,15 +835,8 @@ fn make_attrpath_value_entry<'ir>(path: Vec<'ir, ast::Attr>, value: ast::Expr) -
 }
 
 struct FinalizedAttrSet<'id, 'ir> {
-    stcs: HashMap<'ir, StringId, (GhostRoMaybeThunkRef<'id, 'ir>, TextRange)>,
-    dyns: Vec<
-        'ir,
-        (
-            GhostRoIrRef<'id, 'ir>,
-            GhostRoMaybeThunkRef<'id, 'ir>,
-            TextRange,
-        ),
-    >,
+    stcs: HashMap<'ir, StringId, (MaybeThunk, TextRange)>,
+    dyns: Vec<'ir, (IrRef<'id, 'ir>, MaybeThunk, TextRange)>,
 }
 
 fn downgrade_attrs<'id, 'ir>(
@@ -956,7 +851,7 @@ fn downgrade_attrs<'id, 'ir>(
 fn downgrade_attr<'id, 'ir>(
     attr: ast::Attr,
     ctx: &mut impl DowngradeContext<'id, 'ir>,
-) -> Result<Attr<GhostRoIrRef<'id, 'ir>>> {
+) -> Result<Attr<IrRef<'id, 'ir>>> {
     use ast::Attr::*;
     use ast::InterpolPart::*;
     match attr {
@@ -1017,7 +912,7 @@ fn downgrade_attr<'id, 'ir>(
 fn downgrade_attrpath<'id, 'ir>(
     attrpath: ast::Attrpath,
     ctx: &mut impl DowngradeContext<'id, 'ir>,
-) -> Result<Vec<'ir, Attr<GhostRoIrRef<'id, 'ir>>>> {
+) -> Result<Vec<'ir, Attr<IrRef<'id, 'ir>>>> {
     let bump = ctx.bump();
     attrpath
         .attrs()
@@ -1026,7 +921,7 @@ fn downgrade_attrpath<'id, 'ir>(
 }
 
 struct PatternBindings<'id, 'ir> {
-    body: GhostRoIrRef<'id, 'ir>,
+    body: IrRef<'id, 'ir>,
     required: Vec<'ir, (StringId, TextRange)>,
     optional: Vec<'ir, (StringId, TextRange)>,
 }
@@ -1035,7 +930,7 @@ fn downgrade_pattern_bindings<'id, 'ir, Ctx>(
     pat_entries: impl Iterator<Item = ast::PatEntry>,
     alias: Option<StringId>,
     ctx: &mut Ctx,
-    body_fn: impl FnOnce(&mut Ctx, &[StringId]) -> Result<GhostRoIrRef<'id, 'ir>>,
+    body_fn: impl FnOnce(&mut Ctx, &[StringId]) -> Result<IrRef<'id, 'ir>>,
 ) -> Result<PatternBindings<'id, 'ir>>
 where
     Ctx: DowngradeContext<'id, 'ir>,
@@ -1094,7 +989,6 @@ where
     }
 
     let arg = ctx.new_expr(Ir::Arg { layer: 0 });
-    let arg_thunk = ctx.maybe_thunk(arg);
     ctx.with_let_scope(&keys, |ctx| {
         let vals = params
             .into_iter()
@@ -1106,16 +1000,21 @@ where
                     span,
                 } = param;
                 let default = default.map(|default| default.downgrade(ctx)).transpose()?;
+                // let default = if let Some(default) = default {
+                //     let default = default.clone().downgrade(ctx)?;
+                //     Some(ctx.maybe_thunk(default))
+                // } else {
+                //     None
+                // };
 
-                let expr = ctx.new_expr(Ir::Select {
+                Ok(ctx.new_expr(Ir::Select {
                     expr: arg,
                     attrpath: Vec::from_iter_in([Attr::Str(sym, sym_span)], bump),
                     default,
                     span,
-                });
-                Ok(ctx.maybe_thunk(expr))
+                }))
             })
-            .chain(alias.into_iter().map(|_| Ok(arg_thunk)))
+            .chain(alias.into_iter().map(|_| Ok(arg)))
             .collect_in::<Result<_>>(bump)?;
 
         let body = body_fn(ctx, &keys)?;
@@ -1135,10 +1034,10 @@ fn downgrade_let_bindings<'id, 'ir, Ctx, F>(
     entries: Vec<'ir, ast::Entry>,
     ctx: &mut Ctx,
     body_fn: F,
-) -> Result<GhostRoIrRef<'id, 'ir>>
+) -> Result<IrRef<'id, 'ir>>
 where
     Ctx: DowngradeContext<'id, 'ir>,
-    F: FnOnce(&mut Ctx, &[StringId]) -> Result<GhostRoIrRef<'id, 'ir>>,
+    F: FnOnce(&mut Ctx, &[StringId]) -> Result<IrRef<'id, 'ir>>,
 {
     downgrade_rec_attrs_impl::<_, _, false>(entries, ctx, |ctx, binding_keys, _dyns| {
         body_fn(ctx, binding_keys)
@@ -1148,7 +1047,7 @@ where
 fn downgrade_rec_bindings<'id, 'ir, Ctx>(
     entries: Vec<'ir, ast::Entry>,
     ctx: &mut Ctx,
-) -> Result<GhostRoIrRef<'id, 'ir>>
+) -> Result<IrRef<'id, 'ir>>
 where
     Ctx: DowngradeContext<'id, 'ir>,
 {
@@ -1169,18 +1068,14 @@ fn downgrade_rec_attrs_impl<'id, 'ir, Ctx, F, const ALLOW_DYN: bool>(
     entries: Vec<'ir, ast::Entry>,
     ctx: &mut Ctx,
     body_fn: F,
-) -> Result<GhostRoIrRef<'id, 'ir>>
+) -> Result<IrRef<'id, 'ir>>
 where
     Ctx: DowngradeContext<'id, 'ir>,
     F: FnOnce(
         &mut Ctx,
         &[StringId],
-        &[(
-            GhostRoIrRef<'id, 'ir>,
-            GhostRoMaybeThunkRef<'id, 'ir>,
-            TextRange,
-        )],
-    ) -> Result<GhostRoIrRef<'id, 'ir>>,
+        &[(IrRef<'id, 'ir>, MaybeThunk, TextRange)],
+    ) -> Result<IrRef<'id, 'ir>>,
 {
     let mut pending = PendingAttrSet::new_in(ctx.bump());
     pending.collect_entries(entries.iter().cloned(), ctx)?;
@@ -1195,7 +1090,7 @@ where
         let vals = {
             let mut temp = Vec::with_capacity_in(keys.len(), ctx.bump());
             for sym in &keys {
-                temp.push(finalized.stcs.get(sym).expect("WTF").0);
+                temp.push(finalized.stcs.get(sym).expect("WTF").0.to_ir(ctx));
             }
             temp
         };
@@ -1206,7 +1101,7 @@ where
 fn collect_inherit_lookups<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>>(
     entries: &[ast::Entry],
     ctx: &mut Ctx,
-) -> Result<HashMap<'ir, StringId, (GhostRoMaybeThunkRef<'id, 'ir>, TextRange)>> {
+) -> Result<HashMap<'ir, StringId, (MaybeThunk, TextRange)>> {
     let mut inherit_lookups = HashMap::new_in(ctx.bump());
     for entry in entries {
         if let ast::Entry::Inherit(inherit) = entry
@@ -1246,7 +1141,7 @@ fn collect_binding_syms<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>, const AL
 
 fn finalize_pending_set<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>, const ALLOW_DYN: bool>(
     pending: PendingAttrSet,
-    inherit_lookups: &HashMap<StringId, (GhostRoMaybeThunkRef<'id, 'ir>, TextRange)>,
+    inherit_lookups: &HashMap<StringId, (MaybeThunk, TextRange)>,
     ctx: &mut Ctx,
 ) -> Result<FinalizedAttrSet<'id, 'ir>> {
     let mut stcs = HashMap::new_in(ctx.bump());
@@ -1274,9 +1169,9 @@ fn finalize_pending_set<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>, const ALLOW_D
 
 fn finalize_pending_value<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>, const ALLOW_DYN: bool>(
     value: PendingValue,
-    inherit_lookups: &HashMap<StringId, (GhostRoMaybeThunkRef<'id, 'ir>, TextRange)>,
+    inherit_lookups: &HashMap<StringId, (MaybeThunk, TextRange)>,
     ctx: &mut Ctx,
-) -> Result<GhostRoIrRef<'id, 'ir>> {
+) -> Result<IrRef<'id, 'ir>> {
     match value {
         PendingValue::Expr(expr) => expr.downgrade(ctx),
         PendingValue::InheritFrom(from_expr, sym, span) => {
@@ -1290,10 +1185,9 @@ fn finalize_pending_value<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>, const ALLOW
         }
         PendingValue::InheritScope(sym, span) => {
             if let Some(&(expr, _)) = inherit_lookups.get(&sym) {
-                Ok(ctx.new_expr(Ir::MaybeThunk(expr)))
+                Ok(expr.to_ir(ctx))
             } else {
-                ctx.lookup(sym, span)
-                    .map(|val| ctx.new_expr(Ir::MaybeThunk(val)))
+                ctx.lookup(sym, span).map(|val| val.to_ir(ctx))
             }
         }
         PendingValue::Set(set) => {
@@ -1316,7 +1210,7 @@ fn finalize_pending_value<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>, const ALLOW
 fn downgrade_path<'id, 'ir>(
     parts: impl IntoIterator<Item = ast::InterpolPart<ast::PathContent>>,
     ctx: &mut impl DowngradeContext<'id, 'ir>,
-) -> Result<GhostRoIrRef<'id, 'ir>> {
+) -> Result<IrRef<'id, 'ir>> {
     let bump = ctx.bump();
     let parts = parts
         .into_iter()

fix-ir/src/lib.rs

@@ -0,0 +1,342 @@
+use std::hash::Hash;
+use std::ops::Deref;
+
+use bumpalo::Bump;
+use bumpalo::collections::Vec;
+use fix_builtins::{BUILTINS, BuiltinId};
+use fix_common::StringId;
+use ghost_cell::{GhostCell, GhostToken};
+use num_enum::TryFromPrimitive as _;
+use rnix::{TextRange, ast};
+use string_interner::DefaultStringInterner;
+
+use crate::downgrade::DowngradeContext;
+
+pub mod downgrade;
+
+pub type HashMap<'ir, K, V> = hashbrown::HashMap<K, V, hashbrown::DefaultHashBuilder, &'ir Bump>;
+
+#[repr(transparent)]
+#[derive(Clone, Copy)]
+pub struct IrRef<'id, 'ir>(&'ir GhostCell<'id, Ir<'ir, Self>>);
+
+impl<'id, 'ir> IrRef<'id, 'ir> {
+    pub fn new(ir: &'ir GhostCell<'id, Ir<'ir, Self>>) -> Self {
+        Self(ir)
+    }
+
+    pub fn alloc(bump: &'ir Bump, ir: Ir<'ir, Self>) -> Self {
+        Self(bump.alloc(GhostCell::new(ir)))
+    }
+
+    pub fn borrow<'a>(&'a self, token: &'a GhostToken<'id>) -> &'a Ir<'ir, Self> {
+        self.0.borrow(token)
+    }
+
+    /// Freeze a mutable IR reference into a read-only one, consuming the
+    /// `GhostToken` to prevent any further mutation.
+    ///
+    /// # Safety
+    /// The transmute is sound because:
+    /// - `GhostCell<'id, T>` is `#[repr(transparent)]` over `T`
+    /// - `IrRef<'id, 'ir>` is `#[repr(transparent)]` over
+    ///   `&'ir GhostCell<'id, Ir<'ir, Self>>`
+    /// - `RawIrRef<'ir>` is `#[repr(transparent)]` over `&'ir Ir<'ir, Self>`
+    /// - `Ir<'ir, Ref>` is `#[repr(C)]` and both ref types are pointer-sized
+    ///
+    /// Consuming the `GhostToken` guarantees no `borrow_mut` calls can occur
+    /// afterwards, so the shared `&Ir` references from `RawIrRef::Deref` can
+    /// never alias with mutable references.
+    pub fn freeze(self, _token: GhostToken<'id>) -> RawIrRef<'ir> {
+        unsafe { std::mem::transmute(self) }
+    }
+}
+
+#[repr(transparent)]
+#[derive(Clone, Copy, Debug)]
+pub struct RawIrRef<'ir>(pub &'ir Ir<'ir, Self>);
+
+impl<'ir> Deref for RawIrRef<'ir> {
+    type Target = Ir<'ir, RawIrRef<'ir>>;
+    fn deref(&self) -> &Self::Target {
+        self.0
+    }
+}
+
+#[repr(C)]
+#[derive(Debug, Clone, Copy)]
+pub enum MaybeThunk {
+    Int(i64),
+    Float(f64),
+    Bool(bool),
+    Null,
+    Str(StringId),
+    Path(StringId),
+    Thunk(ThunkId),
+    Arg { layer: usize },
+    Builtin(BuiltinId),
+    Builtins,
+    ReplBinding(StringId),
+    ScopedImportBinding(StringId),
+    WithLookup(StringId),
+}
+
+impl MaybeThunk {
+    fn to_ir<'id, 'ir>(self, ctx: &mut impl DowngradeContext<'id, 'ir>) -> IrRef<'id, 'ir> {
+        use MaybeThunk::*;
+        let ir = match self {
+            Int(x) => Ir::Int(x),
+            Float(x) => Ir::Float(x),
+            Bool(x) => Ir::Bool(x),
+            Null => Ir::Null,
+            Str(x) => Ir::Str(x),
+            Path(x) => Ir::Path(ctx.new_expr(Ir::Str(x))),
+            Thunk(x) => Ir::Thunk(x),
+            Arg { layer } => Ir::Arg { layer },
+            Builtin(x) => Ir::Builtin(x),
+            Builtins => Ir::Builtins,
+            ReplBinding(x) => Ir::ReplBinding(x),
+            ScopedImportBinding(x) => Ir::ScopedImportBinding(x),
+            WithLookup(x) => Ir::WithLookup(x),
+        };
+        ctx.new_expr(ir)
+    }
+}
+
+#[repr(C)]
+#[derive(Debug)]
+pub enum Ir<'ir, Ref> {
+    Int(i64),
+    Float(f64),
+    Bool(bool),
+    Null,
+    Str(StringId),
+    Path(Ref),
+    AttrSet {
+        stcs: HashMap<'ir, StringId, (MaybeThunk, TextRange)>,
+        dyns: Vec<'ir, (Ref, MaybeThunk, TextRange)>,
+    },
+    List {
+        items: Vec<'ir, MaybeThunk>,
+    },
+    ConcatStrings {
+        parts: Vec<'ir, Ref>,
+        force_string: bool,
+    },
+
+    // OPs
+    UnOp {
+        rhs: Ref,
+        kind: UnOpKind,
+    },
+    BinOp {
+        lhs: Ref,
+        rhs: Ref,
+        kind: BinOpKind,
+    },
+    HasAttr {
+        lhs: Ref,
+        rhs: Vec<'ir, Attr<Ref>>,
+    },
+    Select {
+        expr: Ref,
+        attrpath: Vec<'ir, Attr<Ref>>,
+        default: Option<Ref>,
+        span: TextRange,
+    },
+
+    // Conditionals
+    If {
+        cond: Ref,
+        consq: Ref,
+        alter: Ref,
+    },
+    Assert {
+        assertion: Ref,
+        expr: Ref,
+        assertion_raw: String,
+        span: TextRange,
+    },
+
+    With {
+        namespace: MaybeThunk,
+        body: Ref,
+        thunks: Vec<'ir, (ThunkId, Ref)>,
+    },
+    WithLookup(StringId),
+
+    // Function related
+    Func {
+        body: Ref,
+        param: Option<Param<'ir>>,
+        thunks: Vec<'ir, (ThunkId, Ref)>,
+    },
+    Arg {
+        layer: usize,
+    },
+    Call {
+        func: Ref,
+        arg: MaybeThunk,
+        span: TextRange,
+    },
+
+    // Builtins
+    Builtins,
+    Builtin(BuiltinId),
+    BuiltinConst(StringId),
+
+    // Misc
+    TopLevel {
+        body: Ref,
+        thunks: Vec<'ir, (ThunkId, Ref)>,
+    },
+    Thunk(ThunkId),
+    CurPos(TextRange),
+    ReplBinding(StringId),
+    ScopedImportBinding(StringId),
+}
+
+#[repr(transparent)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct ThunkId(pub usize);
+
+#[repr(transparent)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct SpanId(pub u32);
+
+/// Represents a key in an attribute path.
+#[allow(unused)]
+#[derive(Debug)]
+pub enum Attr<Ref> {
+    /// A dynamic attribute key, which is an expression that must evaluate to a string.
+    /// Example: `attrs.${key}`
+    Dynamic(Ref, TextRange),
+    /// A static attribute key.
+    /// Example: `attrs.key`
+    Str(StringId, TextRange),
+}
+
+/// The kinds of binary operations supported in Nix.
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
+pub enum BinOpKind {
+    // Arithmetic
+    Add,
+    Sub,
+    Div,
+    Mul,
+
+    // Comparison
+    Eq,
+    Neq,
+    Lt,
+    Gt,
+    Leq,
+    Geq,
+
+    // Logical
+    And,
+    Or,
+    Impl,
+
+    // Set/String/Path operations
+    Con, // List concatenation (`++`)
+    Upd, // AttrSet update (`//`)
+
+    // Not standard, but part of rnix AST
+    PipeL,
+    PipeR,
+}
+
+impl From<ast::BinOpKind> for BinOpKind {
+    fn from(op: ast::BinOpKind) -> Self {
+        use BinOpKind::*;
+        use ast::BinOpKind as kind;
+        match op {
+            kind::Concat => Con,
+            kind::Update => Upd,
+            kind::Add => Add,
+            kind::Sub => Sub,
+            kind::Mul => Mul,
+            kind::Div => Div,
+            kind::And => And,
+            kind::Equal => Eq,
+            kind::Implication => Impl,
+            kind::Less => Lt,
+            kind::LessOrEq => Leq,
+            kind::More => Gt,
+            kind::MoreOrEq => Geq,
+            kind::NotEqual => Neq,
+            kind::Or => Or,
+            kind::PipeLeft => PipeL,
+            kind::PipeRight => PipeR,
+        }
+    }
+}
+
+/// The kinds of unary operations.
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
+pub enum UnOpKind {
+    Neg, // Negation (`-`)
+    Not, // Logical not (`!`)
+}
+
+impl From<ast::UnaryOpKind> for UnOpKind {
+    fn from(value: ast::UnaryOpKind) -> Self {
+        match value {
+            ast::UnaryOpKind::Invert => UnOpKind::Not,
+            ast::UnaryOpKind::Negate => UnOpKind::Neg,
+        }
+    }
+}
+
+/// Describes the parameters of a function.
+#[derive(Debug)]
+pub struct Param<'ir> {
+    pub required: Vec<'ir, (StringId, TextRange)>,
+    pub optional: Vec<'ir, (StringId, TextRange)>,
+    pub ellipsis: bool,
+}
+
+pub fn new_global_env(
+    strings: &mut DefaultStringInterner,
+) -> hashbrown::HashMap<StringId, Ir<'static, RawIrRef<'static>>> {
+    let mut global_env = hashbrown::HashMap::new();
+    let builtins_sym = StringId(strings.get_or_intern("builtins"));
+    global_env.insert(builtins_sym, Ir::Builtins);
+
+    for (idx, &(name, _)) in BUILTINS.iter().enumerate() {
+        let id = BuiltinId::try_from_primitive(idx as u8).expect("infallible");
+        let name = StringId(strings.get_or_intern(name));
+        global_env.insert(name, Ir::Builtin(id));
+    }
+
+    let consts = [
+        (
+            "__currentSystem",
+            Ir::BuiltinConst(StringId(strings.get_or_intern("currentSystem"))),
+        ),
+        ("__langVersion", Ir::Int(6)),
+        (
+            "__nixVersion",
+            Ir::BuiltinConst(StringId(strings.get_or_intern("nixVersion"))),
+        ),
+        (
+            "__storeDir",
+            Ir::BuiltinConst(StringId(strings.get_or_intern("storeDir"))),
+        ),
+        (
+            "__nixPath",
+            Ir::BuiltinConst(StringId(strings.get_or_intern("nixPath"))),
+        ),
+        ("null", Ir::Null),
+        ("true", Ir::Bool(true)),
+        ("false", Ir::Bool(false)),
+    ];
+
+    for (name, ir) in consts {
+        let name = StringId(strings.get_or_intern(name));
+        global_env.insert(name, ir);
+    }
+
+    global_env
+}

fix-macros/Cargo.toml

@@ -1,15 +0,0 @@
-[package]
-name = "fix-macros"
-version = "0.1.0"
-edition = "2024"
-
-[lib]
-proc-macro = true
-
-[dependencies]
-proc-macro2 = "1.0"
-quote = "1.0"
-syn = { version = "3.0", features = ["full", "visit", "visit-mut"] }
-
-[lints]
-workspace = true

fix-macros/src/lib.rs

@@ -1,49 +0,0 @@
-extern crate proc_macro;
-
-mod handler;
-
-#[proc_macro_attribute]
-pub fn handler(
-    attr: proc_macro::TokenStream,
-    item: proc_macro::TokenStream,
-) -> proc_macro::TokenStream {
-    handler::handler(attr.into(), item.into()).into()
-}
-
-// Adapted from `__unelide_lifetimes` in `gc-arena-derive`.
-// Licensed under the MIT license.
-// See: https://github.com/kyren/gc-arena
-#[proc_macro]
-pub fn unelide_lifetimes(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
-    use quote::ToTokens;
-    use syn::parse::{Parse, ParseStream};
-    use syn::visit_mut::VisitMut;
-
-    struct Input {
-        lt: syn::Lifetime,
-        ty: syn::Type,
-    }
-
-    impl Parse for Input {
-        fn parse(input: ParseStream) -> syn::Result<Self> {
-            let lt: syn::Lifetime = input.parse()?;
-            let _: syn::Token!(;) = input.parse()?;
-            let ty: syn::Type = input.parse()?;
-            Ok(Self { lt, ty })
-        }
-    }
-
-    struct UnelideLifetimes(syn::Lifetime);
-
-    impl VisitMut for UnelideLifetimes {
-        fn visit_lifetime_mut(&mut self, i: &mut syn::Lifetime) {
-            if i.ident == "_" {
-                *i = self.0.clone();
-            }
-        }
-    }
-
-    let mut input = syn::parse_macro_input!(input as Input);
-    UnelideLifetimes(input.lt).visit_type_mut(&mut input.ty);
-    input.ty.to_token_stream().into()
-}

fix-runtime/Cargo.toml

@@ -1,19 +0,0 @@
-[package]
-name = "fix-runtime"
-version = "0.1.0"
-edition = "2024"
-
-[dependencies]
-gc-arena = { workspace = true }
-hashbrown = { workspace = true }
-smallvec = { workspace = true }
-sptr = "0.3"
-string-interner = { workspace = true }
-
-fix-bytecode = { path = "../fix-bytecode" }
-fix-error = { path = "../fix-error" }
-fix-lang = { path = "../fix-lang" }
-fix-macros = { path = "../fix-macros" }
-
-[lints]
-workspace = true

fix-runtime/src/forced.rs

@@ -1,235 +0,0 @@
-use fix_lang::StringId;
-use gc_arena::Mutation;
-
-use crate::{
-    AttrSet, BytecodeReader, Closure, List, Machine, NixNum, NixString, NixType, Null, PrimOp,
-    PrimOpApp, Step, StrictValue, ValueVariant,
-};
-
-pub trait Forced<'gc>: Sized {
-    const WIDTH: usize;
-
-    /// Force and type-check the `WIDTH` slots starting at `base_depth` from
-    /// TOS, deepest-first. If a slot holds a thunk, enter it and return
-    /// `Break::Force`. If a slot holds a value of the wrong type, call
-    /// `finish_type_err` and return `Break::Done`.
-    fn force_and_check<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        base_depth: usize,
-        resume_pc: usize,
-    ) -> Step;
-
-    /// After `force_and_check` returned `Continue`, pop `WIDTH` slots
-    /// (TOS first) and convert. Type assertions are infallible because
-    /// `force_and_check` already validated every slot.
-    fn pop_converted<M: Machine<'gc>>(m: &mut M) -> Self;
-}
-
-impl<'gc> Forced<'gc> for StrictValue<'gc> {
-    const WIDTH: usize = 1;
-
-    #[inline(always)]
-    fn force_and_check<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        base_depth: usize,
-        resume_pc: usize,
-    ) -> Step {
-        m.force_slot_to_pc(base_depth, reader, mc, resume_pc)
-    }
-
-    #[inline(always)]
-    fn pop_converted<M: Machine<'gc>>(m: &mut M) -> Self {
-        m.pop_forced()
-    }
-}
-
-macro_rules! impl_forced {
-    ($($ty:ty),* $(,)?) => {
-        $(
-        impl<'gc> Forced<'gc> for <$ty as ValueVariant<'gc>>::Ty {
-            const WIDTH: usize = 1;
-
-            #[inline(always)]
-            fn force_and_check<M: Machine<'gc>>(
-                m: &mut M,
-                reader: &mut BytecodeReader<'_>,
-                mc: &Mutation<'gc>,
-                base_depth: usize,
-                resume_pc: usize,
-            ) -> Step {
-                m.force_slot_to_pc(base_depth, reader, mc, resume_pc)?;
-                let v = m.peek_forced(base_depth);
-                if !v.is::<$ty>() {
-                    m.finish_type_err(<$ty as ValueVariant>::TYPE, v.ty())
-                } else {
-                    Step::Continue(())
-                }
-            }
-
-            #[inline(always)]
-            fn pop_converted<M: Machine<'gc>>(m: &mut M) -> Self {
-                m.pop_forced()
-                    .downcast::<$ty>()
-                    .expect("type checked in force_and_check")
-            }
-        }
-        )*
-    };
-}
-
-impl_forced! {
-    i32,
-    bool,
-    Null,
-    StringId,
-    PrimOp,
-    i64,
-    NixString,
-    AttrSet<'gc>,
-    List<'gc>,
-    Closure<'gc>,
-    PrimOpApp<'gc>,
-}
-
-impl<'gc> Forced<'gc> for NixNum {
-    const WIDTH: usize = 1;
-
-    #[inline(always)]
-    fn force_and_check<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        base_depth: usize,
-        resume_pc: usize,
-    ) -> Step {
-        m.force_slot_to_pc(base_depth, reader, mc, resume_pc)?;
-        let v = m.peek_forced(base_depth);
-        if v.downcast_num().is_none() {
-            m.finish_type_err(NixType::Int, v.ty())
-        } else {
-            Step::Continue(())
-        }
-    }
-
-    #[inline(always)]
-    fn pop_converted<M: Machine<'gc>>(m: &mut M) -> Self {
-        m.pop_forced()
-            .downcast_num()
-            .expect("type checked in force_and_check")
-    }
-}
-
-impl<'gc> Forced<'gc> for f64 {
-    const WIDTH: usize = 1;
-
-    #[inline(always)]
-    fn force_and_check<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        base_depth: usize,
-        resume_pc: usize,
-    ) -> Step {
-        m.force_slot_to_pc(base_depth, reader, mc, resume_pc)?;
-        let v = m.peek_forced(base_depth);
-        if !v.is::<f64>() {
-            m.finish_type_err(NixType::Float, v.ty())
-        } else {
-            Step::Continue(())
-        }
-    }
-
-    #[inline(always)]
-    fn pop_converted<M: Machine<'gc>>(m: &mut M) -> Self {
-        m.pop_forced()
-            .downcast::<f64>()
-            .expect("type checked in force_and_check")
-    }
-}
-
-impl<'gc, A: Forced<'gc>, B: Forced<'gc>> Forced<'gc> for (A, B) {
-    const WIDTH: usize = A::WIDTH + B::WIDTH;
-
-    #[inline(always)]
-    fn force_and_check<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        base: usize,
-        resume_pc: usize,
-    ) -> Step {
-        A::force_and_check(m, reader, mc, base + B::WIDTH, resume_pc)?;
-        B::force_and_check(m, reader, mc, base, resume_pc)
-    }
-
-    #[inline(always)]
-    fn pop_converted<M: Machine<'gc>>(m: &mut M) -> Self {
-        let b = B::pop_converted(m);
-        let a = A::pop_converted(m);
-        (a, b)
-    }
-}
-
-impl<'gc, A: Forced<'gc>, B: Forced<'gc>, C: Forced<'gc>> Forced<'gc> for (A, B, C) {
-    const WIDTH: usize = A::WIDTH + B::WIDTH + C::WIDTH;
-
-    #[inline(always)]
-    fn force_and_check<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        base: usize,
-        resume_pc: usize,
-    ) -> Step {
-        A::force_and_check(m, reader, mc, base + B::WIDTH + C::WIDTH, resume_pc)?;
-        B::force_and_check(m, reader, mc, base + C::WIDTH, resume_pc)?;
-        C::force_and_check(m, reader, mc, base, resume_pc)
-    }
-
-    #[inline(always)]
-    fn pop_converted<M: Machine<'gc>>(m: &mut M) -> Self {
-        let c = C::pop_converted(m);
-        let b = B::pop_converted(m);
-        let a = A::pop_converted(m);
-        (a, b, c)
-    }
-}
-
-impl<'gc, A: Forced<'gc>, B: Forced<'gc>, C: Forced<'gc>, D: Forced<'gc>> Forced<'gc>
-    for (A, B, C, D)
-{
-    const WIDTH: usize = A::WIDTH + B::WIDTH + C::WIDTH + D::WIDTH;
-
-    #[inline(always)]
-    fn force_and_check<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        base: usize,
-        resume_pc: usize,
-    ) -> Step {
-        A::force_and_check(
-            m,
-            reader,
-            mc,
-            base + B::WIDTH + C::WIDTH + D::WIDTH,
-            resume_pc,
-        )?;
-        B::force_and_check(m, reader, mc, base + C::WIDTH + D::WIDTH, resume_pc)?;
-        C::force_and_check(m, reader, mc, base + D::WIDTH, resume_pc)?;
-        D::force_and_check(m, reader, mc, base, resume_pc)
-    }
-
-    #[inline(always)]
-    fn pop_converted<M: Machine<'gc>>(m: &mut M) -> Self {
-        let d = D::pop_converted(m);
-        let c = C::pop_converted(m);
-        let b = B::pop_converted(m);
-        let a = A::pop_converted(m);
-        (a, b, c, d)
-    }
-}

fix-runtime/src/host.rs

@@ -1,163 +0,0 @@
-use fix_bytecode::InstructionPtr;
-use fix_error::Source;
-use fix_lang::{self, StringId};
-use hashbrown::HashSet;
-
-use crate::{
-    AttrSet, Closure, ExtraScope, List, NixString, NixType, Null, Path, PrimOp, PrimOpApp,
-    StaticValue, StrictValue, StringContext, Thunk, ThunkState, Value,
-};
-
-pub trait VmContext {
-    fn split(&mut self) -> (&mut impl VmCode, &mut impl VmRuntimeCtx);
-}
-
-pub trait VmRuntimeCtx {
-    fn intern_string(&mut self, s: impl AsRef<str>) -> StringId;
-    fn resolve_string(&self, id: StringId) -> &str;
-    fn get_const(&self, id: u32) -> StaticValue;
-    fn add_const(&mut self, val: StaticValue) -> u32;
-}
-
-pub trait VmCode {
-    fn bytecode(&self) -> &[u8];
-    fn compile_with_scope(
-        &mut self,
-        source: Source,
-        extra_scope: Option<ExtraScope>,
-        ctx: &mut impl VmRuntimeCtx,
-    ) -> fix_error::Result<InstructionPtr>;
-}
-
-pub trait VmRuntimeCtxExt: VmRuntimeCtx {
-    fn get_string<'a, 'gc: 'a>(&'a self, val: StrictValue<'gc>) -> Option<&'a str>;
-    fn get_string_or_path<'a, 'gc: 'a>(&'a self, val: StrictValue<'gc>) -> Option<&'a str>;
-    fn get_string_id<'a, 'gc: 'a>(
-        &'a mut self,
-        val: StrictValue<'gc>,
-    ) -> std::result::Result<StringId, NixType>;
-    /// Returns the string context attached to `val`, or `&[]` if `val` is
-    /// either a non-string or a string without context.
-    fn get_string_context<'gc>(&self, val: StrictValue<'gc>) -> &'gc StringContext;
-    fn convert_value(&self, val: Value) -> fix_lang::Value;
-}
-
-impl<T: VmRuntimeCtx> VmRuntimeCtxExt for T {
-    fn get_string<'a, 'gc: 'a>(&'a self, val: StrictValue<'gc>) -> Option<&'a str> {
-        if let Some(sid) = val.downcast::<StringId>() {
-            Some(self.resolve_string(sid))
-        } else {
-            val.downcast::<NixString>().map(|ns| ns.as_ref().as_str())
-        }
-    }
-
-    /// Like `get_string`, but also accepts `Path` values (returning their
-    /// underlying canonical-path string). Use this in places where Nix
-    /// would coerce a path to a string (string interpolation, file IO
-    /// builtins, etc.).
-    fn get_string_or_path<'a, 'gc: 'a>(&'a self, val: StrictValue<'gc>) -> Option<&'a str> {
-        if let Some(p) = val.downcast::<Path>() {
-            Some(self.resolve_string(p.0))
-        } else {
-            self.get_string(val)
-        }
-    }
-
-    fn get_string_id<'a, 'gc: 'a>(
-        &'a mut self,
-        val: StrictValue<'gc>,
-    ) -> std::result::Result<StringId, NixType> {
-        if let Some(sid) = val.downcast::<StringId>() {
-            Ok(sid)
-        } else if let Some(s) = val.downcast::<NixString>().map(|ns| ns.as_ref().as_str()) {
-            Ok(self.intern_string(s))
-        } else {
-            Err(val.ty())
-        }
-    }
-
-    fn get_string_context<'gc>(&self, val: StrictValue<'gc>) -> &'gc StringContext {
-        if let Some(ns) = val.downcast::<NixString>() {
-            ns.as_ref().context()
-        } else {
-            StringContext::empty()
-        }
-    }
-
-    fn convert_value(&self, val: Value) -> fix_lang::Value {
-        self.convert_value_with_seen(val, &mut HashSet::new())
-    }
-}
-
-pub(crate) trait ConvertValueWithSeen: VmRuntimeCtx {
-    fn convert_value_with_seen(&self, val: Value, seen: &mut HashSet<u64>) -> fix_lang::Value;
-}
-
-impl<T: VmRuntimeCtx> ConvertValueWithSeen for T {
-    fn convert_value_with_seen(&self, val: Value, seen: &mut HashSet<u64>) -> fix_lang::Value {
-        use fix_lang::Value;
-        if let Some(i) = val.downcast::<i32>() {
-            Value::Int(i as i64)
-        } else if let Some(gc_i) = val.downcast::<i64>() {
-            Value::Int(*gc_i)
-        } else if let Some(f) = val.downcast::<f64>() {
-            Value::Float(f)
-        } else if let Some(b) = val.downcast::<bool>() {
-            Value::Bool(b)
-        } else if val.is::<Null>() {
-            Value::Null
-        } else if let Some(sid) = val.downcast::<StringId>() {
-            let s = self.resolve_string(sid).to_owned();
-            Value::String(s)
-        } else if let Some(ns) = val.downcast::<NixString>() {
-            Value::String(ns.as_str().to_owned())
-        } else if let Some(p) = val.downcast::<Path>() {
-            Value::Path(self.resolve_string(p.0).to_owned())
-        } else if let Some(attrs) = val.downcast::<AttrSet>() {
-            let bits = val.to_bits();
-            if attrs.entries.is_empty() {
-                return Value::AttrSet(Default::default());
-            }
-            if !seen.insert(bits) {
-                return Value::Repeated;
-            }
-            let mut map = std::collections::BTreeMap::new();
-            for &(key, val) in attrs.entries.iter() {
-                let key = self.resolve_string(key).to_owned();
-                let converted = self.convert_value_with_seen(val, seen);
-                map.insert(fix_lang::Symbol::from(key), converted);
-            }
-            Value::AttrSet(fix_lang::AttrSet::new(map))
-        } else if let Some(list) = val.downcast::<List>() {
-            let bits = val.to_bits();
-            if list.inner.borrow().is_empty() {
-                return Value::List(Default::default());
-            }
-            if !seen.insert(bits) {
-                return Value::Repeated;
-            }
-            let items: Vec<_> = list
-                .inner
-                .borrow()
-                .iter()
-                .copied()
-                .map(|v| self.convert_value_with_seen(v, seen))
-                .collect();
-            Value::List(fix_lang::List::new(items))
-        } else if val.is::<Closure>() {
-            Value::Func
-        } else if let Some(thunk) = val.downcast::<Thunk>() {
-            if let ThunkState::Evaluated(v) = *thunk.borrow() {
-                self.convert_value_with_seen(v.relax(), seen)
-            } else {
-                Value::Thunk
-            }
-        } else if let Some(primop) = val.downcast::<PrimOp>() {
-            Value::PrimOp(primop.id.info().name)
-        } else if let Some(app) = val.downcast::<PrimOpApp>() {
-            Value::PrimOpApp(app.primop.id.info().name)
-        } else {
-            Value::Null
-        }
-    }
-}

fix-runtime/src/lib.rs

@@ -1,23 +0,0 @@
-mod boxing;
-mod forced;
-mod host;
-mod machine;
-mod macro_support;
-mod path_util;
-mod resolve;
-mod slot;
-mod state;
-mod string_context;
-mod value;
-
-pub use fix_bytecode::{BytecodeReader, OperandData};
-pub use forced::*;
-pub use host::*;
-pub use machine::*;
-pub use macro_support::*;
-pub use path_util::*;
-pub use resolve::*;
-pub use slot::*;
-pub use state::*;
-pub use string_context::*;
-pub use value::*;

fix-runtime/src/machine.rs

@@ -1,187 +0,0 @@
-use std::ops::ControlFlow;
-use std::path::{Path, PathBuf};
-
-use fix_error::Error;
-use fix_lang::{self, StringId};
-use gc_arena::{Gc, Mutation};
-
-use crate::{
-    AttrSet, Break, BytecodeReader, CallFrame, ForceMode, Forced, GcEnv, NixType, PendingLoad,
-    Step, StrictValue, Value, VmError,
-};
-
-/// Abstract VM-side operations consumed by instruction handlers and primops.
-///
-/// Implementors maintain a value stack, a call stack, an environment chain,
-/// pending result/error state, and a set of GC-allocated globals. Methods
-/// fall into a few groups:
-///
-/// - Stack ops (`push` / `pop` / `peek` / `replace` / `pop_forced` / ...)
-/// - Forcing primitives (`force_slot` / `force_slot_to_pc`)
-/// - Calling (`call` / `return_from_primop`)
-/// - Call-frame management (`push_call_frame` / `pop_call_frame` / call-depth)
-/// - Environment access (`env` / `set_env` / `local`)
-/// - Result finalization (`finish_ok` / `finish_err` / ...)
-/// - Global lookup (`builtins` / `empty_list` / `empty_attrs` / ...)
-/// - Imports and scope slots (`import_cache_*` / `scope_slot*` / `set_pending_load`)
-pub trait Machine<'gc> {
-    fn push(&mut self, val: Value<'gc>);
-    #[must_use]
-    fn pop(&mut self) -> Value<'gc>;
-    #[must_use]
-    fn peek(&self, depth: usize) -> Value<'gc>;
-    #[must_use]
-    fn peek_forced(&self, depth: usize) -> StrictValue<'gc>;
-    fn pop_forced(&mut self) -> StrictValue<'gc>;
-    fn replace(&mut self, depth: usize, val: Value<'gc>);
-    fn drop_n(&mut self, depth: usize);
-    fn stack_len(&self) -> usize;
-
-    fn force_slot_to_pc(
-        &mut self,
-        depth: usize,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        resume_pc: usize,
-    ) -> Step;
-
-    #[inline(always)]
-    fn force_slot(
-        &mut self,
-        depth: usize,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-    ) -> Step {
-        let pc = reader.inst_start_pc();
-        self.force_slot_to_pc(depth, reader, mc, pc)
-    }
-
-    fn call(
-        &mut self,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        arg: Value<'gc>,
-        resume_pc: usize,
-    ) -> Step;
-
-    #[inline(always)]
-    #[expect(
-        clippy::unreachable,
-        reason = "a primop only returns via `return_from_primop` while its call frame is still on the stack, so `pop_call_frame` is always `Some`"
-    )]
-    fn return_from_primop(&mut self, val: Value<'gc>, reader: &mut BytecodeReader<'_>) -> Step {
-        self.push(val);
-        let Some(CallFrame {
-            pc: ret_pc,
-            thunk: _,
-            env,
-            depth: None,
-        }) = self.pop_call_frame()
-        else {
-            unreachable!()
-        };
-        reader.set_pc(ret_pc);
-        self.dec_call_depth();
-        self.set_env(env);
-        Step::Continue(())
-    }
-
-    fn push_call_frame(&mut self, frame: CallFrame<'gc>);
-    fn pop_call_frame(&mut self) -> Option<CallFrame<'gc>>;
-    fn call_depth(&self) -> usize;
-    fn inc_call_depth(&mut self);
-    fn dec_call_depth(&mut self);
-
-    fn env(&self) -> GcEnv<'gc>;
-    fn set_env(&mut self, env: GcEnv<'gc>);
-
-    #[inline(always)]
-    #[expect(
-        clippy::indexing_slicing,
-        reason = "codegen guarantees the local index is within the resolved frame's `locals`"
-    )]
-    fn local(&self, layer: u8, idx: u32) -> Value<'gc> {
-        let mut cur = self.env();
-        for _ in 0..layer {
-            let prev = cur.borrow().prev.expect("env chain too short");
-            cur = prev;
-        }
-        cur.borrow().locals[idx as usize]
-    }
-
-    fn finish_ok(&mut self, val: fix_lang::Value) -> Step;
-    fn finish_err(&mut self, err: Box<Error>) -> Step;
-    fn finish_type_err(&mut self, expected: NixType, got: NixType) -> Step;
-
-    #[inline(always)]
-    fn finish_vm_err(&mut self, err: VmError) -> Step {
-        self.finish_err(err.into_error())
-    }
-
-    fn builtins(&self) -> Gc<'gc, AttrSet<'gc>>;
-    fn functor_sym(&self) -> StringId;
-    fn empty_list(&self) -> Value<'gc>;
-    fn empty_attrs(&self) -> Value<'gc>;
-    fn force_mode(&self) -> ForceMode;
-
-    fn import_cache_get(&self, path: &Path) -> Option<Value<'gc>>;
-    fn import_cache_insert(&mut self, path: PathBuf, val: Value<'gc>);
-    fn scope_slot(&self, idx: u32) -> Value<'gc>;
-    fn scope_slots_push(&mut self, val: Value<'gc>) -> u32;
-    fn set_pending_load(&mut self, load: PendingLoad);
-}
-
-/// Extension trait with convenience helpers built on top of [`Machine`].
-///
-/// Auto-implemented for every `Machine<'gc>` so callers just need to bring
-/// `MachineExt` (or `Machine`) into scope.
-pub trait MachineExt<'gc>: Machine<'gc> {
-    /// Force the top `T::WIDTH` stack slots and return them as `T`.
-    ///
-    /// If any slot holds a pending thunk, this method pushes a call frame
-    /// whose resume PC is the **start of the current instruction**
-    /// (`reader.inst_start_pc()`), enters the thunk, and returns
-    /// `Break::Force`. When the thunk eventually returns, the VM will
-    /// **re-execute the entire opcode handler from the beginning**.
-    ///
-    /// # Invariants
-    ///
-    /// * **Do not call this method more than once in a single handler.**
-    ///   If you need to force multiple values, use a tuple type such as
-    ///   `(StrictValue, StrictValue)` so they are forced and popped in one
-    ///   atomic operation.
-    /// * The stack layout at the call site must be **identical** every time
-    ///   the handler is re-entered.
-    /// * Propagate the return value with `?` so `Break::Force` correctly
-    ///   unwinds to the dispatch loop.
-    #[inline(always)]
-    fn force_and_retry<T: Forced<'gc>>(
-        &mut self,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-    ) -> ControlFlow<Break, T>
-    where
-        Self: Sized,
-    {
-        let pc = reader.inst_start_pc();
-        self.force_and_retry_pc(reader, mc, pc)
-    }
-
-    /// Same as [`force_and_retry`](Self::force_and_retry) but allows
-    /// specifying a custom resume PC.
-    #[inline(always)]
-    fn force_and_retry_pc<T: Forced<'gc>>(
-        &mut self,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        resume_pc: usize,
-    ) -> ControlFlow<Break, T>
-    where
-        Self: Sized,
-    {
-        T::force_and_check(self, reader, mc, 0, resume_pc)?;
-        ControlFlow::Continue(T::pop_converted(self))
-    }
-}
-
-impl<'gc, M: Machine<'gc>> MachineExt<'gc> for M {}

