runtime, macros: unify NaN-boxed value API under ValueVariant trait

Cargo.toml

@@ -22,77 +22,17 @@ bumpalo = {
 }
 ere = "0.2"
 ghost-cell = "0.2"
-hashbrown = "0.17"
+hashbrown = "0.16"
-num_enum = "0.7"
+num_enum = "0.7.5"
 rnix = "0.14"
 rowan = "0.16"
 smallvec = { version = "1.15", features = ["const_generics", "const_new"] }
-string-interner = "0.20"
+string-interner = "0.19"
-gc-arena = { version = "0.7", features = ["hashbrown", "smallvec"] }
 
-# https://emschwartz.me/your-clippy-config-should-be-stricter/
+[workspace.dependencies.gc-arena]
-# tombi: format.rules.table-keys-order.disabled = true
+git = "https://github.com/kyren/gc-arena"
-[workspace.lints.clippy]
+rev = "75671ae03f53718357b741ed4027560f14e90836"
-# Don't Panic - prevent panics from unwraps and unsafe slicing or indexing
+features = ["allocator-api2", "hashbrown", "smallvec"]
-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.lto]
 inherits = "release"

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='':

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-bytecode/Cargo.toml

@@ -9,6 +9,3 @@ num_enum = { workspace = true }
 string-interner = { workspace = true }
 
 fix-lang = { path = "../fix-lang" }
-
-[lints]
-workspace = true

fix-bytecode/src/disassembler.rs

@@ -2,7 +2,7 @@ use std::fmt::Write;
 
 use colored::Colorize as _;
 
-use crate::{BytecodeReader, Continuation, InstructionPtr, Op};
+use crate::{Continuation, InstructionPtr, Op, OperandType};
 
 pub trait DisassemblerContext {
     fn resolve_string(&self, id: u32) -> &str;
@@ -10,15 +10,99 @@ 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) {
+        use OperandType::*;
+        let tag = self.read_u8();
+        let ty = OperandType::try_from(tag).expect("invalid operand type");
+        match ty {
+            Const => {
+                self.read_u32();
+            }
+            BigInt => {
+                self.read_i64();
+            }
+            Local => {
+                self.read_u8();
+                self.read_u32();
+            }
+            BuiltinConst => {
+                self.read_u32();
+            }
+            Builtins => {}
+            ReplBinding => {
+                self.read_u32();
+            }
+            ScopedImportBinding => {
+                self.read_u32();
+                self.read_u32();
+            }
         }
     }
 
@@ -30,11 +114,6 @@ 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 +122,24 @@ 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() {
+        while self.pc < self.code.len() {
-            let start_pos = self.reader.pc();
+            let start_pos = self.pc;
-            let op_byte = self.reader.read_u8();
+            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 +199,31 @@ 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");
 
         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)")
+                    #[allow(clippy::unwrap_used)]
-                        .expect("writing to String is infallible");
+                    write!(s_fmt, "...\" (total {len} bytes)").unwrap();
                 }
                 ("PushString", format!("@{} {}", idx, s_fmt))
             }
@@ -158,38 +232,38 @@ 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 depth = self.read_u8();
-                let idx = self.reader.read_u32();
+                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 offset = self.read_u32();
-                let slots = self.reader.read_u32();
+                let slots = self.read_u32();
                 ("MakeClosure", format!("-> {:04x} slots={}", offset, slots))
             }
             Op::MakePatternClosure => {
-                let offset = self.reader.read_u32();
+                let offset = self.read_u32();
-                let slots = self.reader.read_u32();
+                let slots = self.read_u32();
-                let req_count = self.reader.read_u16();
+                let req_count = self.read_u16();
-                let opt_count = self.reader.read_u16();
+                let opt_count = self.read_u16();
-                let ellipsis = self.reader.read_u8() != 0;
+                let ellipsis = self.read_u8() != 0;
 
                 let mut arg_str = format!(
                     "-> {:04x} slots={} req={} opt={} ...={})",
@@ -198,18 +272,18 @@ 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 _name_idx = self.read_u32();
-                    let _span_id = self.reader.read_u32();
+                    let _span_id = self.read_u32();
                 }
                 arg_str.push(']');
 
@@ -217,32 +291,31 @@ 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 =
+                let phase = Continuation::try_from(self.read_u8()).expect("invalid primop phase");
-                    Continuation::try_from(self.reader.read_u8()).expect("invalid primop phase");
                 ("DispatchPrimOp", format!("phase={phase:?}"))
             }
 
             Op::MakeAttrs => {
-                let static_count = self.reader.read_u32();
+                let static_count = self.read_u32();
-                let dynamic_count = self.reader.read_u32();
+                let dynamic_count = self.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 key_id = self.read_u32();
                     let _ = write!(args, " [{}={}", self.ctx.resolve_string(key_id), key_id);
-                    let _ = self.reader.read_operand_data();
+                    self.read_operand_data();
-                    let _span_id = self.reader.read_u32();
+                    let _span_id = self.read_u32();
                     args.push(']');
                 }
 
                 for _ in 0..dynamic_count {
                     let _ = write!(args, " [dyn");
-                    let _ = self.reader.read_operand_data();
+                    self.read_operand_data();
-                    let _span_id = self.reader.read_u32();
+                    let _span_id = self.read_u32();
                     args.push(']');
                 }
 
@@ -251,31 +324,31 @@ impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
             Op::MakeEmptyAttrs => ("MakeEmptyAttrs", String::new()),
 
             Op::SelectStatic => {
-                let span_id = self.reader.read_u32();
+                let span_id = self.read_u32();
-                let key_id = self.reader.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 span_id = self.read_u32();
-                let key_id = self.reader.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 +357,7 @@ 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 +365,7 @@ 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 +374,9 @@ 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 +398,7 @@ 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",
@@ -333,55 +406,55 @@ 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 count = self.read_u16();
-                let force = self.reader.read_u8();
+                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_id = self.read_u32();
                 let dir = self.ctx.resolve_string(dir_id);
                 ("ResolvePath", format!("dir={:?}", dir))
             }
             Op::Assert => {
-                let raw_idx = self.reader.read_u32();
+                let raw_idx = self.read_u32();
-                let span_id = self.reader.read_u32();
+                let span_id = self.read_u32();
                 ("Assert", format!("text_id={} span={}", raw_idx, span_id))
             }
             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();
+                let n = self.read_u8();
                 for _ in 0..n {
-                    let _ = self.reader.read_operand_data();
+                    self.read_operand_data();
                 }
                 ("LookupWith", format!("sym={:?} n={}", name, n))
             }
 
             Op::LoadBuiltins => ("LoadBuiltins", String::new()),
             Op::LoadBuiltin => {
-                let id = self.reader.read_u8();
+                let id = self.read_u8();
                 ("LoadBuiltin", format!("id={}", 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 slot = self.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))
             }

fix-bytecode/src/lib.rs

@@ -1,7 +1,4 @@
-#![allow(
+#![allow(dead_code)]
-    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;
@@ -13,7 +10,8 @@ pub mod disassembler;
 pub struct InstructionPtr(pub usize);
 
 #[repr(u8)]
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, TryFromPrimitive)]
+#[allow(clippy::enum_variant_names)]
 pub enum Op {
     PushSmi,
     PushBigInt,
@@ -90,21 +88,6 @@ pub enum Op {
     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 {
@@ -123,7 +106,11 @@ pub enum Const {
     Bool(bool),
     String(StringId),
     Path(StringId),
-    PrimOp(BuiltinId),
+    PrimOp {
+        id: BuiltinId,
+        arity: u8,
+        dispatch_ip: u32,
+    },
     Null,
 }
 
@@ -152,15 +139,13 @@ pub enum Continuation {
     PAdd,
     PAddErrorContext,
 
-    PAll0,
+    PAll,
-    PAll1,
+    PAllCallPred,
-    PAll2,
+    PAllCheck,
-    PAll3,
 
-    PAny0,
+    PAny,
-    PAny1,
+    PAnyCallPred,
-    PAny2,
+    PAnyCheck,
-    PAny3,
 
     PAppendContext,
     PAppendContextLoop,
@@ -184,12 +169,9 @@ pub enum Continuation {
     PConcatStringsSep,
     PConvertHash,
 
-    PDeepSeq0,
+    PDeepSeq,
-    PDeepSeq1,
+    PDeepSeqPush,
-    PDeepSeq2,
+    PDeepSeqLoop,
-    PDeepSeq3,
-    PDeepSeq4,
-    PDeepSeq5,
 
     PDerivation,
     PDerivationStrict,
@@ -203,21 +185,18 @@ pub enum Continuation {
     PFetchTree,
     PFetchUrl,
 