fix-runtime/src/macro_support.rs

@@ -1,165 +0,0 @@
-use std::ops::ControlFlow;
-
-use gc_arena::Mutation;
-
-use crate::{
-    Break, BytecodeReader, Forced, Machine, MachineExt, Slot, SlotContent, Step, StrictValue,
-    Value, ValueVariant,
-};
-
-pub trait UnwrapSlot {
-    type Unwrapped;
-}
-
-impl<T> UnwrapSlot for Slot<T> {
-    type Unwrapped = T;
-}
-
-/// Force-target protocol behind the `#[primop]` `force` form: `Value` only
-/// needs WHNF, `StrictValue` *is* WHNF, and content types are checked through
-/// [`Forced`] on their stored representation.
-pub trait ForceTarget<'gc>: SlotContent<'gc> {
-    /// Type-check the stack slot refined by the previous `force(slot)`; the
-    /// slot is already WHNF when this runs.
-    fn refine_check<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        depth: usize,
-    ) -> Step;
-
-    /// Pop and convert the previous suspension's result into the annotated
-    /// binding's stored representation.
-    fn conv_force<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-    ) -> ControlFlow<Break, <Self as SlotContent<'gc>>::Ty>;
-}
-
-impl<'gc> ForceTarget<'gc> for Value<'gc> {
-    #[inline(always)]
-    fn refine_check<M: Machine<'gc>>(
-        _m: &mut M,
-        _reader: &mut BytecodeReader<'_>,
-        _mc: &Mutation<'gc>,
-        _depth: usize,
-    ) -> Step {
-        Step::Continue(())
-    }
-
-    #[inline(always)]
-    fn conv_force<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-    ) -> ControlFlow<Break, Value<'gc>> {
-        match m.force_and_retry::<StrictValue<'gc>>(reader, mc) {
-            ControlFlow::Continue(v) => ControlFlow::Continue(v.relax()),
-            ControlFlow::Break(b) => ControlFlow::Break(b),
-        }
-    }
-}
-
-impl<'gc> ForceTarget<'gc> for StrictValue<'gc> {
-    #[inline(always)]
-    fn refine_check<M: Machine<'gc>>(
-        _m: &mut M,
-        _reader: &mut BytecodeReader<'_>,
-        _mc: &Mutation<'gc>,
-        _depth: usize,
-    ) -> Step {
-        Step::Continue(())
-    }
-
-    #[inline(always)]
-    fn conv_force<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-    ) -> ControlFlow<Break, StrictValue<'gc>> {
-        m.force_and_retry::<StrictValue<'gc>>(reader, mc)
-    }
-}
-
-impl<'gc, T> ForceTarget<'gc> for T
-where
-    T: ValueVariant<'gc>,
-    <T as ValueVariant<'gc>>::Ty: Forced<'gc>,
-{
-    #[inline(always)]
-    fn refine_check<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        depth: usize,
-    ) -> Step {
-        <<T as ValueVariant<'gc>>::Ty as Forced<'gc>>::force_and_check(
-            m,
-            reader,
-            mc,
-            depth,
-            reader.inst_start_pc(),
-        )
-    }
-
-    #[inline(always)]
-    fn conv_force<M: Machine<'gc>>(
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-    ) -> ControlFlow<Break, <T as SlotContent<'gc>>::Ty> {
-        m.force_and_retry::<<T as ValueVariant<'gc>>::Ty>(reader, mc)
-    }
-}
-
-/// Callee protocol behind `call(&slot, ..)`: an unforced `Slot<Value>` is
-/// WHNF'd before the call; refined slots already hold strict values.
-pub trait CalleeReady<'gc> {
-    fn callee_ready<M: Machine<'gc>>(
-        &self,
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-    ) -> ControlFlow<Break>;
-}
-
-impl<'gc> CalleeReady<'gc> for Slot<Value<'gc>> {
-    #[inline(always)]
-    fn callee_ready<M: Machine<'gc>>(
-        &self,
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-    ) -> ControlFlow<Break> {
-        self.force::<StrictValue<'gc>, M>(m, reader, mc)?;
-        ControlFlow::Continue(())
-    }
-}
-
-impl<'gc> CalleeReady<'gc> for Slot<StrictValue<'gc>> {
-    #[inline(always)]
-    fn callee_ready<M: Machine<'gc>>(
-        &self,
-        _m: &mut M,
-        _reader: &mut BytecodeReader<'_>,
-        _mc: &Mutation<'gc>,
-    ) -> ControlFlow<Break> {
-        ControlFlow::Continue(())
-    }
-}
-
-impl<'gc, T> CalleeReady<'gc> for Slot<T>
-where
-    T: ValueVariant<'gc>,
-{
-    #[inline(always)]
-    fn callee_ready<M: Machine<'gc>>(
-        &self,
-        _m: &mut M,
-        _reader: &mut BytecodeReader<'_>,
-        _mc: &Mutation<'gc>,
-    ) -> ControlFlow<Break> {
-        ControlFlow::Continue(())
-    }
-}

fix-runtime/src/path_util.rs

@@ -1,18 +0,0 @@
-use std::path::{Component, PathBuf};
-
-pub fn canon_path_str(path: impl AsRef<std::path::Path>) -> String {
-    let p = path.as_ref();
-    let mut normalized = PathBuf::new();
-    for component in p.components() {
-        match component {
-            Component::Prefix(p) => normalized.push(p.as_os_str()),
-            Component::RootDir => normalized.push("/"),
-            Component::CurDir => {}
-            Component::ParentDir => {
-                normalized.pop();
-            }
-            Component::Normal(c) => normalized.push(c),
-        }
-    }
-    normalized.to_string_lossy().into_owned()
-}

fix-runtime/src/resolve.rs

@@ -1,32 +0,0 @@
-use fix_bytecode::OperandData;
-use gc_arena::{Gc, Mutation};
-
-use crate::{AttrSet, Machine, Value, VmRuntimeCtx};
-
-/// Resolve a decoded operand into a runtime [`Value`].
-///
-/// The operand decoder ([`crate::BytecodeReader::read_operand_data`])
-/// produces a static enum; this function materializes it against the
-/// running [`Machine`] (env chain, builtins, scope slots, ...).
-#[inline]
-pub fn resolve_operand<'gc, M: Machine<'gc>>(
-    op: &OperandData,
-    mc: &Mutation<'gc>,
-    ctx: &impl VmRuntimeCtx,
-    m: &M,
-) -> Value<'gc> {
-    use OperandData::*;
-    match *op {
-        Const(id) => ctx.get_const(id).into(),
-        BigInt(val) => Value::new(Gc::new(mc, val)),
-        Local { layer, idx } => m.local(layer, idx),
-        BuiltinConst(id) => m.builtins().lookup(id).expect("builtin const must exist"),
-        Builtins => m.builtins().into(),
-        ReplBinding(_id) => todo!(),
-        ScopedImportBinding { slot_id, name } => {
-            let scope = m.scope_slot(slot_id);
-            let attrs = scope.downcast::<AttrSet>().expect("scope must be attrset");
-            attrs.lookup(name).expect("scoped binding not found")
-        }
-    }
-}

fix-runtime/src/slot.rs

@@ -1,86 +0,0 @@
-use std::marker::PhantomData;
-use std::ops::ControlFlow;
-
-use fix_bytecode::BytecodeReader;
-use gc_arena::Mutation;
-
-use crate::{Break, Forced, Machine, NixType, Step, StrictValue, Value, ValueVariant};
-
-pub struct TypeError {
-    pub expected: NixType,
-    pub got: NixType,
-}
-
-pub trait SlotContent<'gc> {
-    type Ty: Into<Value<'gc>> + TryFrom<Value<'gc>> + 'gc;
-}
-
-impl<'gc> SlotContent<'gc> for Value<'gc> {
-    type Ty = Value<'gc>;
-}
-
-impl<'gc> SlotContent<'gc> for StrictValue<'gc> {
-    type Ty = StrictValue<'gc>;
-}
-
-impl<'gc, T> SlotContent<'gc> for T
-where
-    T: ValueVariant<'gc>,
-{
-    type Ty = T::Ty;
-}
-
-pub struct Slot<T> {
-    depth: u8,
-    _marker: PhantomData<T>,
-}
-
-impl<T> Slot<T> {
-    #[inline(always)]
-    pub const fn new(depth: u8) -> Self {
-        Self {
-            depth,
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<'gc, T> Slot<T>
-where
-    T: SlotContent<'gc>,
-    <T::Ty as TryFrom<Value<'gc>>>::Error: std::fmt::Debug,
-{
-    #[inline(always)]
-    pub fn read<M: Machine<'gc>>(&self, m: &M) -> T::Ty {
-        T::Ty::try_from(m.peek(self.depth as usize)).expect("slot held a value of the wrong type")
-    }
-
-    #[inline(always)]
-    pub fn write<M: Machine<'gc>>(&self, m: &mut M, val: T::Ty) {
-        m.replace(self.depth as usize, T::Ty::into(val));
-    }
-}
-
-impl<'gc> Slot<Value<'gc>> {
-    #[inline(always)]
-    pub fn force<T: Forced<'gc>, M: Machine<'gc>>(
-        &self,
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-    ) -> ControlFlow<Break, Slot<T>> {
-        T::force_and_check(m, reader, mc, self.depth as usize, reader.inst_start_pc())?;
-        ControlFlow::Continue(Slot::new(self.depth))
-    }
-
-    #[inline(always)]
-    pub fn force_to_pc<M: Machine<'gc>>(
-        &self,
-        m: &mut M,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        pc: usize,
-    ) -> Step {
-        m.force_slot_to_pc(self.depth as usize, reader, mc, pc)
-    }
-}

fix-runtime/src/state.rs

@@ -1,88 +0,0 @@
-use std::ops::ControlFlow;
-use std::path::PathBuf;
-
-use fix_error::Error;
-use fix_lang::StringId;
-use gc_arena::{Collect, Gc};
-use hashbrown::HashSet;
-
-use crate::{GcEnv, Thunk};
-
-pub enum VmError {
-    Catchable(String),
-    Uncatchable(Box<Error>),
-}
-
-impl From<Box<Error>> for VmError {
-    fn from(e: Box<Error>) -> Self {
-        VmError::Uncatchable(e)
-    }
-}
-
-impl VmError {
-    pub fn into_error(self) -> Box<Error> {
-        match self {
-            VmError::Catchable(_) => todo!("Check for tryEval catch frames"),
-            VmError::Uncatchable(e) => e,
-        }
-    }
-}
-
-pub fn vm_err(msg: impl Into<String>) -> VmError {
-    VmError::Uncatchable(Error::eval_error(msg.into()))
-}
-
-#[derive(Collect, Clone, Copy, Debug, PartialEq, Eq, Default)]
-#[collect(require_static)]
-pub enum ForceMode {
-    #[default]
-    AsIs,
-    Shallow,
-    Deep,
-}
-
-#[repr(u8)]
-pub enum Break {
-    Force,
-    Done,
-    LoadFile,
-}
-
-pub type Step = ControlFlow<Break>;
-
-pub struct ErrorFrame {
-    pub span_id: u32,
-    pub message: Option<String>,
-}
-
-#[derive(Collect, Debug)]
-#[collect(no_drop)]
-pub struct CallFrame<'gc> {
-    pub pc: usize,
-    pub env: GcEnv<'gc>,
-    pub thunk: Option<Gc<'gc, Thunk<'gc>>>,
-    pub depth: Option<usize>,
-}
-
-#[derive(Debug)]
-pub struct PendingLoad {
-    pub path: PathBuf,
-    pub scope: Option<PendingScope>,
-}
-
-#[derive(Debug)]
-pub struct PendingScope {
-    pub keys: HashSet<StringId>,
-    pub slot_id: u32,
-}
-
-/// Extra scope passed to a re-entrant compile from inside a running VM.
-///
-/// Currently only `ScopedImport` is produced (by the `scopedImport` builtin),
-/// but the variant is kept open so REPL bindings could later land here too.
-pub enum ExtraScope {
-    ScopedImport {
-        keys: HashSet<StringId>,
-        slot_id: u32,
-    },
-}

fix-runtime/src/string_context.rs

@@ -1,165 +0,0 @@
-use std::cmp::Ordering;
-
-use smallvec::SmallVec;
-
-/// A string context element
-#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub enum StringContextElem {
-    // Plain store path reference
-    Opaque {
-        path: Box<str>,
-    },
-    // All outputs of a derivation
-    // encoded `=<drvPath>`
-    DrvDeep {
-        drv_path: Box<str>,
-    },
-    // A specific output of a derivation
-    // encoded `!<output>!<drvPath>`
-    Built {
-        drv_path: Box<str>,
-        output: Box<str>,
-    },
-}
-
-impl StringContextElem {
-    /// Decode the CppNix wire form (`!out!/p`, `=/p`, `/p`). Falls back to
-    /// `Opaque` for malformed `!`-prefixed inputs (matching nix-js).
-    pub fn decode(encoded: &str) -> Self {
-        if let Some(drv_path) = encoded.strip_prefix('=') {
-            Self::DrvDeep {
-                drv_path: drv_path.into(),
-            }
-        } else if let Some(rest) = encoded.strip_prefix('!') {
-            if let Some((output, drv_path)) = rest.split_once('!') {
-                Self::Built {
-                    output: output.into(),
-                    drv_path: drv_path.into(),
-                }
-            } else {
-                Self::Opaque {
-                    path: encoded.into(),
-                }
-            }
-        } else {
-            Self::Opaque {
-                path: encoded.into(),
-            }
-        }
-    }
-
-    pub fn encode(&self) -> String {
-        match self {
-            Self::Opaque { path } => path.to_string(),
-            Self::DrvDeep { drv_path } => format!("={drv_path}"),
-            Self::Built { drv_path, output } => format!("!{output}!{drv_path}"),
-        }
-    }
-}
-
-#[derive(Debug, Clone, Default)]
-pub struct StringContext {
-    data: SmallVec<[StringContextElem; 1]>,
-}
-
-impl IntoIterator for StringContext {
-    type Item = StringContextElem;
-    type IntoIter = <SmallVec<[StringContextElem; 1]> as IntoIterator>::IntoIter;
-    fn into_iter(self) -> Self::IntoIter {
-        self.data.into_iter()
-    }
-}
-
-impl<'a> IntoIterator for &'a StringContext {
-    type Item = &'a StringContextElem;
-    type IntoIter = <&'a SmallVec<[StringContextElem; 1]> as IntoIterator>::IntoIter;
-    fn into_iter(self) -> Self::IntoIter {
-        self.data.iter()
-    }
-}
-
-impl<'a> IntoIterator for &'a mut StringContext {
-    type Item = &'a mut StringContextElem;
-    type IntoIter = <&'a mut SmallVec<[StringContextElem; 1]> as IntoIterator>::IntoIter;
-    fn into_iter(self) -> Self::IntoIter {
-        self.data.iter_mut()
-    }
-}
-
-impl FromIterator<StringContextElem> for StringContext {
-    fn from_iter<T: IntoIterator<Item = StringContextElem>>(iter: T) -> Self {
-        Self {
-            data: iter.into_iter().collect(),
-        }
-    }
-}
-
-impl StringContext {
-    pub fn empty() -> &'static Self {
-        static EMPTY: StringContext = StringContext {
-            data: SmallVec::new_const(),
-        };
-        &EMPTY
-    }
-
-    pub fn new() -> Self {
-        Self::default()
-    }
-
-    pub fn is_empty(&self) -> bool {
-        self.data.is_empty()
-    }
-
-    pub fn insert(&mut self, elem: StringContextElem) {
-        match self.data.binary_search(&elem) {
-            Ok(_) => {}
-            Err(pos) => self.data.insert(pos, elem),
-        }
-    }
-
-    #[expect(
-        clippy::indexing_slicing,
-        reason = "`i`/`j` stay strictly below their lengths inside the loop, and the trailing slices use those in-bounds cursors as start indices"
-    )]
-    pub fn merge(&self, other: &Self) -> Self {
-        if self.data.is_empty() {
-            return other.clone();
-        }
-        if other.data.is_empty() {
-            return self.clone();
-        }
-
-        let a = &self.data;
-        let b = &other.data;
-        let mut out = SmallVec::with_capacity(a.len() + b.len());
-        let (mut i, mut j) = (0, 0);
-        while i < a.len() && j < b.len() {
-            match a[i].cmp(&b[j]) {
-                Ordering::Less => {
-                    out.push(a[i].clone());
-                    i += 1;
-                }
-                Ordering::Greater => {
-                    out.push(b[j].clone());
-                    j += 1;
-                }
-                Ordering::Equal => {
-                    out.push(a[i].clone());
-                    i += 1;
-                    j += 1;
-                }
-            }
-        }
-        out.extend(a[i..].iter().cloned());
-        out.extend(b[j..].iter().cloned());
-        Self { data: out }
-    }
-
-    pub fn iter(&self) -> <&Self as IntoIterator>::IntoIter {
-        self.into_iter()
-    }
-
-    pub fn iter_mut(&mut self) -> <&mut Self as IntoIterator>::IntoIter {
-        self.into_iter()
-    }
-}

fix-runtime/src/value.rs

@@ -1,783 +0,0 @@
-use std::cell::RefCell;
-use std::fmt;
-use std::marker::PhantomData;
-use std::mem::size_of;
-use std::ops::Deref;
-
-use fix_bytecode::Continuation;
-use fix_lang::*;
-use fix_macros::unelide_lifetimes;
-use gc_arena::barrier::Unlock;
-use gc_arena::collect::Trace;
-use gc_arena::{Collect, Gc, GcRefLock, Mutation, RefLock};
-use smallvec::SmallVec;
-use string_interner::Symbol;
-use string_interner::symbol::SymbolU32;
-
-use crate::boxing::{RawBox, RawStore, RawTag, Value as RawValue};
-use crate::string_context::StringContext;
-
-mod private {
-    pub trait Cealed {}
-}
-
-pub trait ValueVariant<'gc>: private::Cealed {
-    #[expect(
-        private_bounds,
-        reason = "Storable is a sealed implementation detail of the value system"
-    )]
-    type Ty: Storable<'gc>;
-    const TYPE: NixType;
-}
-
-trait Storable<'gc>: TryFrom<Value<'gc>> + Into<Value<'gc>> + private::Cealed + 'gc {
-    fn is(raw: &RawBox) -> bool;
-
-    fn to_raw_box(self) -> RawBox;
-    /// # Safety
-    ///
-    /// `raw` must represent a valid `Self`.
-    unsafe fn from_raw_box(raw: RawBox) -> Self;
-}
-
-macro_rules! define_value_types {
-    (
-        inline { $($itype:ty => $itag:path, $ity:path, $iname:literal;)* }
-        gc { $($gtype:ty => $gtag:path, $gty:path, $gname:literal;)* }
-    ) => {
-        $(
-        impl Storable<'_> for $itype {
-            #[inline(always)]
-            fn is(value: &RawBox) -> bool {
-                value.tag() == Some($itag)
-            }
-            #[inline(always)]
-            fn to_raw_box(self) -> RawBox {
-                RawBox::from_value(RawValue::store($itag, self))
-            }
-            #[inline(always)]
-            unsafe fn from_raw_box(raw: RawBox) -> Self {
-                // SAFETY: the caller guarantees `raw` represents a valid
-                // `Self` of this inline type, so it holds a `Value` (making
-                // `value()` `Some`) whose payload decodes to this type.
-                unsafe { <Self as RawStore>::from_val(raw.value().unwrap_unchecked()) }
-            }
-        }
-        impl private::Cealed for $itype {}
-        impl<'gc> ValueVariant<'gc> for $itype {
-            type Ty = $itype;
-            const TYPE: NixType = $ity;
-        }
-        impl<'gc> TryFrom<Value<'gc>> for $itype {
-            type Error = ();
-            fn try_from(val: Value<'gc>) -> Result<Self, Self::Error> {
-                <Self as Storable>::is(&val.raw)
-                    // SAFETY: `is` returned true, so `val.raw` represents a
-                    // valid `Self` of this GC type.
-                    .then(|| unsafe { <Self as Storable>::from_raw_box(val.raw) })
-                    .ok_or(())
-            }
-        }
-        )*
-        $(
-        impl<'gc> Storable<'gc> for Gc<'gc, unelide_lifetimes!('gc; $gtype)> {
-            #[inline(always)]
-            fn is(value: &RawBox) -> bool {
-                value.tag() == Some($gtag)
-            }
-            #[inline(always)]
-            fn to_raw_box(self) -> RawBox {
-                RawBox::from_value(RawValue::store($gtag, Gc::as_ptr(self)))
-            }
-            #[inline(always)]
-            unsafe fn from_raw_box(raw: RawBox) -> Self {
-                // SAFETY: the caller guarantees `raw` represents a valid
-                // `Self` of this GC type, so it holds a `Value` (making
-                // `value()` `Some`) whose payload is the pointer originally
-                // produced by `Gc::as_ptr` in `to_raw_box`.
-                unsafe { Gc::from_ptr(<*mut $gtype as RawStore>::from_val(raw.value().unwrap_unchecked())) }
-            }
-        }
-        impl<'gc> TryFrom<Value<'gc>> for Gc<'gc, unelide_lifetimes!('gc; $gtype)> {
-            type Error = ();
-            fn try_from(val: Value<'gc>) -> Result<Self, Self::Error> {
-                <Self as Storable>::is(&val.raw)
-                    // SAFETY: `is` returned true, so `val.raw` represents a
-                    // valid `Self` of this GC type.
-                    .then(|| unsafe { <Self as Storable>::from_raw_box(val.raw) })
-                    .ok_or(())
-            }
-        }
-        impl private::Cealed for Gc<'_, $gtype> {}
-        impl private::Cealed for $gtype {}
-        impl<'gc> ValueVariant<'gc> for unelide_lifetimes!('gc; $gtype) {
-            type Ty = Gc<'gc, unelide_lifetimes!('gc; $gtype)>;
-            const TYPE: NixType = $gty;
-        }
-        )*
-
-        const _: () = assert!(size_of::<Value<'static>>() == 8);
-        $(const _: () = assert!(size_of::<$itype>() <= 6);)*
-
-        const _: () = {
-            let tags: &[(bool, u8)] = &[$(RawTag::neg_val($itag)),*, $(RawTag::neg_val($gtag)),*];
-            let mut mask_false: u8 = 0;
-            let mut mask_true: u8 = 0;
-            let mut i = 0;
-            while i < tags.len() {
-                #[expect(clippy::indexing_slicing, reason = "loop condition guarantees `i < tags.len()`")]
-                let (neg, val) = tags[i];
-                let bit = 1 << val;
-                if neg {
-                    assert!(mask_true & bit == 0, "duplicate true tag id");
-                    mask_true |= bit;
-                } else {
-                    assert!(mask_false & bit == 0, "duplicate false tag id");
-                    mask_false |= bit;
-                }
-                i += 1;
-            }
-        };
-
-        // SAFETY: `trace` visits every reachable `Gc` pointer: for each GC
-        // tag it downcasts to the concrete `Gc` type and forwards `trace`,
-        // while inline tags hold no GC pointers and need no tracing.
-        unsafe impl<'gc> Collect<'gc> for Value<'gc> {
-            const NEEDS_TRACE: bool = true;
-            fn trace<T: Trace<'gc>>(&self, cc: &mut T) {
-                let Some(tag) = self.raw.tag() else { return };
-                match tag {
-                    $($gtag => unsafe {
-                        // SAFETY: `tag` matched `$gtag`, so `downcast` to the
-                        // corresponding GC type is guaranteed to be `Some`.
-                        self.downcast::<$gtype>().unwrap_unchecked().trace(cc)
-                    },)*
-                    $($itag => (),)*
-                    _ => unreachable!("invalid value tag"),
-                }
-            }
-        }
-
-        impl fmt::Debug for Value<'_> {
-            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-                match self.tag() {
-                    // SAFETY: `tag()` is `None`, meaning the `RawBox` holds a
-                    // float, so `float()` is guaranteed to be `Some`.
-                    None => write!(f, "Float({:?})", unsafe {
-                        self.raw.float().unwrap_unchecked()
-                    }),
-                    // SAFETY: `tag()` matched `$itag`, so `downcast` to the
-                    // corresponding inline type is guaranteed to be `Some`.
-                    $(Some($itag) => write!(f, "{}({:?})", $iname, unsafe {
-                        self.downcast::<$itype>().unwrap_unchecked()
-                    }),)*
-                    $(Some($gtag) =>
-                        write!(f, "{}(..)", $gname),)*
-                    _ => unreachable!("invalid value tag"),
-                }
-            }
-        }
-    };
-}
-
-define_value_types! {
-    inline {
-        i32 => RawTag::P1, NixType::Int, "SmallInt";
-        bool => RawTag::P2, NixType::Bool, "Bool";
-        Null => RawTag::P3, NixType::Null, "Null";
-        StringId => RawTag::P4, NixType::String, "SmallString";
-        PrimOp => RawTag::P5, NixType::PrimOp, "PrimOp";
-        Path => RawTag::P6, NixType::Path, "Path";
-    }
-    gc {
-        i64 => RawTag::P7, NixType::Int, "BigInt";
-        NixString => RawTag::N1, NixType::String, "String";
-        AttrSet<'_> => RawTag::N2, NixType::AttrSet, "AttrSet";
-        List<'_> => RawTag::N3, NixType::List, "List";
-        Thunk<'_> => RawTag::N4, NixType::Thunk, "Thunk";
-        Closure<'_> => RawTag::N5, NixType::Closure, "Closure";
-        PrimOpApp<'_> => RawTag::N6, NixType::PrimOpApp, "PrimOpApp";
-    }
-}
-
-impl private::Cealed for f64 {}
-
-impl Storable<'_> for f64 {
-    #[inline(always)]
-    fn is(value: &RawBox) -> bool {
-        value.is_float()
-    }
-    #[inline(always)]
-    fn to_raw_box(self) -> RawBox {
-        RawBox::from_float(self)
-    }
-    #[inline(always)]
-    unsafe fn from_raw_box(raw: RawBox) -> Self {
-        // SAFETY: the caller guarantees `raw` represents a valid `f64`, so
-        // `float()` is guaranteed to be `Some`.
-        unsafe { raw.float().copied().unwrap_unchecked() }
-    }
-}
-
-impl<'gc> ValueVariant<'gc> for f64 {
-    type Ty = f64;
-    const TYPE: NixType = NixType::Float;
-}
-
-impl<'gc> TryFrom<Value<'gc>> for f64 {
-    type Error = ();
-    fn try_from(value: Value<'gc>) -> Result<Self, Self::Error> {
-        value.downcast::<f64>().ok_or(())
-    }
-}
-
-impl<'gc, T: Storable<'gc>> From<T> for Value<'gc> {
-    fn from(value: T) -> Self {
-        Value::new(value)
-    }
-}
-
-/// # Nix runtime value representation
-///
-/// NaN-boxed value fitting in 8 bytes.
-#[derive(Copy, Clone)]
-#[repr(transparent)]
-pub struct Value<'gc> {
-    raw: RawBox,
-    _marker: PhantomData<Gc<'gc, ()>>,
-}
-
-impl Default for Value<'_> {
-    #[inline(always)]
-    fn default() -> Self {
-        Self::new(Null)
-    }
-}
-
-impl<'gc> Value<'gc> {
-    #[inline(always)]
-    const fn tag(self) -> Option<RawTag> {
-        self.raw.tag()
-    }
-}
-
-impl<'gc> Value<'gc> {
-    #[inline]
-    #[expect(
-        private_bounds,
-        reason = "Storable is a sealed implementation detail of the value system"
-    )]
-    pub fn new<T: Storable<'gc>>(val: T) -> Self {
-        Self {
-            raw: val.to_raw_box(),
-            _marker: PhantomData,
-        }
-    }
-
-    #[inline]
-    pub fn make_int(val: i64, mc: &Mutation<'gc>) -> Self {
-        if val >= i32::MIN as i64 && val <= i32::MAX as i64 {
-            Value::new(val as i32)
-        } else {
-            Value::new(Gc::new(mc, val))
-        }
-    }
-
-    #[inline]
-    pub fn is<T: ValueVariant<'gc>>(self) -> bool {
-        T::Ty::is(&self.raw)
-    }
-
-    #[inline]
-    pub fn downcast<T: ValueVariant<'gc>>(self) -> Option<T::Ty> {
-        self.is::<T>()
-            // SAFETY: `is::<T>()` returned true, so `self.raw` represents a
-            // valid `T::Ty`.
-            .then(|| unsafe { T::Ty::from_raw_box(self.raw) })
-    }
-
-    #[inline]
-    pub fn to_bits(self) -> u64 {
-        self.raw.to_bits()
-    }
-
-    #[inline]
-    pub fn downcast_num(self) -> Option<NixNum> {
-        if let Some(i) = self.downcast::<i32>() {
-            Some(NixNum::Int(i as i64))
-        } else if let Some(gc_i) = self.downcast::<i64>() {
-            Some(NixNum::Int(*gc_i))
-        } else {
-            self.downcast::<f64>().map(NixNum::Float)
-        }
-    }
-
-    #[inline]
-    pub fn restrict(self) -> Result<StrictValue<'gc>, Gc<'gc, Thunk<'gc>>> {
-        if let Some(thunk) = self.downcast::<Thunk>() {
-            Err(thunk)
-        } else {
-            Ok(StrictValue(self))
-        }
-    }
-
-    #[inline]
-    #[expect(
-        clippy::unreachable,
-        reason = "the preceding `if`/`else if` chain exhausts every registered value tag"
-    )]
-    pub fn ty(self) -> NixType {
-        if self.is::<f64>() {
-            NixType::Float
-        } else if self.is::<i32>() || self.is::<i64>() {
-            NixType::Int
-        } else if self.is::<bool>() {
-            NixType::Bool
-        } else if self.is::<Null>() {
-            NixType::Null
-        } else if self.is::<StringId>() {
-            NixType::String
-        } else if self.is::<PrimOp>() {
-            NixType::PrimOp
-        } else if self.is::<NixString>() {
-            NixType::String
-        } else if self.is::<Path>() {
-            NixType::Path
-        } else if self.is::<AttrSet>() {
-            NixType::AttrSet
-        } else if self.is::<List>() {
-            NixType::List
-        } else if self.is::<Thunk>() {
-            NixType::Thunk
-        } else if self.is::<Closure>() {
-            NixType::Closure
-        } else if self.is::<PrimOpApp>() {
-            NixType::PrimOpApp
-        } else {
-            unreachable!("value has no recognized type tag")
-        }
-    }
-
-    #[inline]
-    pub fn expect<T: ValueVariant<'gc>>(self) -> Result<T::Ty, NixType> {
-        self.downcast::<T>().ok_or_else(|| self.ty())
-    }
-
-    #[inline]
-    pub fn expect_num(self) -> Result<NixNum, NixType> {
-        self.downcast_num().ok_or_else(|| self.ty())
-    }
-}
-
-#[derive(Copy, Clone, Default)]
-#[repr(transparent)]
-pub struct StaticValue(Value<'static>);
-
-impl<'gc> From<StaticValue> for Value<'gc> {
-    #[inline]
-    fn from(value: StaticValue) -> Self {
-        // SAFETY: StaticValue is guaranteed to not contain any `Gc`.
-        unsafe { std::mem::transmute::<Value<'static>, Value<'gc>>(value.0) }
-    }
-}
-
-impl StaticValue {
-    #[inline]
-    #[expect(
-        private_bounds,
-        reason = "Storable is a sealed implementation detail of the value system"
-    )]
-    pub fn new<T: Storable<'static>>(val: T) -> Self {
-        Self(Value::new(val))
-    }
-
-    #[inline]
-    pub fn is<T: ValueVariant<'static>>(self) -> bool {
-        self.0.is::<T>()
-    }
-
-    #[inline]
-    pub fn downcast<T: ValueVariant<'static>>(self) -> Option<T::Ty> {
-        self.0.downcast::<T>()
-    }
-
-    #[inline]
-    pub fn to_bits(self) -> u64 {
-        self.0.raw.to_bits()
-    }
-}
-
-#[derive(Clone, Copy, Debug)]
-pub struct Null;
-impl RawStore for Null {
-    fn to_val(self, value: &mut RawValue) {
-        value.set_data([0; 6]);
-    }
-    fn from_val(_: &RawValue) -> Self {
-        Self
-    }
-}
-
-impl RawStore for StringId {
-    fn to_val(self, value: &mut RawValue) {
-        (self.0.to_usize() as u32).to_val(value);
-    }
-    fn from_val(value: &RawValue) -> Self {
-        Self(
-            SymbolU32::try_from_usize(u32::from_val(value) as usize)
-                .expect("failed to read StringId from Value"),
-        )
-    }
-}
-
-/// A canonicalized absolute path. Inline value carrying an interned
-/// `StringId` whose contents are the path's absolute, dot-resolved form.
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub struct Path(pub StringId);
-
-impl RawStore for Path {
-    fn to_val(self, value: &mut RawValue) {
-        self.0.to_val(value);
-    }
-    fn from_val(value: &RawValue) -> Self {
-        Self(StringId::from_val(value))
-    }
-}
-
-#[derive(Collect)]
-#[collect(require_static)]
-pub struct NixString {
-    data: Box<str>,
-    context: StringContext,
-}
-
-impl NixString {
-    pub fn new(s: impl Into<Box<str>>) -> Self {
-        Self {
-            data: s.into(),
-            context: StringContext::new(),
-        }
-    }
-
-    /// Construct a `NixString` whose `context` is already sorted+deduped.
-    /// The caller is responsible for invariant maintenance.
-    pub fn with_context(s: impl Into<Box<str>>, context: StringContext) -> Self {
-        Self {
-            data: s.into(),
-            context,
-        }
-    }
-
-    pub fn as_str(&self) -> &str {
-        &self.data
-    }
-
-    pub fn context(&self) -> &StringContext {
-        &self.context
-    }
-
-    pub fn has_context(&self) -> bool {
-        !self.context.is_empty()
-    }
-}
-
-impl fmt::Debug for NixString {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&self.data, f)
-    }
-}
-
-#[derive(Collect, Debug, Default)]
-#[collect(no_drop)]
-pub struct AttrSet<'gc> {
-    pub entries: SmallVec<[(StringId, Value<'gc>); 4]>,
-}
-
-impl<'gc> AttrSet<'gc> {
-    pub fn from_sorted_unchecked(entries: SmallVec<[(StringId, Value<'gc>); 4]>) -> Self {
-        debug_assert!(entries.is_sorted_by_key(|(key, _)| *key));
-        Self { entries }
-    }
-
-    #[expect(
-        clippy::indexing_slicing,
-        reason = "index comes from a successful `binary_search_by_key`, so it is a valid entry index"
-    )]
-    pub fn lookup(&self, key: StringId) -> Option<Value<'gc>> {
-        self.entries
-            .binary_search_by_key(&key, |(k, _)| *k)
-            .ok()
-            .map(|i| self.entries[i].1)
-    }
-
-    pub fn has(&self, key: StringId) -> bool {
-        self.entries.binary_search_by_key(&key, |(k, _)| *k).is_ok()
-    }
-
-    #[expect(
-        clippy::indexing_slicing,
-        reason = "`i`/`j` stay strictly below their lengths inside the loop, and the trailing slices use those in-bounds cursors as start indices"
-    )]
-    pub fn merge(&self, other: &Self, mc: &Mutation<'gc>) -> Gc<'gc, Self> {
-        use std::cmp::Ordering::*;
-
-        debug_assert!(self.entries.is_sorted_by_key(|(key, _)| *key));
-        debug_assert!(other.entries.is_sorted_by_key(|(key, _)| *key));
-
-        let mut entries = SmallVec::new();
-        let mut i = 0;
-        let mut j = 0;
-        while i < self.entries.len() && j < other.entries.len() {
-            match self.entries[i].0.cmp(&other.entries[j].0) {
-                Less => {
-                    entries.push(self.entries[i]);
-                    i += 1;
-                }
-                Greater => {
-                    entries.push(other.entries[j]);
-                    j += 1;
-                }
-                Equal => {
-                    entries.push(other.entries[j]);
-                    i += 1;
-                    j += 1;
-                }
-            }
-        }
-        entries.extend(other.entries[j..].iter().cloned());
-        entries.extend(self.entries[i..].iter().cloned());
-
-        debug_assert!(entries.is_sorted_by_key(|(key, _)| *key));
-
-        Gc::new(mc, AttrSet { entries })
-    }
-}
-
-#[derive(Collect, Debug, Default)]
-#[repr(transparent)]
-#[collect(no_drop)]
-pub struct List<'gc> {
-    pub inner: RefLock<SmallVec<[Value<'gc>; 4]>>,
-}
-
-impl<'gc> List<'gc> {
-    pub fn new(mc: &Mutation<'gc>, data: SmallVec<[Value<'gc>; 4]>) -> Gc<'gc, Self> {
-        Gc::new(
-            mc,
-            Self {
-                inner: RefLock::new(data),
-            },
-        )
-    }
-
-    pub fn new_gc(mc: &Mutation<'gc>) -> Gc<'gc, Self> {
-        Gc::new(mc, Self::default())
-    }
-}
-
-impl<'gc> Unlock for List<'gc> {
-    type Unlocked = RefCell<SmallVec<[Value<'gc>; 4]>>;
-    unsafe fn unlock_unchecked(&self) -> &Self::Unlocked {
-        // SAFETY: the caller upholds the `Unlock` contract (mutation happens
-        // behind a write barrier); we forward that obligation to the inner
-        // `RefLock`'s `unlock_unchecked`.
-        unsafe { self.inner.unlock_unchecked() }
-    }
-}
-
-pub type Thunk<'gc> = RefLock<ThunkState<'gc>>;
-
-#[derive(Collect, Debug)]
-#[collect(no_drop)]
-pub enum ThunkState<'gc> {
-    Pending { ip: usize, env: GcEnv<'gc> },
-    Apply { func: Value<'gc>, arg: Value<'gc> },
-    Blackhole,
-    Evaluated(StrictValue<'gc>),
-}
-
-#[derive(Collect, Debug)]
-#[collect(no_drop)]
-pub struct Env<'gc> {
-    pub locals: SmallVec<[Value<'gc>; 4]>,
-    pub prev: Option<GcEnv<'gc>>,
-}
-pub type GcEnv<'gc> = GcRefLock<'gc, Env<'gc>>;
-
-impl<'gc> Env<'gc> {
-    pub fn empty() -> Self {
-        Env {
-            locals: SmallVec::new(),
-            prev: None,
-        }
-    }
-
-    #[expect(
-        clippy::indexing_slicing,
-        reason = "`locals` was just created with `1 + n_locals` elements, so index 0 is always valid"
-    )]
-    pub fn with_arg(arg: Value<'gc>, n_locals: u32, prev: Gc<'gc, RefLock<Env<'gc>>>) -> Self {
-        let mut locals = smallvec::smallvec![Value::default(); 1 + n_locals as usize];
-        locals[0] = arg;
-        Env {
-            locals,
-            prev: Some(prev),
-        }
-    }
-}
-
-#[derive(Collect, Debug)]
-#[collect(no_drop)]
-pub struct Closure<'gc> {
-    pub ip: u32,
-    pub n_locals: u32,
-    pub env: Gc<'gc, RefLock<Env<'gc>>>,
-    pub pattern: Option<Gc<'gc, PatternInfo>>,
-}
-
-#[derive(Collect, Debug)]
-#[collect(require_static)]
-pub struct PatternInfo {
-    pub required: SmallVec<[StringId; 4]>,
-    pub optional: SmallVec<[StringId; 4]>,
-    pub ellipsis: bool,
-    pub param_spans: Box<[(StringId, u32)]>,
-}
-
-#[repr(packed, Rust)]
-#[derive(Clone, Copy, Debug, Collect)]
-#[collect(require_static)]
-pub struct PrimOp {
-    pub id: BuiltinId,
-    pub arity: u8,
-    pub dispatch_ip: u32,
-}
-
-impl From<BuiltinId> for PrimOp {
-    fn from(id: BuiltinId) -> Self {
-        let BuiltinInfo { arity, .. } = id.info();
-        let dispatch_ip = Continuation::entry_for_builtin(id).ip();
-        Self {
-            id,
-            arity,
-            dispatch_ip,
-        }
-    }
-}
-
-impl RawStore for PrimOp {
-    fn to_val(self, value: &mut RawValue) {
-        let bytes = self.dispatch_ip.to_le_bytes();
-        value.set_data([
-            self.id as u8,
-            self.arity,
-            bytes[0],
-            bytes[1],
-            bytes[2],
-            bytes[3],
-        ]);
-    }
-    fn from_val(value: &RawValue) -> Self {
-        let [id, arity, bytes @ ..] = *value.data();
-        Self {
-            id: BuiltinId::try_from(id).expect("invalid BuiltinId"),
-            arity,
-            dispatch_ip: u32::from_le_bytes(bytes),
-        }
-    }
-}
-
-#[derive(Collect, Debug)]
-#[collect(no_drop)]
-pub struct PrimOpApp<'gc> {
-    pub primop: PrimOp,
-    pub arity: u8,
-    pub args: [Value<'gc>; 3],
-}
-
-#[derive(Copy, Clone, Default, Collect)]
-#[repr(transparent)]
-#[collect(no_drop)]
-pub struct StrictValue<'gc>(Value<'gc>);
-
-impl<'gc> StrictValue<'gc> {
-    #[inline]
-    pub fn relax(self) -> Value<'gc> {
-        self.0
-    }
-}
-
-impl<'gc> Deref for StrictValue<'gc> {
-    type Target = Value<'gc>;
-    #[inline]
-    fn deref(&self) -> &Value<'gc> {
-        &self.0
-    }
-}
-
-impl<'gc> From<StrictValue<'gc>> for Value<'gc> {
-    fn from(value: StrictValue<'gc>) -> Self {
-        value.0
-    }
-}
-
-impl<'gc> TryFrom<Value<'gc>> for StrictValue<'gc> {
-    type Error = Gc<'gc, Thunk<'gc>>;
-    fn try_from(value: Value<'gc>) -> Result<Self, Self::Error> {
-        value.restrict()
-    }
-}
-
-impl fmt::Debug for StrictValue<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&self.0, f)
-    }
-}
-
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Collect)]
-#[collect(require_static)]
-pub enum NixType {
-    Int,
-    Float,
-    Bool,
-    Null,
-    String,
-    Path,
-    AttrSet,
-    List,
-    Thunk,
-    Closure,
-    PrimOp,
-    PrimOpApp,
-}
-
-impl NixType {
-    pub fn display(self) -> &'static str {
-        use NixType::*;
-        match self {
-            Int => "an integer",
-            Float => "a float",
-            Bool => "a boolean",
-            Null => "null",
-            String => "a string",
-            Path => "a path",
-            AttrSet => "a set",
-            List => "a list",
-            Thunk => "a thunk",
-            Closure => "a function",
-            PrimOp => "a built-in function",
-            PrimOpApp => "a partially applied built-in function",
-        }
-    }
-}
-
-impl std::fmt::Display for NixType {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.display())
-    }
-}
-
-pub enum NixNum {
-    Int(i64),
-    Float(f64),
-}

fix-vm/Cargo.toml

@@ -3,20 +3,19 @@ name = "fix-vm"
 version = "0.1.0"
 edition = "2024"
 
-[dependencies]
-gc-arena = { workspace = true }
-hashbrown = { workspace = true }
-smallvec = { workspace = true }
-sysinfo = { version = "0.39", default-features = false, features = ["system"] }
-
-fix-bytecode = { path = "../fix-bytecode" }
-fix-error = { path = "../fix-error" }
-fix-lang = { path = "../fix-lang" }
-fix-macros = { path = "../fix-macros" }
-fix-runtime = { path = "../fix-runtime" }
-
 [features]
 tailcall = []
 
-[lints]
-workspace = true
+[dependencies]
+gc-arena = { workspace = true }
+hashbrown = { workspace = true }
+num_enum = { workspace = true }
+smallvec = { workspace = true }
+string-interner = { workspace = true }
+likely_stable = { workspace = true }
+sptr = "0.3"
+
+fix-builtins = { path = "../fix-builtins" }
+fix-codegen = { path = "../fix-codegen" }
+fix-common = { path = "../fix-common" }
+fix-error = { path = "../fix-error" }

fix-vm/src/boxing.rs

@@ -1,7 +1,4 @@
-#![allow(
-    dead_code,
-    reason = "boxing layer exposes a full API surface; some helpers are used only on specific targets or not yet wired up"
-)]
+#![allow(dead_code)]
 
 use std::fmt;
 use std::num::NonZeroU8;
@@ -27,7 +24,7 @@ impl<T: Default + Copy, const N: usize> ArrayExt<N> for [T; N] {
     }
 }
 
-pub trait RawStore: Sized {
+pub(crate) trait RawStore: Sized {
     fn to_val(self, value: &mut Value);
     fn from_val(value: &Value) -> Self;
 }
@@ -82,48 +79,41 @@ int_store!(i16);
 int_store!(i32);
 
 fn store_ptr<P: Strict + Copy>(value: &mut Value, ptr: P) {
-    cfg_select! {
-        target_pointer_width = "64" => {
+    #[cfg(target_pointer_width = "64")]
+    {
         assert!(
             ptr.addr() <= 0x0000_FFFF_FFFF_FFFF,
             "Pointer too large to store in NaN box"
         );
 
-            // SAFETY: `Value` is `#[repr(C, align(8))]` and exactly 8 bytes, so it is
-            // sound to reinterpret its storage as a `[u8; 8]` that we then treat as `P`
-            // (a pointer-sized value).
         let val = (unsafe { value.whole_mut() } as *mut [u8; 8]).cast::<P>();
 
         let ptr = Strict::map_addr(ptr, |addr| {
             addr | (usize::from(value.header().into_raw()) << 48)
         });
 