-    PFilter0,
+    PFilterForceList,
-    PFilter1,
+    PFilterCallPred,
-    PFilter2,
+    PFilterCheck,
-    PFilter3,
-    PFilter4,
 
     PFilterSource,
     PFindFile,
     PFloor,
-    PFoldlStrict0,
+    PFoldlStrict,
-    PFoldlStrict1,
+    PFoldlStrictEmpty,
-    PFoldlStrict2,
+    PFoldlStrictCall1,
-    PFoldlStrict3,
+    PFoldlStrictCall2,
-    PFoldlStrict4,
+    PFoldlStrictUpdate,
-    PFoldlStrict5,
     PFromJSON,
     PFromTOML,
     PFunctionArgs,
@@ -265,8 +244,7 @@ pub enum Continuation {
     PReadFileType,
     PRemoveAttrs,
     PReplaceStrings,
-    PSeq0,
+    PSeq,
-    PSeq1,
     PSort,
     PSplit,
     PSplitVersion,
@@ -308,11 +286,8 @@ pub enum Continuation {
 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)
@@ -321,14 +296,14 @@ impl TryFrom<u8> for Continuation {
 }
 
 impl Continuation {
-    pub const fn entry_for_builtin(id: BuiltinId) -> Self {
+    pub fn entry_for_builtin(id: BuiltinId) -> Self {
         use BuiltinId::*;
         match id {
             Abort => Self::PAbort,
             Add => Self::PAdd,
             AddErrorContext => Self::PAddErrorContext,
-            All => Self::PAll0,
+            All => Self::PAll,
-            Any => Self::PAny0,
+            Any => Self::PAny,
             AppendContext => Self::PAppendContext,
             AttrNames => Self::PAttrNames,
             AttrValues => Self::PAttrValues,
@@ -344,7 +319,7 @@ impl Continuation {
             ConcatMap => Self::PConcatMap,
             ConcatStringsSep => Self::PConcatStringsSep,
             ConvertHash => Self::PConvertHash,
-            DeepSeq => Self::PDeepSeq0,
+            DeepSeq => Self::PDeepSeq,
             Derivation => Self::PDerivation,
             DerivationStrict => Self::PDerivationStrict,
             DirOf => Self::PDirOf,
@@ -356,11 +331,11 @@ impl Continuation {
             FetchTarball => Self::PFetchTarball,
             FetchTree => Self::PFetchTree,
             FetchUrl => Self::PFetchUrl,
-            Filter => Self::PFilter0,
+            Filter => Self::PFilterForceList,
             FilterSource => Self::PFilterSource,
             FindFile => Self::PFindFile,
             Floor => Self::PFloor,
-            FoldlStrict => Self::PFoldlStrict0,
+            FoldlStrict => Self::PFoldlStrict,
             FromJSON => Self::PFromJSON,
             FromTOML => Self::PFromTOML,
             FunctionArgs => Self::PFunctionArgs,
@@ -404,7 +379,7 @@ impl Continuation {
             RemoveAttrs => Self::PRemoveAttrs,
             ReplaceStrings => Self::PReplaceStrings,
             ScopedImport => Self::PScopedImport,
-            Seq => Self::PSeq0,
+            Seq => Self::PSeq,
             Sort => Self::PSort,
             Split => Self::PSplit,
             SplitVersion => Self::PSplitVersion,
@@ -430,7 +405,7 @@ impl Continuation {
         }
     }
 
-    pub const fn ip(self) -> u32 {
+    pub fn ip(self) -> u32 {
         self as u32 * 2
     }
 }
@@ -441,129 +416,7 @@ pub struct BytecodeReader<'a> {
     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,
@@ -573,7 +426,6 @@ impl<'a> BytecodeReader<'a> {
     }
 
     #[inline(always)]
-    #[must_use]
     pub fn from_after_op(bytecode: &'a [u8], inst_start_pc: usize) -> Self {
         Self {
             bytecode,
@@ -583,21 +435,88 @@ impl<'a> BytecodeReader<'a> {
     }
 
     #[inline(always)]
-    #[must_use]
+    #[cfg_attr(debug_assertions, track_caller)]
-    pub fn read<T: FromBytecode>(&mut self) -> T {
+    fn read_array<const N: usize>(&mut self) -> [u8; N] {
-        T::read(self)
+        let ret = self.bytecode[self.pc..self.pc + N]
+            .try_into()
+            .expect("read_array failed");
+        self.pc += N;
+        ret
     }
 
-    read_aliases! {
+    #[inline(always)]
-        read_op -> Op,
+    pub fn read_op(&mut self) -> Op {
-        read_u8 -> u8,
+        self.inst_start_pc = self.pc;
-        read_u16 -> u16,
+        let byte = self.bytecode[self.pc];
-        read_u32 -> u32,
+        if !(0..Op::Illegal as u8).contains(&byte) {
-        read_i32 -> i32,
+            std::hint::cold_path();
-        read_i64 -> i64,
+            panic!("unknown opcode: {byte:#04x}")
-        read_f64 -> f64,
+        }
-        read_string_id -> StringId,
+        self.pc += 1;
-        read_operand_data -> OperandData,
+        unsafe { std::mem::transmute::<u8, Op>(byte) }
+    }
+
+    #[inline(always)]
+    pub fn read_u8(&mut self) -> u8 {
+        let val = self.bytecode[self.pc];
+        self.pc += 1;
+        val
+    }
+
+    #[inline(always)]
+    pub fn read_u16(&mut self) -> u16 {
+        u16::from_le_bytes(self.read_array())
+    }
+
+    #[inline(always)]
+    pub fn read_u32(&mut self) -> u32 {
+        u32::from_le_bytes(self.read_array())
+    }
+
+    #[inline(always)]
+    pub fn read_i32(&mut self) -> i32 {
+        i32::from_le_bytes(self.read_array())
+    }
+
+    #[inline(always)]
+    pub fn read_i64(&mut self) -> i64 {
+        i64::from_le_bytes(self.read_array())
+    }
+
+    #[inline(always)]
+    pub fn read_f64(&mut self) -> f64 {
+        f64::from_le_bytes(self.read_array())
+    }
+
+    #[inline(always)]
+    pub 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 fn read_operand_data(&mut self) -> 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 => OperandData::Const(self.read_u32()),
+            OperandType::BigInt => OperandData::BigInt(self.read_i64()),
+            OperandType::Local => {
+                let layer = self.read_u8();
+                let idx = self.read_u32();
+                OperandData::Local { layer, idx }
+            }
+            OperandType::BuiltinConst => OperandData::BuiltinConst(self.read_string_id()),
+            OperandType::Builtins => OperandData::Builtins,
+            OperandType::ReplBinding => OperandData::ReplBinding(self.read_string_id()),
+            OperandType::ScopedImportBinding => {
+                let slot_id = self.read_u32();
+                let name = self.read_string_id();
+                OperandData::ScopedImportBinding { slot_id, name }
+            }
+        }
     }
 
     pub fn pc(&self) -> usize {

fix-compiler/Cargo.toml

@@ -17,6 +17,3 @@ fix-error = { path = "../fix-error" }
 fix-lang = { path = "../fix-lang" }
 fix-runtime = { path = "../fix-runtime" }
 tracing = "0.1"
-
-[lints]
-workspace = true

fix-compiler/src/context.rs

@@ -114,13 +114,8 @@ impl<'a, R: VmRuntimeCtx> CompilerCtx<'a, R> {
                 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(OwnedIr { _bump: bump, ir })
-            Ok(unsafe { OwnedIr::new(bump, ir) })
         })
     }
 }
@@ -158,7 +153,15 @@ impl<'a, R: VmRuntimeCtx> BytecodeContext for CompilerCtx<'a, R> {
             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)),
+            PrimOp {
+                id,
+                arity,
+                dispatch_ip,
+            } => StaticValue::new(fix_runtime::PrimOp {
+                id,
+                arity,
+                dispatch_ip,
+            }),
             Null => StaticValue::default(),
         };
         self.runtime.add_const(val)
@@ -285,10 +288,6 @@ impl<'ctx: 'ir, 'id, 'ir, R: VmRuntimeCtx> DowngradeContext<'id, 'ir>
         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,
@@ -365,10 +364,6 @@ impl<'ctx: 'ir, 'id, 'ir, R: VmRuntimeCtx> DowngradeContext<'id, 'ir>
         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(
@@ -430,10 +425,6 @@ impl<'ctx: 'ir, 'id, 'ir, R: VmRuntimeCtx> DowngradeContext<'id, 'ir>
         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,
@@ -499,6 +490,7 @@ enum Scope<'ctx, 'id, 'ir> {
     Repl(&'ctx HashSet<StringId>),
     ScopedImport {
         keys: HashSet<StringId>,
+        #[allow(dead_code)]
         slot_id: u32,
     },
     Let(HashMap<StringId, GhostMaybeThunkRef<'id, 'ir>>),
@@ -542,29 +534,13 @@ impl<'a, 'ctx, 'id, 'ir, R: VmRuntimeCtx> ScopeGuard<'a, 'ctx, 'id, 'ir, R> {
     }
 }
 