-            // SAFETY: `val` points to the `Value`'s 8-byte storage, which is valid and
-            // suitably aligned to hold `P`.
         unsafe { val.write(ptr) };
     }
-        _ => {
-            compile_error!("unsupported pointer width");
-        }
+
+    #[cfg(target_pointer_width = "32")]
+    {
+        let _ = (value, ptr);
+        unimplemented!("32-bit pointer storage not supported");
     }
 }
 
 fn load_ptr<P: Strict>(value: &Value) -> P {
-    cfg_select! {
-        target_pointer_width = "64" => {
-            // SAFETY: `Value` is `#[repr(C, align(8))]` and exactly 8 bytes, so it
-            // is sound to reinterpret its storage as a `[u8; 8]` cast to `P`; the
-            // pointer was originally written through this same `P` layout by
-            // `store_ptr`.
+    #[cfg(target_pointer_width = "64")]
+    {
         let val = (unsafe { value.whole() } as *const [u8; 8]).cast::<P>();
-            // SAFETY: `val` points to the `Value`'s 8-byte storage, which is valid
-            // and suitably aligned to hold `P`.
         let ptr = unsafe { val.read() };
         Strict::map_addr(ptr, |addr| addr & 0x0000_FFFF_FFFF_FFFF)
     }
-        _ => {
-            compile_error!("unsupported pointer width");
-        }
+
+    #[cfg(target_pointer_width = "32")]
+    {
+        let _ = value;
+        unimplemented!("32-bit pointer storage not supported");
     }
 }
 
@@ -167,32 +157,28 @@ enum TagVal {
 }
 
 #[derive(Copy, Clone, PartialEq, Eq)]
-pub struct RawTag(TagVal);
+pub(crate) struct RawTag(TagVal);
 
 impl RawTag {
-    pub const P1: RawTag = RawTag(TagVal::_P1);
-    pub const P2: RawTag = RawTag(TagVal::_P2);
-    pub const P3: RawTag = RawTag(TagVal::_P3);
-    pub const P4: RawTag = RawTag(TagVal::_P4);
-    pub const P5: RawTag = RawTag(TagVal::_P5);
-    pub const P6: RawTag = RawTag(TagVal::_P6);
-    pub const P7: RawTag = RawTag(TagVal::_P7);
+    pub(crate) const P1: RawTag = RawTag(TagVal::_P1);
+    pub(crate) const P2: RawTag = RawTag(TagVal::_P2);
+    pub(crate) const P3: RawTag = RawTag(TagVal::_P3);
+    pub(crate) const P4: RawTag = RawTag(TagVal::_P4);
+    pub(crate) const P5: RawTag = RawTag(TagVal::_P5);
+    pub(crate) const P6: RawTag = RawTag(TagVal::_P6);
+    pub(crate) const P7: RawTag = RawTag(TagVal::_P7);
 
-    pub const N1: RawTag = RawTag(TagVal::_N1);
-    pub const N2: RawTag = RawTag(TagVal::_N2);
-    pub const N3: RawTag = RawTag(TagVal::_N3);
-    pub const N4: RawTag = RawTag(TagVal::_N4);
-    pub const N5: RawTag = RawTag(TagVal::_N5);
-    pub const N6: RawTag = RawTag(TagVal::_N6);
-    pub const N7: RawTag = RawTag(TagVal::_N7);
+    pub(crate) const N1: RawTag = RawTag(TagVal::_N1);
+    pub(crate) const N2: RawTag = RawTag(TagVal::_N2);
+    pub(crate) const N3: RawTag = RawTag(TagVal::_N3);
+    pub(crate) const N4: RawTag = RawTag(TagVal::_N4);
+    pub(crate) const N5: RawTag = RawTag(TagVal::_N5);
+    pub(crate) const N6: RawTag = RawTag(TagVal::_N6);
+    pub(crate) const N7: RawTag = RawTag(TagVal::_N7);
 
     #[inline]
     #[must_use]
     pub(crate) fn new(neg: bool, val: NonZeroU8) -> RawTag {
-        // SAFETY: masking a `NonZeroU8` with `0x07` yields a value in `0..8`;
-        // callers only construct tags from valid tag discriminants in `1..8`,
-        // so the low three bits are in the `1..8` range required by
-        // `new_unchecked`.
         unsafe { Self::new_unchecked(neg, val.get() & 0x07) }
     }
 
@@ -243,9 +229,6 @@ impl RawTag {
             (true, 6) => TagVal::_N6,
             (true, 7) => TagVal::_N7,
 
-            // SAFETY: the caller guarantees `val` is in `1..8`; every
-            // `(neg, val)` combination in that range is matched above, so this
-            // arm cannot be reached.
             _ => unsafe { core::hint::unreachable_unchecked() },
         })
     }
@@ -277,7 +260,7 @@ impl RawTag {
 
     #[inline]
     #[must_use]
-    pub const fn neg_val(self) -> (bool, u8) {
+    pub(crate) const fn neg_val(self) -> (bool, u8) {
         match self.0 {
             TagVal::_P1 => (false, 1),
             TagVal::_P2 => (false, 2),
@@ -319,10 +302,6 @@ impl Header {
 
     #[inline]
     const fn tag(self) -> RawTag {
-        // SAFETY: a `Header` is only ever constructed by `Header::new` from a
-        // `RawTag` whose value is in `1..8`, stored in the low three bits;
-        // `get_tag` recovers exactly those bits, so the argument passed to
-        // `new_unchecked` is in the required `1..8` range.
         unsafe { RawTag::new_unchecked(self.get_sign(), self.get_tag()) }
     }
 
@@ -394,7 +373,7 @@ impl Value {
 
     #[inline]
     #[must_use]
-    pub fn data(&self) -> &[u8; 6] {
+    pub(crate) fn data(&self) -> &[u8; 6] {
         &self.data
     }
 
@@ -408,9 +387,6 @@ impl Value {
     #[must_use]
     unsafe fn whole(&self) -> &[u8; 8] {
         let ptr = (self as *const Value).cast::<[u8; 8]>();
-        // SAFETY: `Value` is `#[repr(C, align(8))]` and exactly 8 bytes with no
-        // padding, so it shares its layout with `[u8; 8]`; `ptr` is derived
-        // from a valid `&Value`, so the reference is valid for reads.
         unsafe { &*ptr }
     }
 
@@ -418,10 +394,6 @@ impl Value {
     #[must_use]
     unsafe fn whole_mut(&mut self) -> &mut [u8; 8] {
         let ptr = (self as *mut Value).cast::<[u8; 8]>();
-        // SAFETY: `Value` is `#[repr(C, align(8))]` and exactly 8 bytes with no
-        // padding, so it shares its layout with `[u8; 8]`; `ptr` is derived
-        // from a unique `&mut Value`, so the reference is valid for reads and
-        // writes.
         unsafe { &mut *ptr }
     }
 }
@@ -463,9 +435,6 @@ impl RawBox {
     #[must_use]
     pub(crate) const fn tag(&self) -> Option<RawTag> {
         if self.is_value() {
-            // SAFETY: `is_value()` returned true, so the union holds a `Value`
-            // (a tagged-NaN bit pattern) rather than a float, making the read
-            // of the `value` field sound.
             Some(unsafe { self.value.tag() })
         } else {
             None
@@ -475,18 +444,12 @@ impl RawBox {
     #[inline]
     #[must_use]
     pub(crate) fn is_float(&self) -> bool {
-        // SAFETY: every 8-byte pattern is simultaneously a valid `f64` and a
-        // valid `u64`, so reading the `float` and `bits` union fields is
-        // always sound.
         (unsafe { !self.float.is_nan() } || unsafe { self.bits & SIGN_MASK == QUIET_NAN })
     }
 
     #[inline]
     #[must_use]
     pub(crate) const fn is_value(&self) -> bool {
-        // SAFETY: every 8-byte pattern is simultaneously a valid `f64` and a
-        // valid `u64`, so reading the `float` and `bits` union fields is
-        // always sound.
         (unsafe { self.float.is_nan() } && unsafe { self.bits & SIGN_MASK != QUIET_NAN })
     }
 
@@ -494,8 +457,6 @@ impl RawBox {
     #[must_use]
     pub(crate) fn float(&self) -> Option<&f64> {
         if self.is_float() {
-            // SAFETY: reading the `float` field is sound because any 8-byte
-            // pattern is a valid `f64`.
             Some(unsafe { &self.float })
         } else {
             None
@@ -506,9 +467,6 @@ impl RawBox {
     #[must_use]
     pub(crate) fn value(&self) -> Option<&Value> {
         if self.is_value() {
-            // SAFETY: `is_value()` returned true, so the union holds a `Value`;
-            // `Value` has no invalid bit patterns, so reading the `value` field
-            // is sound.
             Some(unsafe { &self.value })
         } else {
             None
@@ -517,16 +475,12 @@ impl RawBox {
 
     #[inline]
     pub(crate) fn into_float_unchecked(self) -> f64 {
-        // SAFETY: reading the `float` field is sound because any 8-byte pattern
-        // is a valid `f64`.
         unsafe { self.float }
     }
 
     #[inline]
     #[must_use]
     pub(crate) fn to_bits(self) -> u64 {
-        // SAFETY: reading the `bits` field is sound because any 8-byte pattern
-        // is a valid `u64`.
         unsafe { self.bits }
     }
 }

fix-vm/src/bytecode_reader.rs

@@ -0,0 +1,142 @@
+use fix_codegen::OperandType;
+use fix_common::StringId;
+use num_enum::TryFromPrimitive;
+use string_interner::Symbol as _;
+
+use crate::{AttrKeyData, OperandData, VmRuntimeCtx};
+
+pub(crate) struct BytecodeReader<'a> {
+    bytecode: &'a [u8],
+    pc: usize,
+    inst_start_pc: usize,
+}
+
+impl<'a> BytecodeReader<'a> {
+    #[cfg_attr(feature = "tailcall", allow(dead_code))]
+    pub(crate) fn new(bytecode: &'a [u8], pc: usize) -> Self {
+        Self {
+            bytecode,
+            pc,
+            inst_start_pc: pc,
+        }
+    }
+
+    #[inline(always)]
+    #[cfg_attr(not(feature = "tailcall"), allow(dead_code))]
+    pub(crate) fn from_after_op(bytecode: &'a [u8], inst_start_pc: usize) -> Self {
+        Self {
+            bytecode,
+            pc: inst_start_pc + 1,
+            inst_start_pc,
+        }
+    }
+
+    #[inline(always)]
+    #[cfg_attr(debug_assertions, track_caller)]
+    fn read_array<const N: usize>(&mut self) -> [u8; N] {
+        let ret = self.bytecode[self.pc..self.pc + N]
+            .try_into()
+            .expect("read_array failed");
+        self.pc += N;
+        ret
+    }
+
+    #[inline(always)]
+    #[cfg_attr(feature = "tailcall", allow(dead_code))]
+    pub(crate) fn read_op(&mut self) -> fix_codegen::Op {
+        use fix_codegen::Op;
+        self.inst_start_pc = self.pc;
+        let byte = self.bytecode[self.pc];
+        if !likely_stable::likely((0..Op::Illegal as u8).contains(&byte)) {
+            panic!("unknown opcode: {byte:#04x}")
+        }
+        self.pc += 1;
+        unsafe { std::mem::transmute::<u8, Op>(byte) }
+    }
+
+    #[inline(always)]
+    pub(crate) fn read_u8(&mut self) -> u8 {
+        let val = self.bytecode[self.pc];
+        self.pc += 1;
+        val
+    }
+
+    #[inline(always)]
+    pub(crate) fn read_u16(&mut self) -> u16 {
+        u16::from_le_bytes(self.read_array())
+    }
+
+    #[inline(always)]
+    pub(crate) fn read_u32(&mut self) -> u32 {
+        u32::from_le_bytes(self.read_array())
+    }
+
+    #[inline(always)]
+    pub(crate) fn read_i32(&mut self) -> i32 {
+        i32::from_le_bytes(self.read_array())
+    }
+
+    #[inline(always)]
+    pub(crate) fn read_i64(&mut self) -> i64 {
+        i64::from_le_bytes(self.read_array())
+    }
+
+    #[inline(always)]
+    pub(crate) fn read_f64(&mut self) -> f64 {
+        f64::from_le_bytes(self.read_array())
+    }
+
+    #[inline(always)]
+    pub(crate) fn read_string_id(&mut self) -> StringId {
+        let raw = self.read_u32();
+        #[allow(clippy::unwrap_used)]
+        StringId(string_interner::symbol::SymbolU32::try_from_usize(raw as usize).unwrap())
+    }
+
+    #[inline(always)]
+    pub(crate) fn read_operand_data<C: VmRuntimeCtx>(&mut self, ctx: &C) -> OperandData {
+        let tag = self.read_u8();
+        let Ok(ty) = OperandType::try_from_primitive(tag)
+            .map_err(|err| panic!("unknown operand tag: {:#04x}", err.number));
+        match ty {
+            OperandType::Const => {
+                let id = self.read_u32();
+                OperandData::Const(ctx.get_const(id))
+            }
+            OperandType::Local => {
+                let layer = self.read_u8();
+                let idx = self.read_u32();
+                OperandData::Local { layer, idx }
+            }
+            OperandType::Builtins => OperandData::Builtins,
+            OperandType::BigInt => {
+                let val = self.read_i64();
+                OperandData::BigInt(val)
+            }
+        }
+    }
+
+    #[inline(always)]
+    pub(crate) fn read_attr_key_data(&mut self) -> crate::AttrKeyData {
+        use fix_codegen::AttrKeyType;
+        let tag = self.read_u8();
+        let ty = AttrKeyType::try_from_primitive(tag)
+            .unwrap_or_else(|err| panic!("unknown key tag: {:#04x}", err.number));
+        match ty {
+            AttrKeyType::Static => AttrKeyData::Static(self.read_string_id()),
+            AttrKeyType::Dynamic => AttrKeyData::Dynamic,
+        }
+    }
+
+    pub(crate) fn pc(&self) -> usize {
+        self.pc
+    }
+
+    pub(crate) fn set_pc(&mut self, pc: usize) {
+        self.pc = pc;
+    }
+
+    pub(crate) fn inst_start_pc(&self) -> usize {
+        self.inst_start_pc
+    }
+}

fix-vm/src/dispatch_tailcall.rs

@@ -7,7 +7,6 @@ use crate::{Break, BytecodeReader, Step, Vm, VmRuntimeCtx};
 pub(crate) enum TailResult {
     YieldFuel(u32),
     Done,
-    LoadFile,
 }
 
 pub(crate) type OpFn<'gc, C> = extern "rust-preserve-none" fn(
@@ -22,7 +21,6 @@ pub(crate) type OpFn<'gc, C> = extern "rust-preserve-none" fn(
 
 pub(crate) struct DispatchTable<'gc, C: VmRuntimeCtx>(pub(crate) [OpFn<'gc, C>; 256]);
 
-#[expect(clippy::panic, reason = "illegal opcode should panic")]
 extern "rust-preserve-none" fn op_illegal<'gc, C: VmRuntimeCtx>(
     _vm: &mut Vm<'gc>,
     _mc: &Mutation<'gc>,
@@ -39,7 +37,6 @@ macro_rules! tail_dispatch_after {
     ($result:expr, $new_pc:expr, $vm:ident, $mc:ident, $ctx:ident, $bc:ident, $table:ident, $fuel:ident) => {{
         match $result {
             Step::Continue(()) | Step::Break(Break::Force) => {}
-            Step::Break(Break::LoadFile) => return TailResult::LoadFile,
             Step::Break(Break::Done) => return TailResult::Done,
         }
         let new_pc: u32 = $new_pc;
@@ -62,7 +59,7 @@ macro_rules! tail_fn {
             pc: u32,
             fuel: u32,
         ) -> TailResult {
-            let result = crate::instructions::$name(vm);
+            let result = vm.$name();
             tail_dispatch_after!(result, pc + 1, vm, mc, ctx, bc, table, fuel)
         }
     };
@@ -77,7 +74,7 @@ macro_rules! tail_fn {
             fuel: u32,
         ) -> TailResult {
             let mut reader = BytecodeReader::from_after_op(bc, pc as usize);
-            let result = crate::instructions::$name(vm, &mut reader);
+            let result = vm.$name(&mut reader);
             tail_dispatch_after!(result, reader.pc() as u32, vm, mc, ctx, bc, table, fuel)
         }
     };
@@ -92,7 +89,7 @@ macro_rules! tail_fn {
             fuel: u32,
         ) -> TailResult {
             let mut reader = BytecodeReader::from_after_op(bc, pc as usize);
-            let result = crate::instructions::$name(vm, &mut reader, mc);
+            let result = vm.$name(&mut reader, mc);
             tail_dispatch_after!(result, reader.pc() as u32, vm, mc, ctx, bc, table, fuel)
         }
     };
@@ -107,7 +104,7 @@ macro_rules! tail_fn {
             fuel: u32,
         ) -> TailResult {
             let mut reader = BytecodeReader::from_after_op(bc, pc as usize);
-            let result = crate::instructions::$name(vm, ctx, &mut reader, mc);
+            let result = vm.$name(ctx, &mut reader, mc);
             tail_dispatch_after!(result, reader.pc() as u32, vm, mc, ctx, bc, table, fuel)
         }
     };
@@ -121,7 +118,7 @@ macro_rules! tail_fn {
             pc: u32,
             fuel: u32,
         ) -> TailResult {
-            let result = crate::instructions::$name(vm, ctx);
+            let result = vm.$name(ctx);
             tail_dispatch_after!(result, pc + 1, vm, mc, ctx, bc, table, fuel)
         }
     };
@@ -145,7 +142,7 @@ tail_fn!(op_make_closure, (reader, mc));
 tail_fn!(op_make_pattern_closure, (reader, mc));
 
 tail_fn!(op_call, (ctx, reader, mc));
-tail_fn!(op_dispatch_cont, (ctx, reader, mc));
+tail_fn!(op_dispatch_primop, (ctx, reader, mc));
 tail_fn!(op_return, (ctx, reader, mc));
 
 tail_fn!(op_make_attrs, (ctx, reader, mc));
@@ -183,36 +180,38 @@ tail_fn!(op_jump_if_false, (reader, mc));
 tail_fn!(op_jump_if_true, (reader, mc));
 tail_fn!(op_jump, (reader));
 
-tail_fn!(op_coerce_to_string, (reader, mc));
-
 tail_fn!(op_concat_strings, (ctx, reader, mc));
-tail_fn!(op_resolve_path, (ctx, reader, mc));
+tail_fn!(op_resolve_path, (ctx));
 
-tail_fn!(op_assert, (ctx, reader, mc));
+tail_fn!(op_assert, (reader));
 
+tail_fn!(op_push_with, (ctx, reader, mc));
+tail_fn!(op_pop_with, ());
 tail_fn!(op_lookup_with, (ctx, reader, mc));
+tail_fn!(op_prepare_with, ());
 
 tail_fn!(op_load_builtins, ());
 tail_fn!(op_load_builtin, (reader));
 
+tail_fn!(op_mk_pos, (reader));
 tail_fn!(op_load_repl_binding, (reader));
-tail_fn!(op_load_scoped_binding, (ctx, reader, mc));
+tail_fn!(op_load_scoped_binding, (reader));
 
 macro_rules! table {
     ($($variant:ident => $fn:ident),* $(,)?) => {
         impl<'gc, C: VmRuntimeCtx> DispatchTable<'gc, C> {
-            #[expect(clippy::indexing_slicing, reason = "Op is repr(u8)")]
             pub(crate) const NEW: Self = {
                 let mut arr: [OpFn<'gc, C>; 256] = [op_illegal; 256];
-                $( arr[fix_bytecode::Op::$variant as usize] = $fn; )*
+                $( arr[fix_codegen::Op::$variant as usize] = $fn; )*
                 DispatchTable(arr)
             };
         }
 
-        // Exhaustiveness check: fails to compile if `fix_bytecode::Op` gains,
+        // Exhaustiveness check: fails to compile if `fix_codegen::Op` gains,
         // loses, or renames a variant that isn't wired up above.
-        const _: fn(fix_bytecode::Op) = |op| match op {
-            $( fix_bytecode::Op::$variant => (), )*
+        #[allow(dead_code)]
+        const _: fn(fix_codegen::Op) = |op| match op {
+            $( fix_codegen::Op::$variant => (), )*
         };
     };
 }
@@ -236,7 +235,7 @@ table! {
     MakePatternClosure    => op_make_pattern_closure,
 
     Call                  => op_call,
-    DispatchCont          => op_dispatch_cont,
+    DispatchPrimOp        => op_dispatch_primop,
     Return                => op_return,
 
     MakeAttrs             => op_make_attrs,
@@ -274,28 +273,26 @@ table! {
     JumpIfTrue            => op_jump_if_true,
     Jump                  => op_jump,
 
-    CoerceToString        => op_coerce_to_string,
-
     ConcatStrings         => op_concat_strings,
     ResolvePath           => op_resolve_path,
 
     Assert                => op_assert,
 
+    PushWith              => op_push_with,
+    PopWith               => op_pop_with,
     LookupWith            => op_lookup_with,
+    PrepareWith           => op_prepare_with,
 
     LoadBuiltins          => op_load_builtins,
     LoadBuiltin           => op_load_builtin,
 
+    MkPos                 => op_mk_pos,
     LoadReplBinding       => op_load_repl_binding,
     LoadScopedBinding     => op_load_scoped_binding,
 
     Illegal               => op_illegal,
 }
 
-#[expect(
-    clippy::indexing_slicing,
-    reason = "assume well-formed bytecode; Op is repr(u8)"
-)]
 pub(crate) fn run_tailcall<'gc, C: VmRuntimeCtx>(
     vm: &mut Vm<'gc>,
     mc: &Mutation<'gc>,

fix-vm/src/forced.rs

@@ -0,0 +1,270 @@
+use fix_common::StringId;
+use gc_arena::{Gc, Mutation};
+
+use crate::value::*;
+use crate::{Break, BytecodeReader, NixNum, Step, Vm};
+
+pub(crate) trait Forced<'gc>: Sized {
+    const WIDTH: usize;
+
+    /// Force and type-check the `WIDTH` slots starting at `base_depth` from
+    /// TOS, deepest-first. If a slot holds a thunk, enter it and return
+    /// `Break::Force`. If a slot holds a value of the wrong type, call
+    /// `finish_type_err` and return `Break::Done`.
+    fn force_and_check(
+        vm: &mut Vm<'gc>,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+        base_depth: usize,
+        resume_pc: usize,
+    ) -> Step;
+
+    /// After `force_and_check` returned `Continue`, pop `WIDTH` slots
+    /// (TOS first) and convert. Type assertions are infallible because
+    /// `force_and_check` already validated every slot.
+    fn pop_converted(vm: &mut Vm<'gc>) -> Self;
+}
+
+impl<'gc> Forced<'gc> for StrictValue<'gc> {
+    const WIDTH: usize = 1;
+
+    #[inline(always)]
+    fn force_and_check(
+        vm: &mut Vm<'gc>,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+        base_depth: usize,
+        resume_pc: usize,
+    ) -> Step {
+        vm.force_slot_to_pc(base_depth, reader, mc, resume_pc)
+    }
+
+    #[inline(always)]
+    fn pop_converted(vm: &mut Vm<'gc>) -> Self {
+        vm.pop_forced()
+    }
+}
+
+macro_rules! impl_forced_inline {
+    ($($ty:ty => $nix_ty:expr),* $(,)?) => {
+        $(
+        impl<'gc> Forced<'gc> for $ty {
+            const WIDTH: usize = 1;
+
+            #[inline(always)]
+            fn force_and_check(
+                vm: &mut Vm<'gc>,
+                reader: &mut BytecodeReader<'_>,
+                mc: &Mutation<'gc>,
+                base_depth: usize,
+                resume_pc: usize,
+            ) -> Step {
+                vm.force_slot_to_pc(base_depth, reader, mc, resume_pc)?;
+                let v = vm.peek_forced(base_depth);
+                if v.as_inline::<$ty>().is_none() {
+                    let _: Step = vm.finish_type_err($nix_ty, v.ty());
+                    return Step::Break(Break::Done);
+                }
+                Step::Continue(())
+            }
+
+            #[inline(always)]
+            fn pop_converted(vm: &mut Vm<'gc>) -> Self {
+                vm.pop_forced()
+                    .as_inline::<$ty>()
+                    .expect("type checked in force_and_check")
+            }
+        }
+        )*
+    };
+}
+
+macro_rules! impl_forced_gc {
+    ($($ty:ty => $nix_ty:expr),* $(,)?) => {
+        $(
+        impl<'gc> Forced<'gc> for Gc<'gc, $ty> {
+            const WIDTH: usize = 1;
+
+            #[inline(always)]
+            fn force_and_check(
+                vm: &mut Vm<'gc>,
+                reader: &mut BytecodeReader<'_>,
+                mc: &Mutation<'gc>,
+                base_depth: usize,
+                resume_pc: usize,
+            ) -> Step {
+                vm.force_slot_to_pc(base_depth, reader, mc, resume_pc)?;
+                let v = vm.peek_forced(base_depth);
+                if v.as_gc::<$ty>().is_none() {
+                    let _: Step = vm.finish_type_err($nix_ty, v.ty());
+                    return Step::Break(Break::Done);
+                }
+                Step::Continue(())
+            }
+
+            #[inline(always)]
+            fn pop_converted(vm: &mut Vm<'gc>) -> Self {
+                vm.pop_forced()
+                    .as_gc::<$ty>()
+                    .expect("type checked in force_and_check")
+            }
+        }
+        )*
+    };
+}
+
+impl_forced_inline! {
+    i32 => NixType::Int,
+    bool => NixType::Bool,
+    Null => NixType::Null,
+    StringId => NixType::String,
+    PrimOp => NixType::PrimOp,
+}
+
+impl_forced_gc! {
+    i64 => NixType::Int,
+    NixString => NixType::String,
+    AttrSet<'gc> => NixType::AttrSet,
+    List<'gc> => NixType::List,
+    Closure<'gc> => NixType::Closure,
+    PrimOpApp<'gc> => NixType::PrimOpApp,
+}
+
+impl<'gc> Forced<'gc> for NixNum {
+    const WIDTH: usize = 1;
+
+    #[inline(always)]
+    fn force_and_check(
+        vm: &mut Vm<'gc>,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+        base_depth: usize,
+        resume_pc: usize,
+    ) -> Step {
+        vm.force_slot_to_pc(base_depth, reader, mc, resume_pc)?;
+        let v = vm.peek_forced(base_depth);
+        if v.as_num().is_none() {
+            let _: Step = vm.finish_type_err(NixType::Int, v.ty());
+            return Step::Break(Break::Done);
+        }
+        Step::Continue(())
+    }
+
+    #[inline(always)]
+    fn pop_converted(vm: &mut Vm<'gc>) -> Self {
+        vm.pop_forced()
+            .as_num()
+            .expect("type checked in force_and_check")
+    }
+}
+
+impl<'gc> Forced<'gc> for f64 {
+    const WIDTH: usize = 1;
+
+    #[inline(always)]
+    fn force_and_check(
+        vm: &mut Vm<'gc>,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+        base_depth: usize,
+        resume_pc: usize,
+    ) -> Step {
+        vm.force_slot_to_pc(base_depth, reader, mc, resume_pc)?;
+        let v = vm.peek_forced(base_depth);
+        if v.as_float().is_none() {
+            let _: Step = vm.finish_type_err(NixType::Float, v.ty());
+            return Step::Break(Break::Done);
+        }
+        Step::Continue(())
+    }
+
+    #[inline(always)]
+    fn pop_converted(vm: &mut Vm<'gc>) -> Self {
+        vm.pop_forced()
+            .as_float()
+            .expect("type checked in force_and_check")
+    }
+}
+
+impl<'gc, A: Forced<'gc>, B: Forced<'gc>> Forced<'gc> for (A, B) {
+    const WIDTH: usize = A::WIDTH + B::WIDTH;
+
+    #[inline(always)]
+    fn force_and_check(
+        vm: &mut Vm<'gc>,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+        base: usize,
+        resume_pc: usize,
+    ) -> Step {
+        A::force_and_check(vm, reader, mc, base + B::WIDTH, resume_pc)?;
+        B::force_and_check(vm, reader, mc, base, resume_pc)
+    }
+
+    #[inline(always)]
+    fn pop_converted(vm: &mut Vm<'gc>) -> Self {
+        let b = B::pop_converted(vm);
+        let a = A::pop_converted(vm);
+        (a, b)
+    }
+}
+
+impl<'gc, A: Forced<'gc>, B: Forced<'gc>, C: Forced<'gc>> Forced<'gc> for (A, B, C) {
+    const WIDTH: usize = A::WIDTH + B::WIDTH + C::WIDTH;
+
+    #[inline(always)]
+    fn force_and_check(
+        vm: &mut Vm<'gc>,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+        base: usize,
+        resume_pc: usize,
+    ) -> Step {
+        A::force_and_check(vm, reader, mc, base + B::WIDTH + C::WIDTH, resume_pc)?;
+        B::force_and_check(vm, reader, mc, base + C::WIDTH, resume_pc)?;
+        C::force_and_check(vm, reader, mc, base, resume_pc)
+    }
+
+    #[inline(always)]
+    fn pop_converted(vm: &mut Vm<'gc>) -> Self {
+        let c = C::pop_converted(vm);
+        let b = B::pop_converted(vm);
+        let a = A::pop_converted(vm);
+        (a, b, c)
+    }
+}
+
+impl<'gc, A: Forced<'gc>, B: Forced<'gc>, C: Forced<'gc>, D: Forced<'gc>> Forced<'gc>
+    for (A, B, C, D)
+{
+    const WIDTH: usize = A::WIDTH + B::WIDTH + C::WIDTH + D::WIDTH;
+
+    #[inline(always)]
+    fn force_and_check(
+        vm: &mut Vm<'gc>,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+        base: usize,
+        resume_pc: usize,
+    ) -> Step {
+        A::force_and_check(
+            vm,
+            reader,
+            mc,
+            base + B::WIDTH + C::WIDTH + D::WIDTH,
+            resume_pc,
+        )?;
+        B::force_and_check(vm, reader, mc, base + C::WIDTH + D::WIDTH, resume_pc)?;
+        C::force_and_check(vm, reader, mc, base + D::WIDTH, resume_pc)?;
+        D::force_and_check(vm, reader, mc, base, resume_pc)
+    }
+
+    #[inline(always)]
+    fn pop_converted(vm: &mut Vm<'gc>) -> Self {
+        let d = D::pop_converted(vm);
+        let c = C::pop_converted(vm);
+        let b = B::pop_converted(vm);
+        let a = A::pop_converted(vm);
+        (a, b, c, d)
+    }
+}

fix-vm/src/helpers.rs

@@ -0,0 +1,7 @@
+use fix_error::Error;
+
+use crate::VmError;
+
+pub(crate) fn vm_err(msg: impl Into<String>) -> VmError {
+    VmError::Uncatchable(Error::eval_error(msg.into()))
+}

fix-vm/src/instructions/arithmetic.rs

@@ -1,104 +1,69 @@
 use std::cmp::Ordering;
 
-use fix_runtime::*;
 use gc_arena::{Gc, Mutation, RefLock};
 
-use crate::{BytecodeReader, NixNum, Step, VmError, VmRuntimeCtx};
+use crate::value::*;
+use crate::{BytecodeReader, NixNum, Step, VmError, VmRuntimeCtx, VmRuntimeCtxExt as _};
 
-#[inline(always)]
-pub(crate) fn op_add<'gc, M: Machine<'gc>>(
-    m: &mut M,
+impl<'gc> crate::Vm<'gc> {
+    #[inline(always)]
+    pub(crate) fn op_add(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    let (lhs, rhs) = m.force_and_retry::<(StrictValue, StrictValue)>(reader, mc)?;
-    // if the LHS is a path, the result is a path obtained by
-    // canonicalizing the concatenated string. RHS may be a path or a
-    // string. (A `string + path` keeps the string-typed result, handled
-    // by the next branch.)
-    if lhs.is::<Path>() {
-        let (Some(ls), Some(rs)) = (ctx.get_string_or_path(lhs), ctx.get_string_or_path(rhs))
-        else {
-            return m.finish_err(fix_error::Error::eval_error(format!(
-                "cannot append {} to a path",
-                rhs.ty()
-            )));
-        };
-        let combined = format!("{ls}{rs}");
-        let canon = canon_path_str(&combined);
-        let sid = ctx.intern_string(canon);
-        m.push(Value::new(fix_runtime::Path(sid)));
-        return Step::Continue(());
-    }
-    if let (Some(ls), Some(rs)) = (ctx.get_string(lhs), ctx.get_string_or_path(rhs)) {
-        let merged = ctx
-            .get_string_context(lhs)
-            .merge(ctx.get_string_context(rhs));
-        let ns = Gc::new(
-            mc,
-            crate::NixString::with_context(format!("{ls}{rs}"), merged),
-        );
-        m.push(Value::new(ns));
+    ) -> Step {
+        let (lhs, rhs) = self.try_force::<(StrictValue, StrictValue)>(reader, mc)?;
+        if let (Some(ls), Some(rs)) = (ctx.get_string(lhs), ctx.get_string(rhs)) {
+            let ns = Gc::new(mc, crate::NixString::new(format!("{ls}{rs}")));
+            self.push(Value::new_gc(ns));
             return Step::Continue(());
         }
         let res = numeric_binop(lhs, rhs, mc, i64::wrapping_add, |a, b| a + b);
         match res {
             Ok(val) => {
-            m.push(val);
+                self.push(val);
                 Step::Continue(())
             }
-        Err(e) => m.finish_vm_err(e),
+            Err(e) => self.finish_vm_err(e),
+        }
     }
-}
 
-#[inline(always)]
-pub(crate) fn op_sub<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    op_arith(m, reader, mc, i64::wrapping_sub, |a, b| a - b)
-}
+    #[inline(always)]
+    pub(crate) fn op_sub(&mut self, reader: &mut BytecodeReader<'_>, mc: &Mutation<'gc>) -> Step {
+        self.op_arith(reader, mc, i64::wrapping_sub, |a, b| a - b)
+    }
 
-#[inline(always)]
-pub(crate) fn op_mul<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    op_arith(m, reader, mc, i64::wrapping_mul, |a, b| a * b)
-}
+    #[inline(always)]
+    pub(crate) fn op_mul(&mut self, reader: &mut BytecodeReader<'_>, mc: &Mutation<'gc>) -> Step {
+        self.op_arith(reader, mc, i64::wrapping_mul, |a, b| a * b)
+    }
 
-#[inline(always)]
-fn op_arith<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    fn op_arith(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
         int_op: fn(i64, i64) -> i64,
         float_op: fn(f64, f64) -> f64,
-) -> Step {
-    let (lhs, rhs) = m.force_and_retry::<(StrictValue, StrictValue)>(reader, mc)?;
+    ) -> Step {
+        let (lhs, rhs) = self.try_force::<(StrictValue, StrictValue)>(reader, mc)?;
         let res = numeric_binop(lhs, rhs, mc, int_op, float_op);
         match res {
             Ok(val) => {
-            m.push(val);
+                self.push(val);
                 Step::Continue(())
             }
-        Err(e) => m.finish_vm_err(e),
+            Err(e) => self.finish_vm_err(e),
+        }
     }
-}
 
-#[inline(always)]
-pub(crate) fn op_div<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let (lhs, rhs) = m.force_and_retry::<(StrictValue, StrictValue)>(reader, mc)?;
+    #[inline(always)]
+    pub(crate) fn op_div(&mut self, reader: &mut BytecodeReader<'_>, mc: &Mutation<'gc>) -> Step {
+        let (lhs, rhs) = self.try_force::<(StrictValue, StrictValue)>(reader, mc)?;
         match (get_num(lhs), get_num(rhs)) {
             (_, Some(NixNum::Int(0))) | (_, Some(NixNum::Float(0.))) => {
-            return m.finish_vm_err(VmError::Uncatchable(fix_error::Error::eval_error(
+                return self.finish_vm_err(VmError::Uncatchable(fix_error::Error::eval_error(
                     "division by zero",
                 )));
             }
@@ -107,151 +72,210 @@ pub(crate) fn op_div<'gc, M: Machine<'gc>>(
         let res = numeric_binop(lhs, rhs, mc, |a, b| a / b, |a, b| a / b);
         match res {
             Ok(val) => {
-            m.push(val);
+                self.push(val);
                 Step::Continue(())
             }
-        Err(e) => m.finish_vm_err(e),
+            Err(e) => self.finish_vm_err(e),
+        }
     }
-}
 
-#[inline(always)]
-pub(crate) fn op_eq<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_eq(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    let (lhs, rhs) = m.force_and_retry::<(StrictValue, StrictValue)>(reader, mc)?;
-    crate::primops::start_eq(m, ctx, reader, mc, lhs, rhs, false)
-}
+    ) -> Step {
+        let (lhs, rhs) = self.try_force::<(StrictValue, StrictValue)>(reader, mc)?;
+        let eq = match self.values_equal(ctx, lhs, rhs) {
+            Ok(eq) => eq,
+            Err(e) => return self.finish_vm_err(e),
+        };
+        self.push(Value::new_inline(eq));
+        Step::Continue(())
+    }
 
-#[inline(always)]
-pub(crate) fn op_neq<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_neq(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    let (lhs, rhs) = m.force_and_retry::<(StrictValue, StrictValue)>(reader, mc)?;
-    crate::primops::start_eq(m, ctx, reader, mc, lhs, rhs, true)
-}
+    ) -> Step {
+        let (lhs, rhs) = self.try_force::<(StrictValue, StrictValue)>(reader, mc)?;
+        let eq = match self.values_equal(ctx, lhs, rhs) {
+            Ok(eq) => eq,
+            Err(e) => return self.finish_vm_err(e),
+        };
+        self.push(Value::new_inline(!eq));
+        Step::Continue(())
+    }
 
-#[inline(always)]
-pub(crate) fn op_lt<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_lt(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    compare_values(m, ctx, reader, mc, Ordering::is_lt)
-}
+    ) -> Step {
+        self.compare_values(ctx, reader, mc, Ordering::is_lt)
+    }
 
-#[inline(always)]
-pub(crate) fn op_gt<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_gt(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    compare_values(m, ctx, reader, mc, Ordering::is_gt)
-}
+    ) -> Step {
+        self.compare_values(ctx, reader, mc, Ordering::is_gt)
+    }
 
-#[inline(always)]
-pub(crate) fn op_leq<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_leq(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    compare_values(m, ctx, reader, mc, Ordering::is_le)
-}
+    ) -> Step {
+        self.compare_values(ctx, reader, mc, Ordering::is_le)
+    }
 
-#[inline(always)]
-pub(crate) fn op_geq<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_geq(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    compare_values(m, ctx, reader, mc, Ordering::is_ge)
-}
+    ) -> Step {
+        self.compare_values(ctx, reader, mc, Ordering::is_ge)
+    }
 
-fn compare_values<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    fn compare_values(
+        &mut self,
         ctx: &impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
         pred: fn(Ordering) -> bool,
-) -> Step {
-    let (lhs, rhs) = m.force_and_retry::<(StrictValue, StrictValue)>(reader, mc)?;
-    match compare_values_inner(m, ctx, pred, lhs, rhs) {
+    ) -> Step {
+        let (lhs, rhs) = self.try_force::<(StrictValue, StrictValue)>(reader, mc)?;
+        match self.compare_values_inner(ctx, pred, lhs, rhs) {
             Ok(()) => Step::Continue(()),
-        Err(e) => m.finish_vm_err(e),
+            Err(e) => self.finish_vm_err(e),
+        }
     }
-}
 
-#[inline(always)]
-pub(crate) fn op_concat<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_concat(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    let (l, r) = m.force_and_retry::<(Gc<List>, Gc<List>)>(reader, mc)?;
+    ) -> Step {
+        let (l, r) = self.try_force::<(Gc<List>, Gc<List>)>(reader, mc)?;
         let mut items = smallvec::SmallVec::new();
         items.extend_from_slice(&l.inner.borrow());
         items.extend_from_slice(&r.inner.borrow());
-    m.push(Value::new(Gc::new(
+        self.push(Value::new_gc(Gc::new(
             mc,
             crate::List {
                 inner: RefLock::new(items),
             },
         )));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_update<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_update(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    let (l, r) = m.force_and_retry::<(Gc<AttrSet>, Gc<AttrSet>)>(reader, mc)?;
-    m.push(Value::new(l.merge(&r, mc)));
+    ) -> Step {
+        let (l, r) = self.try_force::<(Gc<AttrSet>, Gc<AttrSet>)>(reader, mc)?;
+        self.push(Value::new_gc(l.merge(&r, mc)));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_neg<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let rhs = m.force_and_retry::<NixNum>(reader, mc)?;
+    #[inline(always)]
+    pub(crate) fn op_neg(&mut self, reader: &mut BytecodeReader<'_>, mc: &Mutation<'gc>) -> Step {
+        let rhs = self.try_force::<NixNum>(reader, mc)?;
         match rhs {
-        NixNum::Int(int) => m.push(Value::make_int(-int, mc)),
-        NixNum::Float(float) => m.push(Value::new(-float)),
+            NixNum::Int(int) => self.push(Value::make_int(-int, mc)),
+            NixNum::Float(float) => self.push(Value::new_float(-float)),
         }
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_not<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let rhs = m.force_and_retry::<bool>(reader, mc)?;
-    m.push(Value::new(!rhs));
+    #[inline(always)]
+    pub(crate) fn op_not(&mut self, reader: &mut BytecodeReader<'_>, mc: &Mutation<'gc>) -> Step {
+        let rhs = self.try_force::<bool>(reader, mc)?;
+        self.push(Value::new_inline(!rhs));
         Step::Continue(())
-}
+    }
 
-fn compare_values_inner<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    pub(crate) fn values_equal(
+        &mut self,
+        ctx: &impl VmRuntimeCtx,
+        lhs: StrictValue<'gc>,
+        rhs: StrictValue<'gc>,
+    ) -> crate::VmResult<bool> {
+        if let (Some(a), Some(b)) = (get_num(lhs), get_num(rhs)) {
+            return Ok(match (a, b) {
+                (NixNum::Int(a), NixNum::Int(b)) => a == b,
+                (NixNum::Float(a), NixNum::Float(b)) => a == b,
+                (NixNum::Int(a), NixNum::Float(b)) => a as f64 == b,
+                (NixNum::Float(a), NixNum::Int(b)) => a == b as f64,
+            });
+        }
+        if let (Some(a), Some(b)) = (lhs.as_inline::<bool>(), rhs.as_inline::<bool>()) {
+            return Ok(a == b);
+        }
+        if lhs.is::<crate::Null>() && rhs.is::<crate::Null>() {
+            return Ok(true);
+        }
+        if let (Some(a), Some(b)) = (ctx.get_string(lhs), ctx.get_string(rhs)) {
+            return Ok(a == b);
+        }
+        if let (Some(a), Some(b)) = (lhs.as_gc::<crate::List>(), rhs.as_gc::<crate::List>()) {
+            if a.inner.borrow().len() != b.inner.borrow().len() {
+                return Ok(false);
+            }
+            for (x, y) in a.inner.borrow().iter().zip(b.inner.borrow().iter()) {
+                let lx = x.restrict().expect("forced");
+                let ly = y.restrict().expect("forced");
+                if !self.values_equal(ctx, lx, ly)? {
+                    return Ok(false);
+                }
+            }
+            return Ok(true);
+        }
+        if let (Some(a), Some(b)) = (lhs.as_gc::<crate::AttrSet>(), rhs.as_gc::<crate::AttrSet>()) {
+            let a = a.entries.borrow();
+            let b = b.entries.borrow();
+            if a.len() != b.len() {
+                return Ok(false);
+            }
+            for ((k1, v1), (k2, v2)) in a.iter().zip(b.iter()) {
+                if k1 != k2 {
+                    return Ok(false);
+                }
+                let lv1 = v1.restrict().expect("forced");
+                let lv2 = v2.restrict().expect("forced");
+                if !self.values_equal(ctx, lv1, lv2)? {
+                    return Ok(false);
+                }
+            }
+            return Ok(true);
+        }
+        Ok(false)
+    }
+
+    fn compare_values_inner(
+        &mut self,
         ctx: &impl VmRuntimeCtx,
         pred: fn(Ordering) -> bool,
         lhs: StrictValue<'gc>,
         rhs: StrictValue<'gc>,
-) -> crate::VmResult<()> {
+    ) -> crate::VmResult<()> {
         if let (Some(a), Some(b)) = (get_num(lhs), get_num(rhs)) {
             let ord = match (a, b) {
                 (NixNum::Int(a), NixNum::Int(b)) => a.cmp(&b),
@@ -263,34 +287,25 @@ fn compare_values_inner<'gc, M: Machine<'gc>>(
                     a.partial_cmp(&(b as f64)).unwrap_or(Ordering::Less)
                 }
             };
-        m.push(Value::new(pred(ord)));
+            self.push(Value::new_inline(pred(ord)));
             return Ok(());
         }
         if let (Some(a), Some(b)) = (ctx.get_string(lhs), ctx.get_string(rhs)) {
-        m.push(Value::new(pred(a.cmp(b))));
-        return Ok(());
-    }
-    if let (Some(a), Some(b)) = (lhs.downcast::<Path>(), rhs.downcast::<Path>()) {
-        let a = ctx.resolve_string(a.0);
-        let b = ctx.resolve_string(b.0);
-        m.push(Value::new(pred(a.cmp(b))));
+            self.push(Value::new_inline(pred(a.cmp(b))));
             return Ok(());
         }
         // TODO: compare other types
-    Err(crate::vm_err(format!(
-        "cannot compare {} with {}",
-        lhs.ty(),
-        rhs.ty()
-    )))
+        Err(crate::vm_err("cannot compare these types"))
+    }
 }
 
 pub(crate) fn get_num(val: StrictValue<'_>) -> Option<NixNum> {
-    if let Some(i) = val.downcast::<i32>() {
-        Some(NixNum::Int(i64::from(i)))
-    } else if let Some(gc_i) = val.downcast::<i64>() {
+    if let Some(i) = val.as_inline::<i32>() {
+        Some(NixNum::Int(i as i64))
+    } else if let Some(gc_i) = val.as_gc::<i64>() {
         Some(NixNum::Int(*gc_i))
     } else {
-        val.downcast::<f64>().map(NixNum::Float)
+        val.as_float().map(NixNum::Float)
     }
 }
 
@@ -304,12 +319,13 @@ fn numeric_binop<'gc>(
 ) -> crate::VmResult<Value<'gc>> {
     match (get_num(lhs), get_num(rhs)) {
         (Some(NixNum::Int(a)), Some(NixNum::Int(b))) => Ok(Value::make_int(int_op(a, b), mc)),
-        (Some(NixNum::Float(a)), Some(NixNum::Float(b))) => Ok(Value::new(float_op(a, b))),
-        (Some(NixNum::Int(a)), Some(NixNum::Float(b))) => Ok(Value::new(float_op(a as f64, b))),
-        (Some(NixNum::Float(a)), Some(NixNum::Int(b))) => Ok(Value::new(float_op(a, b as f64))),
-        _ => Err(crate::vm_err(format!(
-            "cannot perform arithmetic on non-numbers: {:?}",
-            (lhs.ty(), rhs.ty())
-        ))),
+        (Some(NixNum::Float(a)), Some(NixNum::Float(b))) => Ok(Value::new_float(float_op(a, b))),
+        (Some(NixNum::Int(a)), Some(NixNum::Float(b))) => {
+            Ok(Value::new_float(float_op(a as f64, b)))
+        }
+        (Some(NixNum::Float(a)), Some(NixNum::Int(b))) => {
+            Ok(Value::new_float(float_op(a, b as f64)))
+        }
+        _ => Err(crate::vm_err("cannot perform arithmetic on non-numbers")),
     }
 }

fix-vm/src/instructions/builtins.rs

@@ -0,0 +1,447 @@
+use fix_builtins::PrimOpPhase;
+use fix_error::Error;
+use gc_arena::{Gc, Mutation, RefLock};
+use num_enum::TryFromPrimitive as _;
+use smallvec::SmallVec;
+
+use crate::value::*;
+use crate::{BytecodeReader, CallFrame, Step, Vm, VmRuntimeCtx, VmRuntimeCtxExt};
+
+impl<'gc> Vm<'gc> {
+    #[allow(clippy::too_many_lines)]
+    pub(crate) fn op_dispatch_primop(
+        &mut self,
+        ctx: &mut impl VmRuntimeCtx,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        use PrimOpPhase::*;
+        let phase_disc = reader.read_u8();
+        let Ok(phase) = PrimOpPhase::try_from_primitive(phase_disc) else {
+            return self.finish_err(Error::eval_error("invalid primop phase"));
+        };
+        match phase {
+            Abort => self.primop_abort(ctx, reader, mc),
+
+            DeepSeq => self.primop_deep_seq_force_top(reader, mc),
+            DeepSeqPush => self.primop_deep_seq_push(reader, mc),
+            DeepSeqLoop => self.primop_deep_seq_loop(reader, mc),
+            Seq => self.primop_seq(reader, mc),
+
+            FilterForceList => self.primop_filter_force_list(reader, mc),
+            FilterCallPred => self.primop_filter_call_pred(reader, mc),
+            FilterCheck => self.primop_filter_check(reader, mc),
+
+            ForceResultShallow => self.primop_force_result_shallow(ctx, reader, mc),
+            ForceResultShallowPush => self.primop_force_result_shallow_push(ctx, reader, mc),
+            ForceResultShallowLoop => self.primop_force_result_shallow_loop(reader, mc),
+            ForceResultDeepFinish => self.primop_force_result_deep_finish(ctx, reader, mc),
+
+            CallPattern => self.primop_call_pattern(ctx, reader, mc),
+
+            phase => todo!("primop phase {phase:?}"),
+        }
+    }
+
+    fn return_from_primop(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
+        let Some(CallFrame {
+            pc: ret_pc,
+            stack_depth: _,
+            thunk: _,
+            env,
+            with_env,
+        }) = self.call_stack.pop()
+        else {
+            unreachable!()
+        };
+        reader.set_pc(ret_pc);
+        self.call_depth -= 1;
+        self.env = env;
+        self.with_env = with_env;
+        Step::Continue(())
+    }
+
+    pub(crate) fn primop_filter_force_list(
+        &mut self,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        self.force_slot(0, reader, mc)?;
+        let list = match self.peek_forced(0).expect_gc::<List>() {
+            Ok(list) => list,
+            Err(got) => return self.finish_type_err(NixType::List, got),
+        };
+        if list.inner.borrow().is_empty() {
+            return self.return_from_primop(reader);
+        }
+        // prepare stack layout: [ pred list idx acc ]
+        self.push(Value::new_inline(0));
+        self.push(Value::new_gc(List::new_gc(mc)));
+        reader.set_pc(PrimOpPhase::FilterCallPred.ip() as usize);
+        Step::Continue(())
+    }
+
+    pub(crate) fn primop_filter_call_pred(
+        &mut self,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        self.force_slot(3, reader, mc)?;
+        let pred = self.peek_forced(3);
+        #[allow(clippy::unwrap_used)]
+        let idx = self.peek(1).as_inline::<i32>().unwrap();
+        #[allow(clippy::unwrap_used)]
+        let elem = self.peek_forced(2).as_gc::<List>().unwrap().inner.borrow()[idx as usize];
+        self.push(pred.relax());
+        self.call(reader, mc, elem, PrimOpPhase::FilterCheck.ip() as usize)
+    }
+
+    pub(crate) fn primop_filter_check(
+        &mut self,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        let ret = self.try_force::<bool>(reader, mc)?;
+        #[allow(clippy::unwrap_used)]
+        let idx = self.peek(1).as_inline::<i32>().unwrap();
+        #[allow(clippy::unwrap_used)]
+        let list = self.peek_forced(2).as_gc::<List>().unwrap();
+        let list = list.inner.borrow();
+        #[allow(clippy::unwrap_used)]
+        let acc = self.peek_forced(0).as_gc::<List>().unwrap();
+        if ret {
+            let mut acc = acc.unlock(mc).borrow_mut();
+            acc.push(list[idx as usize]);
+        }
+        if idx as usize == list.len() - 1 {
+            let acc = self.pop();
+            let _ = self.pop(); // idx
+            let _ = self.pop(); // list
+            let _ = self.pop(); // pred
+            self.push(acc);
+            return self.return_from_primop(reader);
+        }
+        self.replace(1, Value::new_inline(idx + 1));
+        reader.set_pc(PrimOpPhase::FilterCallPred.ip() as usize);
+        Step::Continue(())
+    }
+
+    pub(crate) fn primop_seq(
+        &mut self,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        // stack: [e1, e2] - force e1, return e2
+        self.force_slot(1, reader, mc)?;
+        let e2 = self.pop();
+        let _ = self.pop();
+        self.push(e2);
+        self.return_from_primop(reader)
+    }
+
+    pub(crate) fn primop_abort(
+        &mut self,
+        ctx: &mut impl VmRuntimeCtx,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        // stack: [msg] - force msg, then abort with it
+        self.force_slot(0, reader, mc)?;
+        let msg_val = self.peek_forced(0);
+        let msg = ctx.get_string(msg_val).unwrap_or("<non-string-value>");
+        self.finish_err(Error::eval_error(format!(
+            "evaluation aborted with the following error message: '{msg}'"
+        )))
+    }
+
+    pub(crate) fn primop_deep_seq_force_top(
+        &mut self,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        // stack: [e1, e2] - force e1, return e2
+        self.force_slot(1, reader, mc)?;
+
+        let e1 = self.peek_forced(1);
+
+        let children: SmallVec<_> = if let Some(attrs) = e1.as_gc::<AttrSet>() {
+            let attrs = attrs.entries.borrow();
+            if attrs.is_empty() {
+                SmallVec::new()
+            } else {
+                attrs.iter().map(|&(_, v)| v).collect()
+            }
+        } else if let Some(list) = e1.as_gc::<List<'gc>>() {
+            let inner = list.inner.borrow();
+            if inner.is_empty() {
+                SmallVec::new()
+            } else {
+                inner.iter().copied().collect()
+            }
+        } else {
+            SmallVec::new()
+        };
+
+        if children.is_empty() {
+            let e2 = self.pop();
+            let _ = self.pop();
+            self.push(e2);
+            return self.return_from_primop(reader);
+        }
+
+        let count = children.len() as i32;
+        let seen: Gc<'gc, List<'gc>> = Gc::new(mc, List::default());
+        let worklist: Gc<'gc, List<'gc>> = List::new(mc, children);
+
+        let e2 = self.pop();
+        let _ = self.pop();
+        self.push(e2);
+        self.push(Value::new_gc(seen));
+        self.push(Value::new_gc(worklist));
+        self.push(Value::new_inline(count));
+        reader.set_pc(PrimOpPhase::DeepSeqPush.ip() as usize);
+        Step::Continue(())
+    }
+
+    pub(crate) fn primop_deep_seq_push(
+        &mut self,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        // stack: [e2, seen, worklist, counter]
+        #[allow(clippy::unwrap_used)]
+        let counter = self.peek(0).as_inline::<i32>().unwrap();
+        if counter == 0 {
+            let _ = self.pop(); // counter
+            let _ = self.pop(); // worklist
+            let _ = self.pop(); // seen
+            return self.return_from_primop(reader);
+        }
+
+        #[allow(clippy::unwrap_used)]
+        let worklist = self.peek_forced(1).as_gc::<List<'gc>>().unwrap();
+        #[allow(clippy::unwrap_used)]
+        let item = worklist.unlock(mc).borrow_mut().pop().unwrap();
+        self.replace(0, Value::new_inline(counter - 1));
+        self.push(item);
+
+        // force item at TOS, resume at DeepSeqLoop after force
+        self.force_slot_to_pc(0, reader, mc, PrimOpPhase::DeepSeqLoop.ip() as usize)?;
+        reader.set_pc(PrimOpPhase::DeepSeqLoop.ip() as usize);
+        Step::Continue(())
+    }
+
+    pub(crate) fn primop_deep_seq_loop(
+        &mut self,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        // stack after pop: [e2, seen, worklist, counter]
+        let item = self.pop();
+        #[allow(clippy::unwrap_used)]
+        let counter = self.peek(0).as_inline::<i32>().unwrap();
+
+        let mut added: usize = 0;
+        if let Some(attrs) = item.as_gc::<AttrSet>() {
+            let attrs = attrs.entries.borrow();
+            #[allow(clippy::unwrap_used)]
+            let seen = self.peek_forced(2).as_gc::<List<'gc>>().unwrap();
+            if !self.is_value_in_seen(seen, item) {
+                self.add_value_to_seen(seen, mc, item);
+                #[allow(clippy::unwrap_used)]
+                let worklist = self.peek_forced(1).as_gc::<List<'gc>>().unwrap();
+                {
+                    let mut wl = worklist.unlock(mc).borrow_mut();
+                    for &(_, v) in attrs.iter() {
+                        wl.push(v);
+                    }
+                    added = attrs.len();
+                }
+            }
+        } else if let Some(list) = item.as_gc::<List<'gc>>() {
+            #[allow(clippy::unwrap_used)]
+            let seen = self.peek_forced(2).as_gc::<List<'gc>>().unwrap();
+            if !self.is_value_in_seen(seen, item) {
+                self.add_value_to_seen(seen, mc, item);
+                #[allow(clippy::unwrap_used)]
+                let worklist = self.peek_forced(1).as_gc::<List<'gc>>().unwrap();
+                {
+                    let inner = list.inner.borrow();
+                    let mut wl = worklist.unlock(mc).borrow_mut();
+                    for &v in inner.iter() {
+                        wl.push(v);
+                    }
+                    added = inner.len();
+                }
+            }
+        }
+
+        self.replace(0, Value::new_inline(counter + added as i32));
+        reader.set_pc(PrimOpPhase::DeepSeqPush.ip() as usize);
+        Step::Continue(())
+    }
+
+    pub(crate) fn primop_force_result_shallow(
+        &mut self,
+        ctx: &mut impl VmRuntimeCtx,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        self.force_slot(0, reader, mc)?;
+        let val = self.peek_forced(0);
+
+        let (count, has_children) = if let Some(attrs) = val.as_gc::<AttrSet>() {
+            let len = attrs.entries.borrow().len();
+            (len, len > 0)
+        } else if let Some(list) = val.as_gc::<List<'gc>>() {
+            let len = list.inner.borrow().len();
+            (len, len > 0)
+        } else {
+            (0, false)
+        };
+
+        if !has_children {
+            let val = self.pop();
+            return self.finish_ok(ctx.convert_value(val));
+        }
+
+        self.push(Value::new_inline(0i32));
+        self.push(Value::new_inline(count as i32));
+        reader.set_pc(PrimOpPhase::ForceResultShallowPush.ip() as usize);
+        Step::Continue(())
+    }
+
+    pub(crate) fn primop_force_result_shallow_push(
+        &mut self,
+        ctx: &mut impl VmRuntimeCtx,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        #[allow(clippy::unwrap_used)]
+        let idx = self.peek(1).as_inline::<i32>().unwrap();
+        #[allow(clippy::unwrap_used)]
+        let len = self.peek(0).as_inline::<i32>().unwrap();
+
+        if idx == len {
+            let _ = self.pop(); // len
+            let _ = self.pop(); // idx
+            let val = self.pop();
+            return self.finish_ok(ctx.convert_value(val));
+        }
+
+        let val = self.peek_forced(2);
+        let child = if let Some(attrs) = val.as_gc::<AttrSet>() {
+            attrs.entries.borrow().get(idx as usize).map(|&(_, v)| v)
+        } else if let Some(list) = val.as_gc::<List<'gc>>() {
+            list.inner.borrow().get(idx as usize).copied()
+        } else {
+            None
+        };
+
+        if let Some(child) = child {
+            self.replace(1, Value::new_inline(idx + 1));
+            self.push(child);
+            self.force_slot_to_pc(
+                0,
+                reader,
+                mc,
+                PrimOpPhase::ForceResultShallowLoop.ip() as usize,
+            )?;
+            reader.set_pc(PrimOpPhase::ForceResultShallowLoop.ip() as usize);
+        }
+        Step::Continue(())
+    }
+
+    pub(crate) fn primop_force_result_shallow_loop(
+        &mut self,
+        reader: &mut BytecodeReader<'_>,
+        _mc: &Mutation<'gc>,
+    ) -> Step {
+        let _ = self.pop(); // forced child
+        reader.set_pc(PrimOpPhase::ForceResultShallowPush.ip() as usize);
+        Step::Continue(())
+    }
+
+    pub(crate) fn primop_force_result_deep_finish(
+        &mut self,
+        ctx: &mut impl VmRuntimeCtx,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        let val = self.try_force::<StrictValue>(reader, mc)?;
+        self.finish_ok(ctx.convert_value(val.relax()))
+    }
+
+    pub(crate) fn primop_call_pattern(
+        &mut self,
+        ctx: &mut impl VmRuntimeCtx,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        let (func, attrset) = self.try_force::<(Gc<Closure>, Gc<AttrSet>)>(reader, mc)?;
+
+        let Closure {
+            ip,
+            n_locals,
+            env,
+            pattern,
+        } = *func;
+        let Some(pattern) = pattern else {
+            unreachable!()
+        };
+        // TODO: get function name
+        // TODO: param spans
+        if !pattern.ellipsis {
+            for key in pattern.required.iter().copied() {
+                if attrset.lookup(key).is_none() {
+                    let name = ctx.resolve_string(key);
+                    return self.finish_err(Error::eval_error(format!(
+                        "function 'anonymous lambda' called without required argument '{name}'"
+                    )));
+                }
+            }
+            for &(key, _) in attrset.entries.borrow().iter() {
+                let is_expected =
+                    pattern.required.contains(&key) || pattern.optional.contains(&key);
+                if !is_expected {
+                    let name = ctx.resolve_string(key);
+                    return self.finish_err(Error::eval_error(format!(
+                        "function 'anonymous lambda' called with unexpected argument '{name}'"
+                    )));
+                }
+            }
+        }
+
+        let new_env = Gc::new(
+            mc,
+            RefLock::new(Env::with_arg(Value::new_gc(attrset), n_locals, env)),
+        );
+        reader.set_pc(ip as usize);
+        self.env = new_env;
+
+        Step::Continue(())
+    }
+
+    fn is_value_in_seen(&self, seen: Gc<'gc, List<'gc>>, val: Value<'gc>) -> bool {
+        if !is_container(val) {
+            return false;
+        }
+        let target = val.to_bits();
+        for &v in seen.inner.borrow().iter() {
+            if v.to_bits() == target {
+                return true;
+            }
+        }
+        false
+    }
+
+    fn add_value_to_seen(&self, seen: Gc<'gc, List<'gc>>, mc: &Mutation<'gc>, val: Value<'gc>) {
+        if is_container(val) {
+            seen.unlock(mc).borrow_mut().push(val);
+        }
+    }
+}
+
+fn is_container(val: Value<'_>) -> bool {
+    val.is::<AttrSet>() || val.is::<List<'_>>()
+}

fix-vm/src/instructions/calls.rs

@@ -1,42 +1,40 @@
-use fix_bytecode::Continuation;
+use fix_builtins::PrimOpPhase;
 use fix_error::Error;
-use fix_runtime::{resolve_operand, *};
 use gc_arena::{Gc, Mutation, RefLock};
 
+use crate::value::*;
 use crate::{
     BytecodeReader, CallFrame, Closure, Env, ForceMode, Step, ThunkState, VmRuntimeCtx,
     VmRuntimeCtxExt,
 };
 
-#[inline(always)]
-#[expect(
-    clippy::indexing_slicing,
-    reason = "app.args is a fixed [Value; 3]; indices are bounded by primop arity (<= 3) validated at PrimOpApp construction"
-)]
-pub(crate) fn call<'gc, M: Machine<'gc>>(
-    m: &mut M,
+impl<'gc> crate::Vm<'gc> {
+    #[inline(always)]
+    pub(crate) fn call(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
         arg: Value<'gc>,
         resume_pc: usize,
-) -> Step {
-    let func = m.force_and_retry::<StrictValue>(reader, mc)?;
-    if m.call_depth() > 10000 {
-        return m.finish_err(Error::eval_error("stack overflow; max-call-depth exceeded"));
+    ) -> Step {
+        let func = self.try_force::<StrictValue>(reader, mc)?;
+        if self.call_depth > 10000 {
+            return self.finish_err(Error::eval_error("stack overflow; max-call-depth exceeded"));
         }
-    m.inc_call_depth();
-    if let Some(closure) = func.downcast::<Closure>() {
+        self.call_depth += 1;
+        if let Some(closure) = func.as_gc::<Closure>() {
             if closure.pattern.is_some() {
                 // FIXME: better DX...
-            m.push(func.relax());
-            m.push(arg);
-            m.push_call_frame(CallFrame {
+                self.push(func.relax());
+                self.push(arg);
+                self.call_stack.push(CallFrame {
                     pc: resume_pc,
+                    stack_depth: 0,
                     thunk: None,
-                env: m.env(),
-                depth: None,
+                    env: self.env,
+                    with_env: self.with_env,
                 });
-            reader.set_pc(Continuation::CallPattern.ip() as usize);
+                reader.set_pc(PrimOpPhase::CallPattern.ip() as usize);
                 return Step::Continue(());
             }
 
@@ -44,22 +42,24 @@ pub(crate) fn call<'gc, M: Machine<'gc>>(
             let n_locals = closure.n_locals;
             let env = closure.env;
             let new_env = Gc::new(mc, RefLock::new(Env::with_arg(arg, n_locals, env)));
-        m.push_call_frame(CallFrame {
+            self.call_stack.push(CallFrame {
                 pc: resume_pc,
+                stack_depth: 0,
                 thunk: None,
-            env: m.env(),
-            depth: None,
+                env: self.env,
+                with_env: self.with_env,
             });
             reader.set_pc(ip as usize);
-        m.set_env(new_env);
-    } else if let Some(primop) = func.downcast::<PrimOp>() {
+            self.env = new_env;
+        } else if let Some(primop) = func.as_inline::<PrimOp>() {
             if primop.arity == 1 {
-            m.push(arg);
-            m.push_call_frame(CallFrame {
+                self.push(arg);
+                self.call_stack.push(CallFrame {
                     pc: resume_pc,
+                    stack_depth: 0,
                     thunk: None,
-                env: m.env(),
-                depth: None,
+                    env: self.env,
+                    with_env: self.with_env,
                 });
                 reader.set_pc(primop.dispatch_ip as usize)
             } else {
@@ -68,104 +68,82 @@ pub(crate) fn call<'gc, M: Machine<'gc>>(
                     arity: primop.arity - 1,
                     args: [arg, Value::default(), Value::default()],
                 };
-            m.push(Value::new(Gc::new(mc, app)));
+                self.push(Value::new_gc(Gc::new(mc, app)));
             }
-    } else if let Some(app) = func.downcast::<PrimOpApp>() {
+        } else if let Some(app) = func.as_gc::<PrimOpApp>() {
             if app.arity == 1 {
                 for i in 0..app.primop.arity - 1 {
-                m.push(app.args[i as usize]);
+                    self.push(app.args[i as usize]);
                 }
-            m.push(arg);
-            m.push_call_frame(CallFrame {
+                self.push(arg);
+                self.call_stack.push(CallFrame {
                     pc: resume_pc,
+                    stack_depth: 0,
                     thunk: None,
-                env: m.env(),
-                depth: None,
+                    env: self.env,
+                    with_env: self.with_env,
                 });
                 reader.set_pc(app.primop.dispatch_ip as usize)
             } else {
-            let position = (app.primop.arity - app.arity) as usize;
-            let mut new_app = PrimOpApp {
+                let new_app = PrimOpApp {
                     arity: app.arity - 1,
                     ..*app
                 };
-            new_app.args[position] = arg;
-            m.push(Value::new(Gc::new(mc, new_app)))
+                self.push(Value::new_gc(Gc::new(mc, new_app)))
             }
-    } else if let Some(attrs) = func.downcast::<AttrSet>()
-        && let Some(functor) = attrs.lookup(m.functor_sym())
-    {
-        // f arg  =>  (f.__functor f) arg
-        //
-        // Stage the work for `CallFunctor1` so retries during force are
-        // safe: the stack invariant `[..., orig_arg, self, functor]`
-        // holds every time control re-enters phase 1.
-        m.dec_call_depth();
-        m.push_call_frame(CallFrame {
-            pc: resume_pc,
-            thunk: None,
-            env: m.env(),
-            depth: None,
-        });
-        m.push(arg);
-        m.push(func.relax());
-        m.push(functor);
-        reader.set_pc(Continuation::CallFunctor1.ip() as usize);
-        return Step::Continue(());
         } else {
-        return m.finish_err(Error::eval_error(format!(
-            "attempt to call something which is not a function but {}",
-            func.ty()
-        )));
+            todo!("call other types: {func:?}")
         }
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_call<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_call(
+        &mut self,
         ctx: &impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    let arg = resolve_operand(&reader.read_operand_data(), mc, ctx, m);
+    ) -> Step {
+        let arg = reader.read_operand_data(ctx).resolve(mc, self);
         let pc = reader.pc();
-    m.call(reader, mc, arg, pc)
-}
+        self.call(reader, mc, arg, pc)
+    }
 
-#[inline(always)]
-pub(crate) fn op_return<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_return(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
+    ) -> Step {
+        let val = self.try_force::<StrictValue>(reader, mc)?;
         let Some(CallFrame {
             pc: ret_pc,
+            stack_depth,
             thunk,
             env,
-        depth,
-    }) = m.pop_call_frame()
+            with_env,
+        }) = self.call_stack.pop()
         else {
-        match m.force_mode() {
-            ForceMode::AsIs => return m.finish_ok(ctx.convert_value(val.relax())),
+            match self.force_mode {
+                ForceMode::AsIs => return self.finish_ok(ctx.convert_value(val.relax())),
                 ForceMode::Shallow => {
-                m.push(val.relax());
-                reader.set_pc(Continuation::ForceResultShallow.ip() as usize);
+                    self.push(val.relax());
+                    reader.set_pc(PrimOpPhase::ForceResultShallow.ip() as usize);
                     return Step::Continue(());
                 }
                 ForceMode::Deep => {
-                m.push(val.relax());
-                m.push(val.relax());
-                m.push_call_frame(CallFrame {
-                    pc: Continuation::ForceResultDeepFinish.ip() as usize,
+                    self.push(val.relax());
+                    self.push(val.relax());
+                    self.call_stack.push(CallFrame {
+                        pc: PrimOpPhase::ForceResultDeepFinish.ip() as usize,
+                        stack_depth: 0,
                         thunk: None,
-                    env: m.env(),
-                    depth: None,
+                        env: self.env,
+                        with_env: self.with_env,
                     });
-                m.inc_call_depth();
-                reader.set_pc(Continuation::PDeepSeq0.ip() as usize);
+                    self.call_depth += 1;
+                    reader.set_pc(PrimOpPhase::DeepSeq.ip() as usize);
                     return Step::Continue(());
                 }
             }
@@ -173,23 +151,13 @@ pub(crate) fn op_return<'gc, M: Machine<'gc>>(
         reader.set_pc(ret_pc);
         if let Some(outer_thunk) = thunk {
             *outer_thunk.borrow_mut(mc) = ThunkState::Evaluated(val);
-        if let Some(depth) = depth {
-            m.replace(depth, val.relax());
-        }
+            self.replace(stack_depth, val.relax());
         } else {
-        m.dec_call_depth();
-        m.push(val.relax())
+            self.call_depth -= 1;
+            self.push(val.relax())
         }
-    m.set_env(env);
+        self.env = env;
+        self.with_env = with_env;
         Step::Continue(())
-}
-
-#[inline(always)]
-pub(crate) fn op_dispatch_cont<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    crate::primops::dispatch_cont(m, ctx, reader, mc)
+    }
 }

fix-vm/src/instructions/closures.rs

@@ -1,32 +1,33 @@
-use fix_runtime::Machine;
 use gc_arena::{Gc, Mutation, RefLock};
 
 use crate::{BytecodeReader, Step, ThunkState, Value};
 
-#[inline(always)]
-pub(crate) fn op_make_thunk<'gc, M: Machine<'gc>>(
-    m: &mut M,
+impl<'gc> crate::Vm<'gc> {
+    #[inline(always)]
+    pub(crate) fn op_make_thunk(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let entry_point = reader.read_u32();
         let thunk = Gc::new(
             mc,
             RefLock::new(ThunkState::Pending {
                 ip: entry_point as usize,
-            env: m.env(),
+                env: self.env,
+                with_env: self.with_env,
             }),
         );
-    m.push(Value::new(thunk));
+        self.push(Value::new_gc(thunk));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_make_closure<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_make_closure(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let entry_point = reader.read_u32();
         let n_locals = reader.read_u32();
         let closure = Gc::new(
@@ -34,20 +35,20 @@ pub(crate) fn op_make_closure<'gc, M: Machine<'gc>>(
             crate::Closure {
                 ip: entry_point,
                 n_locals,
-            env: m.env(),
+                env: self.env,
                 pattern: None,
             },
         );
-    m.push(Value::new(closure));
+        self.push(Value::new_gc(closure));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_make_pattern_closure<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_make_pattern_closure(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let entry_point = reader.read_u32();
         let n_locals = reader.read_u32();
         let req_count = reader.read_u16() as usize;
@@ -84,10 +85,11 @@ pub(crate) fn op_make_pattern_closure<'gc, M: Machine<'gc>>(
             crate::Closure {
                 ip: entry_point,
                 n_locals,
-            env: m.env(),
+                env: self.env,
                 pattern: Some(pattern),
             },
         );
-    m.push(Value::new(closure));
+        self.push(Value::new_gc(closure));
         Step::Continue(())
+    }
 }

fix-vm/src/instructions/collections.rs

@@ -1,136 +1,112 @@
+use fix_common::StringId;
 use fix_error::Error;
-use fix_lang::StringId;
-use fix_runtime::{Machine, MachineExt, NixType, resolve_operand};
 use gc_arena::{Gc, RefLock};
 use smallvec::SmallVec;
 
+use crate::value::NixType;
 use crate::{
-    AttrSet, BytecodeReader, List, Step, StrictValue, Value, VmRuntimeCtx, VmRuntimeCtxExt,
+    AttrKeyData, AttrSet, BytecodeReader, List, OperandData, Step, StrictValue, Value,
+    VmRuntimeCtx, VmRuntimeCtxExt,
 };
 
-#[inline(always)]
-pub(crate) fn op_make_attrs<'gc, M: Machine<'gc>>(
-    m: &mut M,
+impl<'gc> crate::Vm<'gc> {
+    #[inline(always)]
+    pub(crate) fn op_make_attrs(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &gc_arena::Mutation<'gc>,
-) -> Step {
-    let static_count = reader.read_u32() as usize;
-    let dynamic_count = reader.read_u32() as usize;
-
-    for i in 0..dynamic_count {
-        let depth = dynamic_count - 1 - i;
-        m.force_slot_to_pc(depth, reader, mc, reader.inst_start_pc())?;
+    ) -> Step {
+        let count = reader.read_u32() as usize;
+        let mut entries: SmallVec<[AttrEntry; 4]> = SmallVec::with_capacity(count);
+        for _ in 0..count {
+            let key = reader.read_attr_key_data();
+            let val = reader.read_operand_data(ctx);
+            let _span_id = reader.read_u32();
+            entries.push(AttrEntry { key, val });
+        }
+        let mut kv: SmallVec<[(crate::StringId, Value); 4]> = SmallVec::with_capacity(count);
+        for entry in &entries {
+            let key_sid = match &entry.key {
+                AttrKeyData::Static(sid) => *sid,
+                AttrKeyData::Dynamic => {
+                    todo!()
                 }
-
-    let mut dyn_keys: SmallVec<[_; 2]> = SmallVec::with_capacity(dynamic_count);
-    for i in 0..dynamic_count {
-        let depth = dynamic_count - 1 - i;
-        let key_val = m.peek_forced(depth);
-        let key_sid = match ctx.get_string_id(key_val) {
-            Ok(id) => Some(id),
-            Err(NixType::Null) => None,
-            Err(got) => return m.finish_type_err(NixType::String, got),
             };
-        dyn_keys.push(key_sid);
+            let val = entry.val.resolve(mc, self);
+            kv.push((key_sid, val));
         }
-
-    m.drop_n(dynamic_count);
-
-    let mut kv: SmallVec<[(crate::StringId, Value); 4]> =
-        SmallVec::with_capacity(static_count + dynamic_count);
-
-    for _ in 0..static_count {
-        let key = reader.read_string_id();
-        let val = resolve_operand(&reader.read_operand_data(), mc, ctx, m);
-        let _span_id = reader.read_u32();
-        kv.push((key, val));
-    }
-
-    for key in dyn_keys {
-        let val = resolve_operand(&reader.read_operand_data(), mc, ctx, m);
-        let _span_id = reader.read_u32();
-        if let Some(key) = key {
-            kv.push((key, val))
-        }
-    }
-
         kv.sort_by_key(|(k, _)| *k);
         let attrs = Gc::new(mc, AttrSet::from_sorted_unchecked(kv));
-    m.push(Value::new(attrs));
+        self.push(Value::new_gc(attrs));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_make_empty_attrs<'gc, M: Machine<'gc>>(m: &mut M) -> Step {
-    m.push(m.empty_attrs());
+    #[inline(always)]
+    pub(crate) fn op_make_empty_attrs(&mut self) -> Step {
+        self.push(self.empty_attrs);
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_select_static<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_select_static(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &gc_arena::Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let _span_id = reader.read_u32();
         let key = reader.read_string_id();
 
-    let attrset = m.force_and_retry::<Gc<AttrSet>>(reader, mc)?;
+        let attrset = self.try_force::<Gc<AttrSet>>(reader, mc)?;
 
         match attrset.lookup(key) {
             Some(v) => {
-            m.push(v);
+                self.push(v);
             }
-        None => return select_skip(m, key, ctx, reader),
+            None => return self.select_skip(key, ctx, reader),
         }
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_select_dynamic<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_select_dynamic(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &gc_arena::Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let _span_id = reader.read_u32();
 
-    let (attrset, key_val) = m.force_and_retry::<(Gc<AttrSet>, StrictValue)>(reader, mc)?;
+        let (attrset, key_val) = self.try_force::<(Gc<AttrSet>, StrictValue)>(reader, mc)?;
 
         let key_sid = match ctx.get_string_id(key_val) {
             Ok(id) => id,
-        Err(got) => return m.finish_type_err(NixType::String, got),
+            Err(got) => return self.finish_type_err(NixType::String, got),
         };
 
         match attrset.lookup(key_sid) {
             Some(v) => {
-            m.push(v);
+                self.push(v);
             }
-        None => return select_skip(m, key_sid, ctx, reader),
+            None => return self.select_skip(key_sid, ctx, reader),
         }
         Step::Continue(())
-}
+    }
 
-/// Skip the rest of a **Select** attrpath after a missing attribute.
-/// Only recognises Select opcodes and jumps; encountering any other
-/// opcode means we've reached the end of the select sequence and
-/// should report the missing-attribute error.
-#[expect(
-    clippy::cast_sign_loss,
-    reason = "jump target = pc + offset is a non-negative bytecode address by codegen invariant"
-)]
-fn select_skip<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    /// Skip the rest of a **Select** attrpath after a missing attribute.
+    /// Only recognises Select opcodes and jumps; encountering any other
+    /// opcode means we've reached the end of the select sequence and
+    /// should report the missing-attribute error.
+    fn select_skip(
+        &mut self,
         key: StringId,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
-) -> Step {
-    use fix_bytecode::Op::*;
+    ) -> Step {
+        use fix_codegen::Op::*;
         loop {
             match reader.read_op() {
-            // Skip rest of the attrpath
                 SelectStatic => {
                     reader.set_pc(reader.pc() + 4 + 4);
                 }
@@ -141,34 +117,23 @@ fn select_skip<'gc, M: Machine<'gc>>(
                     reader.set_pc(reader.pc() + 4);
                     break Step::Continue(());
                 }
-
-            // Default (`a.b or c`)
                 JumpIfSelectFailed => {
                     let offset = reader.read_i32();
                     reader.set_pc(((reader.pc() as isize) + (offset as isize)) as usize);
                 }
-
-            // Report error
                 _ => {
                     let name = ctx.resolve_string(key);
-                return m.finish_err(Error::eval_error(format!("attribute '{name}' missing")));
+                    return self
+                        .finish_err(Error::eval_error(format!("attribute '{name}' missing")));
+                }
             }
         }
     }
-}
 
-/// Skip the rest of a **HasAttr** attrpath after an intermediate
-/// lookup failed. Only recognises HasAttr opcodes and jumps.
-#[expect(
-    clippy::cast_sign_loss,
-    reason = "jump target = pc + offset is a non-negative bytecode address by codegen invariant"
-)]
-#[expect(
-    clippy::unreachable,
-    reason = "has_attr_skip only runs over a codegen-produced HasAttr attrpath sequence; any other opcode is a codegen bug"
-)]
-fn has_attr_skip(reader: &mut BytecodeReader<'_>) -> Step {
-    use fix_bytecode::Op::*;
+    /// Skip the rest of a **HasAttr** attrpath after an intermediate
+    /// lookup failed. Only recognises HasAttr opcodes and jumps.
+    fn has_attr_skip(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
+        use fix_codegen::Op::*;
         loop {
             match reader.read_op() {
                 HasAttrPathStatic => {
@@ -197,96 +162,86 @@ fn has_attr_skip(reader: &mut BytecodeReader<'_>) -> Step {
                 }
             }
         }
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_has_attr_path_static<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_has_attr_path_static(
+        &mut self,
         _ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &gc_arena::Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let _span_id = reader.read_u32();
         let key = reader.read_string_id();
 
-    let current = m.force_and_retry::<StrictValue>(reader, mc)?;
+        let current = self.try_force::<StrictValue>(reader, mc)?;
 
         match current
-        .downcast::<AttrSet>()
+            .as_gc::<AttrSet>()
             .and_then(|attrs| attrs.lookup(key))
         {
             Some(v) => {
-            m.push(v);
+                self.push(v);
             }
-        None => return has_attr_skip(reader),
+            None => return self.has_attr_skip(reader),
         }
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_has_attr_path_dynamic<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_has_attr_path_dynamic(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &gc_arena::Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let _span_id = reader.read_u32();
 
-    let (current, key_val) = m.force_and_retry::<(StrictValue, StrictValue)>(reader, mc)?;
+        let (current, key_val) = self.try_force::<(StrictValue, StrictValue)>(reader, mc)?;
 
         let key_sid = match ctx.get_string_id(key_val) {
             Ok(id) => id,
-        Err(got) => return m.finish_type_err(NixType::String, got),
+            Err(got) => return self.finish_type_err(NixType::String, got),
         };
 
         match current
-        .downcast::<AttrSet>()
+            .as_gc::<AttrSet>()
             .and_then(|attrs| attrs.lookup(key_sid))
         {
             Some(v) => {
-            m.push(v);
+                self.push(v);
             }
-        None => return has_attr_skip(reader),
+            None => return self.has_attr_skip(reader),
         }
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_jump_if_select_failed<'gc, M: Machine<'gc>>(
-    _m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-) -> Step {
+    #[inline(always)]
+    pub(crate) fn op_jump_if_select_failed(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
         // No-op
         let _offset = reader.read_i32();
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-#[expect(
-    clippy::cast_sign_loss,
-    reason = "jump target = pc + offset is a non-negative bytecode address by codegen invariant"
-)]
-pub(crate) fn op_jump_if_select_succeeded<'gc, M: Machine<'gc>>(
-    _m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-) -> Step {
+    #[inline(always)]
+    pub(crate) fn op_jump_if_select_succeeded(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
         let offset = reader.read_i32();
         reader.set_pc(((reader.pc() as isize) + (offset as isize)) as usize);
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_has_attr_static<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_has_attr_static(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &gc_arena::Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let key = reader.read_string_id();
-    let current = m.force_and_retry::<StrictValue>(reader, mc)?;
+        let current = self.try_force::<StrictValue>(reader, mc)?;
 
-    m.push(Value::new(
+        self.push(Value::new_inline(
             current
-            .downcast::<AttrSet>()
+                .as_gc::<AttrSet>()
                 .and_then(|attrs| attrs.lookup(key))
                 .is_some(),
         ));
@@ -294,25 +249,25 @@ pub(crate) fn op_has_attr_static<'gc, M: Machine<'gc>>(
         reader.set_pc(reader.pc() + 1);
 
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_has_attr_dynamic<'gc, M: MachineExt<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_has_attr_dynamic(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &gc_arena::Mutation<'gc>,
-) -> Step {
-    let (current, dyn_key) = m.force_and_retry::<(StrictValue, StrictValue)>(reader, mc)?;
+    ) -> Step {
+        let (current, dyn_key) = self.try_force::<(StrictValue, StrictValue)>(reader, mc)?;
 
         let key_sid = match ctx.get_string_id(dyn_key) {
             Ok(id) => id,
-        Err(got) => return m.finish_type_err(NixType::String, got),
+            Err(got) => return self.finish_type_err(NixType::String, got),
         };
 
-    m.push(Value::new(
+        self.push(Value::new_inline(
             current
-            .downcast::<AttrSet>()
+                .as_gc::<AttrSet>()
                 .and_then(|attrs| attrs.lookup(key_sid))
                 .is_some(),
         ));
@@ -320,26 +275,26 @@ pub(crate) fn op_has_attr_dynamic<'gc, M: MachineExt<'gc>>(
         reader.set_pc(reader.pc() + 1);
 
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_has_attr_resolve<'gc, M: Machine<'gc>>(m: &mut M) -> Step {
+    #[inline(always)]
+    pub(crate) fn op_has_attr_resolve(&mut self) -> Step {
         // If we reach here, has_attr check has failed, push false (AttrSet is already popped)
-    m.push(Value::new(false));
+        self.push(Value::new_inline(false));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_make_list<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_make_list(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &gc_arena::Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let count = reader.read_u32() as usize;
         let mut items: SmallVec<[Value; 4]> = SmallVec::with_capacity(count);
         for _ in 0..count {
-        items.push(resolve_operand(&reader.read_operand_data(), mc, ctx, m));
+            items.push(reader.read_operand_data(ctx).resolve(mc, self));
         }
         let list = Gc::new(
             mc,
@@ -347,12 +302,18 @@ pub(crate) fn op_make_list<'gc, M: Machine<'gc>>(
                 inner: RefLock::new(items),
             },
         );
-    m.push(Value::new(list));
+        self.push(Value::new_gc(list));
         Step::Continue(())
+    }
+
+    #[inline(always)]
+    pub(crate) fn op_make_empty_list(&mut self) -> Step {
+        self.push(self.empty_list);
+        Step::Continue(())
+    }
 }
 
-#[inline(always)]
-pub(crate) fn op_make_empty_list<'gc, M: Machine<'gc>>(m: &mut M) -> Step {
-    m.push(m.empty_list());
-    Step::Continue(())
+pub(crate) struct AttrEntry {
+    pub(crate) key: AttrKeyData,
+    pub(crate) val: OperandData,
 }

fix-vm/src/instructions/control.rs

@@ -1,70 +1,46 @@
-use fix_error::Error;
-use fix_runtime::*;
-use gc_arena::Mutation;
+use crate::value::*;
+use crate::{BytecodeReader, Step};
 
-use crate::{BytecodeReader, Step, VmRuntimeCtx};
-
-#[inline(always)]
-#[expect(
-    clippy::cast_sign_loss,
-    reason = "jump target = pc + offset is a non-negative bytecode address by codegen invariant"
-)]
-pub(crate) fn op_jump_if_false<'gc, M: Machine<'gc>>(
-    m: &mut M,
+impl<'gc> crate::Vm<'gc> {
+    #[inline(always)]
+    pub(crate) fn op_jump_if_false(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &gc_arena::Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let offset = reader.read_i32();
-    let cond = m.force_and_retry::<StrictValue>(reader, mc)?;
-    if cond.downcast::<bool>() == Some(false) {
+        let cond = self.try_force::<StrictValue>(reader, mc)?;
+        if cond.as_inline::<bool>() == Some(false) {
             reader.set_pc(((reader.pc() as isize) + (offset as isize)) as usize);
         }
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-#[expect(
-    clippy::cast_sign_loss,
-    reason = "jump target = pc + offset is a non-negative bytecode address by codegen invariant"
-)]
-pub(crate) fn op_jump_if_true<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_jump_if_true(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
+        mc: &gc_arena::Mutation<'gc>,
+    ) -> Step {
         let offset = reader.read_i32();
-    let cond = m.force_and_retry::<StrictValue>(reader, mc)?;
-    if cond.downcast::<bool>() == Some(true) {
+        let cond = self.try_force::<StrictValue>(reader, mc)?;
+        if cond.as_inline::<bool>() == Some(true) {
             reader.set_pc(((reader.pc() as isize) + (offset as isize)) as usize);
         }
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-#[expect(
-    clippy::cast_sign_loss,
-    reason = "jump target = pc + offset is a non-negative bytecode address by codegen invariant"
-)]
-pub(crate) fn op_jump<'gc, M: Machine<'gc>>(_m: &mut M, reader: &mut BytecodeReader<'_>) -> Step {
+    #[inline(always)]
+    pub(crate) fn op_jump(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
         let offset = reader.read_i32();
         reader.set_pc(((reader.pc() as isize) + (offset as isize)) as usize);
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_assert<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let raw_id = reader.read_string_id();
-    let raw = ctx.resolve_string(raw_id);
+    #[inline(always)]
+    pub(crate) fn op_assert(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
+        let _raw_idx = reader.read_u32();
         let _span_id = reader.read_u32();
-    let assertion = m.force_and_retry::<bool>(reader, mc)?;
-    if !assertion {
-        // FIXME: use catchable error
-        return m.finish_err(Error::eval_error(format!("assertion '{raw}' failed")));
+        todo!("implement Assert (force TOS)");
     }
-    Step::Continue(())
 }

fix-vm/src/instructions/literals.rs

@@ -1,63 +1,55 @@
-use fix_runtime::Machine;
 use gc_arena::{Gc, Mutation};
 
 use crate::{BytecodeReader, Step, Value};
 