-mod sealed {
+struct OwnedIr {
-    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;
+impl OwnedIr {
+    fn as_ref<'ir>(&'ir self) -> RawIrRef<'ir> {
+        unsafe { std::mem::transmute::<RawIrRef<'static>, RawIrRef<'ir>>(self.ir) }
+    }
+}

fix-compiler/src/ir.rs

@@ -3,7 +3,7 @@ use std::marker::PhantomData;
 
 use bumpalo::Bump;
 use bumpalo::collections::Vec;
-use fix_lang::{BuiltinId, StringId};
+use fix_lang::{BUILTINS, BuiltinId, StringId};
 use ghost_cell::{GhostCell, GhostToken};
 use rnix::{TextRange, ast};
 use string_interner::DefaultStringInterner;
@@ -222,6 +222,7 @@ pub enum Ir<'ir, R: RefExt<'ir> + ?Sized + 'ir> {
 pub struct ThunkId(pub usize);
 
 /// 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.
@@ -290,8 +291,9 @@ pub fn new_global_env(
     let builtins_sym = StringId(strings.get_or_intern("builtins"));
     global_env.insert(builtins_sym, MaybeThunk::Builtins);
 
-    for id in BuiltinId::ALL {
+    for (idx, &(name, _)) in BUILTINS.iter().enumerate() {
-        let name = StringId(strings.get_or_intern(id.info().global_name));
+        let id = BuiltinId::try_from(idx as u8).expect("infallible");
+        let name = StringId(strings.get_or_intern(name));
         global_env.insert(name, MaybeThunk::Builtin(id));
     }
 

fix-compiler/src/ir/downgrade.rs

@@ -156,10 +156,6 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
         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)
@@ -466,14 +462,16 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
             body: GhostRoIrRef<'id, 'ir>,
         }
 
-        let (ret, thunks) = ctx.with_thunk_scope(|ctx| -> Result<Ret> {
+        let (ret, thunks) = ctx.with_thunk_scope(|ctx| {
-            let (param, body) = match raw_param {
+            let param;
+            let body;
+
+            match raw_param {
                 ast::Param::IdentParam(id) => {
                     let param_sym = ctx.intern_string(id.to_string());
-                    (
+                    param = None;
-                        None,
+
-                        ctx.with_param_scope(param_sym, |ctx| body_ast.downgrade(ctx))?,
+                    body = ctx.with_param_scope(param_sym, |ctx| body_ast.downgrade(ctx))?;
-                    )
                 }
                 ast::Param::Pattern(pattern) => {
                     let alias = pattern
@@ -495,18 +493,17 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
                         body_ast.clone().downgrade(ctx)
                     })?;
 
-                    (
+                    param = Some(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?;
 
@@ -553,10 +550,6 @@ 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 +651,6 @@ 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 +665,6 @@ 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>,

fix-compiler/src/lib.rs

@@ -1,5 +1,5 @@
-use fix_bytecode::{Const, InstructionPtr, Op, OperandType};
+use fix_bytecode::{Const, Continuation, InstructionPtr, Op, OperandType};
-use fix_lang::StringId;
+use fix_lang::{BUILTINS, StringId};
 use hashbrown::HashMap;
 use rnix::TextRange;
 use string_interner::Symbol as _;
@@ -54,6 +54,7 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         }
     }
 
+    #[must_use]
     fn inline_maybe_thunk(&self, val: &MaybeThunk) -> InlineOperand {
         use MaybeThunk::*;
         match *val {
@@ -74,7 +75,14 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                 InlineOperand::Local { layer, local }
             }
             Arg { layer } => InlineOperand::Local { layer, local: 0 },
-            Builtin(id) => InlineOperand::Const(Const::PrimOp(id)),
+            Builtin(id) => {
+                let (_, arity) = BUILTINS[id as usize];
+                InlineOperand::Const(Const::PrimOp {
+                    id,
+                    arity,
+                    dispatch_ip: Continuation::entry_for_builtin(id).ip(),
+                })
+            }
             BuiltinConst(id) => InlineOperand::BuiltinConst(id),
             Builtins => InlineOperand::Builtins,
             ReplBinding(id) => InlineOperand::ReplBinding(id),
@@ -178,10 +186,6 @@ 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());
     }
@@ -210,10 +214,6 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         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) {
         for scope in self.scope_stack.iter().rev() {
             if let Some(&local_idx) = scope.thunk_map.get(&id) {
@@ -520,10 +520,6 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         }
     }
 
-    #[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 {
@@ -716,25 +712,14 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         }
 
         if let Some(default) = default {
-            // FIXME: i32???
+            let before: i32 = self.ctx.get_code().len().try_into().unwrap();
-            let before: i32 = self
-                .ctx
-                .get_code()
-                .len()
-                .try_into()
-                .expect("emitted code length fits in i32");
             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
+            let after: i32 = self.ctx.get_code().len().try_into().unwrap();
-                .ctx
-                .get_code()
-                .len()
-                .try_into()
-                .expect("emitted code length fits in i32");
             // 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 +730,6 @@ 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);
 

fix-error/Cargo.toml

@@ -7,6 +7,3 @@ edition = "2024"
 miette = { version = "7.6", features = ["fancy"] }
 rnix = { workspace = true }
 thiserror = "2.0"
-
-[lints]
-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-lang/Cargo.toml

@@ -8,6 +8,3 @@ ere = { workspace = true }
 gc-arena = { workspace = true }
 num_enum = { workspace = true }
 string-interner = { workspace = true }
-
-[lints]
-workspace = true

fix-lang/src/lib.rs

@@ -8,7 +8,7 @@ use num_enum::TryFromPrimitive;
 
 macro_rules! define_builtins {
     ($(($name:literal, $variant:ident, $arity:expr)),* $(,)?) => {
-        const BUILTINS: &[(&str, u8)] = &[
+        pub const BUILTINS: &[(&str, u8)] = &[
             $(($name, $arity),)*
         ];
 
@@ -18,10 +18,6 @@ macro_rules! define_builtins {
         pub enum BuiltinId {
             $($variant,)*
         }
-
-        impl BuiltinId {
-            pub const ALL: [Self; BUILTINS.len()] = [$(Self::$variant,)*];
-        }
     };
 }
 
@@ -131,36 +127,6 @@ define_builtins! {
     ("__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)]
 #[collect(require_static)]
@@ -461,10 +427,6 @@ 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 +451,11 @@ fn fmt_nix_float(f: &mut Formatter<'_>, x: f64) -> FmtResult {
     };
 
     if formatted.contains('.') {
-        if let Some((head, tail)) = formatted.split_once('e') {
+        if let Some(e_pos) = formatted.find('e') {
-            let trimmed = head.trim_end_matches('0').trim_end_matches('.');
+            let trimmed = formatted[..e_pos]
-            write!(f, "{trimmed}e{tail}")
+                .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-macros/Cargo.toml

@@ -7,9 +7,7 @@ edition = "2024"
 proc-macro = true
 
 [dependencies]
+manyhow = "0.11"
 proc-macro2 = "1.0"
 quote = "1.0"
-syn = { version = "3.0", features = ["full", "visit", "visit-mut"] }
+syn = { version = "2.0", features = ["full", "visit"] }
-
-[lints]
-workspace = true

fix-macros/src/lib.rs

@@ -1,15 +1,5 @@
 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

fix-runtime/Cargo.toml

@@ -14,6 +14,3 @@ 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/boxing.rs

@@ -1,7 +1,4 @@
-#![allow(
+#![allow(dead_code)]
-    dead_code,
-    reason = "boxing layer exposes a full API surface; some helpers are used only on specific targets or not yet wired up"
-)]
 
 use std::fmt;
 use std::num::NonZeroU8;
@@ -82,48 +79,41 @@ int_store!(i16);
 int_store!(i32);
 
 fn store_ptr<P: Strict + Copy>(value: &mut Value, ptr: P) {
-    cfg_select! {
+    #[cfg(target_pointer_width = "64")]
-        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! {
+    #[cfg(target_pointer_width = "64")]
-        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`.
         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");
     }
 }
 
@@ -189,10 +179,6 @@ impl RawTag {
     #[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() },
         })
     }
@@ -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()) }
     }
 