-#[inline(always)]
-pub(crate) fn op_push_smi<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-) -> Step {
+impl<'gc> crate::Vm<'gc> {
+    #[inline(always)]
+    pub(crate) fn op_push_smi(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
         let val = reader.read_i32();
-    m.push(Value::new(val));
+        self.push(Value::new_inline(val));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_push_bigint<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_push_bigint(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let val = reader.read_i64();
-    m.push(Value::new(Gc::new(mc, val)));
+        self.push(Value::new_gc(Gc::new(mc, val)));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_push_float<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-) -> Step {
+    #[inline(always)]
+    pub(crate) fn op_push_float(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
         let val = reader.read_f64();
-    m.push(Value::new(val));
+        self.push(Value::new_float(val));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_push_string<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-) -> Step {
+    #[inline(always)]
+    pub(crate) fn op_push_string(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
         let sid = reader.read_string_id();
-    m.push(Value::new(sid));
+        self.push(Value::new_inline(sid));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_push_null<'gc, M: Machine<'gc>>(m: &mut M) -> Step {
-    m.push(Value::new(crate::Null));
+    #[inline(always)]
+    pub(crate) fn op_push_null(&mut self) -> Step {
+        self.push(Value::new_inline(crate::Null));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_push_true<'gc, M: Machine<'gc>>(m: &mut M) -> Step {
-    m.push(Value::new(true));
+    #[inline(always)]
+    pub(crate) fn op_push_true(&mut self) -> Step {
+        self.push(Value::new_inline(true));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_push_false<'gc, M: Machine<'gc>>(m: &mut M) -> Step {
-    m.push(Value::new(false));
+    #[inline(always)]
+    pub(crate) fn op_push_false(&mut self) -> Step {
+        self.push(Value::new_inline(false));
         Step::Continue(())
+    }
 }

fix-vm/src/instructions/misc.rs

@@ -1,183 +1,64 @@
-use std::path::PathBuf;
+use fix_builtins::BuiltinId;
+use num_enum::TryFromPrimitive;
 
-use fix_bytecode::Continuation;
-use fix_error::Error;
-use fix_lang::{BuiltinId, StringId};
-use fix_runtime::{
-    AttrSet, Machine, MachineExt, NixString, Path, StrictValue, StringContext, canon_path_str,
-};
+use crate::{BytecodeReader, PrimOp, Step, Value, VmRuntimeCtx};
 
-use crate::{BytecodeReader, PrimOp, Step, Value, VmRuntimeCtx, VmRuntimeCtxExt};
-
-#[inline(always)]
-pub(crate) fn op_load_builtins<'gc, M: Machine<'gc>>(m: &mut M) -> Step {
-    m.push(m.builtins().into());
+impl<'gc> crate::Vm<'gc> {
+    #[inline(always)]
+    pub(crate) fn op_load_builtins(&mut self) -> Step {
+        self.push(self.builtins);
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-#[expect(
-    clippy::panic,
-    reason = "codegen only emits LoadBuiltin with valid BuiltinId bytes; an unknown id is a codegen/bytecode-corruption bug"
-)]
-pub(crate) fn op_load_builtin<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-) -> Step {
-    let Ok(id) = BuiltinId::try_from(reader.read_u8())
+    #[inline(always)]
+    pub(crate) fn op_load_builtin(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
+        let Ok(id) = BuiltinId::try_from_primitive(reader.read_u8())
             .map_err(|err| panic!("unknown builtin id: {}", err.number));
-    m.push(Value::new(PrimOp {
+        self.push(Value::new_inline(PrimOp {
             id,
-        arity: id.info().arity,
-        dispatch_ip: Continuation::entry_for_builtin(id).ip(),
+            arity: fix_builtins::BUILTINS[id as usize].1,
+            dispatch_ip: id.entry_phase().ip(),
         }));
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_load_repl_binding<'gc, M: Machine<'gc>>(
-    _m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-) -> Step {
+    #[inline(always)]
+    pub(crate) fn op_mk_pos(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
+        let _span_id = reader.read_u32();
+        todo!("MkPos");
+    }
+
+    #[inline(always)]
+    pub(crate) fn op_load_repl_binding(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
         let _name = reader.read_string_id();
         todo!("LoadReplBinding");
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_load_scoped_binding<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &impl VmRuntimeCtx,
+    #[inline(always)]
+    pub(crate) fn op_load_scoped_binding(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
+        let _name = reader.read_string_id();
+        todo!("LoadScopedBinding");
+    }
+
+    #[inline(always)]
+    pub(crate) fn op_concat_strings(
+        &mut self,
+        ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         _mc: &gc_arena::Mutation<'gc>,
-) -> Step {
-    let slot_id = reader.read_u32();
-    let name = reader.read_string_id();
-    let scope = m.scope_slot(slot_id);
-    let Some(attrs) = scope.downcast::<AttrSet>() else {
-        return m.finish_err(Error::eval_error("internal: scope slot is not an attrset"));
-    };
-    match attrs.lookup(name) {
-        Some(val) => {
-            m.push(val);
-            Step::Continue(())
-        }
-        None => m.finish_err(Error::eval_error(format!(
-            "scoped binding '{}' not found",
-            ctx.resolve_string(name)
-        ))),
-    }
-}
-
-#[inline(always)]
-pub(crate) fn op_coerce_to_string<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &gc_arena::Mutation<'gc>,
-) -> Step {
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    if val.is::<StringId>() || val.is::<NixString>() {
-        m.push(val.relax());
-    } else if let Some(p) = val.downcast::<Path>() {
-        // Coercing a path to a string yields the canonical path text.
-        // FIXME: copy to store
-        m.push(Value::new(p.0));
-    } else {
-        todo!("coerce other types to string: {:?}", val.ty());
-    }
-    Step::Continue(())
-}
-
-#[inline(always)]
-pub(crate) fn op_concat_strings<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &gc_arena::Mutation<'gc>,
-) -> Step {
-    let count = reader.read_u16() as usize;
+    ) -> Step {
+        let _parts_count = reader.read_u16() as usize;
         let _force_string = reader.read_u8() != 0;
-
-    let mut total_len = 0;
-    let mut has_any_context = false;
-    for i in 0..count {
-        let val = m.peek_forced(count - 1 - i);
-        let s = ctx.get_string(val).expect("coerced");
-        total_len += s.len();
-        if !ctx.get_string_context(val).is_empty() {
-            has_any_context = true;
+        let mut _operands: smallvec::SmallVec<[crate::OperandData; 4]> =
+            smallvec::SmallVec::with_capacity(_parts_count);
+        for _ in 0.._parts_count {
+            _operands.push(reader.read_operand_data(ctx));
         }
+        todo!("implement ConcatStrings (force parts, coerce to string, concatenate)");
     }
 
-    let mut result = String::with_capacity(total_len);
-    let mut merged = StringContext::new();
-    for i in 0..count {
-        let val = m.peek_forced(count - 1 - i);
-        let s = ctx.get_string(val).expect("coerced");
-        result.push_str(s);
-        if has_any_context {
-            let ctx = ctx.get_string_context(val);
-            if !ctx.is_empty() {
-                merged = merged.merge(ctx);
+    #[inline(always)]
+    pub(crate) fn op_resolve_path(&mut self, _ctx: &mut impl VmRuntimeCtx) -> Step {
+        todo!("implement ResolvePath");
     }
-        }
-    }
-
-    m.drop_n(count);
-
-    if merged.is_empty() {
-        let sid = ctx.intern_string(result);
-        m.push(Value::new(sid));
-    } else {
-        let ns = gc_arena::Gc::new(mc, NixString::with_context(result, merged));
-        m.push(Value::new(ns));
-    }
-    Step::Continue(())
-}
-
-#[inline(always)]
-pub(crate) fn op_resolve_path<'gc, M: MachineExt<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &gc_arena::Mutation<'gc>,
-) -> Step {
-    let path_val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    let dir_id = reader.read_string_id();
-    // Already a path: keep as-is. ResolvePath is idempotent on paths.
-    if let Some(p) = path_val.downcast::<Path>() {
-        m.push(Value::new(p));
-        return Step::Continue(());
-    }
-    let path = match ctx.get_string(path_val) {
-        Some(s) => s.to_owned(),
-        None => {
-            return m.finish_err(Error::eval_error(format!(
-                "expected a string for path, got {}",
-                path_val.ty()
-            )));
-        }
-    };
-    let resolved = match resolve_path_str(ctx.resolve_string(dir_id), &path) {
-        Ok(s) => s,
-        Err(e) => return m.finish_err(e),
-    };
-    let sid = ctx.intern_string(resolved);
-    m.push(Value::new(Path(sid)));
-    Step::Continue(())
-}
-
-fn resolve_path_str(current_dir: &str, path: &str) -> Result<String, Box<Error>> {
-    let raw = if path.starts_with('/') {
-        return Ok(canon_path_str(path));
-    } else if let Some(rest) = path.strip_prefix("~/") {
-        let mut dir =
-            std::env::home_dir().ok_or_else(|| Error::eval_error("home dir not defined"))?;
-        dir.push(rest);
-        dir
-    } else {
-        let mut dir = PathBuf::from(current_dir);
-        dir.push(path);
-        dir
-    };
-    Ok(canon_path_str(&raw))
 }

fix-vm/src/instructions/mod.rs

@@ -1,4 +1,5 @@
 pub(crate) mod arithmetic;
+pub(crate) mod builtins;
 pub(crate) mod calls;
 pub(crate) mod closures;
 pub(crate) mod collections;
@@ -7,13 +8,3 @@ pub(crate) mod literals;
 pub(crate) mod misc;
 pub(crate) mod variables;
 pub(crate) mod with_scope;
-
-pub(crate) use arithmetic::*;
-pub(crate) use calls::*;
-pub(crate) use closures::*;
-pub(crate) use collections::*;
-pub(crate) use control::*;
-pub(crate) use literals::*;
-pub(crate) use misc::*;
-pub(crate) use variables::*;
-pub(crate) use with_scope::*;

fix-vm/src/instructions/variables.rs

@@ -1,68 +1,50 @@
-use fix_runtime::Machine;
-
 use crate::{BytecodeReader, Mutation, Step, Value};
 
-#[inline(always)]
-#[expect(
-    clippy::indexing_slicing,
-    reason = "local slot index is produced by codegen and bounded by the frame's AllocLocals count"
-)]
-pub(crate) fn op_load_local<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-) -> Step {
+impl<'gc> crate::Vm<'gc> {
+    #[inline(always)]
+    pub(crate) fn op_load_local(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
         let idx = reader.read_u32() as usize;
-    m.push(m.env().borrow().locals[idx]);
+        self.push(self.env.borrow().locals[idx]);
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-#[expect(
-    clippy::indexing_slicing,
-    reason = "local slot index is produced by codegen and bounded by the target frame's AllocLocals count"
-)]
-pub(crate) fn op_load_outer<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-) -> Step {
+    #[inline(always)]
+    pub(crate) fn op_load_outer(&mut self, reader: &mut BytecodeReader<'_>) -> Step {
         let layer = reader.read_u8();
         let idx = reader.read_u32() as usize;
-    let mut cur = m.env();
+        let mut cur = self.env;
         for _ in 0..layer {
             let prev = cur.borrow().prev.expect("LoadOuter: env chain too short");
             cur = prev;
         }
         let val = cur.borrow().locals[idx];
-    m.push(val);
+        self.push(val);
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-#[expect(
-    clippy::indexing_slicing,
-    reason = "local slot index is produced by codegen and bounded by the frame's AllocLocals count"
-)]
-pub(crate) fn op_store_local<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_store_local(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let idx = reader.read_u32() as usize;
-    let val = m.pop();
-    m.env().borrow_mut(mc).locals[idx] = val;
+        let val = self.pop();
+        self.env.borrow_mut(mc).locals[idx] = val;
         Step::Continue(())
-}
+    }
 
-#[inline(always)]
-pub(crate) fn op_alloc_locals<'gc, M: Machine<'gc>>(
-    m: &mut M,
+    #[inline(always)]
+    pub(crate) fn op_alloc_locals(
+        &mut self,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
-) -> Step {
+    ) -> Step {
         let count = reader.read_u32() as usize;
-    m.env()
+        self.env
             .borrow_mut(mc)
             .locals
             .extend(std::iter::repeat_n(Value::default(), count));
         Step::Continue(())
+    }
 }

fix-vm/src/instructions/with_scope.rs

@@ -1,84 +1,83 @@
+use fix_common::Symbol;
 use fix_error::Error;
-use fix_lang::Symbol;
-use fix_runtime::{resolve_operand, *};
-use smallvec::SmallVec;
+use gc_arena::Gc;
 
-use crate::{Break, BytecodeReader, CallFrame, Step, VmRuntimeCtx};
+use crate::value::*;
+use crate::{BytecodeReader, CallFrame, Step, VmRuntimeCtx, WithEnv};
 
-#[inline(always)]
-#[expect(
-    clippy::indexing_slicing,
-    clippy::cast_sign_loss,
-    reason = "counter is a non-negative with-scope index in 0..n, staying within the namespaces vec of length n"
-)]
-pub(crate) fn op_lookup_with<'gc, M: Machine<'gc>>(
-    m: &mut M,
+impl<'gc> crate::Vm<'gc> {
+    #[inline(always)]
+    pub(crate) fn op_push_with(
+        &mut self,
         ctx: &mut impl VmRuntimeCtx,
         reader: &mut BytecodeReader<'_>,
         mc: &gc_arena::Mutation<'gc>,
-) -> Step {
-    let counter = m
-        .peek_forced(0)
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
-
-    let name = reader.read_string_id();
-    let n = reader.read_u8();
-    let mut namespaces = SmallVec::<[_; 2]>::new();
-    for _ in 0..n {
-        namespaces.push(resolve_operand(&reader.read_operand_data(), mc, ctx, m));
+    ) -> Step {
+        let env = reader.read_operand_data(ctx).resolve(mc, self);
+        let scope = Gc::new(
+            mc,
+            WithEnv {
+                env,
+                prev: self.with_env,
+            },
+        );
+        self.with_env = Some(scope);
+        Step::Continue(())
     }
 
-    let resume_pc = reader.inst_start_pc();
-    let namespace = match namespaces[counter as usize].restrict() {
-        Ok(val) => val,
-        Err(thunk) => {
-            let mut state = thunk.borrow_mut(mc);
-            match *state {
-                ThunkState::Pending { ip, env } => {
-                    *state = ThunkState::Blackhole;
-                    m.push_call_frame(CallFrame {
-                        thunk: Some(thunk),
-                        pc: resume_pc,
-                        env: m.env(),
-                        depth: None,
-                    });
-                    m.set_env(env);
-                    reader.set_pc(ip);
-                    return Step::Break(Break::Force);
-                }
-                ThunkState::Evaluated(v) => v,
-                ThunkState::Apply { func, arg } => {
-                    m.push_call_frame(CallFrame {
-                        thunk: Some(thunk),
-                        pc: resume_pc,
-                        env: m.env(),
-                        depth: None,
-                    });
-                    m.push(func);
-                    return m.call(reader, mc, arg, resume_pc);
-                }
-                ThunkState::Blackhole => {
-                    return m.finish_err(Error::eval_error("infinite recursion encountered"));
-                }
-            }
-        }
+    #[inline(always)]
+    pub(crate) fn op_pop_with(&mut self) -> Step {
+        let Some(scope) = self.with_env else {
+            unreachable!("no with_scope to pop");
         };
+        self.with_env = scope.prev;
+        Step::Continue(())
+    }
 
-    if let Some(val) = namespace
-        .downcast::<AttrSet>()
-        .and_then(|attrs| attrs.lookup(name))
-    {
-        m.replace(0, val);
-    } else if counter + 1 == n as i32 {
-        return m.finish_err(Error::eval_error(format!(
+    #[inline(always)]
+    pub(crate) fn op_prepare_with(&mut self) -> Step {
+        self.call_stack.push(CallFrame {
+            pc: usize::MAX,
+            stack_depth: 0,
+            thunk: None,
+            env: self.env,
+            with_env: self.with_env,
+        });
+        Step::Continue(())
+    }
+
+    #[inline(always)]
+    pub(crate) fn op_lookup_with(
+        &mut self,
+        ctx: &mut impl VmRuntimeCtx,
+        reader: &mut BytecodeReader<'_>,
+        mc: &gc_arena::Mutation<'gc>,
+    ) -> Step {
+        let name = reader.read_string_id();
+
+        let Some(&WithEnv { env, prev }) = self.with_env.as_deref() else {
+            let Some(CallFrame { with_env, .. }) = self.call_stack.pop() else {
+                unreachable!()
+            };
+            self.with_env = with_env;
+            return self.finish_err(Error::eval_error(format!(
                 "undefined variable '{}'",
                 Symbol::from(ctx.resolve_string(name))
             )));
-    } else {
-        m.replace(0, Value::new(counter + 1));
-        reader.set_pc(resume_pc);
-    }
+        };
+        self.push(env);
+        let env = self.try_force::<Gc<AttrSet>>(reader, mc)?;
+        let Some(val) = env.lookup(name) else {
+            reader.set_pc(reader.inst_start_pc());
+            self.with_env = prev;
+            return Step::Continue(());
+        };
 
+        self.push(val);
+        let Some(CallFrame { with_env, .. }) = self.call_stack.pop() else {
+            unreachable!()
+        };
+        self.with_env = with_env;
         Step::Continue(())
+    }
 }

fix-vm/src/lib.rs

@@ -1,7 +1,5 @@
-#![cfg_attr(
-    feature = "tailcall",
-    expect(incomplete_features, reason = "for testing purpose only")
-)]
+#![warn(clippy::unwrap_used)]
+#![cfg_attr(feature = "tailcall", expect(incomplete_features))]
 #![cfg_attr(
     feature = "tailcall",
     feature(explicit_tail_calls, rust_preserve_none_cc)
@@ -9,69 +7,265 @@
 
 use std::path::PathBuf;
 
-use fix_bytecode::{Continuation, InstructionPtr};
+use fix_builtins::{BUILTINS, BuiltinId};
+use fix_codegen::InstructionPtr;
+use fix_common::StringId;
 use fix_error::{Error, Result, Source};
-use fix_lang::{BuiltinId, StringId};
-use gc_arena::metrics::Pacing;
+use gc_arena::arena::CollectionPhase;
 use gc_arena::{Arena, Collect, Gc, Mutation, RefLock, Rootable};
-use hashbrown::HashMap;
+use hashbrown::{HashMap, HashSet};
+use num_enum::TryFromPrimitive;
 use smallvec::SmallVec;
 
+mod boxing;
+mod bytecode_reader;
 #[cfg(feature = "tailcall")]
 mod dispatch_tailcall;
-pub use fix_runtime::*;
-#[doc(hidden)]
-#[path = "macro_support.rs"]
-pub mod __macro_support;
-mod instructions;
-mod primops;
-extern crate self as fix_vm;
+mod forced;
+mod value;
+pub use value::StaticValue;
+use value::*;
+mod helpers;
+pub(crate) mod instructions;
+pub(crate) use bytecode_reader::BytecodeReader;
+pub(crate) use forced::Forced;
+use helpers::*;
 
 type VmResult<T> = std::result::Result<T, VmError>;
 
+#[allow(dead_code)]
+enum VmError {
+    Catchable(String),
+    Uncatchable(Box<Error>),
+}
+
+impl From<Box<Error>> for VmError {
+    fn from(e: Box<Error>) -> Self {
+        VmError::Uncatchable(e)
+    }
+}
+
+impl VmError {
+    fn into_error(self) -> Box<Error> {
+        match self {
+            VmError::Catchable(_) => todo!("Check for tryEval catch frames"),
+            VmError::Uncatchable(e) => e,
+        }
+    }
+}
+
+#[derive(Collect, Clone, Copy, Debug, PartialEq, Eq, Default)]
+#[collect(require_static)]
+pub enum ForceMode {
+    #[default]
+    AsIs,
+    Shallow,
+    Deep,
+}
+
+pub trait VmContext {
+    fn split(&mut self) -> (&mut impl VmCode, &mut impl VmRuntimeCtx);
+}
+
+pub trait VmRuntimeCtx {
+    fn intern_string(&mut self, s: impl AsRef<str>) -> StringId;
+    fn resolve_string(&self, id: StringId) -> &str;
+    fn get_const(&self, id: u32) -> StaticValue;
+    fn add_const(&mut self, val: StaticValue) -> u32;
+}
+
+pub trait VmCode {
+    fn bytecode(&self) -> &[u8];
+    fn compile(
+        &mut self,
+        source: Source,
+        ctx: &mut impl VmRuntimeCtx,
+    ) -> fix_error::Result<InstructionPtr>;
+}
+
+pub(crate) trait VmRuntimeCtxExt: VmRuntimeCtx {
+    fn get_string<'a, 'gc: 'a>(&'a self, val: StrictValue<'gc>) -> Option<&'a str>;
+    fn get_string_id<'a, 'gc: 'a>(
+        &'a mut self,
+        val: StrictValue<'gc>,
+    ) -> std::result::Result<StringId, NixType>;
+    fn convert_value(&self, val: Value) -> fix_common::Value;
+}
+
+impl<T: VmRuntimeCtx> VmRuntimeCtxExt for T {
+    fn get_string<'a, 'gc: 'a>(&'a self, val: StrictValue<'gc>) -> Option<&'a str> {
+        if let Some(sid) = val.as_inline::<StringId>() {
+            Some(self.resolve_string(sid))
+        } else {
+            val.as_gc::<NixString>().map(|ns| ns.as_ref().as_str())
+        }
+    }
+
+    fn get_string_id<'a, 'gc: 'a>(
+        &'a mut self,
+        val: StrictValue<'gc>,
+    ) -> std::result::Result<StringId, NixType> {
+        if let Some(sid) = val.as_inline::<StringId>() {
+            Ok(sid)
+        } else if let Some(s) = val.as_gc::<NixString>().map(|ns| ns.as_ref().as_str()) {
+            Ok(self.intern_string(s))
+        } else {
+            Err(val.ty())
+        }
+    }
+
+    fn convert_value(&self, val: Value) -> fix_common::Value {
+        self.convert_value_with_seen(val, &mut HashSet::new())
+    }
+}
+
+trait ConvertValueWithSeen: VmRuntimeCtx {
+    fn convert_value_with_seen(&self, val: Value, seen: &mut HashSet<u64>) -> fix_common::Value;
+}
+
+impl<T: VmRuntimeCtx> ConvertValueWithSeen for T {
+    fn convert_value_with_seen(&self, val: Value, seen: &mut HashSet<u64>) -> fix_common::Value {
+        use fix_common::Value;
+        if let Some(i) = val.as_inline::<i32>() {
+            Value::Int(i as i64)
+        } else if let Some(gc_i) = val.as_gc::<i64>() {
+            Value::Int(*gc_i)
+        } else if let Some(f) = val.as_float() {
+            Value::Float(f)
+        } else if let Some(b) = val.as_inline::<bool>() {
+            Value::Bool(b)
+        } else if val.is::<Null>() {
+            Value::Null
+        } else if let Some(sid) = val.as_inline::<StringId>() {
+            let s = self.resolve_string(sid).to_owned();
+            Value::String(s)
+        } else if let Some(ns) = val.as_gc::<NixString>() {
+            Value::String(ns.as_str().to_owned())
+        } else if let Some(attrs) = val.as_gc::<AttrSet>() {
+            let bits = val.to_bits();
+            if attrs.entries.borrow().is_empty() {
+                return Value::AttrSet(Default::default());
+            }
+            if !seen.insert(bits) {
+                return Value::Repeated;
+            }
+            let mut map = std::collections::BTreeMap::new();
+            for &(key, val) in attrs.entries.borrow().iter() {
+                let key = self.resolve_string(key).to_owned();
+                let converted = self.convert_value_with_seen(val, seen);
+                map.insert(fix_common::Symbol::from(key), converted);
+            }
+            Value::AttrSet(fix_common::AttrSet::new(map))
+        } else if let Some(list) = val.as_gc::<List>() {
+            let bits = val.to_bits();
+            if list.inner.borrow().is_empty() {
+                return Value::List(Default::default());
+            }
+            if !seen.insert(bits) {
+                return Value::Repeated;
+            }
+            let items: Vec<_> = list
+                .inner
+                .borrow()
+                .iter()
+                .copied()
+                .map(|v| self.convert_value_with_seen(v, seen))
+                .collect();
+            Value::List(fix_common::List::new(items))
+        } else if val.is::<Closure>() {
+            Value::Func
+        } else if let Some(thunk) = val.as_gc::<Thunk>() {
+            if let ThunkState::Evaluated(v) = *thunk.borrow() {
+                self.convert_value_with_seen(v.relax(), seen)
+            } else {
+                Value::Thunk
+            }
+        } else if let Some(primop) = val.as_inline::<PrimOp>() {
+            let name = fix_builtins::BUILTINS[primop.id as usize].0;
+            Value::PrimOp(name.strip_prefix("__").unwrap_or(name))
+        } else if let Some(app) = val.as_gc::<PrimOpApp>() {
+            let name = fix_builtins::BUILTINS[app.primop.id as usize].0;
+            Value::PrimOpApp(name.strip_prefix("__").unwrap_or(name))
+        } else {
+            Value::Null
+        }
+    }
+}
+
+#[repr(u8)]
+pub(crate) enum Break {
+    Force,
+    Done,
+}
+
+pub(crate) type Step = std::ops::ControlFlow<Break>;
+
 #[derive(Collect)]
 #[collect(no_drop)]
 pub struct Vm<'gc> {
-    stack: Vec<Value<'gc>>,
-    call_stack: Vec<CallFrame<'gc>>,
-    call_depth: usize,
-    #[expect(
-        dead_code,
-        reason = "error_context is reserved for tryEval catch-frame tracking, not yet wired up"
-    )]
+    pub(crate) stack: Vec<Value<'gc>>,
+    pub(crate) call_stack: Vec<CallFrame<'gc>>,
+    pub(crate) call_depth: usize,
+    #[allow(dead_code)]
     #[collect(require_static)]
-    error_context: Vec<ErrorFrame>,
+    pub(crate) error_context: Vec<ErrorFrame>,
 
-    env: GcEnv<'gc>,
+    pub(crate) env: GcEnv<'gc>,
+    pub(crate) with_env: Option<GcWithEnv<'gc>>,
 
-    import_cache: HashMap<PathBuf, Value<'gc>>,
-    scope_slots: Vec<Value<'gc>>,
+    pub(crate) import_cache: HashMap<PathBuf, Value<'gc>>,
 
-    builtins: Gc<'gc, AttrSet<'gc>>,
-    empty_list: Value<'gc>,
-    empty_attrs: Value<'gc>,
+    pub(crate) builtins: Value<'gc>,
+    pub(crate) empty_list: Value<'gc>,
+    pub(crate) empty_attrs: Value<'gc>,
 
-    force_mode: ForceMode,
+    pub(crate) force_mode: ForceMode,
 
     #[collect(require_static)]
-    result: Option<Result<fix_lang::Value>>,
-
-    #[collect(require_static)]
-    pending_load: Option<PendingLoad>,
-
-    functor_sym: StringId,
+    pub(crate) result: Option<Result<fix_common::Value>>,
 }
 
-fn init_builtins<'gc>(mc: &Mutation<'gc>, ctx: &mut impl VmRuntimeCtx) -> Gc<'gc, AttrSet<'gc>> {
-    let mut entries = SmallVec::with_capacity(BuiltinId::TOTAL);
+pub(crate) enum OperandData {
+    Const(StaticValue),
+    Local { layer: u8, idx: u32 },
+    Builtins,
+    BigInt(i64),
+}
 
-    for id in BuiltinId::ALL {
-        let arity = id.info().arity;
-        let name = ctx.intern_string(id.info().name);
-        let dispatch_ip = Continuation::entry_for_builtin(id).ip();
+impl OperandData {
+    pub(crate) fn resolve<'gc>(&self, mc: &Mutation<'gc>, root: &Vm<'gc>) -> Value<'gc> {
+        match *self {
+            OperandData::Const(sv) => sv.into(),
+            OperandData::Local { layer, idx } => {
+                let mut cur = root.env;
+                for _ in 0..layer {
+                    let prev = cur.borrow().prev.expect("env chain too short");
+                    cur = prev;
+                }
+                cur.borrow().locals[idx as usize]
+            }
+            OperandData::Builtins => root.builtins,
+            OperandData::BigInt(val) => Value::new_gc(Gc::new(mc, val)),
+        }
+    }
+}
+
+pub(crate) enum AttrKeyData {
+    Static(StringId),
+    Dynamic,
+}
+
+fn init_builtins<'gc>(mc: &Mutation<'gc>, ctx: &mut impl VmRuntimeCtx) -> Value<'gc> {
+    let mut entries = SmallVec::with_capacity(BUILTINS.len());
+
+    for (idx, &(name, arity)) in BUILTINS.iter().enumerate() {
+        let id = BuiltinId::try_from_primitive(idx as u8).expect("infallible");
+        let name = name.strip_prefix("__").unwrap_or(name);
+        let name = ctx.intern_string(name);
+        let dispatch_ip = id.entry_phase().ip();
         entries.push((
             name,
-            Value::new(PrimOp {
+            Value::new_inline(PrimOp {
                 id,
                 arity,
                 dispatch_ip,
@@ -82,15 +276,21 @@ fn init_builtins<'gc>(mc: &Mutation<'gc>, ctx: &mut impl VmRuntimeCtx) -> Gc<'gc
     let consts = [
         (
             "__currentSystem",
-            Value::new(ctx.intern_string("x86_64-linux")),
+            Value::new_inline(ctx.intern_string("x86_64-linux")),
         ),
-        ("__langVersion", Value::new(6i32)),
-        ("__nixVersion", Value::new(ctx.intern_string("2.24.0"))),
-        ("__storeDir", Value::new(ctx.intern_string("/nix/store"))),
-        ("__nixPath", Value::new(Gc::new(mc, List::default()))),
-        ("null", Value::new(Null)),
-        ("true", Value::new(true)),
-        ("false", Value::new(false)),
+        ("__langVersion", Value::new_inline(6i32)),
+        (
+            "__nixVersion",
+            Value::new_inline(ctx.intern_string("2.24.0")),
+        ),
+        (
+            "__storeDir",
+            Value::new_inline(ctx.intern_string("/nix/store")),
+        ),
+        ("__nixPath", Value::new_gc(Gc::new(mc, List::default()))),
+        ("null", Value::new_inline(Null)),
+        ("true", Value::new_inline(true)),
+        ("false", Value::new_inline(false)),
     ];
 
     for (name, val) in consts {
@@ -101,15 +301,15 @@ fn init_builtins<'gc>(mc: &Mutation<'gc>, ctx: &mut impl VmRuntimeCtx) -> Gc<'gc
 
     let self_ref_thunk = Gc::new(mc, RefLock::new(ThunkState::Blackhole));
     let sym = ctx.intern_string("builtins");
-    entries.push((sym, Value::new(self_ref_thunk)));
+    entries.push((sym, Value::new_gc(self_ref_thunk)));
 
     entries.sort_by_key(|(k, _)| *k);
 
     let builtins_set = Gc::new(mc, AttrSet::from_sorted_unchecked(entries));
-    let builtins_value = Value::new(builtins_set);
+    let builtins_value = Value::new_gc(builtins_set);
     *self_ref_thunk.borrow_mut(mc) =
         ThunkState::Evaluated(builtins_value.restrict().expect("builtins is not a thunk"));
-    builtins_set
+    builtins_value
 }
 
 impl<'gc> Vm<'gc> {
@@ -122,37 +322,59 @@ impl<'gc> Vm<'gc> {
             error_context: Vec::with_capacity(1024),
 
             env: Gc::new(mc, RefLock::new(Env::empty())),
+            with_env: None,
 
             import_cache: HashMap::new(),
-            scope_slots: Vec::new(),
 
             builtins,
-            empty_list: Value::new(Gc::new(mc, List::default())),
-            empty_attrs: Value::new(Gc::new(mc, AttrSet::default())),
+            empty_list: Value::new_gc(Gc::new(mc, List::default())),
+            empty_attrs: Value::new_gc(Gc::new(mc, AttrSet::default())),
 
             force_mode,
 
             result: None,
-            pending_load: None,
-
-            functor_sym: ctx.intern_string("__functor"),
         }
     }
-}
 
-impl<'gc> Machine<'gc> for Vm<'gc> {
     #[inline(always)]
-    fn push(&mut self, val: Value<'gc>) {
+    pub(crate) fn finish_ok(&mut self, val: fix_common::Value) -> Step {
+        self.result = Some(Ok(val));
+        Step::Break(Break::Done)
+    }
+
+    #[inline(always)]
+    pub(crate) fn finish_err(&mut self, err: Box<Error>) -> Step {
+        self.result = Some(Err(err));
+        Step::Break(Break::Done)
+    }
+
+    #[inline(always)]
+    pub(crate) fn finish_type_err(&mut self, expected: NixType, got: NixType) -> Step {
+        self.result = Some(Err(Error::eval_error(format!(
+            "expected {expected}, got {got}"
+        ))));
+        Step::Break(Break::Done)
+    }
+
+    #[inline(always)]
+    pub(crate) fn finish_vm_err(&mut self, err: VmError) -> Step {
+        self.finish_err(err.into_error())
+    }
+
+    #[inline(always)]
+    pub(crate) fn push(&mut self, val: Value<'gc>) {
         self.stack.push(val);
     }
 
     #[inline(always)]
-    fn pop(&mut self) -> Value<'gc> {
+    #[must_use]
+    pub(crate) fn pop(&mut self) -> Value<'gc> {
         self.stack.pop().expect("stack underflow")
     }
 
     #[inline(always)]
-    fn peek(&self, depth: usize) -> Value<'gc> {
+    #[must_use]
+    pub(crate) fn peek(&mut self, depth: usize) -> Value<'gc> {
         *self
             .stack
             .get(self.stack.len() - depth - 1)
@@ -160,7 +382,8 @@ impl<'gc> Machine<'gc> for Vm<'gc> {
     }
 
     #[inline(always)]
-    fn peek_forced(&self, depth: usize) -> StrictValue<'gc> {
+    #[must_use]
+    pub(crate) fn peek_forced(&mut self, depth: usize) -> StrictValue<'gc> {
         self.stack
             .get(self.stack.len() - depth - 1)
             .expect("stack underflow")
@@ -169,16 +392,7 @@ impl<'gc> Machine<'gc> for Vm<'gc> {
     }
 
     #[inline(always)]
-    fn pop_forced(&mut self) -> StrictValue<'gc> {
-        self.stack
-            .pop()
-            .expect("stack underflow")
-            .restrict()
-            .expect("forced")
-    }
-
-    #[inline(always)]
-    fn replace(&mut self, depth: usize, val: Value<'gc>) {
+    pub(crate) fn replace(&mut self, depth: usize, val: Value<'gc>) {
         let len = self.stack.len();
         *self
             .stack
@@ -187,200 +401,112 @@ impl<'gc> Machine<'gc> for Vm<'gc> {
     }
 
     #[inline(always)]
-    fn drop_n(&mut self, depth: usize) {
-        self.stack.truncate(self.stack.len() - depth);
+    #[cfg_attr(debug_assertions, track_caller)]
+    pub(crate) fn pop_forced(&mut self) -> StrictValue<'gc> {
+        self.stack
+            .pop()
+            .expect("stack underflow")
+            .restrict()
+            .expect("forced")
     }
 
     #[inline(always)]
-    fn stack_len(&self) -> usize {
-        self.stack.len()
+    pub(crate) fn try_force<T: Forced<'gc>>(
+        &mut self,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> std::ops::ControlFlow<Break, T> {
+        self.try_force_to_pc(reader, mc, reader.inst_start_pc())
     }
 
     #[inline(always)]
-    fn force_slot_to_pc(
+    pub(crate) fn try_force_to_pc<T: Forced<'gc>>(
+        &mut self,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+        resume_pc: usize,
+    ) -> std::ops::ControlFlow<Break, T> {
+        T::force_and_check(self, reader, mc, 0, resume_pc)?;
+        std::ops::ControlFlow::Continue(T::pop_converted(self))
+    }
+
+    #[inline(always)]
+    #[allow(unused)]
+    pub(crate) fn force_slot(
+        &mut self,
+        depth: usize,
+        reader: &mut BytecodeReader<'_>,
+        mc: &Mutation<'gc>,
+    ) -> Step {
+        self.force_slot_to_pc(depth, reader, mc, reader.inst_start_pc())
+    }
+
+    #[inline(always)]
+    pub(crate) fn force_slot_to_pc(
         &mut self,
         depth: usize,
         reader: &mut BytecodeReader<'_>,
         mc: &Mutation<'gc>,
         resume_pc: usize,
     ) -> Step {
-        let Some(thunk) = self.peek(depth).downcast::<Thunk>() else {
+        let Some(thunk) = self.peek(depth).as_gc::<Thunk>() else {
             return Step::Continue(());
         };
         let mut state = thunk.borrow_mut(mc);
         match *state {
-            ThunkState::Pending { ip, env } => {
+            ThunkState::Pending { ip, env, with_env } => {
                 *state = ThunkState::Blackhole;
+                drop(state);
                 self.call_stack.push(CallFrame {
                     thunk: Some(thunk),
+                    stack_depth: depth,
                     pc: resume_pc,
                     env: self.env,
-                    depth: Some(depth),
+                    with_env: self.with_env,
                 });
                 self.env = env;
+                self.with_env = with_env;
                 reader.set_pc(ip);
                 Step::Break(Break::Force)
             }
             ThunkState::Evaluated(v) => {
+                drop(state);
                 self.replace(depth, v.relax());
                 Step::Continue(())
             }
-            ThunkState::Apply { func, arg } => {
-                self.call_stack.push(CallFrame {
-                    thunk: Some(thunk),
-                    pc: resume_pc,
-                    env: self.env,
-                    depth: Some(depth),
-                });
-                self.push(func);
-                self.call(reader, mc, arg, resume_pc)
-            }
+            ThunkState::Apply { .. } => todo!("force apply"),
             ThunkState::Blackhole => {
+                drop(state);
                 self.finish_err(Error::eval_error("infinite recursion encountered"))
             }
         }
     }
-
-    #[inline(always)]
-    fn call(
-        &mut self,
-        reader: &mut BytecodeReader<'_>,
-        mc: &Mutation<'gc>,
-        arg: Value<'gc>,
-        resume_pc: usize,
-    ) -> Step {
-        instructions::call(self, reader, mc, arg, resume_pc)
-    }
-
-    #[inline(always)]
-    fn push_call_frame(&mut self, frame: CallFrame<'gc>) {
-        self.call_stack.push(frame);
-    }
-
-    #[inline(always)]
-    fn pop_call_frame(&mut self) -> Option<CallFrame<'gc>> {
-        self.call_stack.pop()
-    }
-
-    #[inline(always)]
-    fn call_depth(&self) -> usize {
-        self.call_depth
-    }
-
-    #[inline(always)]
-    fn inc_call_depth(&mut self) {
-        self.call_depth += 1;
-    }
-
-    #[inline(always)]
-    fn dec_call_depth(&mut self) {
-        self.call_depth -= 1;
-    }
-
-    #[inline(always)]
-    fn env(&self) -> GcEnv<'gc> {
-        self.env
-    }
-
-    #[inline(always)]
-    fn set_env(&mut self, env: GcEnv<'gc>) {
-        self.env = env;
-    }
-
-    #[inline(always)]
-    fn finish_ok(&mut self, val: fix_lang::Value) -> Step {
-        self.result = Some(Ok(val));
-        Step::Break(Break::Done)
-    }
-
-    #[inline(always)]
-    fn finish_err(&mut self, err: Box<Error>) -> Step {
-        self.result = Some(Err(err));
-        Step::Break(Break::Done)
-    }
-
-    #[inline(always)]
-    fn finish_type_err(&mut self, expected: NixType, got: NixType) -> Step {
-        self.result = Some(Err(Error::eval_error(format!(
-            "expected {expected}, got {got}"
-        ))));
-        Step::Break(Break::Done)
-    }
-
-    #[inline(always)]
-    fn builtins(&self) -> Gc<'gc, AttrSet<'gc>> {
-        self.builtins
-    }
-
-    #[inline(always)]
-    fn functor_sym(&self) -> StringId {
-        self.functor_sym
-    }
-
-    #[inline(always)]
-    fn empty_list(&self) -> Value<'gc> {
-        self.empty_list
-    }
-
-    #[inline(always)]
-    fn empty_attrs(&self) -> Value<'gc> {
-        self.empty_attrs
-    }
-
-    #[inline(always)]
-    fn force_mode(&self) -> ForceMode {
-        self.force_mode
-    }
-
-    #[inline(always)]
-    fn import_cache_get(&self, path: &std::path::Path) -> Option<Value<'gc>> {
-        self.import_cache.get(path).copied()
-    }
-
-    #[inline(always)]
-    fn import_cache_insert(&mut self, path: PathBuf, val: Value<'gc>) {
-        self.import_cache.insert(path, val);
-    }
-
-    #[inline(always)]
-    fn scope_slot(&self, idx: u32) -> Value<'gc> {
-        *self
-            .scope_slots
-            .get(idx as usize)
-            .expect("invalid scope slot")
-    }
-
-    #[inline(always)]
-    fn scope_slots_push(&mut self, val: Value<'gc>) -> u32 {
-        let idx = self.scope_slots.len() as u32;
-        self.scope_slots.push(val);
-        idx
-    }
-
-    #[inline(always)]
-    fn set_pending_load(&mut self, load: PendingLoad) {
-        self.pending_load = Some(load);
-    }
 }
 
-enum Action {
+#[allow(dead_code)]
+struct ErrorFrame {
+    span_id: u32,
+    message: Option<String>,
+}
+
+#[derive(Collect, Debug)]
+#[collect(no_drop)]
+pub(crate) struct CallFrame<'gc> {
+    pub(crate) pc: usize,
+    pub(crate) stack_depth: usize,
+    pub(crate) thunk: Option<Gc<'gc, Thunk<'gc>>>,
+    pub(crate) env: Gc<'gc, RefLock<Env<'gc>>>,
+    pub(crate) with_env: Option<Gc<'gc, WithEnv<'gc>>>,
+}
+
+pub(crate) enum Action {
     Continue { pc: usize },
-    Done(Result<fix_lang::Value>),
-    LoadFile(PendingLoad),
+    Done(Result<fix_common::Value>),
 }
 
-/// Compute initial heap size mirroring CppNix's strategy: 25% of physical RAM,
-/// clamped to [32 MiB, 384 MiB]. Used as `Pacing::min_sleep` so the collector
-/// defers the first cycle until the heap reaches this size.
-fn initial_heap_size() -> usize {
-    const MIN_SIZE: usize = 32 * 1024 * 1024;
-    const MAX_SIZE: usize = 384 * 1024 * 1024;
-
-    let mut sys = sysinfo::System::new();
-    sys.refresh_memory();
-    let total = sys.total_memory() as usize;
-    let quarter = total / 4;
-    quarter.clamp(MIN_SIZE, MAX_SIZE)
+pub(crate) enum NixNum {
+    Int(i64),
+    Float(f64),
 }
 
 impl Vm<'_> {
@@ -388,13 +514,11 @@ impl Vm<'_> {
         ctx: &mut C,
         ip: InstructionPtr,
         force_mode: ForceMode,
-    ) -> Result<fix_lang::Value> {
+    ) -> Result<fix_common::Value> {
         let (code, runtime) = ctx.split();
         let mut arena: Arena<Rootable![Vm<'_>]> = Arena::new(|mc| Vm::new(force_mode, mc, runtime));
-        arena.metrics().set_pacing(Pacing {
-            min_sleep: initial_heap_size(),
-            ..Pacing::STOP_THE_WORLD
-        });
+
+        const COLLECTOR_GRANULARITY: f64 = 1024.0;
 
         let mut pc = ip.0;
         loop {
@@ -402,27 +526,13 @@ impl Vm<'_> {
             match arena.mutate_root(|mc, root| root.dispatch_batch(bytecode, runtime, pc, mc)) {
                 Action::Continue { pc: new_pc } => {
                     pc = new_pc;
-                    if arena.metrics().allocation_debt() > 0.0 {
-                        arena.finish_cycle();
+                    if arena.metrics().allocation_debt() > COLLECTOR_GRANULARITY {
+                        if arena.collection_phase() == CollectionPhase::Sweeping {
+                            arena.collect_debt();
+                        } else if let Some(marked) = arena.mark_debt() {
+                            marked.start_sweeping();
                         }
                     }
-                Action::LoadFile(load) => {
-                    let source = match Source::new_file(load.path) {
-                        Ok(src) => src,
-                        Err(err) => break Err(Error::eval_error(format!("import failed: {err}"))),
-                    };
-                    let extra_scope = load.scope.map(|s| ExtraScope::ScopedImport {
-                        keys: s.keys,
-                        slot_id: s.slot_id,
-                    });
-                    let new_ip = match code.compile_with_scope(source, extra_scope, runtime) {
-                        Ok(ip) => ip,
-                        Err(err) => break Err(err),
-                    };
-                    pc = new_ip.0;
-                    arena.mutate_root(|mc, root| {
-                        root.env = Gc::new(mc, RefLock::new(Env::empty()));
-                    });
                 }
                 Action::Done(done) => break done,
             }
@@ -455,21 +565,12 @@ impl<'gc> Vm<'gc> {
                 TailResult::Done => {
                     Action::Done(self.result.take().expect("TailResult::Done without result"))
                 }
-                TailResult::LoadFile => Action::LoadFile(
-                    self.pending_load
-                        .take()
-                        .expect("TailResult::LoadFile without pending_load"),
-                ),
             }
         }
     }
 