@@ -344,7 +323,7 @@ impl Header {
 
 #[derive(Copy, Clone, Debug, PartialEq)]
 #[repr(C, align(8))]
-pub(crate) struct Value {
+pub struct Value {
     #[cfg(target_endian = "big")]
     header: Header,
     data: [u8; 6],
@@ -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-runtime/src/forced.rs

@@ -2,8 +2,8 @@ use fix_lang::StringId;
 use gc_arena::Mutation;
 
 use crate::{
-    AttrSet, BytecodeReader, Closure, List, Machine, NixNum, NixString, NixType, Null, PrimOp,
+    AttrSet, Break, BytecodeReader, Closure, List, Machine, NixNum, NixString, NixType, Null,
-    PrimOpApp, Step, StrictValue, ValueVariant,
+    PrimOp, PrimOpApp, Step, StrictValue, ValueVariant,
 };
 
 pub trait Forced<'gc>: Sized {
@@ -50,7 +50,7 @@ impl<'gc> Forced<'gc> for StrictValue<'gc> {
 macro_rules! impl_forced {
     ($($ty:ty),* $(,)?) => {
         $(
-        impl<'gc> Forced<'gc> for <$ty as ValueVariant<'gc>>::Ty {
+        impl<'gc> Forced<'gc> for <$ty as ValueVariant>::Ty<'gc> {
             const WIDTH: usize = 1;
 
             #[inline(always)]
@@ -63,11 +63,11 @@ macro_rules! impl_forced {
             ) -> Step {
                 m.force_slot_to_pc(base_depth, reader, mc, resume_pc)?;
                 let v = m.peek_forced(base_depth);
-                if !v.is::<$ty>() {
+                if v.downcast::<$ty>().is_none() {
-                    m.finish_type_err(<$ty as ValueVariant>::TYPE, v.ty())
+                    let _: Step = m.finish_type_err(<$ty as ValueVariant>::TYPE, v.ty());
-                } else {
+                    return Step::Break(Break::Done);
-                    Step::Continue(())
                 }
+                Step::Continue(())
             }
 
             #[inline(always)]
@@ -109,10 +109,10 @@ impl<'gc> Forced<'gc> for NixNum {
         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())
+            let _: Step = m.finish_type_err(NixType::Int, v.ty());
-        } else {
+            return Step::Break(Break::Done);
-            Step::Continue(())
         }
+        Step::Continue(())
     }
 
     #[inline(always)]
@@ -136,11 +136,11 @@ impl<'gc> Forced<'gc> for f64 {
     ) -> Step {
         m.force_slot_to_pc(base_depth, reader, mc, resume_pc)?;
         let v = m.peek_forced(base_depth);
-        if !v.is::<f64>() {
+        if v.downcast::<f64>().is_none() {
-            m.finish_type_err(NixType::Float, v.ty())
+            let _: Step = m.finish_type_err(NixType::Float, v.ty());
-        } else {
+            return Step::Break(Break::Done);
-            Step::Continue(())
         }
+        Step::Continue(())
     }
 
     #[inline(always)]

fix-runtime/src/host.rs

@@ -1,6 +1,6 @@
 use fix_bytecode::InstructionPtr;
 use fix_error::Source;
-use fix_lang::{self, StringId};
+use fix_lang::{self, BUILTINS, StringId};
 use hashbrown::HashSet;
 
 use crate::{
@@ -153,9 +153,11 @@ impl<T: VmRuntimeCtx> ConvertValueWithSeen for T {
                 Value::Thunk
             }
         } else if let Some(primop) = val.downcast::<PrimOp>() {
-            Value::PrimOp(primop.id.info().name)
+            let name = BUILTINS[primop.id as usize].0;
+            Value::PrimOp(name.strip_prefix("__").unwrap_or(name))
         } else if let Some(app) = val.downcast::<PrimOpApp>() {
-            Value::PrimOpApp(app.primop.id.info().name)
+            let name = BUILTINS[app.primop.id as usize].0;
+            Value::PrimOpApp(name.strip_prefix("__").unwrap_or(name))
         } else {
             Value::Null
         }

fix-runtime/src/lib.rs

@@ -2,10 +2,8 @@ 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;
@@ -14,10 +12,8 @@ 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

@@ -3,11 +3,11 @@ use std::path::{Path, PathBuf};
 
 use fix_error::Error;
 use fix_lang::{self, StringId};
-use gc_arena::{Gc, Mutation};
+use gc_arena::Mutation;
 
 use crate::{
-    AttrSet, Break, BytecodeReader, CallFrame, ForceMode, Forced, GcEnv, NixType, PendingLoad,
+    Break, BytecodeReader, CallFrame, ForceMode, Forced, GcEnv, NixType, PendingLoad, Step,
-    Step, StrictValue, Value, VmError,
+    StrictValue, Value, VmError,
 };
 
 /// Abstract VM-side operations consumed by instruction handlers and primops.
@@ -65,17 +65,12 @@ pub trait Machine<'gc> {
     ) -> 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!()
@@ -96,10 +91,6 @@ pub trait Machine<'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 {
@@ -118,7 +109,7 @@ pub trait Machine<'gc> {
         self.finish_err(err.into_error())
     }
 
-    fn builtins(&self) -> Gc<'gc, AttrSet<'gc>>;
+    fn builtins(&self) -> Value<'gc>;
     fn functor_sym(&self) -> StringId;
     fn empty_list(&self) -> Value<'gc>;
     fn empty_attrs(&self) -> Value<'gc>;

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/resolve.rs

@@ -20,12 +20,20 @@ pub fn resolve_operand<'gc, M: Machine<'gc>>(
         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"),
+        #[allow(clippy::unwrap_used)]
-        Builtins => m.builtins().into(),
+        BuiltinConst(id) => m
+            .builtins()
+            .downcast::<AttrSet>()
+            .unwrap()
+            .lookup(id)
+            .unwrap(),
+        Builtins => m.builtins(),
         ReplBinding(_id) => todo!(),
         ScopedImportBinding { slot_id, name } => {
             let scope = m.scope_slot(slot_id);
+            #[allow(clippy::unwrap_used)]
             let attrs = scope.downcast::<AttrSet>().expect("scope must be attrset");
+            #[allow(clippy::unwrap_used)]
             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

@@ -8,6 +8,7 @@ use hashbrown::HashSet;
 
 use crate::{GcEnv, Thunk};
 
+#[allow(dead_code)]
 pub enum VmError {
     Catchable(String),
     Uncatchable(Box<Error>),
@@ -50,6 +51,7 @@ pub enum Break {
 
 pub type Step = ControlFlow<Break>;
 
+#[allow(dead_code)]
 pub struct ErrorFrame {
     pub span_id: u32,
     pub message: Option<String>,
@@ -59,9 +61,8 @@ pub struct ErrorFrame {
 #[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>,
+    pub env: GcEnv<'gc>,
 }
 
 #[derive(Debug)]

fix-runtime/src/string_context.rs

@@ -31,10 +31,10 @@ impl StringContextElem {
                 drv_path: drv_path.into(),
             }
         } else if let Some(rest) = encoded.strip_prefix('!') {
-            if let Some((output, drv_path)) = rest.split_once('!') {
+            if let Some(second_bang) = rest.find('!') {
                 Self::Built {
-                    output: output.into(),
+                    output: rest[..second_bang].into(),
-                    drv_path: drv_path.into(),
+                    drv_path: rest[second_bang + 1..].into(),
                 }
             } else {
                 Self::Opaque {
@@ -117,10 +117,6 @@ impl StringContext {
         }
     }
 
-    #[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();

fix-runtime/src/value.rs

@@ -4,9 +4,7 @@ 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};
@@ -21,23 +19,27 @@ mod private {
     pub trait Cealed {}
 }
 
-pub trait ValueVariant<'gc>: private::Cealed {
+pub trait ValueVariant: private::Cealed {
-    #[expect(
+    type Ty<'gc>: 'gc;
-        private_bounds,
-        reason = "Storable is a sealed implementation detail of the value system"
-    )]
-    type Ty: Storable<'gc>;
     const TYPE: NixType;
+    fn is_value(value: &Value<'_>) -> bool;
+    /// # Safety
+    ///
+    /// [`Self::is_value`] must hold for `value`.
+    unsafe fn from_raw<'gc>(value: &Value<'gc>) -> Self::Ty<'gc>;
 }
 