     #[inline(always)]
     #[cfg(not(feature = "tailcall"))]
-    #[expect(
-        clippy::unreachable,
-        reason = "Op::Illegal is a sentinel never emitted by codegen; reaching it is a codegen bug"
-    )]
     fn execute_batch(
         &mut self,
         bytecode: &[u8],
@@ -477,15 +578,12 @@ impl<'gc> Vm<'gc> {
         pc: usize,
         mc: &Mutation<'gc>,
     ) -> Action {
-        use fix_bytecode::Op::*;
-        use instructions::*;
+        use fix_codegen::Op::*;
 
         let mut reader = BytecodeReader::new(bytecode, pc);
         let mut fuel = Self::DEFAULT_FUEL_AMOUNT;
 
         loop {
-            use crate::instructions::op_dispatch_cont;
-
             if fuel == 0 {
                 return Action::Continue { pc: reader.pc() };
             }
@@ -494,75 +592,78 @@ impl<'gc> Vm<'gc> {
             let op = reader.read_op();
 
             let result = match op {
-                PushSmi => op_push_smi(self, &mut reader),
-                PushBigInt => op_push_bigint(self, &mut reader, mc),
-                PushFloat => op_push_float(self, &mut reader),
-                PushString => op_push_string(self, &mut reader),
-                PushNull => op_push_null(self),
-                PushTrue => op_push_true(self),
-                PushFalse => op_push_false(self),
+                PushSmi => self.op_push_smi(&mut reader),
+                PushBigInt => self.op_push_bigint(&mut reader, mc),
+                PushFloat => self.op_push_float(&mut reader),
+                PushString => self.op_push_string(&mut reader),
+                PushNull => self.op_push_null(),
+                PushTrue => self.op_push_true(),
+                PushFalse => self.op_push_false(),
 
-                LoadLocal => op_load_local(self, &mut reader),
-                LoadOuter => op_load_outer(self, &mut reader),
-                StoreLocal => op_store_local(self, &mut reader, mc),
-                AllocLocals => op_alloc_locals(self, &mut reader, mc),
+                LoadLocal => self.op_load_local(&mut reader),
+                LoadOuter => self.op_load_outer(&mut reader),
+                StoreLocal => self.op_store_local(&mut reader, mc),
+                AllocLocals => self.op_alloc_locals(&mut reader, mc),
 
-                MakeThunk => op_make_thunk(self, &mut reader, mc),
-                MakeClosure => op_make_closure(self, &mut reader, mc),
-                MakePatternClosure => op_make_pattern_closure(self, &mut reader, mc),
+                MakeThunk => self.op_make_thunk(&mut reader, mc),
+                MakeClosure => self.op_make_closure(&mut reader, mc),
+                MakePatternClosure => self.op_make_pattern_closure(&mut reader, mc),
 
-                Call => op_call(self, ctx, &mut reader, mc),
-                DispatchCont => op_dispatch_cont(self, ctx, &mut reader, mc),
-                Return => op_return(self, ctx, &mut reader, mc),
+                Call => self.op_call(ctx, &mut reader, mc),
+                DispatchPrimOp => self.op_dispatch_primop(ctx, &mut reader, mc),
+                Return => self.op_return(ctx, &mut reader, mc),
 
-                MakeAttrs => op_make_attrs(self, ctx, &mut reader, mc),
-                MakeEmptyAttrs => op_make_empty_attrs(self),
-                SelectStatic => op_select_static(self, ctx, &mut reader, mc),
-                SelectDynamic => op_select_dynamic(self, ctx, &mut reader, mc),
-                HasAttrPathStatic => op_has_attr_path_static(self, ctx, &mut reader, mc),
-                HasAttrPathDynamic => op_has_attr_path_dynamic(self, ctx, &mut reader, mc),
-                HasAttrStatic => op_has_attr_static(self, &mut reader, mc),
-                HasAttrDynamic => op_has_attr_dynamic(self, ctx, &mut reader, mc),
-                HasAttrResolve => op_has_attr_resolve(self),
-                JumpIfSelectFailed => op_jump_if_select_failed(self, &mut reader),
-                JumpIfSelectSucceeded => op_jump_if_select_succeeded(self, &mut reader),
+                MakeAttrs => self.op_make_attrs(ctx, &mut reader, mc),
+                MakeEmptyAttrs => self.op_make_empty_attrs(),
+                SelectStatic => self.op_select_static(ctx, &mut reader, mc),
+                SelectDynamic => self.op_select_dynamic(ctx, &mut reader, mc),
+                HasAttrPathStatic => self.op_has_attr_path_static(ctx, &mut reader, mc),
+                HasAttrPathDynamic => self.op_has_attr_path_dynamic(ctx, &mut reader, mc),
+                HasAttrStatic => self.op_has_attr_static(&mut reader, mc),
+                HasAttrDynamic => self.op_has_attr_dynamic(ctx, &mut reader, mc),
+                HasAttrResolve => self.op_has_attr_resolve(),
+                JumpIfSelectFailed => self.op_jump_if_select_failed(&mut reader),
+                JumpIfSelectSucceeded => self.op_jump_if_select_succeeded(&mut reader),
 
-                MakeList => op_make_list(self, ctx, &mut reader, mc),
-                MakeEmptyList => op_make_empty_list(self),
+                MakeList => self.op_make_list(ctx, &mut reader, mc),
+                MakeEmptyList => self.op_make_empty_list(),
 
-                OpAdd => op_add(self, ctx, &mut reader, mc),
-                OpSub => op_sub(self, &mut reader, mc),
-                OpMul => op_mul(self, &mut reader, mc),
-                OpDiv => op_div(self, &mut reader, mc),
-                OpEq => op_eq(self, ctx, &mut reader, mc),
-                OpNeq => op_neq(self, ctx, &mut reader, mc),
-                OpLt => op_lt(self, ctx, &mut reader, mc),
-                OpGt => op_gt(self, ctx, &mut reader, mc),
-                OpLeq => op_leq(self, ctx, &mut reader, mc),
-                OpGeq => op_geq(self, ctx, &mut reader, mc),
-                OpConcat => op_concat(self, &mut reader, mc),
-                OpUpdate => op_update(self, &mut reader, mc),
+                OpAdd => self.op_add(ctx, &mut reader, mc),
+                OpSub => self.op_sub(&mut reader, mc),
+                OpMul => self.op_mul(&mut reader, mc),
+                OpDiv => self.op_div(&mut reader, mc),
+                OpEq => self.op_eq(ctx, &mut reader, mc),
+                OpNeq => self.op_neq(ctx, &mut reader, mc),
+                OpLt => self.op_lt(ctx, &mut reader, mc),
+                OpGt => self.op_gt(ctx, &mut reader, mc),
+                OpLeq => self.op_leq(ctx, &mut reader, mc),
+                OpGeq => self.op_geq(ctx, &mut reader, mc),
+                OpConcat => self.op_concat(&mut reader, mc),
+                OpUpdate => self.op_update(&mut reader, mc),
 
-                OpNeg => op_neg(self, &mut reader, mc),
-                OpNot => op_not(self, &mut reader, mc),
+                OpNeg => self.op_neg(&mut reader, mc),
+                OpNot => self.op_not(&mut reader, mc),
 
-                JumpIfFalse => op_jump_if_false(self, &mut reader, mc),
-                JumpIfTrue => op_jump_if_true(self, &mut reader, mc),
-                Jump => op_jump(self, &mut reader),
+                JumpIfFalse => self.op_jump_if_false(&mut reader, mc),
+                JumpIfTrue => self.op_jump_if_true(&mut reader, mc),
+                Jump => self.op_jump(&mut reader),
 
-                ConcatStrings => op_concat_strings(self, ctx, &mut reader, mc),
-                CoerceToString => op_coerce_to_string(self, &mut reader, mc),
-                ResolvePath => op_resolve_path(self, ctx, &mut reader, mc),
+                ConcatStrings => self.op_concat_strings(ctx, &mut reader, mc),
+                ResolvePath => self.op_resolve_path(ctx),
 
-                Assert => op_assert(self, ctx, &mut reader, mc),
+                Assert => self.op_assert(&mut reader),
 
-                LookupWith => op_lookup_with(self, ctx, &mut reader, mc),
+                PushWith => self.op_push_with(ctx, &mut reader, mc),
+                PopWith => self.op_pop_with(),
+                LookupWith => self.op_lookup_with(ctx, &mut reader, mc),
+                PrepareWith => self.op_prepare_with(),
 
-                LoadBuiltins => op_load_builtins(self),
-                LoadBuiltin => op_load_builtin(self, &mut reader),
+                LoadBuiltins => self.op_load_builtins(),
+                LoadBuiltin => self.op_load_builtin(&mut reader),
 
-                LoadReplBinding => op_load_repl_binding(self, &mut reader),
-                LoadScopedBinding => op_load_scoped_binding(self, ctx, &mut reader, mc),
+                MkPos => self.op_mk_pos(&mut reader),
+                LoadReplBinding => self.op_load_repl_binding(&mut reader),
+                LoadScopedBinding => self.op_load_scoped_binding(&mut reader),
 
                 Illegal => unreachable!(),
             };
@@ -572,13 +673,6 @@ impl<'gc> Vm<'gc> {
                 Step::Break(Break::Done) => {
                     return Action::Done(self.result.take().expect("Break::Done without result"));
                 }
-                Step::Break(Break::LoadFile) => {
-                    return Action::LoadFile(
-                        self.pending_load
-                            .take()
-                            .expect("Break::LoadFile without pending_load"),
-                    );
-                }
             }
         }
     }

fix-vm/src/macro_support.rs

@@ -1,36 +0,0 @@
-//! Single macro-facing path for the `#[primop]` support surface: the traits
-//! generated code type-checks through (defined in `fix_runtime`, where the
-//! impl sets are coherent) and the stub trio that keeps un-expanded primop
-//! sources resolving in tooling.
-
-use std::future::Future;
-
-pub use fix_runtime::{CalleeReady, ForceTarget, UnwrapSlot};
-use fix_runtime::{Slot, Value};
-
-macro_rules! type_hint {
-    () => {
-        if false {
-            return async {
-                unreachable!();
-            };
-        }
-    };
-}
-
-#[expect(clippy::panic, reason = "deliberately panic when the stub is called")]
-pub fn force<T>(_: Slot<Value<'_>>) -> impl Future<Output = Slot<T>> {
-    type_hint!();
-    panic!("stub `force` called at runtime")
-}
-
-#[expect(clippy::panic, reason = "deliberately panic when the stub is called")]
-pub fn call<T, A, R>(_: &T, _: A) -> impl Future<Output = R> {
-    type_hint!();
-    panic!("stub `call` called at runtime")
-}
-
-#[expect(clippy::panic, reason = "deliberately panic when the stub is called")]
-pub fn spill<T>(_: T) -> Slot<T> {
-    panic!("stub `spill` called at runtime")
-}

fix-vm/src/primops/context.rs

@@ -1,499 +0,0 @@
-//! `builtins.hasContext`, `builtins.getContext`, `builtins.appendContext`,
-//! `builtins.unsafeDiscardStringContext`,
-//! `builtins.unsafeDiscardOutputDependency`.
-//!
-//! See `fix-runtime/src/string_context.rs` for the
-//! `StringContextElem` type.
-
-use fix_bytecode::Continuation;
-use fix_error::Error;
-use fix_lang::StringId;
-use fix_runtime::{
-    AttrSet, BytecodeReader, List as VmList, Machine, MachineExt, NixString, NixType, Step,
-    StrictValue, StringContext, StringContextElem, Value, VmRuntimeCtx, VmRuntimeCtxExt,
-};
-use gc_arena::{Gc, Mutation};
-use smallvec::SmallVec;
-
-pub fn has_context<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    if !val.is::<StringId>() && val.downcast::<NixString>().is_none() {
-        return m.finish_type_err(NixType::String, val.ty());
-    }
-    let has_ctx = !ctx.get_string_context(val).is_empty();
-    m.return_from_primop(Value::new(has_ctx), reader)
-}
-
-pub fn unsafe_discard_string_context<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    if let Some(sid) = val.downcast::<StringId>() {
-        return m.return_from_primop(Value::new(sid), reader);
-    }
-    let Some(ns) = val.downcast::<NixString>() else {
-        return m.finish_type_err(NixType::String, val.ty());
-    };
-    let sid = ctx.intern_string(ns.as_str());
-    m.return_from_primop(Value::new(sid), reader)
-}
-
-pub fn unsafe_discard_output_dependency<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    if let Some(sid) = val.downcast::<StringId>() {
-        return m.return_from_primop(Value::new(sid), reader);
-    }
-    let Some(ns) = val.downcast::<NixString>() else {
-        return m.finish_type_err(NixType::String, val.ty());
-    };
-    if ns.context().is_empty() {
-        let sid = ctx.intern_string(ns.as_str());
-        return m.return_from_primop(Value::new(sid), reader);
-    }
-
-    let mut new_ctx = StringContext::new();
-    for elem in ns.context() {
-        let replacement = match elem {
-            StringContextElem::DrvDeep { drv_path } => StringContextElem::Opaque {
-                path: drv_path.clone(),
-            },
-            other => other.clone(),
-        };
-        new_ctx.insert(replacement);
-    }
-
-    let s: Box<str> = ns.as_str().into();
-    let new_ns = Gc::new(mc, NixString::with_context(s, new_ctx));
-    m.return_from_primop(Value::new(new_ns), reader)
-}
-
-pub fn get_context<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    if !val.is::<StringId>() && val.downcast::<NixString>().is_none() {
-        return m.finish_type_err(NixType::String, val.ty());
-    }
-    let elems = ctx.get_string_context(val);
-
-    struct Info {
-        path: bool,
-        all_outputs: bool,
-        outputs: SmallVec<[Box<str>; 2]>,
-    }
-    impl Info {
-        fn new() -> Self {
-            Self {
-                path: false,
-                all_outputs: false,
-                outputs: SmallVec::new(),
-            }
-        }
-    }
-    let mut by_path: std::collections::BTreeMap<Box<str>, Info> = std::collections::BTreeMap::new();
-    for elem in elems {
-        match elem {
-            StringContextElem::Opaque { path } => {
-                by_path.entry(path.clone()).or_insert_with(Info::new).path = true;
-            }
-            StringContextElem::DrvDeep { drv_path } => {
-                by_path
-                    .entry(drv_path.clone())
-                    .or_insert_with(Info::new)
-                    .all_outputs = true;
-            }
-            StringContextElem::Built { drv_path, output } => {
-                by_path
-                    .entry(drv_path.clone())
-                    .or_insert_with(Info::new)
-                    .outputs
-                    .push(output.clone());
-            }
-        }
-    }
-
-    let mut outer_entries: SmallVec<[(StringId, Value<'gc>); 4]> = SmallVec::new();
-    for (path, mut info) in by_path {
-        info.outputs.sort();
-        info.outputs.dedup();
-
-        let mut sub: SmallVec<[(StringId, Value<'gc>); 4]> = SmallVec::new();
-        if info.all_outputs {
-            sub.push((ctx.intern_string("allOutputs"), Value::new(true)));
-        }
-        if !info.outputs.is_empty() {
-            let items: smallvec::SmallVec<[Value<'gc>; 4]> = info
-                .outputs
-                .iter()
-                .map(|o| Value::new(ctx.intern_string(o)))
-                .collect();
-            let list = VmList::new(mc, items);
-            sub.push((ctx.intern_string("outputs"), Value::new(list)));
-        }
-        if info.path {
-            sub.push((ctx.intern_string("path"), Value::new(true)));
-        }
-        sub.sort_by_key(|(k, _)| *k);
-        let sub_attrs = Gc::new(mc, AttrSet::from_sorted_unchecked(sub));
-
-        outer_entries.push((ctx.intern_string(&path), Value::new(sub_attrs)));
-    }
-    outer_entries.sort_by_key(|(k, _)| *k);
-
-    let outer = Gc::new(mc, AttrSet::from_sorted_unchecked(outer_entries));
-    m.return_from_primop(Value::new(outer), reader)
-}
-
-/// appendContext :: String -> AttrSet -> String
-/// The context AttrSet maps store-path strings to `{ path?: Bool, allOutputs?:
-/// Bool, outputs?: [String] }`. Each present field contributes one
-/// StringContextElem to the result.
-///
-/// Requires forcing nested attrset values and list elements lazily, so it's
-/// structured as a state machine with the following stack layout:
-///
-///   [strVal, attrs, idx, acc]                       - outer loop
-///   [strVal, attrs, idx, acc, entryAttrs]           - after entry forced
-///   [strVal, attrs, idx, acc, list]                 - after `outputs` forced
-///   [strVal, attrs, idx, acc, list, oidx]           - output-element loop
-///   [strVal, attrs, idx, acc, list, oidx, outElem]  - after element forced
-///
-/// `acc` is a sentinel `NixString` whose `data` is empty and whose `context`
-/// is the accumulator. The string value itself is preserved in `strVal` and
-/// retrieved at finalization.
-///
-// TODO: handle thunk-valued `path` and `allOutputs` sub-attrs; currently they
-// must be already-evaluated booleans.
-pub fn append_context<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let (str_val, attrs) = m.force_and_retry::<(StrictValue, Gc<AttrSet>)>(reader, mc)?;
-
-    let initial_ctx: StringContext = ctx.get_string_context(str_val).clone();
-    let acc = Gc::new(mc, NixString::with_context("", initial_ctx));
-
-    m.push(str_val.relax());
-    m.push(Value::new(attrs));
-    m.push(Value::new(0i32));
-    m.push(Value::new(acc));
-
-    reader.set_pc(Continuation::PAppendContextLoop.ip() as usize);
-    Step::Continue(())
-}
-
-#[expect(
-    clippy::indexing_slicing,
-    clippy::cast_sign_loss,
-    reason = "idx is a non-negative loop counter guarded by `idx as usize >= attrs.entries.len()`, so it indexes attrs.entries in bounds"
-)]
-pub fn append_context_loop<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let idx = m
-        .peek(1)
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
-    let attrs = m
-        .peek_forced(2)
-        .downcast::<AttrSet>()
-        .expect("stack slot must be an attrset");
-
-    if idx as usize >= attrs.entries.len() {
-        return append_context_finalize(m, ctx, reader, mc);
-    }
-
-    let entry_val = attrs.entries[idx as usize].1;
-    m.push(entry_val);
-    m.force_slot_to_pc(
-        0,
-        reader,
-        mc,
-        Continuation::PAppendContextEntryForced.ip() as usize,
-    )?;
-    reader.set_pc(Continuation::PAppendContextEntryForced.ip() as usize);
-    Step::Continue(())
-}
-
-#[expect(
-    clippy::indexing_slicing,
-    clippy::cast_sign_loss,
-    reason = "idx is the same non-negative outer-loop counter, in range for outer.entries validated by append_context_loop"
-)]
-pub fn append_context_entry_forced<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    // Stack: [strVal, attrs, idx, acc, entryAttrs(thunk)]
-    // The slot still holds the Thunk pointer; re-force to extract the now-
-    // Evaluated value into the slot.
-    m.force_slot(0, reader, mc)?;
-    let entry_val = m.peek_forced(0);
-    let Some(entry_attrs) = entry_val.downcast::<AttrSet>() else {
-        return m.finish_type_err(NixType::AttrSet, entry_val.ty());
-    };
-
-    let idx = m
-        .peek(2)
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
-    let outer = m
-        .peek_forced(3)
-        .downcast::<AttrSet>()
-        .expect("stack slot must be an attrset");
-    let path_key = outer.entries[idx as usize].0;
-    let path_str_owned: Box<str> = ctx.resolve_string(path_key).into();
-    if !path_str_owned.starts_with("/nix/store/") {
-        return m.finish_err(Error::eval_error(format!(
-            "context key '{path_str_owned}' is not a store path"
-        )));
-    }
-
-    // Eagerly handle `path` and `allOutputs` (assumed already-forced
-    // booleans - most callers either set them to literal `true` or omit
-    // them entirely).
-    // TODO: force these two attributes correctly
-    let path_id = ctx.intern_string("path");
-    let all_outputs_id = ctx.intern_string("allOutputs");
-    let outputs_id = ctx.intern_string("outputs");
-
-    let acc_gc = m
-        .peek(1)
-        .downcast::<NixString>()
-        .expect("stack slot must be a string");
-    let mut new_acc: StringContext = acc_gc.context().iter().cloned().collect();
-
-    if let Some(v) = entry_attrs.lookup(path_id)
-        && v.downcast::<bool>() == Some(true)
-    {
-        new_acc.insert(StringContextElem::Opaque {
-            path: path_str_owned.clone(),
-        });
-    }
-
-    if let Some(v) = entry_attrs.lookup(all_outputs_id)
-        && v.downcast::<bool>() == Some(true)
-    {
-        if !path_str_owned.ends_with(".drv") {
-            return m.finish_err(Error::eval_error(format!(
-                "tried to add all-outputs context of {path_str_owned}, which is not a derivation, to a string"
-            )));
-        }
-        new_acc.insert(StringContextElem::DrvDeep {
-            drv_path: path_str_owned.clone(),
-        });
-    }
-
-    let new_acc_gc = Gc::new(mc, NixString::with_context("", new_acc));
-    m.replace(1, Value::new(new_acc_gc));
-
-    if let Some(outputs_val) = entry_attrs.lookup(outputs_id) {
-        m.replace(0, outputs_val);
-        m.force_slot_to_pc(
-            0,
-            reader,
-            mc,
-            Continuation::PAppendContextOutputsForced.ip() as usize,
-        )?;
-        reader.set_pc(Continuation::PAppendContextOutputsForced.ip() as usize);
-        return Step::Continue(());
-    }
-
-    m.drop_n(1);
-    let idx_back = m
-        .peek(1)
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
-    m.replace(1, Value::new(idx_back + 1));
-    reader.set_pc(Continuation::PAppendContextLoop.ip() as usize);
-    Step::Continue(())
-}
-
-pub fn append_context_outputs_forced<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    _ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    m.force_slot(0, reader, mc)?;
-    let list_val = m.peek_forced(0);
-    let Some(list) = list_val.downcast::<VmList>() else {
-        return m.finish_type_err(NixType::List, list_val.ty());
-    };
-    if list.inner.borrow().is_empty() {
-        // Stack: [strVal, attrs, idx, acc, list] -> drop list, bump idx.
-        m.drop_n(1);
-        let idx_back = m
-            .peek(1)
-            .downcast::<i32>()
-            .expect("stack slot must be an integer");
-        m.replace(1, Value::new(idx_back + 1));
-        reader.set_pc(Continuation::PAppendContextLoop.ip() as usize);
-        return Step::Continue(());
-    }
-
-    m.push(Value::new(0i32));
-    reader.set_pc(Continuation::PAppendContextOutputElementLoop.ip() as usize);
-    Step::Continue(())
-}
-
-#[expect(
-    clippy::indexing_slicing,
-    clippy::cast_sign_loss,
-    reason = "oidx is a non-negative loop counter guarded by `oidx as usize >= len`, so it indexes the list in bounds"
-)]
-pub fn append_context_output_element_loop<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    _ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let oidx = m
-        .peek(0)
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
-    let list = m
-        .peek_forced(1)
-        .downcast::<VmList>()
-        .expect("stack slot must be a list");
-    let len = list.inner.borrow().len();
-    if oidx as usize >= len {
-        // Stack: [strVal, attrs, idx, acc, list, oidx] -> drop oidx & list,
-        // bump idx in place.
-        m.drop_n(2);
-        let idx_back = m
-            .peek(1)
-            .downcast::<i32>()
-            .expect("stack slot must be an integer");
-        m.replace(1, Value::new(idx_back + 1));
-        reader.set_pc(Continuation::PAppendContextLoop.ip() as usize);
-        return Step::Continue(());
-    }
-
-    let elem = list.inner.borrow()[oidx as usize];
-    m.push(elem);
-    m.force_slot_to_pc(
-        0,
-        reader,
-        mc,
-        Continuation::PAppendContextOutputElementForced.ip() as usize,
-    )?;
-    reader.set_pc(Continuation::PAppendContextOutputElementForced.ip() as usize);
-    Step::Continue(())
-}
-
-#[expect(
-    clippy::indexing_slicing,
-    clippy::cast_sign_loss,
-    reason = "idx is the non-negative outer-loop counter, in range for outer.entries validated by append_context_loop"
-)]
-pub fn append_context_output_element_forced<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    m.force_slot(0, reader, mc)?;
-    let elem = m.peek_forced(0);
-    let Some(output_name) = ctx.get_string(elem) else {
-        return m.finish_type_err(NixType::String, elem.ty());
-    };
-    let output_name: Box<str> = output_name.into();
-
-    let idx = m
-        .peek(4)
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
-    let outer = m
-        .peek_forced(5)
-        .downcast::<AttrSet>()
-        .expect("stack slot must be an attrset");
-    let path_key = outer.entries[idx as usize].0;
-    let path_str: Box<str> = ctx.resolve_string(path_key).into();
-    if !path_str.ends_with(".drv") {
-        return m.finish_err(Error::eval_error(format!(
-            "tried to add derivation output context of {path_str}, which is not a derivation, to a string"
-        )));
-    }
-
-    let acc_gc = m
-        .peek(3)
-        .downcast::<NixString>()
-        .expect("stack slot must be a string");
-    let mut new_acc: StringContext = acc_gc.context().iter().cloned().collect();
-    new_acc.insert(StringContextElem::Built {
-        drv_path: path_str,
-        output: output_name,
-    });
-    let new_acc_gc = Gc::new(mc, NixString::with_context("", new_acc));
-    m.replace(3, Value::new(new_acc_gc));
-
-    // Stack: [strVal, attrs, idx, acc, list, oidx, outElem] -> drop outElem,
-    // bump oidx in place.
-    m.drop_n(1);
-    let oidx = m
-        .peek(0)
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
-    m.replace(0, Value::new(oidx + 1));
-    reader.set_pc(Continuation::PAppendContextOutputElementLoop.ip() as usize);
-    Step::Continue(())
-}
-
-#[expect(
-    clippy::panic,
-    reason = "strVal was forced to WHNF at appendContext entry, so restrict() can never observe a thunk here"
-)]
-fn append_context_finalize<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    // Stack: [strVal, attrs, idx, acc]
-    let acc_gc = m
-        .pop()
-        .downcast::<NixString>()
-        .expect("stack slot must be a string");
-    m.drop_n(2);
-    let str_val_raw = m.pop();
-
-    // The strVal was already forced at entry; restrict() is infallible here.
-    let str_val = str_val_raw
-        .restrict()
-        .unwrap_or_else(|_| panic!("appendContext: strVal unexpectedly a thunk"));
-
-    let s_str = ctx.get_string(str_val).unwrap_or("").to_owned();
-    let context: StringContext = acc_gc.context().iter().cloned().collect();
-    let result = if context.is_empty() {
-        let sid = ctx.intern_string(s_str);
-        Value::new(sid)
-    } else {
-        let ns = Gc::new(mc, NixString::with_context(s_str, context));
-        Value::new(ns)
-    };
-    m.return_from_primop(result, reader)
-}

fix-vm/src/primops/control.rs

@@ -1,313 +0,0 @@
-use fix_bytecode::Continuation;
-use fix_error::{Error, Result};
-use fix_macros::handler;
-use fix_runtime::{
-    AttrSet, BytecodeReader, Closure, Env, List, Machine, MachineExt, Slot, Step, StrictValue,
-    Value, VmRuntimeCtx, VmRuntimeCtxExt,
-};
-use gc_arena::{Gc, Mutation, RefLock};
-use smallvec::SmallVec;
-
-use crate::primops::stubs::*;
-
-#[handler(name = PSeq)]
-fn seq<'gc>(mc: &Mutation<'gc>, e1: Slot<Value<'gc>>, e2: Slot<Value<'gc>>) -> Result<Value<'gc>> {
-    let _e1: Slot<StrictValue<'gc>> = force(e1).await?;
-    Ok(e2.get())
-}
-
-#[handler(name = PDeepSeq)]
-fn deep_seq<'gc>(
-    mc: &Mutation<'gc>,
-    e1: Slot<Value<'gc>>,
-    e2: Slot<Value<'gc>>,
-) -> Result<Value<'gc>> {
-    let e1: Slot<StrictValue<'gc>> = force(e1).await?;
-    if collect_children(e1.get()).is_empty() {
-        return Ok(e2.get());
-    }
-    let seen: Slot<List<'gc>> = spill(Gc::new(mc, List::default()));
-    let worklist: Slot<List<'gc>> = spill(List::new(mc, collect_children(e1.get())));
-    let count: Slot<i32> = spill(worklist.get().inner.borrow().len() as i32);
-    loop {
-        if count.get() == 0 {
-            return Ok(e2.get());
-        }
-        let item = worklist
-            .get()
-            .unlock(mc)
-            .borrow_mut()
-            .pop()
-            .expect("worklist is non-empty while count > 0");
-        count.set(count.get() - 1);
-        let item: Slot<StrictValue<'gc>> = force(item).await?;
-        let added = push_children(mc, seen.get(), worklist.get(), item);
-        count.set(count.get() + added);
-    }
-}
-
-fn collect_children<'gc>(val: StrictValue<'gc>) -> SmallVec<[Value<'gc>; 4]> {
-    if let Some(attrs) = val.downcast::<AttrSet<'gc>>() {
-        attrs.entries.iter().map(|&(_, v)| v).collect()
-    } else if let Some(list) = val.downcast::<List<'gc>>() {
-        list.inner.borrow().iter().copied().collect()
-    } else {
-        SmallVec::new()
-    }
-}
-
-fn push_children<'gc>(
-    mc: &Mutation<'gc>,
-    seen: Gc<'gc, List<'gc>>,
-    worklist: Gc<'gc, List<'gc>>,
-    item: StrictValue<'gc>,
-) -> i32 {
-    let mut added = 0i32;
-    if let Some(attrs) = item.downcast::<AttrSet<'gc>>()
-        && !is_value_in_seen(seen, item.relax())
-    {
-        add_value_to_seen(seen, mc, item.relax());
-        let mut wl = worklist.unlock(mc).borrow_mut();
-        for &(_, v) in attrs.entries.iter() {
-            wl.push(v);
-        }
-        added = attrs.entries.len() as i32;
-    } else if let Some(list) = item.downcast::<List<'gc>>()
-        && !is_value_in_seen(seen, item.relax())
-    {
-        add_value_to_seen(seen, mc, item.relax());
-        let inner = list.inner.borrow();
-        let mut wl = worklist.unlock(mc).borrow_mut();
-        for &v in inner.iter() {
-            wl.push(v);
-        }
-        added = inner.len() as i32;
-    }
-    added
-}
-
-pub fn abort<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    // stack: [msg] - force msg, then abort with it
-    m.force_slot(0, reader, mc)?;
-    let msg_val = m.peek_forced(0);
-    let msg = ctx.get_string(msg_val).unwrap_or("<non-string-value>");
-    m.finish_err(Error::eval_error(format!(
-        "evaluation aborted with the following error message: '{msg}'"
-    )))
-}
-
-pub fn force_result_shallow<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    m.force_slot(0, reader, mc)?;
-    let val = m.peek_forced(0);
-
-    let (count, has_children) = if let Some(attrs) = val.downcast::<AttrSet>() {
-        let len = attrs.entries.len();
-        (len, len > 0)
-    } else if let Some(list) = val.downcast::<List>() {
-        let len = list.inner.borrow().len();
-        (len, len > 0)
-    } else {
-        (0, false)
-    };
-
-    if !has_children {
-        let val = m.pop();
-        return m.finish_ok(ctx.convert_value(val));
-    }
-
-    m.push(Value::new(0i32));
-    m.push(Value::new(count as i32));
-    reader.set_pc(Continuation::ForceResultShallowPush.ip() as usize);
-    Step::Continue(())
-}
-
-#[expect(
-    clippy::cast_sign_loss,
-    reason = "idx is a non-negative loop counter (0..=len); used only with .get(), so the cast is always a valid index or safely out of range"
-)]
-pub fn force_result_shallow_push<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let idx = m
-        .peek(1)
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
-    let len = m
-        .peek(0)
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
-
-    if idx == len {
-        m.drop_n(2);
-        let val = m.pop();
-        return m.finish_ok(ctx.convert_value(val));
-    }
-
-    let val = m.peek_forced(2);
-    let child = if let Some(attrs) = val.downcast::<AttrSet>() {
-        attrs.entries.get(idx as usize).map(|&(_, v)| v)
-    } else if let Some(list) = val.downcast::<List>() {
-        list.inner.borrow().get(idx as usize).copied()
-    } else {
-        None
-    };
-
-    if let Some(child) = child {
-        m.replace(1, Value::new(idx + 1));
-        m.push(child);
-        m.force_slot_to_pc(
-            0,
-            reader,
-            mc,
-            Continuation::ForceResultShallowLoop.ip() as usize,
-        )?;
-        reader.set_pc(Continuation::ForceResultShallowLoop.ip() as usize);
-    }
-    Step::Continue(())
-}
-
-pub fn force_result_shallow_loop<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    _mc: &Mutation<'gc>,
-) -> Step {
-    m.drop_n(1);
-    reader.set_pc(Continuation::ForceResultShallowPush.ip() as usize);
-    Step::Continue(())
-}
-
-pub fn force_result_deep_finish<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    m.finish_ok(ctx.convert_value(val.relax()))
-}
-
-fn is_value_in_seen<'gc>(seen: Gc<'gc, List<'gc>>, val: Value<'gc>) -> bool {
-    if !is_container(val) {
-        return false;
-    }
-    let target = val.to_bits();
-    for &v in seen.inner.borrow().iter() {
-        if v.to_bits() == target {
-            return true;
-        }
-    }
-    false
-}
-
-fn add_value_to_seen<'gc>(seen: Gc<'gc, List<'gc>>, mc: &Mutation<'gc>, val: Value<'gc>) {
-    if is_container(val) {
-        seen.unlock(mc).borrow_mut().push(val);
-    }
-}
-
-pub fn call_functor_1<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    // Stack invariant on every (re-)entry: [..., orig_arg, self, functor]
-    // where `functor` is TOS. Retries during force land back here safely.
-    let functor = m.force_and_retry::<StrictValue>(reader, mc)?;
-    // Stack now: [..., orig_arg, self]
-    let self_val = m.pop();
-    m.push(functor.relax());
-    // Stack: [..., orig_arg, functor]
-    // Call 1: functor(self). Resume into CallFunctor2 once it returns.
-    m.call(
-        reader,
-        mc,
-        self_val,
-        Continuation::CallFunctor2.ip() as usize,
-    )
-}
-
-pub fn call_functor_2<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    // Stack on entry: [..., orig_arg, intermediate]
-    // call_stack top: synthetic frame with caller's resume_pc.
-    let intermediate = m.pop();
-    let orig_arg = m.pop();
-    let saved = m.pop_call_frame().expect("functor outer frame missing");
-    m.set_env(saved.env);
-    m.push(intermediate);
-    // Call 2: intermediate(orig_arg). Resume to caller.
-    m.call(reader, mc, orig_arg, saved.pc)
-}
-
-#[expect(
-    clippy::unreachable,
-    reason = "CallPattern is only dispatched for closures whose pattern is Some, established when the Call opcode routed here"
-)]
-pub fn call_pattern<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let (func, attrset) = m.force_and_retry::<(Gc<Closure>, Gc<AttrSet>)>(reader, mc)?;
-
-    let Closure {
-        ip,
-        n_locals,
-        env,
-        pattern,
-    } = *func;
-    let Some(pattern) = pattern else {
-        unreachable!()
-    };
-    // TODO: get function name
-    // TODO: param spans
-    if !pattern.ellipsis {
-        for key in pattern.required.iter().copied() {
-            if attrset.lookup(key).is_none() {
-                let name = ctx.resolve_string(key);
-                return m.finish_err(Error::eval_error(format!(
-                    "function 'anonymous lambda' called without required argument '{name}'"
-                )));
-            }
-        }
-        for &(key, _) in attrset.entries.iter() {
-            let is_expected = pattern.required.contains(&key) || pattern.optional.contains(&key);
-            if !is_expected {
-                let name = ctx.resolve_string(key);
-                return m.finish_err(Error::eval_error(format!(
-                    "function 'anonymous lambda' called with unexpected argument '{name}'"
-                )));
-            }
-        }
-    }
-
-    let new_env = Gc::new(
-        mc,
-        RefLock::new(Env::with_arg(Value::new(attrset), n_locals, env)),
-    );
-    reader.set_pc(ip as usize);
-    m.set_env(new_env);
-
-    Step::Continue(())
-}
-
-fn is_container(val: Value<'_>) -> bool {
-    val.is::<AttrSet>() || val.is::<List<'_>>()
-}

fix-vm/src/primops/conv.rs

@@ -1,55 +0,0 @@
-use fix_error::Error;
-use fix_lang::StringId;
-use fix_runtime::{
-    BytecodeReader, Machine, MachineExt, NixString, NixType, Path, Step, StrictValue, Value,
-    VmRuntimeCtx,
-};
-use gc_arena::Mutation;
-
-pub fn to_string<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    _ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    if val.is::<StringId>() || val.is::<NixString>() {
-        return m.return_from_primop(val.relax(), reader);
-    }
-    if let Some(p) = val.downcast::<Path>() {
-        return m.return_from_primop(Value::new(p.0), reader);
-    }
-    //  TODO: derivations / `__toString` / `outPath`,
-    //        numbers, lists.
-    m.finish_err(Error::eval_error(format!(
-        "cannot coerce {} to a string",
-        val.ty()
-    )))
-}
-
-#[expect(
-    clippy::unreachable,
-    reason = "val was forced to WHNF by force_and_retry, so its type is never Thunk here"
-)]
-pub fn type_of<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    let name: &str = match val.ty() {
-        NixType::Int => "int",
-        NixType::Float => "float",
-        NixType::Bool => "bool",
-        NixType::Null => "null",
-        NixType::String => "string",
-        NixType::Path => "path",
-        NixType::AttrSet => "set",
-        NixType::List => "list",
-        NixType::Closure | NixType::PrimOp | NixType::PrimOpApp => "lambda",
-        NixType::Thunk => unreachable!("forced"),
-    };
-    let sid = ctx.intern_string(name);
-    m.return_from_primop(Value::new(sid), reader)
-}

fix-vm/src/primops/eq.rs

@@ -1,240 +0,0 @@
-use fix_bytecode::Continuation;
-use fix_runtime::{
-    AttrSet, BytecodeReader, CallFrame, List, Machine, MachineExt, NixNum, Null, Path, Step,
-    StrictValue, Value, VmRuntimeCtx, VmRuntimeCtxExt,
-};
-use gc_arena::{Gc, Mutation};
-use smallvec::SmallVec;
-
-pub fn start_eq<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-    lhs: StrictValue<'gc>,
-    rhs: StrictValue<'gc>,
-    negate: bool,
-) -> Step {
-    match shallow_eq(ctx, lhs, rhs) {
-        ShallowEq::True => {
-            m.push(Value::new(!negate));
-            Step::Continue(())
-        }
-        ShallowEq::False => {
-            m.push(Value::new(negate));
-            Step::Continue(())
-        }
-        ShallowEq::RecurseList(la, lb) => {
-            let lhs_init: SmallVec<[Value<'gc>; 4]> = la.inner.borrow().iter().copied().collect();
-            let rhs_init: SmallVec<[Value<'gc>; 4]> = lb.inner.borrow().iter().copied().collect();
-            enter_eq_machine(m, reader, mc, negate, lhs_init, rhs_init)
-        }
-        ShallowEq::RecurseAttrs(a, b) => {
-            let lhs_init: SmallVec<[Value<'gc>; 4]> = a.entries.iter().map(|&(_, v)| v).collect();
-            let rhs_init: SmallVec<[Value<'gc>; 4]> = b.entries.iter().map(|&(_, v)| v).collect();
-            enter_eq_machine(m, reader, mc, negate, lhs_init, rhs_init)
-        }
-    }
-}
-
-pub fn eq_step<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let rhs_q = m
-        .peek(0)
-        .downcast::<List>()
-        .expect("eq state corrupted: rhs_queue");
-    let lhs_q = m
-        .peek(1)
-        .downcast::<List>()
-        .expect("eq state corrupted: lhs_queue");
-    let result = m
-        .peek(2)
-        .downcast::<bool>()
-        .expect("eq state corrupted: result");
-
-    if !result || lhs_q.inner.borrow().is_empty() {
-        return finalize(m, reader);
-    }
-
-    let lhs = lhs_q
-        .unlock(mc)
-        .borrow_mut()
-        .pop()
-        .expect("non-empty lhs queue");
-    let rhs = rhs_q
-        .unlock(mc)
-        .borrow_mut()
-        .pop()
-        .expect("non-empty rhs queue");
-    m.push(lhs);
-    m.push(rhs);
-    reader.set_pc(Continuation::EqForce.ip() as usize);
-    Step::Continue(())
-}
-
-pub fn eq_force<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let (lhs, rhs) = m.force_and_retry::<(StrictValue, StrictValue)>(reader, mc)?;
-    apply_pair(m, ctx, mc, lhs, rhs);
-    reader.set_pc(Continuation::EqStep.ip() as usize);
-    Step::Continue(())
-}
-
-fn finalize<'gc, M: Machine<'gc>>(m: &mut M, reader: &mut BytecodeReader<'_>) -> Step {
-    m.drop_n(2);
-    let result = m
-        .pop()
-        .downcast::<bool>()
-        .expect("eq state corrupted: result");
-    let negate = m
-        .pop()
-        .downcast::<bool>()
-        .expect("eq state corrupted: negate");
-    m.return_from_primop(Value::new(result ^ negate), reader)
-}
-
-fn apply_pair<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &impl VmRuntimeCtx,
-    mc: &Mutation<'gc>,
-    lhs: StrictValue<'gc>,
-    rhs: StrictValue<'gc>,
-) {
-    match shallow_eq(ctx, lhs, rhs) {
-        ShallowEq::True => {}
-        ShallowEq::False => {
-            m.replace(2, Value::new(false));
-        }
-        ShallowEq::RecurseList(la, lb) => {
-            extend_queues(
-                m,
-                mc,
-                la.inner.borrow().iter().copied(),
-                lb.inner.borrow().iter().copied(),
-            );
-        }
-        ShallowEq::RecurseAttrs(a, b) => {
-            extend_queues(
-                m,
-                mc,
-                a.entries.iter().map(|&(_, v)| v),
-                b.entries.iter().map(|&(_, v)| v),
-            );
-        }
-    }
-}
-
-fn extend_queues<'gc, M, L, R>(m: &mut M, mc: &Mutation<'gc>, lhs_iter: L, rhs_iter: R)
-where
-    M: Machine<'gc>,
-    L: IntoIterator<Item = Value<'gc>>,
-    R: IntoIterator<Item = Value<'gc>>,
-{
-    let rhs_q = m
-        .peek(0)
-        .downcast::<List>()
-        .expect("eq state corrupted: rhs_queue");
-    let lhs_q = m
-        .peek(1)
-        .downcast::<List>()
-        .expect("eq state corrupted: lhs_queue");
-    let mut lq = lhs_q.unlock(mc).borrow_mut();
-    let mut rq = rhs_q.unlock(mc).borrow_mut();
-    for (x, y) in lhs_iter.into_iter().zip(rhs_iter) {
-        lq.push(x);
-        rq.push(y);
-    }
-}
-
-fn enter_eq_machine<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-    negate: bool,
-    lhs_init: SmallVec<[Value<'gc>; 4]>,
-    rhs_init: SmallVec<[Value<'gc>; 4]>,
-) -> Step {
-    let resume_pc = reader.pc();
-    m.push_call_frame(CallFrame {
-        pc: resume_pc,
-        thunk: None,
-        env: m.env(),
-        depth: None,
-    });
-    m.inc_call_depth();
-    m.push(Value::new(negate));
-    m.push(Value::new(true));
-    m.push(Value::new(List::new(mc, lhs_init)));
-    m.push(Value::new(List::new(mc, rhs_init)));
-    reader.set_pc(Continuation::EqStep.ip() as usize);
-    Step::Continue(())
-}
-
-enum ShallowEq<'gc> {
-    True,
-    False,
-    RecurseList(Gc<'gc, List<'gc>>, Gc<'gc, List<'gc>>),
-    RecurseAttrs(Gc<'gc, AttrSet<'gc>>, Gc<'gc, AttrSet<'gc>>),
-}
-
-fn shallow_eq<'gc>(
-    ctx: &impl VmRuntimeCtx,
-    lhs: StrictValue<'gc>,
-    rhs: StrictValue<'gc>,
-) -> ShallowEq<'gc> {
-    if let (Some(a), Some(b)) = (lhs.downcast_num(), rhs.downcast_num()) {
-        let eq = match (a, b) {
-            (NixNum::Int(a), NixNum::Int(b)) => a == b,
-            (NixNum::Float(a), NixNum::Float(b)) => a == b,
-            (NixNum::Int(a), NixNum::Float(b)) => a as f64 == b,
-            (NixNum::Float(a), NixNum::Int(b)) => a == b as f64,
-        };
-        return bool_outcome(eq);
-    }
-    if let (Some(a), Some(b)) = (lhs.downcast::<bool>(), rhs.downcast::<bool>()) {
-        return bool_outcome(a == b);
-    }
-    if lhs.is::<Null>() && rhs.is::<Null>() {
-        return ShallowEq::True;
-    }
-    if let (Some(a), Some(b)) = (lhs.downcast::<Path>(), rhs.downcast::<Path>()) {
-        return bool_outcome(a.0 == b.0);
-    }
-    if let (Some(a), Some(b)) = (ctx.get_string(lhs), ctx.get_string(rhs)) {
-        return bool_outcome(a == b);
-    }
-    if let (Some(a), Some(b)) = (lhs.downcast::<List>(), rhs.downcast::<List>()) {
-        if a.inner.borrow().len() != b.inner.borrow().len() {
-            return ShallowEq::False;
-        }
-        return ShallowEq::RecurseList(a, b);
-    }
-    if let (Some(a), Some(b)) = (
-        lhs.downcast::<AttrSet<'gc>>(),
-        rhs.downcast::<AttrSet<'gc>>(),
-    ) {
-        let ae = &a.entries;
-        let be = &b.entries;
-        if ae.len() != be.len() {
-            return ShallowEq::False;
-        }
-        for (l, r) in ae.iter().zip(be.iter()) {
-            if l.0 != r.0 {
-                return ShallowEq::False;
-            }
-        }
-        return ShallowEq::RecurseAttrs(a, b);
-    }
-    ShallowEq::False
-}
-
-fn bool_outcome<'gc>(b: bool) -> ShallowEq<'gc> {
-    if b { ShallowEq::True } else { ShallowEq::False }
-}

fix-vm/src/primops/io.rs

@@ -1,199 +0,0 @@
-use std::path::PathBuf;
-
-use fix_bytecode::Continuation;
-use fix_error::Error;
-use fix_lang::StringId;
-use fix_runtime::{
-    AttrSet, Break, BytecodeReader, CallFrame, Machine, MachineExt, Path, PendingLoad,
-    PendingScope, Step, StrictValue, Value, VmRuntimeCtx, VmRuntimeCtxExt, canon_path_str,
-};
-use gc_arena::{Gc, Mutation};
-use hashbrown::HashSet;
-
-pub fn import<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    // stack: [path]
-    let path_val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    let path_str = match ctx.get_string_or_path(path_val) {
-        Some(s) => s.to_owned(),
-        None => {
-            return m.finish_err(Error::eval_error(format!(
-                "expected a path or string, got {}",
-                path_val.ty()
-            )));
-        }
-    };
-    let abs = match resolve_import_target(&path_str) {
-        Ok(p) => p,
-        Err(e) => return m.finish_err(e),
-    };
-
-    if let Some(cached) = m.import_cache_get(&abs) {
-        return m.return_from_primop(cached, reader);
-    }
-
-    // Stash the resolved path on the stack as a string-id so the
-    // finalizer can use it as the cache key. The slot we pop here was
-    // freed by `force_and_retry`, so we simply push.
-    let path_sid = ctx.intern_string(abs.to_string_lossy());
-    m.push(Value::new(path_sid));
-    let env = m.env();
-    m.push_call_frame(CallFrame {
-        pc: Continuation::PImportFinalize.ip() as usize,
-        thunk: None,
-        env,
-        depth: None,
-    });
-
-    m.set_pending_load(PendingLoad {
-        path: abs,
-        scope: None,
-    });
-    Step::Break(Break::LoadFile)
-}
-
-#[expect(
-    clippy::unreachable,
-    reason = "import always pushes the PImportFinalize call frame before this runs, so pop_call_frame is always Some"
-)]
-pub fn import_finalize<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-) -> Step {
-    // stack: [path_sid, return_value]
-    let val = m.pop();
-    let path_sid = m
-        .pop()
-        .downcast::<StringId>()
-        .expect("stack slot must be a string");
-    // The cache key is keyed by the absolute path string we interned in
-    // `import`. Resolve it back to the host PathBuf.
-    let path_str = ctx.resolve_string(path_sid).to_owned();
-    m.import_cache_insert(PathBuf::from(path_str), val);
-    m.push(val);
-    let Some(CallFrame {
-        pc: ret_pc,
-        thunk: _,
-        env,
-        depth: None,
-    }) = m.pop_call_frame()
-    else {
-        unreachable!()
-    };
-    reader.set_pc(ret_pc);
-    // FIXME:
-    // m.dec_call_depth();
-    m.set_env(env);
-    Step::Continue(())
-}
-
-pub fn scoped_import<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    // stack: [scope, path]
-    let (scope_attrs, path_val) = m.force_and_retry::<(Gc<AttrSet>, StrictValue)>(reader, mc)?;
-    let path_str = match ctx.get_string_or_path(path_val) {
-        Some(s) => s.to_owned(),
-        None => {
-            return m.finish_err(Error::eval_error(format!(
-                "expected a path or string, got {}",
-                path_val.ty()
-            )));
-        }
-    };
-    let abs = match resolve_import_target(&path_str) {
-        Ok(p) => p,
-        Err(e) => return m.finish_err(e),
-    };
-
-    let keys: HashSet<StringId> = scope_attrs.entries.iter().map(|&(k, _)| k).collect();
-    let slot_id = m.scope_slots_push(Value::new(scope_attrs));
-
-    let env = m.env();
-    m.push_call_frame(CallFrame {
-        pc: Continuation::PScopedImportFinalize.ip() as usize,
-        thunk: None,
-        env,
-        depth: None,
-    });
-
-    m.set_pending_load(PendingLoad {
-        path: abs,
-        scope: Some(PendingScope { keys, slot_id }),
-    });
-    Step::Break(Break::LoadFile)
-}
-
-pub fn scoped_import_finalize<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    _ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    _mc: &Mutation<'gc>,
-) -> Step {
-    // stack: [return_value]
-    // We intentionally do NOT pop the slot from `scope_slots` so that
-    // closures or thunks created inside the imported file can still
-    // resolve their scope after `scopedImport` returns.
-    let val = m.pop();
-    m.return_from_primop(val, reader)
-}
-
-pub fn path_exists<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let path_val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    // pathExists requires an absolute path. A `Path` value is
-    // always absolute; a string is accepted only if it starts with `/`.
-    let (path, is_path_value) = if let Some(p) = path_val.downcast::<Path>() {
-        (ctx.resolve_string(p.0).to_owned(), true)
-    } else if let Some(s) = ctx.get_string(path_val) {
-        (s.to_owned(), false)
-    } else {
-        return m.finish_err(Error::eval_error(format!(
-            "expected a path or string, got {}",
-            path_val.ty()
-        )));
-    };
-    if !is_path_value && !path.starts_with('/') {
-        return m.finish_err(Error::eval_error(format!(
-            "string '{path}' doesn't represent an absolute path"
-        )));
-    }
-    // CppNix collapses consecutive slashes and resolves `.` / `..` lexically
-    // before checking. Trailing-slash / trailing-dot mean "must be a directory".
-    let must_be_dir = path.ends_with('/') || path.ends_with("/.");
-    let canon = canon_path_str(&path);
-    let p = std::path::Path::new(&canon);
-    let exists = if must_be_dir {
-        std::fs::metadata(p).map(|m| m.is_dir()).unwrap_or(false)
-    } else {
-        std::fs::symlink_metadata(p).is_ok()
-    };
-    m.return_from_primop(Value::new(exists), reader)
-}
-
-/// Convert the user-supplied path string into an absolute, dotted-segment
-/// resolved `PathBuf` and append `default.nix` if the target is a directory.
-fn resolve_import_target(path: &str) -> Result<PathBuf, Box<Error>> {
-    let mut abs = PathBuf::from(path);
-    if !abs.is_absolute() {
-        return Err(Error::eval_error(format!(
-            "import: expected an absolute path, got '{path}'"
-        )));
-    }
-    if abs.is_dir() {
-        abs.push("default.nix");
-    }
-    Ok(abs)
-}

fix-vm/src/primops/list.rs

@@ -1,116 +0,0 @@
-use fix_error::Result;
-use fix_macros::handler;
-use fix_runtime::{List, Slot, StrictValue, Value};
-use gc_arena::Mutation;
-
-use crate::primops::stubs::*;
-
-#[handler(name = PFilter)]
-fn filter<'gc>(
-    mc: &Mutation<'gc>,
-    pred: Slot<Value<'gc>>,
-    list: Slot<Value<'gc>>,
-) -> Result<Value<'gc>> {
-    let list: Slot<List<'gc>> = force(list).await?;
-    if list.get().inner.borrow().is_empty() {
-        return Ok(Value::new(list.get()));
-    }
-    let idx: Slot<i32> = spill(0i32);
-    let acc: Slot<List<'gc>> = spill(List::new_gc(mc));
-    loop {
-        #[expect(
-            clippy::indexing_slicing,
-            reason = "idx is a non-negative loop counter in 0..list.len(), so it indexes the list in bounds"
-        )]
-        let keep: bool = call(&pred, list.get().inner.borrow()[idx.get() as usize]).await?;
-        if keep {
-            #[expect(
-                clippy::indexing_slicing,
-                reason = "idx is a non-negative loop counter in 0..list.len(), so it indexes the list in bounds"
-            )]
-            let elem = list.get().inner.borrow()[idx.get() as usize];
-            acc.get().unlock(mc).borrow_mut().push(elem);
-        }
-        if idx.get() as usize == list.get().inner.borrow().len() - 1 {
-            return Ok(Value::new(acc.get()));
-        }
-        idx.set(idx.get() + 1);
-    }
-}
-
-#[handler(name = PAll)]
-fn all<'gc>(
-    mc: &Mutation<'gc>,
-    pred: Slot<Value<'gc>>,
-    list: Slot<Value<'gc>>,
-) -> Result<Value<'gc>> {
-    let list: Slot<List<'gc>> = force(list).await?;
-    if list.get().inner.borrow().is_empty() {
-        return Ok(Value::new(true));
-    }
-    let idx: Slot<i32> = spill(0i32);
-    loop {
-        #[expect(
-            clippy::indexing_slicing,
-            reason = "idx is a non-negative loop counter in 0..list.len(), so it indexes the list in bounds"
-        )]
-        let keep: bool = call(&pred, list.get().inner.borrow()[idx.get() as usize]).await?;
-        if !keep || idx.get() as usize + 1 == list.get().inner.borrow().len() {
-            return Ok(Value::new(keep));
-        }
-        idx.set(idx.get() + 1);
-    }
-}
-
-#[handler(name = PAny)]
-fn any<'gc>(
-    mc: &Mutation<'gc>,
-    pred: Slot<Value<'gc>>,
-    list: Slot<Value<'gc>>,
-) -> Result<Value<'gc>> {
-    let list: Slot<List<'gc>> = force(list).await?;
-    if list.get().inner.borrow().is_empty() {
-        return Ok(Value::new(false));
-    }
-    let idx: Slot<i32> = spill(0i32);
-    loop {
-        #[expect(
-            clippy::indexing_slicing,
-            reason = "idx is a non-negative loop counter in 0..list.len(), so it indexes the list in bounds"
-        )]
-        let keep: bool = call(&pred, list.get().inner.borrow()[idx.get() as usize]).await?;
-        if keep || idx.get() as usize + 1 == list.get().inner.borrow().len() {
-            return Ok(Value::new(keep));
-        }
-        idx.set(idx.get() + 1);
-    }
-}
-
-#[handler(name = PFoldlStrict)]
-fn foldl_strict<'gc>(
-    mc: &Mutation<'gc>,
-    op: Slot<Value<'gc>>,
-    nul: Slot<Value<'gc>>,
-    list: Slot<Value<'gc>>,
-) -> Result<Value<'gc>> {
-    let list: Slot<List<'gc>> = force(list).await?;
-    if list.get().inner.borrow().is_empty() {
-        return Ok(nul.get());
-    }
-    let idx: Slot<i32> = spill(0i32);
-    let acc = spill(nul.get());
-    loop {
-        let f = call(&op, acc.get()).await?;
-        #[expect(
-            clippy::indexing_slicing,
-            reason = "idx is a non-negative loop counter in 0..list.len(), so it indexes the list in bounds"
-        )]
-        let new_acc: StrictValue<'gc> =
-            call(&f, list.get().inner.borrow()[idx.get() as usize]).await?;
-        acc.set(new_acc.relax());
-        if idx.get() as usize + 1 == list.get().inner.borrow().len() {
-            return Ok(acc.get());
-        }
-        idx.set(idx.get() + 1);
-    }
-}

fix-vm/src/primops/mod.rs

@@ -1,88 +0,0 @@
-mod context;
-mod control;
-mod conv;
-mod eq;
-mod io;
-mod list;
-mod path;
-mod stubs;
-
-pub use context::*;
-pub use control::*;
-pub use conv::*;
-pub use eq::*;
-use fix_bytecode::Continuation;
-use fix_error::Error;
-use fix_runtime::{BytecodeReader, Machine, Step, VmRuntimeCtx};
-use gc_arena::Mutation;
-pub use io::*;
-pub use list::*;
-pub use path::*;
-
-pub fn dispatch_cont<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    use Continuation::*;
-    let cont = reader.read_u8();
-    let Ok(cont) = Continuation::try_from(cont) else {
-        return m.finish_err(Error::eval_error("invalid primop phase"));
-    };
-    match cont {
-        PAbort => abort(m, ctx, reader, mc),
-
-        PAll0 | PAll1 | PAll2 | PAll3 => all(m, reader, mc, cont),
-        PAny0 | PAny1 | PAny2 | PAny3 => any(m, reader, mc, cont),
-        PDeepSeq0 | PDeepSeq1 | PDeepSeq2 | PDeepSeq3 | PDeepSeq4 | PDeepSeq5 => {
-            deep_seq(m, reader, mc, cont)
-        }
-        PSeq0 | PSeq1 => seq(m, reader, mc, cont),
-
-        PFilter0 | PFilter1 | PFilter2 | PFilter3 | PFilter4 => filter(m, reader, mc, cont),
-
-        PFoldlStrict0 | PFoldlStrict1 | PFoldlStrict2 | PFoldlStrict3 | PFoldlStrict4 | PFoldlStrict5 => {
-            foldl_strict(m, reader, mc, cont)
-        }
-
-        ForceResultShallow => force_result_shallow(m, ctx, reader, mc),
-        ForceResultShallowPush => force_result_shallow_push(m, ctx, reader, mc),
-        ForceResultShallowLoop => force_result_shallow_loop(m, reader, mc),
-        ForceResultDeepFinish => force_result_deep_finish(m, ctx, reader, mc),
-
-        EqStep => eq_step(m, reader, mc),
-        EqForce => eq_force(m, ctx, reader, mc),
-
-        CallPattern => call_pattern(m, ctx, reader, mc),
-        CallFunctor1 => call_functor_1(m, reader, mc),
-        CallFunctor2 => call_functor_2(m, reader, mc),
-
-        PImport => import(m, ctx, reader, mc),
-        PImportFinalize => import_finalize(m, ctx, reader),
-        PScopedImport => scoped_import(m, ctx, reader, mc),
-        PScopedImportFinalize => scoped_import_finalize(m, ctx, reader, mc),
-
-        PPathExists => path_exists(m, ctx, reader, mc),
-        PToPath => to_path(m, ctx, reader, mc),
-        PIsPath => is_path(m, reader, mc),
-        PToString => to_string(m, ctx, reader, mc),
-        PTypeOf => type_of(m, ctx, reader, mc),
-
-        PHasContext => has_context(m, ctx, reader, mc),
-        PGetContext => get_context(m, ctx, reader, mc),
-        PAppendContext => append_context(m, ctx, reader, mc),
-        PAppendContextLoop => append_context_loop(m, ctx, reader, mc),
-        PAppendContextEntryForced => append_context_entry_forced(m, ctx, reader, mc),
-        PAppendContextOutputsForced => append_context_outputs_forced(m, ctx, reader, mc),
-        PAppendContextOutputElementLoop => append_context_output_element_loop(m, ctx, reader, mc),
-        PAppendContextOutputElementForced => {
-            append_context_output_element_forced(m, ctx, reader, mc)
-        }
-
-        PUnsafeDiscardStringContext => unsafe_discard_string_context(m, ctx, reader, mc),
-        PUnsafeDiscardOutputDependency => unsafe_discard_output_dependency(m, ctx, reader, mc),
-
-        phase => todo!("primop phase {phase:?}"),
-    }
-}

fix-vm/src/primops/path.rs

@@ -1,43 +0,0 @@
-use fix_error::Error;
-use fix_runtime::{
-    BytecodeReader, Machine, MachineExt, Path, Step, StrictValue, Value, VmRuntimeCtx,
-    VmRuntimeCtxExt, canon_path_str,
-};
-use gc_arena::Mutation;
-
-pub fn to_path<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    ctx: &mut impl VmRuntimeCtx,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    // coerce to path THEN TO STRING
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    if let Some(Path(s)) = val.downcast::<Path>() {
-        return m.return_from_primop(Value::new(s), reader);
-    }
-    let Some(s) = ctx.get_string(val) else {
-        return m.finish_err(Error::eval_error(format!(
-            "cannot coerce {} to a path",
-            val.ty()
-        )));
-    };
-    if !s.starts_with('/') {
-        return m.finish_err(Error::eval_error(format!(
-            "string '{s}' doesn't represent an absolute path"
-        )));
-    }
-    let canon = canon_path_str(s);
-    let sid = ctx.intern_string(canon);
-    m.return_from_primop(Value::new(sid), reader)
-}
-
-pub fn is_path<'gc, M: Machine<'gc>>(
-    m: &mut M,
-    reader: &mut BytecodeReader<'_>,
-    mc: &Mutation<'gc>,
-) -> Step {
-    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
-    let is_path = val.is::<Path>();
-    m.return_from_primop(Value::new(is_path), reader)
-}

fix-vm/src/primops/stubs.rs

@@ -1,9 +0,0 @@
-//! Fallback definitions for the `#[primop]` surface syntax.
-//!
-//! `force`, `call`, and `spill` are recognized and rewritten by the
-//! `#[primop]` proc macro, so compiled code never calls them. They exist only
-//! so the un-expanded source name-resolves in tooling that does not run the
-//! macro (e.g. rust-analyzer while the macro crate is being rebuilt). Calling
-//! one for real is impossible: they never return.
-
-pub use crate::__macro_support::{call, force, spill};

fix-vm/src/value.rs

@@ -0,0 +1,720 @@
+#![allow(dead_code)]
+
+use std::cell::RefCell;
+use std::fmt;
+use std::marker::PhantomData;
+use std::mem::size_of;
+use std::ops::Deref;
+
+use fix_builtins::BuiltinId;
+use fix_common::*;
+use gc_arena::barrier::Unlock;
+use gc_arena::collect::Trace;
+use gc_arena::{Collect, Gc, GcRefLock, Mutation, RefLock};
+use num_enum::TryFromPrimitive;
+use smallvec::SmallVec;
+use string_interner::Symbol;
+use string_interner::symbol::SymbolU32;
+
+use crate::NixNum;
+use crate::boxing::{RawBox, RawStore, RawTag, Value as RawValue};
+
+mod private {
+    pub trait Cealed {}
+}
+
+/// # Safety
+///
+/// TAG must be unique among all implementors.
+#[allow(private_interfaces)]
+pub unsafe trait Storable: private::Cealed {
+    const TAG: RawTag;
+}
+#[allow(private_bounds)]
+pub trait InlineStorable: Storable + RawStore {}
+pub trait GcStorable: Storable {}
+
+macro_rules! define_value_types {
+    (
+        inline { $($itype:ty => $itag:expr, $iname:literal;)* }
+        gc { $($gtype:ty => $gtag:expr, $gname:literal;)* }
+    ) => {
+        $(
+        #[allow(private_interfaces)]
+        unsafe impl Storable for $itype {
+            const TAG: RawTag = $itag;
+        }
+        impl InlineStorable for $itype {}
+        impl private::Cealed for $itype {}
+        )*
+        $(
+        #[allow(private_interfaces)]
+        unsafe impl Storable for $gtype {
+            const TAG: RawTag = $gtag;
+        }
+        impl GcStorable for $gtype {}
+        impl private::Cealed for $gtype {}
+        )*
+
+        const _: () = assert!(size_of::<Value<'static>>() == 8);
+        $(const _: () = assert!(size_of::<$itype>() <= 6);)*
+
+        const _: () = {
+            let tags: &[(bool, u8)] = &[$(RawTag::neg_val($itag)),*, $(RawTag::neg_val($gtag)),*];
+            let mut mask_false: u8 = 0;
+            let mut mask_true: u8 = 0;
+            let mut i = 0;
+            while i < tags.len() {
+                let (neg, val) = tags[i];
+                let bit = 1 << val;
+                if neg {
+                    assert!(mask_true & bit == 0, "duplicate true tag id");
+                    mask_true |= bit;
+                } else {
+                    assert!(mask_false & bit == 0, "duplicate false tag id");
+                    mask_false |= bit;
+                }
+                i += 1;
+            }
+        };
+
+        unsafe impl<'gc> Collect<'gc> for Value<'gc> {
+            const NEEDS_TRACE: bool = true;
+            fn trace<T: Trace<'gc>>(&self, cc: &mut T) {
+                let Some(tag) = self.raw.tag() else { return };
+                match tag {
+                    $(<$gtype as Storable>::TAG => unsafe {
+                        self.load_gc::<$gtype>().trace(cc)
+                    },)*
+                    $(<$itype as Storable>::TAG => (),)*
+                    _ => unreachable!("invalid value tag"),
+                }
+            }
+        }
+
+        impl fmt::Debug for Value<'_> {
+            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+                match self.tag() {
+                    None => write!(f, "Float({:?})", unsafe {
+                        self.raw.float().unwrap_unchecked()
+                    }),
+                    $(Some(<$itype as Storable>::TAG) => write!(f, "{}({:?})", $iname, unsafe {
+                        self.as_inline::<$itype>().unwrap_unchecked()
+                    }),)*
+                    $(Some(<$gtype as Storable>::TAG) =>
+                        write!(f, "{}(..)", $gname),)*
+                    _ => unreachable!("invalid value tag"),
+                }
+            }
+        }
+    };
+}
+
+define_value_types! {
+    inline {
+        i32 => RawTag::P1, "SmallInt";
+        bool => RawTag::P2, "Bool";
+        Null => RawTag::P3, "Null";
+        StringId => RawTag::P4, "SmallString";
+        PrimOp => RawTag::P5, "PrimOp";
+    }
+    gc {
+        i64 => RawTag::P6, "BigInt";
+        NixString => RawTag::P7, "String";
+        AttrSet<'_> => RawTag::N1, "AttrSet";
+        List<'_> => RawTag::N2, "List";
+        Thunk<'_> => RawTag::N3, "Thunk";
+        Closure<'_> => RawTag::N4, "Closure";
+        PrimOpApp<'_> => RawTag::N5, "PrimOpApp";
+    }
+}
+
+/// # Nix runtime value representation
+///
+/// NaN-boxed value fitting in 8 bytes.
+#[derive(Copy, Clone)]
+#[repr(transparent)]
+pub struct Value<'gc> {
+    raw: RawBox,
+    _marker: PhantomData<Gc<'gc, ()>>,
+}
+
+impl Default for Value<'_> {
+    #[inline(always)]
+    fn default() -> Self {
+        Self::new_inline(Null)
+    }
+}
+
+impl<'gc> Value<'gc> {
+    #[inline(always)]
+    fn from_raw_value(rv: RawValue) -> Self {
+        Self {
+            raw: RawBox::from_value(rv),
+            _marker: PhantomData,
+        }
+    }
+
+    /// Load a GC pointer from a value with a negative tag.
+    ///
+    /// # Safety
+    ///
+    /// The value must actually store a `Gc<'gc, T>` with the matching type.
+    #[inline(always)]
+    unsafe fn load_gc<T: GcStorable>(self) -> Gc<'gc, T> {
+        unsafe {
+            let rv = self.raw.value().unwrap_unchecked();
+            let ptr: *const T = <*const T as RawStore>::from_val(rv);
+            Gc::from_ptr(ptr)
+        }
+    }
+
+    #[inline(always)]
+    const fn tag(self) -> Option<RawTag> {
+        self.raw.tag()
+    }
+}
+
+impl<'gc> Value<'gc> {
+    #[inline]
+    pub fn new_float(val: f64) -> Self {
+        Self {
+            raw: RawBox::from_float(val),
+            _marker: PhantomData,
+        }
+    }
+
+    #[inline]
+    pub fn new_inline<T: InlineStorable>(val: T) -> Self {
+        Self::from_raw_value(RawValue::store(T::TAG, val))
+    }
+
+    #[inline]
+    pub fn new_gc<T: GcStorable>(gc: Gc<'gc, T>) -> Self {
+        let ptr = Gc::as_ptr(gc);
+        Self::from_raw_value(RawValue::store(T::TAG, ptr))
+    }
+
+    #[inline]
+    pub fn make_int(val: i64, mc: &Mutation<'gc>) -> Self {
+        if val >= i32::MIN as i64 && val <= i32::MAX as i64 {
+            Value::new_inline(val as i32)
+        } else {
+            Value::new_gc(Gc::new(mc, val))
+        }
+    }
+}
+
+impl<'gc> Value<'gc> {
+    #[inline]
+    pub fn is_float(self) -> bool {
+        self.raw.is_float()
+    }
+
+    #[inline]
+    pub fn is<T: Storable>(self) -> bool {
+        self.tag() == Some(T::TAG)
+    }
+}
+
+impl<'gc> Value<'gc> {
+    #[inline]
+    pub fn as_float(self) -> Option<f64> {
+        self.raw.float().copied()
+    }
+
+    #[inline]
+    pub fn as_inline<T: InlineStorable>(self) -> Option<T> {
+        if self.is::<T>() {
+            Some(unsafe {
+                let rv = self.raw.value().unwrap_unchecked();
+                T::from_val(rv)
+            })
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    pub fn as_gc<T: GcStorable>(self) -> Option<Gc<'gc, T>> {
+        if self.is::<T>() {
+            Some(unsafe {
+                let rv = self.raw.value().unwrap_unchecked();
+                let ptr: *const T = <*const T as RawStore>::from_val(rv);
+                Gc::from_ptr(ptr)
+            })
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    pub(crate) fn to_bits(self) -> u64 {
+        self.raw.to_bits()
+    }
+
+    #[inline]
+    pub fn as_num(self) -> Option<NixNum> {
+        if let Some(i) = self.as_inline::<i32>() {
+            Some(NixNum::Int(i as i64))
+        } else if let Some(gc_i) = self.as_gc::<i64>() {
+            Some(NixNum::Int(*gc_i))
+        } else {
+            self.as_float().map(NixNum::Float)
+        }
+    }
+
+    #[inline]
+    pub fn restrict(self) -> Result<StrictValue<'gc>, Gc<'gc, Thunk<'gc>>> {
+        if let Some(thunk) = self.as_gc::<Thunk<'gc>>() {
+            Err(thunk)
+        } else {
+            Ok(StrictValue(self))
+        }
+    }
+
+    #[inline]
+    pub fn ty(self) -> NixType {
+        if self.is_float() {
+            NixType::Float
+        } else if self.is::<i32>() || self.is::<i64>() {
+            NixType::Int
+        } else if self.is::<bool>() {
+            NixType::Bool
+        } else if self.is::<Null>() {
+            NixType::Null
+        } else if self.is::<StringId>() {
+            NixType::String
+        } else if self.is::<PrimOp>() {
+            NixType::PrimOp
+        } else if self.is::<NixString>() {
+            NixType::String
+        } else if self.is::<AttrSet>() {
+            NixType::AttrSet
+        } else if self.is::<List>() {
+            NixType::List
+        } else if self.is::<Thunk>() {
+            NixType::Thunk
+        } else if self.is::<Closure>() {
+            NixType::Closure
+        } else if self.is::<PrimOpApp>() {
+            NixType::PrimOpApp
+        } else {
+            unreachable!("value has no recognized type tag")
+        }
+    }
+
+    #[inline]
+    pub(crate) fn expect_inline<T: InlineStorable>(self) -> Result<T, NixType> {
+        self.as_inline::<T>().ok_or_else(|| self.ty())
+    }
+
+    #[inline]
+    pub(crate) fn expect_gc<T: GcStorable>(self) -> Result<Gc<'gc, T>, NixType> {
+        self.as_gc::<T>().ok_or_else(|| self.ty())
+    }
+
+    #[inline]
+    pub(crate) fn expect_num(self) -> Result<NixNum, NixType> {
+        self.as_num().ok_or_else(|| self.ty())
+    }
+
+    #[inline]
+    pub(crate) fn expect_bool(self) -> Result<bool, NixType> {
+        self.as_inline::<bool>().ok_or_else(|| self.ty())
+    }
+
+    #[inline]
+    pub(crate) fn expect_float(self) -> Result<f64, NixType> {
+        self.as_float().ok_or_else(|| self.ty())
+    }
+}
+
+#[derive(Copy, Clone, Default)]
+#[repr(transparent)]
+pub struct StaticValue(Value<'static>);
+
+impl<'gc> From<StaticValue> for Value<'gc> {
+    #[inline]
+    fn from(value: StaticValue) -> Self {
+        // SAFETY: StaticValue is guaranteed to not contain any `Gc`.
+        unsafe { std::mem::transmute::<Value<'static>, Value<'gc>>(value.0) }
+    }
+}
+
+impl StaticValue {
+    #[inline]
+    pub fn new_float(val: f64) -> Self {
+        Self(Value::new_float(val))
+    }
+    #[inline]
+    pub fn new_inline<T: InlineStorable>(val: T) -> Self {
+        Self(Value::new_inline(val))
+    }
+    #[inline]
+    pub fn new_primop(id: BuiltinId, arity: u8, dispatch_ip: u32) -> Self {
+        Self(Value::new_inline(PrimOp {
+            id,
+            arity,
+            dispatch_ip,
+        }))
+    }
+    #[inline]
+    pub fn is_float(self) -> bool {
+        self.0.is_float()
+    }
+    #[inline]
+    pub fn is<T: InlineStorable>(self) -> bool {
+        self.0.is::<T>()
+    }
+    #[inline]
+    pub fn as_float(self) -> Option<f64> {
+        self.0.as_float()
+    }
+    #[inline]
+    pub fn as_inline<T: InlineStorable>(self) -> Option<T> {
+        self.0.as_inline::<T>()
+    }
+    #[inline]
+    pub fn to_bits(self) -> u64 {
+        self.0.raw.to_bits()
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+pub(crate) struct Null;
+impl RawStore for Null {
+    fn to_val(self, value: &mut RawValue) {
+        value.set_data([0; 6]);
+    }
+    fn from_val(_: &RawValue) -> Self {
+        Self
+    }
+}
+
+impl RawStore for StringId {
+    fn to_val(self, value: &mut RawValue) {
+        (self.0.to_usize() as u32).to_val(value);
+    }
+    fn from_val(value: &RawValue) -> Self {
+        Self(
+            SymbolU32::try_from_usize(u32::from_val(value) as usize)
+                .expect("failed to read StringId from Value"),
+        )
+    }
+}
+
+/// Heap-allocated Nix string.
+///
+/// Stored on the GC heap via `Gc<'gc, NixString>`. The string data itself
+/// lives in a standard `Box<str>` owned by this struct; the GC only manages
+/// the outer allocation.
+#[derive(Collect)]
+#[collect(require_static)]
+pub(crate) struct NixString {
+    data: Box<str>,
+    // TODO: string context for derivation dependency tracking
+}
+
+impl NixString {
+    pub(crate) fn new(s: impl Into<Box<str>>) -> Self {
+        Self { data: s.into() }
+    }
+
+    pub(crate) fn as_str(&self) -> &str {
+        &self.data
+    }
+}
+
+impl fmt::Debug for NixString {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Debug::fmt(&self.data, f)
+    }
+}
+
+#[derive(Collect, Debug, Default)]
+#[collect(no_drop)]
+pub(crate) struct AttrSet<'gc> {
+    pub(crate) entries: RefLock<SmallVec<[(StringId, Value<'gc>); 4]>>,
+}
+
+impl<'gc> Unlock for AttrSet<'gc> {
+    type Unlocked = RefCell<SmallVec<[(StringId, Value<'gc>); 4]>>;
+    unsafe fn unlock_unchecked(&self) -> &Self::Unlocked {
+        unsafe { self.entries.unlock_unchecked() }
+    }
+}
+
+impl<'gc> AttrSet<'gc> {
+    pub(crate) fn from_sorted_unchecked(entries: SmallVec<[(StringId, Value<'gc>); 4]>) -> Self {
+        debug_assert!(entries.is_sorted_by_key(|(key, _)| *key));
+        Self {
+            entries: RefLock::new(entries),
+        }
+    }
+
+    pub(crate) fn lookup(&self, key: StringId) -> Option<Value<'gc>> {
+        let entries = self.entries.borrow();
+        entries
+            .binary_search_by_key(&key, |(k, _)| *k)
+            .ok()
+            .map(|i| entries[i].1)
+    }
+
+    pub(crate) fn has(&self, key: StringId) -> bool {
+        self.entries
+            .borrow()
+            .binary_search_by_key(&key, |(k, _)| *k)
+            .is_ok()
+    }
+
+    pub(crate) fn merge(&self, other: &Self, mc: &Mutation<'gc>) -> Gc<'gc, Self> {
+        use std::cmp::Ordering::*;
+
+        let self_entries = self.entries.borrow();
+        let other_entries = other.entries.borrow();
+        debug_assert!(self_entries.is_sorted_by_key(|(key, _)| *key));
+        debug_assert!(other_entries.is_sorted_by_key(|(key, _)| *key));
+
+        let mut entries = SmallVec::new();
+        let mut i = 0;
+        let mut j = 0;
+        while i < self_entries.len() && j < other_entries.len() {
+            match self_entries[i].0.cmp(&other_entries[j].0) {
+                Less => {
+                    entries.push(self_entries[i]);
+                    i += 1;
+                }
+                Greater => {
+                    entries.push(other_entries[j]);
+                    j += 1;
+                }
+                Equal => {
+                    entries.push(other_entries[j]);
+                    i += 1;
+                    j += 1;
+                }
+            }
+        }
+        entries.extend(other_entries[j..].iter().cloned());
+        entries.extend(self_entries[i..].iter().cloned());
+
+        debug_assert!(entries.is_sorted_by_key(|(key, _)| *key));
+
+        Gc::new(
+            mc,
+            AttrSet {
+                entries: RefLock::new(entries),
+            },
+        )
+    }
+}
+
+#[derive(Collect, Debug, Default)]
+#[repr(transparent)]
+#[collect(no_drop)]
+pub(crate) struct List<'gc> {
+    pub(crate) inner: RefLock<SmallVec<[Value<'gc>; 4]>>,
+}
+
+impl<'gc> List<'gc> {
+    pub(crate) fn new(mc: &Mutation<'gc>, data: SmallVec<[Value<'gc>; 4]>) -> Gc<'gc, Self> {
+        Gc::new(
+            mc,
+            Self {
+                inner: RefLock::new(data),
+            },
+        )
+    }
+
+    pub(crate) fn new_gc(mc: &Mutation<'gc>) -> Gc<'gc, Self> {
+        Gc::new(mc, Self::default())
+    }
+}
+
+impl<'gc> Unlock for List<'gc> {
+    type Unlocked = RefCell<SmallVec<[Value<'gc>; 4]>>;
+    unsafe fn unlock_unchecked(&self) -> &Self::Unlocked {
+        unsafe { self.inner.unlock_unchecked() }
+    }
+}
+
+pub(crate) type Thunk<'gc> = RefLock<ThunkState<'gc>>;
+
+#[derive(Collect, Debug)]
+#[collect(no_drop)]
+pub(crate) enum ThunkState<'gc> {
+    Pending {
+        ip: usize,
+        env: GcEnv<'gc>,
+        with_env: Option<GcWithEnv<'gc>>,
+    },
+    Apply {
+        func: Value<'gc>,
+        arg: Value<'gc>,
+    },
+    Blackhole,
+    Evaluated(StrictValue<'gc>),
+}
+
+#[derive(Collect, Debug)]
+#[collect(no_drop)]
+pub(crate) struct Env<'gc> {
+    pub(crate) locals: SmallVec<[Value<'gc>; 4]>,
+    pub(crate) prev: Option<GcEnv<'gc>>,
+}
+pub(crate) type GcEnv<'gc> = GcRefLock<'gc, Env<'gc>>;
+
+#[derive(Collect, Debug)]
+#[collect(no_drop)]
+pub(crate) struct WithEnv<'gc> {
+    pub(crate) env: Value<'gc>,
+    pub(crate) prev: Option<GcWithEnv<'gc>>,
+}
+pub(crate) type GcWithEnv<'gc> = Gc<'gc, WithEnv<'gc>>;
+
+impl<'gc> Env<'gc> {
+    pub(crate) fn empty() -> Self {
+        Env {
+            locals: SmallVec::new(),
+            prev: None,
+        }
+    }
+
+    pub(crate) fn with_arg(
+        arg: Value<'gc>,
+        n_locals: u32,
+        prev: Gc<'gc, RefLock<Env<'gc>>>,
+    ) -> Self {
+        let mut locals = smallvec::smallvec![Value::default(); 1 + n_locals as usize];
+        locals[0] = arg;
+        Env {
+            locals,
+            prev: Some(prev),
+        }
+    }
+}
+
+#[derive(Collect, Debug)]
+#[collect(no_drop)]
+pub(crate) struct Closure<'gc> {
+    pub(crate) ip: u32,
+    pub(crate) n_locals: u32,
+    pub(crate) env: Gc<'gc, RefLock<Env<'gc>>>,
+    pub(crate) pattern: Option<Gc<'gc, PatternInfo>>,
+}
+
+#[derive(Collect, Debug)]
+#[collect(require_static)]
+pub(crate) struct PatternInfo {
+    pub(crate) required: SmallVec<[StringId; 4]>,
+    pub(crate) optional: SmallVec<[StringId; 4]>,
+    pub(crate) ellipsis: bool,
+    pub(crate) param_spans: Box<[(StringId, u32)]>,
+}
+
+#[repr(packed, Rust)]
+#[derive(Clone, Copy, Debug, Collect)]
+#[collect(require_static)]
+pub(crate) struct PrimOp {
+    pub(crate) id: BuiltinId,
+    pub(crate) arity: u8,
+    pub(crate) dispatch_ip: u32,
+}
+
+impl RawStore for PrimOp {
+    fn to_val(self, value: &mut RawValue) {
+        let bytes = self.dispatch_ip.to_le_bytes();
+        value.set_data([
+            self.id as u8,
+            self.arity,
+            bytes[0],
+            bytes[1],
+            bytes[2],
+            bytes[3],
+        ]);
+    }
+    fn from_val(value: &RawValue) -> Self {
+        let [id, arity, bytes @ ..] = *value.data();
+        Self {
+            id: BuiltinId::try_from_primitive(id).expect("invalid BuiltinId"),
+            arity,
+            dispatch_ip: u32::from_le_bytes(bytes),
+        }
+    }
+}
+
+#[derive(Collect, Debug)]
+#[collect(no_drop)]
+pub(crate) struct PrimOpApp<'gc> {
+    pub(crate) primop: PrimOp,
+    pub(crate) arity: u8,
+    pub(crate) args: [Value<'gc>; 3],
+}
+
+#[derive(Copy, Clone, Default, Collect)]
+#[repr(transparent)]
+#[collect(no_drop)]
+pub(crate) struct StrictValue<'gc>(Value<'gc>);
+
+impl<'gc> StrictValue<'gc> {
+    #[inline]
+    pub(crate) fn relax(self) -> Value<'gc> {
+        self.0
+    }
+}
+
+impl<'gc> Deref for StrictValue<'gc> {
+    type Target = Value<'gc>;
+    #[inline]
+    fn deref(&self) -> &Value<'gc> {
+        &self.0
+    }
+}
+
+impl fmt::Debug for StrictValue<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Debug::fmt(&self.0, f)
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Collect)]
+#[collect(require_static)]
+pub(crate) enum NixType {
+    Int,
+    Float,
+    Bool,
+    Null,
+    String,
+    AttrSet,
+    List,
+    Thunk,
+    Closure,
+    PrimOp,
+    PrimOpApp,
+}
+
+impl NixType {
+    pub fn display(self) -> &'static str {
+        use NixType::*;
+        match self {
+            Int => "an integer",
+            Float => "a float",
+            Bool => "a boolean",
+            Null => "null",
+            String => "a string",
+            AttrSet => "a set",
+            List => "a list",
+            Thunk => "a thunk",
+            Closure => "a function",
+            PrimOp => "a built-in function",
+            PrimOpApp => "a partially applied built-in function",
+        }
+    }
+}
+
+impl std::fmt::Display for NixType {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.display())
+    }
+}

fix/Cargo.toml

@@ -3,18 +3,6 @@ name = "fix"
 version = "0.1.0"
 edition = "2024"
 
-[[bench]]
-harness = false
-name = "basic_ops"
-
-[[bench]]
-harness = false
-name = "builtins"
-
-[[bench]]
-harness = false
-name = "thunk_scope"
-
 [dependencies]
 mimalloc = "0.1"
 
@@ -29,28 +17,42 @@ clap = { version = "4", features = ["derive"] }
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 
-miette = { version = "7.4", features = ["fancy"] }
 # Error Reporting
 thiserror = "2"
+miette = { version = "7.4", features = ["fancy"] }
 
 # Data Structure
 hashbrown = { workspace = true }
 string-interner = { workspace = true }
 
-ere = { workspace = true }
+# Memory Management
+bumpalo = { workspace = true }
 
-fix-bytecode = { path = "../fix-bytecode" }
-fix-compiler = { path = "../fix-compiler" }
+rnix = { workspace = true }
+
+ere = { workspace = true }
+ghost-cell = { workspace = true }
+
+fix-builtins = { path = "../fix-builtins" }
+fix-common = { path = "../fix-common" }
+fix-codegen = { path = "../fix-codegen" }
 fix-error = { path = "../fix-error" }
-fix-lang = { path = "../fix-lang" }
-fix-runtime = { path = "../fix-runtime" }
+fix-ir = { path = "../fix-ir" }
 fix-vm = { path = "../fix-vm" }
 
 [dev-dependencies]
 criterion = { version = "0.8", features = ["html_reports"] }
-serial_test = "4.0"
 tempfile = "3.24"
 test-log = { version = "0.2", features = ["trace"] }
 
-[lints]
-workspace = true
+[[bench]]
+name = "basic_ops"
+harness = false
+
+[[bench]]
+name = "builtins"
+harness = false
+
+[[bench]]
+name = "thunk_scope"
+harness = false

fix/benches/utils.rs

@@ -1,9 +1,8 @@
-#![allow(clippy::allow_attributes_without_reason)]
-#![allow(dead_code, clippy::unwrap_used, clippy::unwrap_in_result)]
+#![allow(dead_code)]
 
 use fix::Evaluator;
+use fix_common::Value;
 use fix_error::{Result, Source};
-use fix_lang::Value;
 
 pub fn eval(expr: &str) -> Value {
     Evaluator::new()

fix/src/lib.rs

@@ -1,13 +1,20 @@
-use fix_bytecode::InstructionPtr;
-use fix_bytecode::disassembler::{Disassembler, DisassemblerContext};
-use fix_compiler::{CodeState, ExtraScope};
-use fix_error::{Result, Source};
-use fix_lang::StringId;
-use fix_runtime::{ForceMode, StaticValue, VmCode, VmContext, VmRuntimeCtx};
-use fix_vm::Vm;
+#![warn(clippy::unwrap_used)]
+#![allow(dead_code)]
+
+use bumpalo::Bump;
+use fix_builtins::PrimOpPhase;
+use fix_codegen::disassembler::{Disassembler, DisassemblerContext};
+use fix_codegen::{BytecodeContext, InstructionPtr, Op};
+use fix_common::{StringId, Symbol};
+use fix_error::{Error, Result, Source};
+use fix_ir::downgrade::{Downgrade as _, DowngradeContext};
+use fix_ir::{Ir, IrRef, MaybeThunk, RawIrRef, ThunkId};
+use fix_vm::{ForceMode, StaticValue, Vm, VmCode, VmContext, VmRuntimeCtx};
+use ghost_cell::{GhostCell, GhostToken};
 use hashbrown::{HashMap, HashSet};
 use string_interner::{DefaultStringInterner, Symbol as _};
 
+mod derivation;
 pub mod logging;
 
 #[global_allocator]
@@ -18,6 +25,14 @@ pub struct RuntimeState {
     pub constants: Constants,
 }
 
+pub struct CodeState {
+    pub bytecode: Vec<u8>,
+    pub sources: Vec<Source>,
+    pub spans: Vec<(usize, rnix::TextRange)>,
+    pub thunk_count: usize,
+    pub global_env: HashMap<StringId, Ir<'static, RawIrRef<'static>>>,
+}
+
 pub struct Evaluator {
     pub runtime: RuntimeState,
     pub code: CodeState,
@@ -32,25 +47,36 @@ impl Default for Evaluator {
 impl Evaluator {
     pub fn new() -> Self {
         let mut strings = DefaultStringInterner::new();
-        let code = CodeState::new(&mut strings);
+        let global_env = fix_ir::new_global_env(&mut strings);
+        let mut bytecode = Vec::with_capacity(PrimOpPhase::Illegal as usize * 2);
+        for phase in 0..=PrimOpPhase::Illegal as u8 {
+            bytecode.push(Op::DispatchPrimOp as u8);
+            bytecode.push(phase);
+        }
         Self {
             runtime: RuntimeState {
                 strings,
                 constants: Constants::default(),
             },
-            code,
+            code: CodeState {
+                sources: Vec::new(),
+                spans: Vec::new(),
+                thunk_count: 0,
+                bytecode,
+                global_env,
+            },
         }
     }
 