-trait Storable<'gc>: TryFrom<Value<'gc>> + Into<Value<'gc>> + private::Cealed + 'gc {
+/// # Safety
-    fn is(raw: &RawBox) -> bool;
+///
-
+/// Each implementor must round-trip through [`Self::to_raw_box`] /
+/// [`Self::from_raw_box`] and must be the sole owner of its NaN-boxed
+/// representation (tagged payload or float).
+pub(crate) unsafe trait Storable: private::Cealed {
     fn to_raw_box(self) -> RawBox;
     /// # Safety
     ///
     /// `raw` must represent a valid `Self`.
-    unsafe fn from_raw_box(raw: RawBox) -> Self;
+    unsafe fn from_raw_box(raw: &RawBox) -> Self;
 }
 
 macro_rules! define_value_types {
@@ -46,73 +48,54 @@ macro_rules! define_value_types {
         gc { $($gtype:ty => $gtag:path, $gty:path, $gname:literal;)* }
     ) => {
         $(
-        impl Storable<'_> for $itype {
+        unsafe 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 {
-            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 {
+        impl ValueVariant for $itype {
-            type Ty = $itype;
+            type Ty<'gc> = $itype;
             const TYPE: NixType = $ity;
+            #[inline(always)]
+            fn is_value(value: &Value<'_>) -> bool {
+                value.raw.tag() == Some($itag)
             }
-        impl<'gc> TryFrom<Value<'gc>> for $itype {
+            #[inline(always)]
-            type Error = ();
+            unsafe fn from_raw<'gc>(value: &Value<'gc>) -> Self::Ty<'gc> {
-            fn try_from(val: Value<'gc>) -> Result<Self, Self::Error> {
+                unsafe { <$itype as Storable>::from_raw_box(&value.raw) }
-                <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)> {
+        unsafe impl Storable for 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 {
-            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) {
+        impl ValueVariant for $gtype {
-            type Ty = Gc<'gc, unelide_lifetimes!('gc; $gtype)>;
+            type Ty<'gc> = Gc<'gc, fix_macros::unelide_lifetimes!('gc; $gtype)>;
             const TYPE: NixType = $gty;
+            #[inline(always)]
+            fn is_value(value: &Value<'_>) -> bool {
+                value.raw.tag() == Some($gtag)
+            }
+            #[inline(always)]
+            unsafe fn from_raw<'gc>(value: &Value<'gc>) -> Self::Ty<'gc> {
+                unsafe {
+                    <Gc<'gc, fix_macros::unelide_lifetimes!('gc; $gtype)> as Storable>::from_raw_box(
+                        &value.raw,
+                    )
+                }
+            }
         }
         )*
 
@@ -125,7 +108,6 @@ macro_rules! define_value_types {
             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 {
@@ -139,17 +121,12 @@ macro_rules! define_value_types {
             }
         };
 
-        // 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 => (),)*
@@ -161,13 +138,9 @@ macro_rules! define_value_types {
         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()
                     }),)*
@@ -196,44 +169,31 @@ define_value_types! {
         List<'_> => RawTag::N3, NixType::List, "List";
         Thunk<'_> => RawTag::N4, NixType::Thunk, "Thunk";
         Closure<'_> => RawTag::N5, NixType::Closure, "Closure";
-        PrimOpApp<'_> => RawTag::N6, NixType::PrimOpApp, "PrimOpApp";
+        PrimOpApp<'_> => RawTag::N6, NixType::Closure, "PrimOpApp";
     }
 }
 
 impl private::Cealed for f64 {}
 
-impl Storable<'_> for f64 {
+unsafe 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 {
-    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 {
+impl ValueVariant for f64 {
-    type Ty = f64;
+    type Ty<'gc> = f64;
     const TYPE: NixType = NixType::Float;
-}
+    #[inline(always)]
-
+    fn is_value(value: &Value<'_>) -> bool {
-impl<'gc> TryFrom<Value<'gc>> for f64 {
+        value.raw.is_float()
-    type Error = ();
-    fn try_from(value: Value<'gc>) -> Result<Self, Self::Error> {
-        value.downcast::<f64>().ok_or(())
     }
-}
+    #[inline(always)]
-
+    unsafe fn from_raw<'gc>(value: &Value<'gc>) -> Self::Ty<'gc> {
-impl<'gc, T: Storable<'gc>> From<T> for Value<'gc> {
+        unsafe { <f64 as Storable>::from_raw_box(&value.raw) }
-    fn from(value: T) -> Self {
-        Value::new(value)
     }
 }
 
@@ -263,11 +223,8 @@ impl<'gc> Value<'gc> {
 
 impl<'gc> Value<'gc> {
     #[inline]
-    #[expect(
+    #[allow(private_bounds)]
-        private_bounds,
+    pub fn new<T: Storable>(val: T) -> Self {
-        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,
@@ -284,16 +241,13 @@ impl<'gc> Value<'gc> {
     }
 
     #[inline]
-    pub fn is<T: ValueVariant<'gc>>(self) -> bool {
+    pub fn is<T: ValueVariant>(self) -> bool {
-        T::Ty::is(&self.raw)
+        T::is_value(&self)
     }
 
     #[inline]
-    pub fn downcast<T: ValueVariant<'gc>>(self) -> Option<T::Ty> {
+    pub fn downcast<T: ValueVariant>(self) -> Option<T::Ty<'gc>> {
-        self.is::<T>()
+        self.is::<T>().then(|| unsafe { T::from_raw(&self) })
-            // SAFETY: `is::<T>()` returned true, so `self.raw` represents a
-            // valid `T::Ty`.
-            .then(|| unsafe { T::Ty::from_raw_box(self.raw) })
     }
 
     #[inline]
@@ -322,10 +276,6 @@ impl<'gc> Value<'gc> {
     }
 
     #[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
@@ -359,7 +309,7 @@ impl<'gc> Value<'gc> {
     }
 
     #[inline]
-    pub fn expect<T: ValueVariant<'gc>>(self) -> Result<T::Ty, NixType> {
+    pub fn expect<T: ValueVariant>(self) -> Result<T::Ty<'gc>, NixType> {
         self.downcast::<T>().ok_or_else(|| self.ty())
     }
 
@@ -383,21 +333,18 @@ impl<'gc> From<StaticValue> for Value<'gc> {
 
 impl StaticValue {
     #[inline]
-    #[expect(
+    #[allow(private_bounds)]
-        private_bounds,
+    pub fn new<T: Storable + 'static>(val: T) -> Self {
-        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 {
+    pub fn is<T: ValueVariant>(self) -> bool {
         self.0.is::<T>()
     }
 
     #[inline]
-    pub fn downcast<T: ValueVariant<'static>>(self) -> Option<T::Ty> {
+    pub fn downcast<T: ValueVariant>(self) -> Option<T::Ty<'static>> {
         self.0.downcast::<T>()
     }
 
@@ -499,10 +446,6 @@ impl<'gc> AttrSet<'gc> {
         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)
@@ -514,10 +457,6 @@ impl<'gc> AttrSet<'gc> {
         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::*;
 
@@ -578,9 +517,6 @@ impl<'gc> List<'gc> {
 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() }
     }
 }
@@ -604,6 +540,14 @@ pub struct Env<'gc> {
 }
 pub type GcEnv<'gc> = GcRefLock<'gc, Env<'gc>>;
 
+#[derive(Collect, Debug)]
+#[collect(no_drop)]
+pub struct WithEnv<'gc> {
+    pub env: Value<'gc>,
+    pub prev: Option<GcWithEnv<'gc>>,
+}
+pub type GcWithEnv<'gc> = Gc<'gc, WithEnv<'gc>>;
+
 impl<'gc> Env<'gc> {
     pub fn empty() -> Self {
         Env {
@@ -612,10 +556,6 @@ impl<'gc> Env<'gc> {
         }
     }
 
-    #[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;
@@ -653,18 +593,6 @@ pub struct PrimOp {
     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();
@@ -715,19 +643,6 @@ impl<'gc> Deref for StrictValue<'gc> {
     }
 }
 
-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)

fix-vm/Cargo.toml

@@ -7,16 +7,12 @@ edition = "2024"
 gc-arena = { workspace = true }
 hashbrown = { workspace = true }
 smallvec = { workspace = true }
-sysinfo = { version = "0.39", default-features = false, features = ["system"] }
+sysinfo = { version = "0.38", 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

fix-vm/src/dispatch_tailcall.rs

@@ -22,7 +22,6 @@ 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>,
@@ -201,7 +200,6 @@ tail_fn!(op_load_scoped_binding, (ctx, reader, mc));
 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; )*
@@ -211,6 +209,7 @@ macro_rules! table {
 
         // Exhaustiveness check: fails to compile if `fix_bytecode::Op` gains,
         // loses, or renames a variant that isn't wired up above.
+        #[allow(dead_code)]
         const _: fn(fix_bytecode::Op) = |op| match op {
             $( fix_bytecode::Op::$variant => (), )*
         };
@@ -292,10 +291,6 @@ table! {
     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/instructions/calls.rs

@@ -9,10 +9,6 @@ use crate::{
 };
 
 #[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,
     reader: &mut BytecodeReader<'_>,
@@ -34,7 +30,6 @@ pub(crate) fn call<'gc, M: Machine<'gc>>(
                 pc: resume_pc,
                 thunk: None,
                 env: m.env(),
-                depth: None,
             });
             reader.set_pc(Continuation::CallPattern.ip() as usize);
             return Step::Continue(());
@@ -48,7 +43,6 @@ pub(crate) fn call<'gc, M: Machine<'gc>>(
             pc: resume_pc,
             thunk: None,
             env: m.env(),
-            depth: None,
         });
         reader.set_pc(ip as usize);
         m.set_env(new_env);
@@ -59,7 +53,6 @@ pub(crate) fn call<'gc, M: Machine<'gc>>(
                 pc: resume_pc,
                 thunk: None,
                 env: m.env(),
-                depth: None,
             });
             reader.set_pc(primop.dispatch_ip as usize)
         } else {
@@ -80,7 +73,6 @@ pub(crate) fn call<'gc, M: Machine<'gc>>(
                 pc: resume_pc,
                 thunk: None,
                 env: m.env(),
-                depth: None,
             });
             reader.set_pc(app.primop.dispatch_ip as usize)
         } else {
@@ -105,7 +97,6 @@ pub(crate) fn call<'gc, M: Machine<'gc>>(
             pc: resume_pc,
             thunk: None,
             env: m.env(),
-            depth: None,
         });
         m.push(arg);
         m.push(func.relax());
@@ -145,7 +136,6 @@ pub(crate) fn op_return<'gc, M: Machine<'gc>>(
         pc: ret_pc,
         thunk,
         env,
-        depth,
     }) = m.pop_call_frame()
     else {
         match m.force_mode() {
@@ -162,10 +152,9 @@ pub(crate) fn op_return<'gc, M: Machine<'gc>>(
                     pc: Continuation::ForceResultDeepFinish.ip() as usize,
                     thunk: None,
                     env: m.env(),
-                    depth: None,
                 });
                 m.inc_call_depth();
-                reader.set_pc(Continuation::PDeepSeq0.ip() as usize);
+                reader.set_pc(Continuation::PDeepSeq.ip() as usize);
                 return Step::Continue(());
             }
         }
@@ -173,9 +162,6 @@ 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());
-        }
     } else {
         m.dec_call_depth();
         m.push(val.relax())

fix-vm/src/instructions/collections.rs

@@ -117,10 +117,6 @@ pub(crate) fn op_select_dynamic<'gc, M: Machine<'gc>>(
 /// 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,
     key: StringId,
@@ -130,7 +126,6 @@ fn select_skip<'gc, M: Machine<'gc>>(
     use fix_bytecode::Op::*;
     loop {
         match reader.read_op() {
-            // Skip rest of the attrpath
             SelectStatic => {
                 reader.set_pc(reader.pc() + 4 + 4);
             }
@@ -141,14 +136,10 @@ 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")));
@@ -159,14 +150,6 @@ fn select_skip<'gc, M: Machine<'gc>>(
 
 /// 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::*;
     loop {
@@ -262,10 +245,6 @@ pub(crate) fn op_jump_if_select_failed<'gc, M: Machine<'gc>>(
 }
 
 #[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<'_>,

fix-vm/src/instructions/control.rs

@@ -5,10 +5,6 @@ use gc_arena::Mutation;
 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,
     reader: &mut BytecodeReader<'_>,
@@ -23,10 +19,6 @@ pub(crate) fn op_jump_if_false<'gc, M: Machine<'gc>>(
 }
 
 #[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,
     reader: &mut BytecodeReader<'_>,
@@ -41,10 +33,6 @@ pub(crate) fn op_jump_if_true<'gc, M: Machine<'gc>>(
 }
 
 #[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 {
     let offset = reader.read_i32();
     reader.set_pc(((reader.pc() as isize) + (offset as isize)) as usize);

fix-vm/src/instructions/misc.rs

@@ -2,7 +2,7 @@ use std::path::PathBuf;
 
 use fix_bytecode::Continuation;
 use fix_error::Error;
-use fix_lang::{BuiltinId, StringId};
+use fix_lang::{BUILTINS, BuiltinId, StringId};
 use fix_runtime::{
     AttrSet, Machine, MachineExt, NixString, Path, StrictValue, StringContext, canon_path_str,
 };
@@ -11,15 +11,11 @@ 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());
+    m.push(m.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<'_>,
@@ -28,7 +24,7 @@ pub(crate) fn op_load_builtin<'gc, M: Machine<'gc>>(
         .map_err(|err| panic!("unknown builtin id: {}", err.number));
     m.push(Value::new(PrimOp {
         id,
-        arity: id.info().arity,
+        arity: BUILTINS[id as usize].1,
         dispatch_ip: Continuation::entry_for_builtin(id).ip(),
     }));
     Step::Continue(())

fix-vm/src/instructions/variables.rs

@@ -3,10 +3,6 @@ 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<'_>,
@@ -17,10 +13,6 @@ pub(crate) fn op_load_local<'gc, M: Machine<'gc>>(
 }
 
 #[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<'_>,
@@ -38,10 +30,6 @@ pub(crate) fn op_load_outer<'gc, M: Machine<'gc>>(
 }
 
 #[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,
     reader: &mut BytecodeReader<'_>,

fix-vm/src/instructions/with_scope.rs

@@ -6,21 +6,14 @@ use smallvec::SmallVec;
 use crate::{Break, BytecodeReader, CallFrame, Step, VmRuntimeCtx};
 
 #[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,
     ctx: &mut impl VmRuntimeCtx,
     reader: &mut BytecodeReader<'_>,
     mc: &gc_arena::Mutation<'gc>,
 ) -> Step {
-    let counter = m
+    #[allow(clippy::unwrap_used)]
-        .peek_forced(0)
+    let counter = m.peek_forced(0).downcast::<i32>().unwrap();
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
 
     let name = reader.read_string_id();
     let n = reader.read_u8();
@@ -41,7 +34,6 @@ pub(crate) fn op_lookup_with<'gc, M: Machine<'gc>>(
                         thunk: Some(thunk),
                         pc: resume_pc,
                         env: m.env(),
-                        depth: None,
                     });
                     m.set_env(env);
                     reader.set_pc(ip);
@@ -53,7 +45,6 @@ pub(crate) fn op_lookup_with<'gc, M: Machine<'gc>>(
                         thunk: Some(thunk),
                         pc: resume_pc,
                         env: m.env(),
-                        depth: None,
                     });
                     m.push(func);
                     return m.call(reader, mc, arg, resume_pc);

fix-vm/src/lib.rs

@@ -1,7 +1,5 @@
-#![cfg_attr(
+#![warn(clippy::unwrap_used)]
-    feature = "tailcall",
+#![cfg_attr(feature = "tailcall", expect(incomplete_features))]
-    expect(incomplete_features, reason = "for testing purpose only")
-)]
 #![cfg_attr(
     feature = "tailcall",
     feature(explicit_tail_calls, rust_preserve_none_cc)
@@ -11,7 +9,7 @@ use std::path::PathBuf;
 
 use fix_bytecode::{Continuation, InstructionPtr};
 use fix_error::{Error, Result, Source};
-use fix_lang::{BuiltinId, StringId};
+use fix_lang::{BUILTINS, BuiltinId, StringId};
 use gc_arena::metrics::Pacing;
 use gc_arena::{Arena, Collect, Gc, Mutation, RefLock, Rootable};
 use hashbrown::HashMap;
@@ -20,12 +18,8 @@ use smallvec::SmallVec;
 #[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;
 
 type VmResult<T> = std::result::Result<T, VmError>;
 
@@ -35,10 +29,7 @@ pub struct Vm<'gc> {
     stack: Vec<Value<'gc>>,
     call_stack: Vec<CallFrame<'gc>>,
     call_depth: usize,
-    #[expect(
+    #[allow(dead_code)]
-        dead_code,
-        reason = "error_context is reserved for tryEval catch-frame tracking, not yet wired up"
-    )]
     #[collect(require_static)]
     error_context: Vec<ErrorFrame>,
 
@@ -47,7 +38,7 @@ pub struct Vm<'gc> {
     import_cache: HashMap<PathBuf, Value<'gc>>,
     scope_slots: Vec<Value<'gc>>,
 
-    builtins: Gc<'gc, AttrSet<'gc>>,
+    builtins: Value<'gc>,
     empty_list: Value<'gc>,
     empty_attrs: Value<'gc>,
 