-    pub fn eval(&mut self, source: Source) -> Result<fix_lang::Value> {
+    pub fn eval(&mut self, source: Source) -> Result<fix_common::Value> {
         self.do_eval(source, None, ForceMode::AsIs)
     }
 
-    pub fn eval_shallow(&mut self, source: Source) -> Result<fix_lang::Value> {
+    pub fn eval_shallow(&mut self, source: Source) -> Result<fix_common::Value> {
         self.do_eval(source, None, ForceMode::Shallow)
     }
 
-    pub fn eval_deep(&mut self, source: Source) -> Result<fix_lang::Value> {
+    pub fn eval_deep(&mut self, source: Source) -> Result<fix_common::Value> {
         self.do_eval(source, None, ForceMode::Deep)
     }
 
@@ -58,19 +84,23 @@ impl Evaluator {
         &mut self,
         source: Source,
         scope: &HashSet<StringId>,
-    ) -> Result<fix_lang::Value> {
-        self.do_eval(source, Some(ExtraScope::Repl(scope)), ForceMode::Shallow)
+    ) -> Result<fix_common::Value> {
+        self.do_eval(source, Some(Scope::Repl(scope)), ForceMode::Shallow)
     }
 
     fn do_eval<'ctx>(
         &'ctx mut self,
         source: Source,
-        extra_scope: Option<ExtraScope<'ctx>>,
+        extra_scope: Option<Scope<'ctx>>,
         force_mode: ForceMode,
-    ) -> Result<fix_lang::Value> {
-        let ip = self
-            .code
-            .compile_bytecode(source, extra_scope, &mut self.runtime)?;
+    ) -> Result<fix_common::Value> {
+        let ip = {
+            let mut compiler = CompilerCtx {
+                code: &mut self.code,
+                runtime: &mut self.runtime,
+            };
+            compiler.compile_bytecode(source, extra_scope)?
+        };
         Vm::run(self, ip, force_mode)
     }
 
@@ -79,12 +109,16 @@ impl Evaluator {
         _ident: &str,
         _expr: &str,
         _scope: &mut HashSet<StringId>,
-    ) -> Result<fix_lang::Value> {
-        todo!("add_binding")
+    ) -> Result<fix_common::Value> {
+        todo!()
     }
 
     pub fn compile_bytecode(&mut self, source: Source) -> Result<InstructionPtr> {
-        self.code.compile_bytecode(source, None, &mut self.runtime)
+        let mut compiler = CompilerCtx {
+            code: &mut self.code,
+            runtime: &mut self.runtime,
+        };
+        compiler.compile_bytecode(source, None)
     }
 
     pub fn disassemble_colored(&self, ip: InstructionPtr) -> String {
@@ -97,24 +131,131 @@ impl VmRuntimeCtx for RuntimeState {
         StringId(self.strings.get_or_intern(s))
     }
     fn resolve_string(&self, id: StringId) -> &str {
-        self.strings
-            .resolve(id.0)
-            .expect("interned string id must resolve")
+        #[allow(clippy::unwrap_used)]
+        self.strings.resolve(id.0).unwrap()
     }
     fn get_const(&self, id: u32) -> StaticValue {
-        self.constants.get(id).expect("const id must be valid")
+        #[allow(clippy::unwrap_used)]
+        self.constants.get(id).unwrap()
     }
     fn add_const(&mut self, val: StaticValue) -> u32 {
         self.constants.insert(val)
     }
 }
 
+impl VmCode for CodeState {
+    fn bytecode(&self) -> &[u8] {
+        &self.bytecode
+    }
+    fn compile(
+        &mut self,
+        source: Source,
+        runtime: &mut impl VmRuntimeCtx,
+    ) -> Result<InstructionPtr> {
+        let mut compiler = CompilerCtx {
+            code: self,
+            runtime,
+        };
+        compiler.compile_bytecode(source, None)
+    }
+}
+
 impl VmContext for Evaluator {
     fn split(&mut self) -> (&mut impl VmCode, &mut impl VmRuntimeCtx) {
         (&mut self.code, &mut self.runtime)
     }
 }
 
+struct CompilerCtx<'a, R: VmRuntimeCtx> {
+    code: &'a mut CodeState,
+    runtime: &'a mut R,
+}
+
+impl<'a, R: VmRuntimeCtx> CompilerCtx<'a, R> {
+    fn compile_bytecode(
+        &mut self,
+        source: Source,
+        extra_scope: Option<Scope>,
+    ) -> Result<InstructionPtr> {
+        let root = self.downgrade(source, extra_scope)?;
+        let ip = fix_codegen::compile_bytecode(root.as_ref(), self);
+        Ok(ip)
+    }
+
+    fn downgrade(&mut self, source: Source, extra_scope: Option<Scope>) -> Result<OwnedIr> {
+        tracing::debug!("Parsing Nix expression");
+
+        self.code.sources.push(source.clone());
+
+        let root = rnix::Root::parse(&source.src);
+        handle_parse_error(root.errors(), source.clone()).map_or(Ok(()), Err)?;
+
+        tracing::debug!("Downgrading Nix expression");
+        let expr = root
+            .tree()
+            .expr()
+            .ok_or_else(|| Error::parse_error("unexpected EOF".into()))?;
+        let bump = Bump::new();
+        GhostToken::new(|token| {
+            let downgrade_ctx = DowngradeCtx::new(
+                &bump,
+                token,
+                self.runtime,
+                &self.code.global_env,
+                extra_scope,
+                &mut self.code.thunk_count,
+                source,
+            );
+            let ir = downgrade_ctx.downgrade_toplevel(expr)?;
+            let ir = unsafe { std::mem::transmute::<RawIrRef<'_>, RawIrRef<'static>>(ir) };
+            Ok(OwnedIr { _bump: bump, ir })
+        })
+    }
+}
+
+impl<'a, R: VmRuntimeCtx> BytecodeContext for CompilerCtx<'a, R> {
+    fn intern_string(&mut self, s: &str) -> StringId {
+        self.runtime.intern_string(s)
+    }
+
+    fn register_span(&mut self, range: rnix::TextRange) -> u32 {
+        let id = self.code.spans.len();
+        let source_id = self
+            .code
+            .sources
+            .len()
+            .checked_sub(1)
+            .expect("current_source not set");
+        self.code.spans.push((source_id, range));
+        id as u32
+    }
+
+    fn get_code(&self) -> &[u8] {
+        &self.code.bytecode
+    }
+
+    fn get_code_mut(&mut self) -> &mut Vec<u8> {
+        &mut self.code.bytecode
+    }
+
+    fn add_constant(&mut self, val: fix_codegen::Const) -> u32 {
+        use fix_codegen::Const::*;
+        let val = match val {
+            Smi(x) => StaticValue::new_inline(x),
+            Float(x) => StaticValue::new_float(x),
+            Bool(x) => StaticValue::new_inline(x),
+            String(x) => StaticValue::new_inline(x),
+            PrimOp {
+                id,
+                arity,
+                dispatch_ip,
+            } => StaticValue::new_primop(id, arity, dispatch_ip),
+            Null => StaticValue::default(),
+        };
+        self.runtime.add_const(val)
+    }
+}
+
 #[derive(Default)]
 pub struct Constants {
     data: Vec<StaticValue>,
@@ -136,14 +277,338 @@ impl Constants {
     }
 }
 
+fn parse_error_span(error: &rnix::ParseError) -> Option<rnix::TextRange> {
+    use rnix::ParseError::*;
+    match error {
+        Unexpected(range)
+        | UnexpectedExtra(range)
+        | UnexpectedWanted(_, range, _)
+        | UnexpectedDoubleBind(range)
+        | DuplicatedArgs(range, _) => Some(*range),
+        _ => None,
+    }
+}
+
+fn handle_parse_error<'a>(
+    errors: impl IntoIterator<Item = &'a rnix::ParseError>,
+    source: Source,
+) -> Option<Box<Error>> {
+    for err in errors {
+        if let Some(span) = parse_error_span(err) {
+            return Some(
+                Error::parse_error(err.to_string())
+                    .with_source(source)
+                    .with_span(span),
+            );
+        }
+    }
+    None
+}
+
+struct DowngradeCtx<'ctx, 'id, 'ir, R: VmRuntimeCtx> {
+    bump: &'ir Bump,
+    token: GhostToken<'id>,
+    runtime: &'ctx mut R,
+    source: Source,
+    scopes: Vec<Scope<'ctx>>,
+    with_scope_count: u32,
+    arg_count: u32,
+    thunk_count: &'ctx mut usize,
+    thunk_scopes: Vec<ThunkScope<'id, 'ir>>,
+}
+
+fn should_thunk<'id>(ir: IrRef<'id, '_>, token: &GhostToken<'id>) -> bool {
+    !matches!(
+        ir.borrow(token),
+        Ir::Builtin(_)
+            | Ir::Builtins
+            | Ir::Int(_)
+            | Ir::Float(_)
+            | Ir::Bool(_)
+            | Ir::Null
+            | Ir::Str(_)
+            | Ir::Thunk(_)
+    )
+}
+
+impl<'ctx, 'id, 'ir, R: VmRuntimeCtx> DowngradeCtx<'ctx, 'id, 'ir, R> {
+    fn new(
+        bump: &'ir Bump,
+        token: GhostToken<'id>,
+        runtime: &'ctx mut R,
+        global: &'ctx HashMap<StringId, Ir<'static, RawIrRef<'static>>>,
+        extra_scope: Option<Scope<'ctx>>,
+        thunk_count: &'ctx mut usize,
+        source: Source,
+    ) -> Self {
+        Self {
+            bump,
+            token,
+            runtime,
+            source,
+            scopes: std::iter::once(Scope::Global(global))
+                .chain(extra_scope)
+                .collect(),
+            thunk_count,
+            arg_count: 0,
+            with_scope_count: 0,
+            thunk_scopes: vec![ThunkScope::new_in(bump)],
+        }
+    }
+}
+
+impl<'ctx: 'ir, 'id, 'ir, R: VmRuntimeCtx> DowngradeContext<'id, 'ir>
+    for DowngradeCtx<'ctx, 'id, 'ir, R>
+{
+    fn new_expr(&self, expr: Ir<'ir, IrRef<'id, 'ir>>) -> IrRef<'id, 'ir> {
+        IrRef::new(self.bump.alloc(GhostCell::new(expr)))
+    }
+
+    fn maybe_thunk(&mut self, ir: IrRef<'id, 'ir>) -> MaybeThunk {
+        use MaybeThunk::*;
+        match *ir.borrow(&self.token) {
+            Ir::Builtin(x) => return Builtin(x),
+            Ir::Int(x) => return Int(x),
+            Ir::Float(x) => return Float(x),
+            Ir::Bool(x) => return Bool(x),
+            Ir::Str(x) => return Str(x),
+            Ir::Thunk(x) => return Thunk(x),
+            Ir::Arg { layer } => return Arg { layer },
+            Ir::Builtins => return Builtins,
+            Ir::Null => return Null,
+            _ => (),
+        }
+        let id = ThunkId(*self.thunk_count);
+        *self.thunk_count = self.thunk_count.checked_add(1).expect("thunk id overflow");
+        self.thunk_scopes
+            .last_mut()
+            .expect("no active cache scope")
+            .add_binding(id, ir, &self.token);
+        Thunk(id)
+    }
+
+    fn intern_string(&mut self, sym: impl AsRef<str>) -> StringId {
+        self.runtime.intern_string(sym)
+    }
+
+    fn resolve_sym(&self, id: StringId) -> Symbol<'_> {
+        self.runtime.resolve_string(id).into()
+    }
+
+    fn lookup(&self, sym: StringId, span: rnix::TextRange) -> Result<MaybeThunk> {
+        for scope in self.scopes.iter().rev() {
+            match scope {
+                &Scope::Global(global_scope) => {
+                    use MaybeThunk::*;
+                    if let Some(expr) = global_scope.get(&sym) {
+                        let val = match expr {
+                            Ir::Builtins => Builtins,
+                            Ir::Builtin(s) => Builtin(*s),
+                            Ir::Bool(b) => Bool(*b),
+                            Ir::Null => Null,
+                            _ => unreachable!("globals should only contain leaf IR nodes"),
+                        };
+                        return Ok(val);
+                    }
+                }
+                &Scope::Repl(repl_bindings) => {
+                    if repl_bindings.contains(&sym) {
+                        return Ok(MaybeThunk::ReplBinding(sym));
+                    }
+                }
+                Scope::ScopedImport(scoped_bindings) => {
+                    if scoped_bindings.contains(&sym) {
+                        return Ok(MaybeThunk::ScopedImportBinding(sym));
+                    }
+                }
+                Scope::Let(let_scope) => {
+                    if let Some(&expr) = let_scope.get(&sym) {
+                        return Ok(MaybeThunk::Thunk(expr));
+                    }
+                }
+                &Scope::Param {
+                    sym: param_sym,
+                    abs_layer,
+                } => {
+                    if param_sym == sym {
+                        return Ok(MaybeThunk::Arg {
+                            layer: self.thunk_scopes.len() - abs_layer,
+                        });
+                    }
+                }
+            }
+        }
+
+        if self.with_scope_count > 0 {
+            Ok(MaybeThunk::WithLookup(sym))
+        } else {
+            Err(Error::downgrade_error(
+                format!("'{}' not found", self.resolve_sym(sym)),
+                self.get_current_source(),
+                span,
+            ))
+        }
+    }
+
+    fn get_current_source(&self) -> Source {
+        self.source.clone()
+    }
+
+    fn with_let_scope<F, Ret>(&mut self, keys: &[StringId], f: F) -> Result<Ret>
+    where
+        F: FnOnce(&mut Self) -> Result<(bumpalo::collections::Vec<'ir, IrRef<'id, 'ir>>, Ret)>,
+    {
+        let base = *self.thunk_count;
+        *self.thunk_count = self
+            .thunk_count
+            .checked_add(keys.len())
+            .expect("thunk id overflow");
+        let iter = keys
+            .iter()
+            .enumerate()
+            .map(|(offset, &key)| (key, ThunkId(base + offset)));
+        self.scopes.push(Scope::Let(iter.collect()));
+        let (vals, ret) = {
+            let mut guard = ScopeGuard { ctx: self };
+            f(guard.as_ctx())?
+        };
+        assert_eq!(keys.len(), vals.len());
+        let scope = self.thunk_scopes.last_mut().expect("no active thunk scope");
+        scope.extend_bindings((base..base + keys.len()).map(ThunkId).zip(vals));
+        Ok(ret)
+    }
+
+    fn with_param_scope<F, Ret>(&mut self, sym: StringId, f: F) -> Ret
+    where
+        F: FnOnce(&mut Self) -> Ret,
+    {
+        self.scopes.push(Scope::Param {
+            sym,
+            abs_layer: self.thunk_scopes.len(),
+        });
+        let mut guard = ScopeGuard { ctx: self };
+        f(guard.as_ctx())
+    }
+
+    fn with_with_scope<F, Ret>(&mut self, f: F) -> Ret
+    where
+        F: FnOnce(&mut Self) -> Ret,
+    {
+        self.with_scope_count += 1;
+        let ret = f(self);
+        self.with_scope_count -= 1;
+        ret
+    }
+
+    fn with_thunk_scope<F, Ret>(
+        &mut self,
+        f: F,
+    ) -> (
+        Ret,
+        bumpalo::collections::Vec<'ir, (ThunkId, IrRef<'id, 'ir>)>,
+    )
+    where
+        F: FnOnce(&mut Self) -> Ret,
+    {
+        self.thunk_scopes.push(ThunkScope::new_in(self.bump));
+        let ret = f(self);
+        (
+            ret,
+            self.thunk_scopes
+                .pop()
+                .expect("no thunk scope left???")
+                .bindings,
+        )
+    }
+
+    fn bump(&self) -> &'ir bumpalo::Bump {
+        self.bump
+    }
+}
+
+impl<'id, 'ir, 'ctx: 'ir, R: VmRuntimeCtx> DowngradeCtx<'ctx, 'id, 'ir, R> {
+    fn downgrade_toplevel(mut self, root: rnix::ast::Expr) -> Result<RawIrRef<'ir>> {
+        let body = root.downgrade(&mut self)?;
+        let thunks = self
+            .thunk_scopes
+            .pop()
+            .expect("no thunk scope left???")
+            .bindings;
+        let ir = IrRef::alloc(self.bump, Ir::TopLevel { body, thunks });
+        Ok(ir.freeze(self.token))
+    }
+}
+
+struct ThunkScope<'id, 'ir> {
+    bindings: bumpalo::collections::Vec<'ir, (ThunkId, IrRef<'id, 'ir>)>,
+}
+
+impl<'id, 'ir> ThunkScope<'id, 'ir> {
+    fn new_in(bump: &'ir Bump) -> Self {
+        Self {
+            bindings: bumpalo::collections::Vec::new_in(bump),
+        }
+    }
+
+    fn add_binding(&mut self, id: ThunkId, ir: IrRef<'id, 'ir>, _token: &GhostToken<'id>) {
+        self.bindings.push((id, ir));
+    }
+
+    fn extend_bindings(&mut self, iter: impl IntoIterator<Item = (ThunkId, IrRef<'id, 'ir>)>) {
+        self.bindings.extend(iter);
+    }
+}
+
+enum Scope<'ctx> {
+    Global(&'ctx HashMap<StringId, Ir<'static, RawIrRef<'static>>>),
+    Repl(&'ctx HashSet<StringId>),
+    ScopedImport(HashSet<StringId>),
+    Let(HashMap<StringId, ThunkId>),
+    Param { sym: StringId, abs_layer: usize },
+}
+
+struct ScopeGuard<'a, 'ctx, 'id, 'ir, R: VmRuntimeCtx> {
+    ctx: &'a mut DowngradeCtx<'ctx, 'id, 'ir, R>,
+}
+
+impl<'a, 'ctx, 'id, 'ir, R: VmRuntimeCtx> Drop for ScopeGuard<'a, 'ctx, 'id, 'ir, R> {
+    fn drop(&mut self) {
+        self.ctx.scopes.pop();
+    }
+}
+
+impl<'a, 'ctx, 'id, 'ir, R: VmRuntimeCtx> ScopeGuard<'a, 'ctx, 'id, 'ir, R> {
+    fn as_ctx(&mut self) -> &mut DowngradeCtx<'ctx, 'id, 'ir, R> {
+        self.ctx
+    }
+}
+
+struct OwnedIr {
+    _bump: Bump,
+    ir: RawIrRef<'static>,
+}
+
+impl OwnedIr {
+    unsafe fn new(ir: RawIrRef<'_>, bump: Bump) -> Self {
+        Self {
+            _bump: bump,
+            ir: unsafe { std::mem::transmute::<RawIrRef<'_>, RawIrRef<'static>>(ir) },
+        }
+    }
+
+    fn as_ref(&self) -> RawIrRef<'_> {
+        self.ir
+    }
+}
+
 impl DisassemblerContext for Evaluator {
     fn get_code(&self) -> &[u8] {
         &self.code.bytecode
     }
 
+    #[allow(clippy::unwrap_used)]
     fn resolve_string(&self, id: u32) -> &str {
-        let id = string_interner::symbol::SymbolU32::try_from_usize(id as usize)
-            .expect("invalid string id");
-        self.runtime.strings.resolve(id).expect("invalid string id")
+        let id = string_interner::symbol::SymbolU32::try_from_usize(id as usize).unwrap();
+        self.runtime.strings.resolve(id).unwrap()
     }
 }

fix/src/logging.rs

@@ -5,7 +5,7 @@ use tracing_subscriber::layer::SubscriberExt;
 use tracing_subscriber::util::SubscriberInitExt;
 use tracing_subscriber::{EnvFilter, Layer, fmt};
 
-pub fn init_logging() -> Result<(), miette::InstallError> {
+pub fn init_logging() {
     let is_terminal = std::io::stderr().is_terminal();
     let show_time = env::var("NIX_JS_LOG_TIME")
         .map(|v| v == "1" || v.to_lowercase() == "true")
@@ -32,10 +32,10 @@ pub fn init_logging() -> Result<(), miette::InstallError> {
         .with(fmt_layer)
         .init();
 
-    init_miette_handler()
+    init_miette_handler();
 }
 
-fn init_miette_handler() -> Result<(), miette::InstallError> {
+fn init_miette_handler() {
     let is_terminal = std::io::stderr().is_terminal();
     miette::set_hook(Box::new(move |_| {
         Box::new(
@@ -46,4 +46,5 @@ fn init_miette_handler() -> Result<(), miette::InstallError> {
                 .build(),
         )
     }))
+    .ok();
 }

fix/src/main.rs

@@ -20,49 +20,33 @@ struct Cli {
 enum Command {
     Compile {
         #[clap(flatten)]
-        source: ExprSourceArgs,
+        source: ExprSource,
         #[arg(long)]
         silent: bool,
     },
     Eval {
         #[clap(flatten)]
-        source: ExprSourceArgs,
+        source: ExprSource,
     },
     Repl,
 }
 
 #[derive(Args)]
 #[group(required = true, multiple = false)]
-struct ExprSourceArgs {
+struct ExprSource {
     #[clap(short, long)]
     expr: Option<String>,
     #[clap(short, long)]
     file: Option<PathBuf>,
 }
 
-enum ExprSource {
-    Expr(String),
-    File(PathBuf),
-}
-
-#[expect(
-    clippy::unreachable,
-    reason = "clap's arg group guarantees exactly one of --expr/--file is set"
-)]
-impl From<ExprSourceArgs> for ExprSource {
-    fn from(args: ExprSourceArgs) -> Self {
-        match (args.expr, args.file) {
-            (Some(expr), None) => ExprSource::Expr(expr),
-            (None, Some(file)) => ExprSource::File(file),
-            _ => unreachable!(),
-        }
-    }
-}
-
 fn run_compile(eval: &mut Evaluator, src: ExprSource, silent: bool) -> Result<()> {
-    let src = match src {
-        ExprSource::Expr(expr) => Source::new_eval(expr)?,
-        ExprSource::File(file) => Source::new_file(file)?,
+    let src = if let Some(expr) = src.expr {
+        Source::new_eval(expr)?
+    } else if let Some(file) = src.file {
+        Source::new_file(file)?
+    } else {
+        unreachable!()
     };
     match eval.compile_bytecode(src) {
         Ok(ip) => {
@@ -79,9 +63,12 @@ fn run_compile(eval: &mut Evaluator, src: ExprSource, silent: bool) -> Result<()
 }
 
 fn run_eval(eval: &mut Evaluator, src: ExprSource) -> Result<()> {
-    let src = match src {
-        ExprSource::Expr(expr) => Source::new_eval(expr)?,
-        ExprSource::File(file) => Source::new_file(file)?,
+    let src = if let Some(expr) = src.expr {
+        Source::new_eval(expr)?
+    } else if let Some(file) = src.file {
+        Source::new_file(file)?
+    } else {
+        unreachable!()
     };
     match eval.eval_deep(src) {
         Ok(value) => {
@@ -106,9 +93,7 @@ fn run_repl(eval: &mut Evaluator) -> Result<()> {
                 if line.trim().is_empty() {
                     continue;
                 }
-                if let Err(err) = rl.add_history_entry(line.as_str()) {
-                    eprintln!("[WARN] Failed to add history entry: {err}");
-                }
+                let _ = rl.add_history_entry(line.as_str());
                 if let Some([Some(_), Some(ident), Some(rest)]) = RE.exec(&line) {
                     if let Some(expr) = rest.strip_prefix('=') {
                         let expr = expr.trim_start();
@@ -152,15 +137,15 @@ fn run_repl(eval: &mut Evaluator) -> Result<()> {
 }
 
 fn main() -> Result<()> {
-    fix::logging::init_logging()?;
+    fix::logging::init_logging();
 
     let cli = Cli::parse();
 
     let mut eval = Evaluator::new();
 
     match cli.command {
-        Command::Compile { source, silent } => run_compile(&mut eval, source.into(), silent),
-        Command::Eval { source } => run_eval(&mut eval, source.into()),
+        Command::Compile { source, silent } => run_compile(&mut eval, source, silent),
+        Command::Eval { source } => run_eval(&mut eval, source),
         Command::Repl => run_repl(&mut eval),
     }
 }

fix/src/string_context.rs

@@ -0,0 +1,209 @@
+use std::collections::{BTreeMap, BTreeSet, VecDeque};
+
+pub enum StringContextElem {
+    Opaque { path: String },
+    DrvDeep { drv_path: String },
+    Built { drv_path: String, output: String },
+}
+
+impl StringContextElem {
+    pub fn decode(encoded: &str) -> Self {
+        if let Some(drv_path) = encoded.strip_prefix('=') {
+            StringContextElem::DrvDeep {
+                drv_path: drv_path.to_string(),
+            }
+        } else if let Some(rest) = encoded.strip_prefix('!') {
+            if let Some(second_bang) = rest.find('!') {
+                let output = rest[..second_bang].to_string();
+                let drv_path = rest[second_bang + 1..].to_string();
+                StringContextElem::Built { drv_path, output }
+            } else {
+                StringContextElem::Opaque {
+                    path: encoded.to_string(),
+                }
+            }
+        } else {
+            StringContextElem::Opaque {
+                path: encoded.to_string(),
+            }
+        }
+    }
+}
+
+pub type InputDrvs = BTreeMap<String, BTreeSet<String>>;
+pub type Srcs = BTreeSet<String>;
+pub fn extract_input_drvs_and_srcs(context: &[String]) -> Result<(InputDrvs, Srcs), String> {
+    let mut input_drvs: BTreeMap<String, BTreeSet<String>> = BTreeMap::new();
+    let mut input_srcs: BTreeSet<String> = BTreeSet::new();
+
+    for encoded in context {
+        match StringContextElem::decode(encoded) {
+            StringContextElem::Opaque { path } => {
+                input_srcs.insert(path);
+            }
+            StringContextElem::DrvDeep { drv_path } => {
+                compute_fs_closure(&drv_path, &mut input_drvs, &mut input_srcs)?;
+            }
+            StringContextElem::Built { drv_path, output } => {
+                input_drvs.entry(drv_path).or_default().insert(output);
+            }
+        }
+    }
+
+    Ok((input_drvs, input_srcs))
+}
+
+fn compute_fs_closure(
+    drv_path: &str,
+    input_drvs: &mut BTreeMap<String, BTreeSet<String>>,
+    input_srcs: &mut BTreeSet<String>,
+) -> Result<(), String> {
+    let mut queue: VecDeque<String> = VecDeque::new();
+    let mut visited: BTreeSet<String> = BTreeSet::new();
+
+    queue.push_back(drv_path.to_string());
+
+    while let Some(current_path) = queue.pop_front() {
+        if visited.contains(&current_path) {
+            continue;
+        }
+        visited.insert(current_path.clone());
+        input_srcs.insert(current_path.clone());
+
+        if !current_path.ends_with(".drv") {
+            continue;
+        }
+
+        let content = std::fs::read_to_string(&current_path)
+            .map_err(|e| format!("failed to read derivation {}: {}", current_path, e))?;
+
+        let inputs = parse_derivation_inputs(&content)
+            .ok_or_else(|| format!("failed to parse derivation {}", current_path))?;
+
+        for src in inputs.input_srcs {
+            input_srcs.insert(src.clone());
+            if !visited.contains(&src) {
+                queue.push_back(src);
+            }
+        }
+
+        for (dep_drv, outputs) in inputs.input_drvs {
+            input_srcs.insert(dep_drv.clone());
+            let entry = input_drvs.entry(dep_drv.clone()).or_default();
+            for output in outputs {
+                entry.insert(output);
+            }
+            if !visited.contains(&dep_drv) {
+                queue.push_back(dep_drv);
+            }
+        }
+    }
+
+    Ok(())
+}
+
+struct DerivationInputs {
+    input_drvs: Vec<(String, Vec<String>)>,
+    input_srcs: Vec<String>,
+}
+
+fn parse_derivation_inputs(aterm: &str) -> Option<DerivationInputs> {
+    let aterm = aterm.strip_prefix("Derive([")?;
+
+    let mut bracket_count: i32 = 1;
+    let mut pos = 0;
+    let bytes = aterm.as_bytes();
+    while pos < bytes.len() && bracket_count > 0 {
+        match bytes[pos] {
+            b'[' => bracket_count += 1,
+            b']' => bracket_count -= 1,
+            _ => {}
+        }
+        pos += 1;
+    }
+    if bracket_count != 0 {
+        return None;
+    }
+
+    let rest = &aterm[pos..];
+    let rest = rest.strip_prefix(",[")?;
+
+    let mut input_drvs = Vec::new();
+    let mut bracket_count: i32 = 1;
+    let mut start = 0;
+    pos = 0;
+    let bytes = rest.as_bytes();
+
+    while pos < bytes.len() && bracket_count > 0 {
+        match bytes[pos] {
+            b'[' => bracket_count += 1,
+            b']' => bracket_count -= 1,
+            b'(' if bracket_count == 1 => {
+                start = pos;
+            }
+            b')' if bracket_count == 1 => {
+                let entry = &rest[start + 1..pos];
+                if let Some((drv_path, outputs)) = parse_input_drv_entry(entry) {
+                    input_drvs.push((drv_path, outputs));
+                }
+            }
+            _ => {}
+        }
+        pos += 1;
+    }
+
+    let rest = &rest[pos..];
+    let rest = rest.strip_prefix(",[")?;
+
+    let mut input_srcs = Vec::new();
+    bracket_count = 1;
+    pos = 0;
+    let bytes = rest.as_bytes();
+
+    while pos < bytes.len() && bracket_count > 0 {
+        match bytes[pos] {
+            b'[' => bracket_count += 1,
+            b']' => bracket_count -= 1,
+            b'"' if bracket_count == 1 => {
+                pos += 1;
+                let src_start = pos;
+                while pos < bytes.len() && bytes[pos] != b'"' {
+                    if bytes[pos] == b'\\' && pos + 1 < bytes.len() {
+                        pos += 2;
+                    } else {
+                        pos += 1;
+                    }
+                }
+                let src = std::str::from_utf8(&bytes[src_start..pos]).ok()?;
+                input_srcs.push(src.to_string());
+            }
+            _ => {}
+        }
+        pos += 1;
+    }
+
+    Some(DerivationInputs {
+        input_drvs,
+        input_srcs,
+    })
+}
+
+fn parse_input_drv_entry(entry: &str) -> Option<(String, Vec<String>)> {
+    let entry = entry.strip_prefix('"')?;
+    let quote_end = entry.find('"')?;
+    let drv_path = entry[..quote_end].to_string();
+
+    let rest = &entry[quote_end + 1..];
+    let rest = rest.strip_prefix(",[")?;
+    let rest = rest.strip_suffix(']')?;
+
+    let mut outputs = Vec::new();
+    for part in rest.split(',') {
+        let part = part.trim();
+        if let Some(name) = part.strip_prefix('"').and_then(|s| s.strip_suffix('"')) {
+            outputs.push(name.to_string());
+        }
+    }
+
+    Some((drv_path, outputs))
+}

fix/tests/tests/derivation.rs

@@ -1,4 +1,4 @@
-use fix_lang::Value;
+use fix_common::Value;
 
 use crate::utils::{eval_deep, eval_deep_result};
 
@@ -402,6 +402,7 @@ fn fixed_output_sha256_flat() {
 
 #[test_log::test]
 fn fixed_output_missing_hashalgo() {
+    assert!(
         eval_deep_result(
             r#"derivation {
             name = "default";
@@ -410,7 +411,8 @@ fn fixed_output_missing_hashalgo() {
             outputHash = "0000000000000000000000000000000000000000000000000000000000000000";
         }"#,
         )
-    .unwrap_err();
+        .is_err()
+    );
 }
 
 #[test_log::test]

fix/tests/tests/io_operations.rs

@@ -1,6 +1,6 @@
 use fix::Evaluator;
+use fix_common::Value;
 use fix_error::Source;
-use fix_lang::Value;
 
 use crate::utils::{eval, eval_result};
 
@@ -350,7 +350,7 @@ fn read_dir_nonexistent_fails() {
     let expr = r#"builtins.readDir "/nonexistent/directory""#;
     let result = eval_result(expr);
 
-    result.unwrap_err();
+    assert!(result.is_err());
 }
 
 #[test_log::test]

fix/tests/tests/lang.rs

@@ -3,9 +3,8 @@
 use std::path::PathBuf;
 
 use fix::Evaluator;
+use fix_common::Value;
 use fix_error::{Source, SourceType};
-use fix_lang::Value;
-use serial_test::serial;
 
 fn get_lang_dir() -> PathBuf {
     PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("tests/tests/lang")
@@ -161,14 +160,9 @@ mod okay {
     eval_okay_test!(getattrpos);
     eval_okay_test!(getattrpos_functionargs);
     eval_okay_test!(getattrpos_undefined);
-    eval_okay_test!(
-        #[serial(env)]
-        getenv,
-        || {
-            // SAFETY: guarded with #[serial_test::serial]
+    eval_okay_test!(getenv, || {
         unsafe { std::env::set_var("TEST_VAR", "foo") };
-        }
-    );
+    });
     eval_okay_test!(groupBy);
     eval_okay_test!(r#if);
     eval_okay_test!(ind_string);
@@ -200,16 +194,11 @@ mod okay {
     eval_okay_test!(partition);
     eval_okay_test!(path);
     eval_okay_test!(pathexists);
-    eval_okay_test!(
-        #[serial(env)]
-        path_string_interpolation,
-        || {
-            // SAFETY: guarded with #[serial_test::serial]
+    eval_okay_test!(path_string_interpolation, || {
         unsafe {
             std::env::set_var("HOME", "/fake-home");
         }
-        }
-    );
+    });
     eval_okay_test!(patterns);
     eval_okay_test!(print);
     eval_okay_test!(readDir);

fix/tests/tests/main.rs

@@ -1,11 +1,3 @@
-#![allow(clippy::allow_attributes_without_reason)]
-#![allow(
-    dead_code,
-    clippy::unwrap_used,
-    clippy::unwrap_in_result,
-    clippy::panic
-)]
-
 mod derivation;
 mod findfile;
 mod io_operations;

fix/tests/tests/string_context.rs

@@ -1,5 +1,5 @@
 use fix::Evaluator;
-use fix_lang::Value;
+use fix_common::Value;
 
 use crate::utils::eval_result;
 
@@ -348,7 +348,7 @@ fn substring_zero_length_empty_value() {
 }
 
 #[test_log::test]
-#[expect(non_snake_case)]
+#[allow(non_snake_case)]
 fn concatStringsSep_preserves_context() {
     let result = eval(
         r#"
@@ -365,7 +365,7 @@ fn concatStringsSep_preserves_context() {
 }
 
 #[test_log::test]
-#[expect(non_snake_case)]
+#[allow(non_snake_case)]
 fn concatStringsSep_merges_contexts() {
     let result = eval(
         r#"
@@ -383,7 +383,7 @@ fn concatStringsSep_merges_contexts() {
 }
 
 #[test_log::test]
-#[expect(non_snake_case)]
+#[allow(non_snake_case)]
 fn concatStringsSep_separator_has_context() {
     let result = eval(
         r#"
@@ -398,7 +398,7 @@ fn concatStringsSep_separator_has_context() {
 }
 
 #[test_log::test]
-#[expect(non_snake_case)]
+#[allow(non_snake_case)]
 fn replaceStrings_input_context_preserved() {
     let result = eval(
         r#"
@@ -413,7 +413,7 @@ fn replaceStrings_input_context_preserved() {
 }
 
 #[test_log::test]
-#[expect(non_snake_case)]
+#[allow(non_snake_case)]
 fn replaceStrings_replacement_context_collected() {
     let result = eval(
         r#"
@@ -428,7 +428,7 @@ fn replaceStrings_replacement_context_collected() {
 }
 
 #[test_log::test]
-#[expect(non_snake_case)]
+#[allow(non_snake_case)]
 fn replaceStrings_merges_contexts() {
     let result = eval(
         r#"
@@ -446,7 +446,7 @@ fn replaceStrings_merges_contexts() {
 }
 
 #[test_log::test]
-#[expect(non_snake_case)]
+#[allow(non_snake_case)]
 fn replaceStrings_lazy_evaluation_context() {
     let result = eval(
         r#"
@@ -461,7 +461,7 @@ fn replaceStrings_lazy_evaluation_context() {
 }
 
 #[test_log::test]
-#[expect(non_snake_case)]
+#[allow(non_snake_case)]
 fn baseNameOf_preserves_context() {
     let result = eval(
         r#"

fix/tests/tests/utils.rs

@@ -1,6 +1,8 @@
+#![allow(dead_code)]
+
 use fix::Evaluator;
+use fix_common::Value;
 use fix_error::{Result, Source};
-use fix_lang::Value;
 
 pub fn eval(expr: &str) -> Value {
     Evaluator::new()

flake.lock

@@ -1,5 +1,65 @@
 {
   "nodes": {
+    "blueprint": {
+      "inputs": {
+        "nixpkgs": [
+          "llm-agents",
+          "nixpkgs"
+        ],
+        "systems": [
+          "llm-agents",
+          "systems"
+        ]
+      },
+      "locked": {
+        "lastModified": 1776249299,
+        "narHash": "sha256-Dt9t1TGRmJFc0xVYhttNBD6QsAgHOHCArqGa0AyjrJY=",
+        "owner": "numtide",
+        "repo": "blueprint",
+        "rev": "56131e8628f173d24a27f6d27c0215eff57e40dd",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "blueprint",
+        "type": "github"
+      }
+    },
+    "bun2nix": {
+      "inputs": {
+        "flake-parts": [
+          "llm-agents",
+          "flake-parts"
+        ],
+        "import-tree": "import-tree",
+        "nixpkgs": [
+          "llm-agents",
+          "nixpkgs"
+        ],
+        "systems": [
+          "llm-agents",
+          "systems"
+        ],
+        "treefmt-nix": [
+          "llm-agents",
+          "treefmt-nix"
+        ]
+      },
+      "locked": {
+        "lastModified": 1776192490,
+        "narHash": "sha256-5gYQNEs0/vDkHhg63aHS5g0IwG/8HNvU1Vr00cElofk=",
+        "owner": "nix-community",
+        "repo": "bun2nix",
+        "rev": "6ef9f144616eedea90b364bb408ef2e1de7b310a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "ref": "staging-2.1.0",
+        "repo": "bun2nix",
+        "type": "github"
+      }
+    },
     "fenix": {
       "inputs": {
         "nixpkgs": [
@@ -8,11 +68,11 @@
         "rust-analyzer-src": "rust-analyzer-src"
       },
       "locked": {
-        "lastModified": 1784017020,
-        "narHash": "sha256-49WO85egjNtN1vMgJ3zUjDh5IqO+ou4zZY80WQ6EKGg=",
+        "lastModified": 1777018861,
+        "narHash": "sha256-l+dfxHtTq1jQM53xgYudV8ciECFmJ72PcRAqRS4ys04=",
         "owner": "nix-community",
         "repo": "fenix",
-        "rev": "fa2a0be0f712d7147d1677d33d15ea7b0589cdb4",
+        "rev": "7b33c6466f781cd699fe250c5b69dc4193da67a7",
         "type": "github"
       },
       "original": {
@@ -24,24 +84,85 @@
     "flake-compat": {
       "flake": false,
       "locked": {
-        "lastModified": 1777699697,
-        "narHash": "sha256-Eg9b/rq/ECYwNwEXs5i9wHyhxNI0JrYx2srdI2uZMaQ=",
-        "rev": "382052b74656a369c5408822af3f2501e9b1af81",
+        "lastModified": 1751685974,
+        "narHash": "sha256-NKw96t+BgHIYzHUjkTK95FqYRVKB8DHpVhefWSz/kTw=",
+        "rev": "549f2762aebeff29a2e5ece7a7dc0f955281a1d1",
         "type": "tarball",
-        "url": "https://git.lix.systems/api/v1/repos/lix-project/flake-compat/archive/382052b74656a369c5408822af3f2501e9b1af81.tar.gz"
+        "url": "https://git.lix.systems/api/v1/repos/lix-project/flake-compat/archive/549f2762aebeff29a2e5ece7a7dc0f955281a1d1.tar.gz"
       },
       "original": {
         "type": "tarball",
         "url": "https://git.lix.systems/lix-project/flake-compat/archive/main.tar.gz"
       }
     },
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "llm-agents",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1775087534,
+        "narHash": "sha256-91qqW8lhL7TLwgQWijoGBbiD4t7/q75KTi8NxjVmSmA=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "3107b77cd68437b9a76194f0f7f9c55f2329ca5b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "import-tree": {
+      "locked": {
+        "lastModified": 1763762820,
+        "narHash": "sha256-ZvYKbFib3AEwiNMLsejb/CWs/OL/srFQ8AogkebEPF0=",
+        "owner": "vic",
+        "repo": "import-tree",
+        "rev": "3c23749d8013ec6daa1d7255057590e9ca726646",
+        "type": "github"
+      },
+      "original": {
+        "owner": "vic",
+        "repo": "import-tree",
+        "type": "github"
+      }
+    },
+    "llm-agents": {
+      "inputs": {
+        "blueprint": "blueprint",
+        "bun2nix": "bun2nix",
+        "flake-parts": "flake-parts",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "systems": "systems",
+        "treefmt-nix": "treefmt-nix"
+      },
+      "locked": {
+        "lastModified": 1777019177,
+        "narHash": "sha256-YjPvucTsKmGO9QVNz07x7sSsK11PB0jtMniRkTolbq4=",
+        "owner": "numtide",
+        "repo": "llm-agents.nix",
+        "rev": "8ff0f2a7fcd176b4547da6879ad549de2bbded41",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "llm-agents.nix",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1784007870,
-        "narHash": "sha256-djcLt/JJphyNt4eDY9XTly+/WbCK5lqWq9lSgCmJkkQ=",
+        "lastModified": 1776548001,
+        "narHash": "sha256-ZSK0NL4a1BwVbbTBoSnWgbJy9HeZFXLYQizjb2DPF24=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "18b9261cb3294b6d2a06d03f96872827b8fe2698",
+        "rev": "b12141ef619e0a9c1c84dc8c684040326f27cdcc",
         "type": "github"
       },
       "original": {
@@ -55,17 +176,18 @@
       "inputs": {
         "fenix": "fenix",
         "flake-compat": "flake-compat",
+        "llm-agents": "llm-agents",
         "nixpkgs": "nixpkgs"
       }
     },
     "rust-analyzer-src": {
       "flake": false,
       "locked": {
-        "lastModified": 1783975201,
-        "narHash": "sha256-oyHWTfKWk06nTynCO8ByEAx/KEARvOOyTVnwinOmK3Q=",
+        "lastModified": 1776800521,
+        "narHash": "sha256-f8YJfwAOsLFpIoqZuX3yF69UvMLrkx7iVzMH1pJU7cM=",
         "owner": "rust-lang",
         "repo": "rust-analyzer",
-        "rev": "63a6f0d4bcfd3bbcf36383fcbcbcd93456ed1653",
+        "rev": "8954b66d43225e62c92e8bbcc8500191b5cceb1e",
         "type": "github"
       },
       "original": {
@@ -74,6 +196,42 @@
         "repo": "rust-analyzer",
         "type": "github"
       }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "llm-agents",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1775636079,
+        "narHash": "sha256-pc20NRoMdiar8oPQceQT47UUZMBTiMdUuWrYu2obUP0=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "790751ff7fd3801feeaf96d7dc416a8d581265ba",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
+      }
     }
   },
   "root": "root",

flake.nix

@@ -3,13 +3,17 @@
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
     fenix.url = "github:nix-community/fenix";
     fenix.inputs.nixpkgs.follows = "nixpkgs";
+    llm-agents = {
+      url = "github:numtide/llm-agents.nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
     flake-compat = {
       url = "https://git.lix.systems/lix-project/flake-compat/archive/main.tar.gz";
       flake = false;
     };
   };
   outputs =
-    { nixpkgs, fenix, ... }:
+    inputs@{ nixpkgs, fenix, ... }:
     let
       forAllSystems = nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed;
     in
@@ -20,11 +24,35 @@
           pkgs = import nixpkgs {
             inherit system;
             config.allowUnfree = true;
-            overlays = [ fenix.overlays.default ];
           };
+          llm-agents = inputs.llm-agents.packages.${pkgs.stdenv.hostPlatform.system};
         in
         {
-          default = import ./devShell.nix { inherit pkgs; };
+          default = pkgs.mkShell {
+            packages = with pkgs; [
+              (fenix.packages.${system}.latest.withComponents [
+                "cargo"
+                "clippy"
+                "rust-src"
+                "rustc"
+                "rustfmt"
+                "rust-analyzer"
+              ])
+              cargo-machete
+              cargo-bloat
+              lldb
+              valgrind
+              kdePackages.kcachegrind
+              hyperfine
+              just
+              samply
+              tokei
+
+              llm-agents.claude-code
+              llm-agents.opencode
+              llm-agents.forge
+            ];
+          };
         }
       );
     };

shell.nix

@@ -0,0 +1,16 @@
+let
+  lockFile = builtins.fromJSON (builtins.readFile ./flake.lock);
+  flake-compat-node = lockFile.nodes.${lockFile.nodes.root.inputs.flake-compat};
+  flake-compat = builtins.fetchTarball {
+    inherit (flake-compat-node.locked) url;
+    sha256 = flake-compat-node.locked.narHash;
+  };
+
+  flake = (
+    import flake-compat {
+      src = ./.;
+      copySourceTreeToStore = false;
+    }
+  );
+in
+  flake.shellNix