@@ -62,12 +53,13 @@ pub struct Vm<'gc> {
     functor_sym: StringId,
 }
 
-fn init_builtins<'gc>(mc: &Mutation<'gc>, ctx: &mut impl VmRuntimeCtx) -> Gc<'gc, AttrSet<'gc>> {
+fn init_builtins<'gc>(mc: &Mutation<'gc>, ctx: &mut impl VmRuntimeCtx) -> Value<'gc> {
-    let mut entries = SmallVec::with_capacity(BuiltinId::TOTAL);
+    let mut entries = SmallVec::with_capacity(BUILTINS.len());
 
-    for id in BuiltinId::ALL {
+    for (idx, &(name, arity)) in BUILTINS.iter().enumerate() {
-        let arity = id.info().arity;
+        let id = BuiltinId::try_from(idx as u8).expect("infallible");
-        let name = ctx.intern_string(id.info().name);
+        let name = name.strip_prefix("__").unwrap_or(name);
+        let name = ctx.intern_string(name);
         let dispatch_ip = Continuation::entry_for_builtin(id).ip();
         entries.push((
             name,
@@ -109,7 +101,7 @@ fn init_builtins<'gc>(mc: &Mutation<'gc>, ctx: &mut impl VmRuntimeCtx) -> Gc<'gc
     let builtins_value = Value::new(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> {
@@ -215,7 +207,6 @@ impl<'gc> Machine<'gc> for Vm<'gc> {
                     thunk: Some(thunk),
                     pc: resume_pc,
                     env: self.env,
-                    depth: Some(depth),
                 });
                 self.env = env;
                 reader.set_pc(ip);
@@ -230,7 +221,6 @@ impl<'gc> Machine<'gc> for Vm<'gc> {
                     thunk: Some(thunk),
                     pc: resume_pc,
                     env: self.env,
-                    depth: Some(depth),
                 });
                 self.push(func);
                 self.call(reader, mc, arg, resume_pc)
@@ -308,7 +298,7 @@ impl<'gc> Machine<'gc> for Vm<'gc> {
     }
 
     #[inline(always)]
-    fn builtins(&self) -> Gc<'gc, AttrSet<'gc>> {
+    fn builtins(&self) -> Value<'gc> {
         self.builtins
     }
 
@@ -466,10 +456,6 @@ impl<'gc> Vm<'gc> {
 
     #[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],

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

@@ -200,25 +200,16 @@ pub fn append_context<'gc, M: Machine<'gc>>(
     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
+    #[allow(clippy::unwrap_used)]
-        .peek(1)
+    let idx = m.peek(1).downcast::<i32>().unwrap();
-        .downcast::<i32>()
+    #[allow(clippy::unwrap_used)]
-        .expect("stack slot must be an integer");
+    let attrs = m.peek_forced(2).downcast::<AttrSet>().unwrap();
-    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);
@@ -236,11 +227,6 @@ pub fn append_context_loop<'gc, M: Machine<'gc>>(
     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,
@@ -256,14 +242,10 @@ pub fn append_context_entry_forced<'gc, M: Machine<'gc>>(
         return m.finish_type_err(NixType::AttrSet, entry_val.ty());
     };
 
-    let idx = m
+    #[allow(clippy::unwrap_used)]
-        .peek(2)
+    let idx = m.peek(2).downcast::<i32>().unwrap();
-        .downcast::<i32>()
+    #[allow(clippy::unwrap_used)]
-        .expect("stack slot must be an integer");
+    let outer = m.peek_forced(3).downcast::<AttrSet>().unwrap();
-    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/") {
@@ -280,10 +262,8 @@ pub fn append_context_entry_forced<'gc, M: Machine<'gc>>(
     let all_outputs_id = ctx.intern_string("allOutputs");
     let outputs_id = ctx.intern_string("outputs");
 
-    let acc_gc = m
+    #[allow(clippy::unwrap_used)]
-        .peek(1)
+    let acc_gc = m.peek(1).downcast::<NixString>().unwrap();
-        .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)
@@ -322,11 +302,9 @@ pub fn append_context_entry_forced<'gc, M: Machine<'gc>>(
         return Step::Continue(());
     }
 
-    m.drop_n(1);
+    let _ = m.pop();
-    let idx_back = m
+    #[allow(clippy::unwrap_used)]
-        .peek(1)
+    let idx_back = m.peek(1).downcast::<i32>().unwrap();
-        .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(())
@@ -345,11 +323,9 @@ pub fn append_context_outputs_forced<'gc, M: Machine<'gc>>(
     };
     if list.inner.borrow().is_empty() {
         // Stack: [strVal, attrs, idx, acc, list] -> drop list, bump idx.
-        m.drop_n(1);
+        let _ = m.pop();
-        let idx_back = m
+        #[allow(clippy::unwrap_used)]
-            .peek(1)
+        let idx_back = m.peek(1).downcast::<i32>().unwrap();
-            .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(());
@@ -360,34 +336,24 @@ pub fn append_context_outputs_forced<'gc, M: Machine<'gc>>(
     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
+    #[allow(clippy::unwrap_used)]
-        .peek(0)
+    let oidx = m.peek(0).downcast::<i32>().unwrap();
-        .downcast::<i32>()
+    #[allow(clippy::unwrap_used)]
-        .expect("stack slot must be an integer");
+    let list = m.peek_forced(1).downcast::<VmList>().unwrap();
-    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 _ = m.pop();
-        let idx_back = m
+        let _ = m.pop();
-            .peek(1)
+        #[allow(clippy::unwrap_used)]
-            .downcast::<i32>()
+        let idx_back = m.peek(1).downcast::<i32>().unwrap();
-            .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(());
@@ -405,11 +371,6 @@ pub fn append_context_output_element_loop<'gc, M: Machine<'gc>>(
     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,
@@ -423,14 +384,10 @@ pub fn append_context_output_element_forced<'gc, M: Machine<'gc>>(
     };
     let output_name: Box<str> = output_name.into();
 
-    let idx = m
+    #[allow(clippy::unwrap_used)]
-        .peek(4)
+    let idx = m.peek(4).downcast::<i32>().unwrap();
-        .downcast::<i32>()
+    #[allow(clippy::unwrap_used)]
-        .expect("stack slot must be an integer");
+    let outer = m.peek_forced(5).downcast::<AttrSet>().unwrap();
-    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") {
@@ -439,10 +396,8 @@ pub fn append_context_output_element_forced<'gc, M: Machine<'gc>>(
         )));
     }
 
-    let acc_gc = m
+    #[allow(clippy::unwrap_used)]
-        .peek(3)
+    let acc_gc = m.peek(3).downcast::<NixString>().unwrap();
-        .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,
@@ -453,20 +408,14 @@ pub fn append_context_output_element_forced<'gc, M: Machine<'gc>>(
 
     // Stack: [strVal, attrs, idx, acc, list, oidx, outElem] -> drop outElem,
     // bump oidx in place.
-    m.drop_n(1);
+    let _ = m.pop();
-    let oidx = m
+    #[allow(clippy::unwrap_used)]
-        .peek(0)
+    let oidx = m.peek(0).downcast::<i32>().unwrap();
-        .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,
@@ -474,11 +423,10 @@ fn append_context_finalize<'gc, M: Machine<'gc>>(
     mc: &Mutation<'gc>,
 ) -> Step {
     // Stack: [strVal, attrs, idx, acc]
-    let acc_gc = m
+    #[allow(clippy::unwrap_used)]
-        .pop()
+    let acc_gc = m.pop().downcast::<NixString>().unwrap();
-        .downcast::<NixString>()
+    let _ = m.pop(); // idx
-        .expect("stack slot must be a string");
+    let _ = m.pop(); // attrs
-    m.drop_n(2);
     let str_val_raw = m.pop();
 
     // The strVal was already forced at entry; restrict() is infallible here.

fix-vm/src/primops/control.rs

@@ -1,89 +1,22 @@
 use fix_bytecode::Continuation;
-use fix_error::{Error, Result};
+use fix_error::Error;
-use fix_macros::handler;
 use fix_runtime::{
-    AttrSet, BytecodeReader, Closure, Env, List, Machine, MachineExt, Slot, Step, StrictValue,
+    AttrSet, BytecodeReader, Closure, Env, List, Machine, MachineExt, Step, StrictValue, Value,
-    Value, VmRuntimeCtx, VmRuntimeCtxExt,
+    VmRuntimeCtx, VmRuntimeCtxExt,
 };
 use gc_arena::{Gc, Mutation, RefLock};
 use smallvec::SmallVec;
 
-use crate::primops::stubs::*;
+pub fn seq<'gc, M: Machine<'gc>>(
-
+    m: &mut M,
-#[handler(name = PSeq)]
+    reader: &mut BytecodeReader<'_>,
-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>>,
+) -> Step {
-    e2: Slot<Value<'gc>>,
+    // stack: [e1, e2] - force e1, return e2
-) -> Result<Value<'gc>> {
+    m.force_slot(1, reader, mc)?;
-    let e1: Slot<StrictValue<'gc>> = force(e1).await?;
+    let e2 = m.pop();
-    if collect_children(e1.get()).is_empty() {
+    let _ = m.pop();
-        return Ok(e2.get());
+    m.return_from_primop(e2, reader)
-    }
-    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>>(
@@ -101,6 +34,133 @@ pub fn abort<'gc, M: Machine<'gc>>(
     )))
 }
 
+pub fn deep_seq_force_top<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    // stack: [e1, e2] - force e1, return e2
+    m.force_slot(1, reader, mc)?;
+
+    let e1 = m.peek_forced(1);
+
+    let children: SmallVec<_> = if let Some(attrs) = e1.downcast::<AttrSet>() {
+        let attrs = &attrs.entries;
+        if attrs.is_empty() {
+            SmallVec::new()
+        } else {
+            attrs.iter().map(|&(_, v)| v).collect()
+        }
+    } else if let Some(list) = e1.downcast::<List>() {
+        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 = m.pop();
+        let _ = m.pop();
+        return m.return_from_primop(e2, reader);
+    }
+
+    let count = children.len() as i32;
+    let seen = Gc::new(mc, List::default());
+    let worklist = List::new(mc, children);
+
+    let e2 = m.pop();
+    let _ = m.pop();
+    m.push(e2);
+    m.push(Value::new(seen));
+    m.push(Value::new(worklist));
+    m.push(Value::new(count));
+    reader.set_pc(Continuation::PDeepSeqPush.ip() as usize);
+    Step::Continue(())
+}
+
+pub fn deep_seq_push<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    // stack: [e2, seen, worklist, counter]
+    #[allow(clippy::unwrap_used)]
+    let counter = m.peek(0).downcast::<i32>().unwrap();
+    if counter == 0 {
+        let _ = m.pop(); // counter
+        let _ = m.pop(); // worklist
+        let _ = m.pop(); // seen
+        let val = m.pop();
+        return m.return_from_primop(val, reader);
+    }
+
+    #[allow(clippy::unwrap_used)]
+    let worklist = m.peek_forced(1).downcast::<List>().unwrap();
+    #[allow(clippy::unwrap_used)]
+    let item = worklist.unlock(mc).borrow_mut().pop().unwrap();
+    m.replace(0, Value::new(counter - 1));
+    m.push(item);
+
+    // force item at TOS, resume at DeepSeqLoop after force
+    m.force_slot_to_pc(0, reader, mc, Continuation::PDeepSeqLoop.ip() as usize)?;
+    reader.set_pc(Continuation::PDeepSeqLoop.ip() as usize);
+    Step::Continue(())
+}
+
+pub fn deep_seq_loop<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    // stack after pop: [e2, seen, worklist, counter]
+    let item = m.pop();
+    #[allow(clippy::unwrap_used)]
+    let counter = m.peek(0).downcast::<i32>().unwrap();
+
+    let mut added: usize = 0;
+    if let Some(attrs) = item.downcast::<AttrSet>() {
+        let attrs = &attrs.entries;
+        #[allow(clippy::unwrap_used)]
+        let seen = m.peek_forced(2).downcast::<List>().unwrap();
+        if !is_value_in_seen(seen, item) {
+            add_value_to_seen(seen, mc, item);
+            #[allow(clippy::unwrap_used)]
+            let worklist = m.peek_forced(1).downcast::<List>().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.downcast::<List>() {
+        #[allow(clippy::unwrap_used)]
+        let seen = m.peek_forced(2).downcast::<List>().unwrap();
+        if !is_value_in_seen(seen, item) {
+            add_value_to_seen(seen, mc, item);
+            #[allow(clippy::unwrap_used)]
+            let worklist = m.peek_forced(1).downcast::<List>().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();
+            }
+        }
+    }
+
+    m.replace(0, Value::new(counter + added as i32));
+    reader.set_pc(Continuation::PDeepSeqPush.ip() as usize);
+    Step::Continue(())
+}
+
 pub fn force_result_shallow<'gc, M: Machine<'gc>>(
     m: &mut M,
     ctx: &mut impl VmRuntimeCtx,
@@ -131,27 +191,20 @@ pub fn force_result_shallow<'gc, M: Machine<'gc>>(
     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
+    #[allow(clippy::unwrap_used)]
-        .peek(1)
+    let idx = m.peek(1).downcast::<i32>().unwrap();
-        .downcast::<i32>()
+    #[allow(clippy::unwrap_used)]
-        .expect("stack slot must be an integer");
+    let len = m.peek(0).downcast::<i32>().unwrap();
-    let len = m
-        .peek(0)
-        .downcast::<i32>()
-        .expect("stack slot must be an integer");
 
     if idx == len {
-        m.drop_n(2);
+        let _ = m.pop(); // len
+        let _ = m.pop(); // idx
         let val = m.pop();
         return m.finish_ok(ctx.convert_value(val));
     }
@@ -184,7 +237,7 @@ pub fn force_result_shallow_loop<'gc, M: Machine<'gc>>(
     reader: &mut BytecodeReader<'_>,
     _mc: &Mutation<'gc>,
 ) -> Step {
-    m.drop_n(1);
+    let _ = m.pop(); // forced child
     reader.set_pc(Continuation::ForceResultShallowPush.ip() as usize);
     Step::Continue(())
 }
@@ -255,10 +308,6 @@ pub fn call_functor_2<'gc, M: Machine<'gc>>(
     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,

fix-vm/src/primops/conv.rs

@@ -27,10 +27,6 @@ pub fn to_string<'gc, M: Machine<'gc>>(
     )))
 }
 
-#[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,

fix-vm/src/primops/eq.rs

@@ -88,7 +88,8 @@ pub fn eq_force<'gc, M: Machine<'gc>>(
 }
 
 fn finalize<'gc, M: Machine<'gc>>(m: &mut M, reader: &mut BytecodeReader<'_>) -> Step {
-    m.drop_n(2);
+    let _ = m.pop();
+    let _ = m.pop();
     let result = m
         .pop()
         .downcast::<bool>()
@@ -166,7 +167,6 @@ fn enter_eq_machine<'gc, M: Machine<'gc>>(
         pc: resume_pc,
         thunk: None,
         env: m.env(),
-        depth: None,
     });
     m.inc_call_depth();
     m.push(Value::new(negate));

fix-vm/src/primops/io.rs

@@ -46,7 +46,6 @@ pub fn import<'gc, M: Machine<'gc>>(
         pc: Continuation::PImportFinalize.ip() as usize,
         thunk: None,
         env,
-        depth: None,
     });
 
     m.set_pending_load(PendingLoad {
@@ -56,10 +55,6 @@ pub fn import<'gc, M: Machine<'gc>>(
     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,
@@ -67,10 +62,8 @@ pub fn import_finalize<'gc, M: Machine<'gc>>(
 ) -> Step {
     // stack: [path_sid, return_value]
     let val = m.pop();
-    let path_sid = m
+    #[allow(clippy::unwrap_used)]
-        .pop()
+    let path_sid = m.pop().downcast::<StringId>().unwrap();
-        .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();
@@ -80,7 +73,6 @@ pub fn import_finalize<'gc, M: Machine<'gc>>(
         pc: ret_pc,
         thunk: _,
         env,
-        depth: None,
     }) = m.pop_call_frame()
     else {
         unreachable!()
@@ -122,7 +114,6 @@ pub fn scoped_import<'gc, M: Machine<'gc>>(
         pc: Continuation::PScopedImportFinalize.ip() as usize,
         thunk: None,
         env,
-        depth: None,
     });
 
     m.set_pending_load(PendingLoad {

fix-vm/src/primops/list.rs

@@ -1,116 +1,288 @@
-use fix_error::Result;
+use fix_bytecode::Continuation;
-use fix_macros::handler;
+use fix_runtime::{BytecodeReader, List, Machine, MachineExt, NixType, Step, StrictValue, Value};
-use fix_runtime::{List, Slot, StrictValue, Value};
 use gc_arena::Mutation;
 
-use crate::primops::stubs::*;
+pub fn filter_force_list<'gc, M: Machine<'gc>>(
-
+    m: &mut M,
-#[handler(name = PFilter)]
+    reader: &mut BytecodeReader<'_>,
-fn filter<'gc>(
     mc: &Mutation<'gc>,
-    pred: Slot<Value<'gc>>,
+) -> Step {
-    list: Slot<Value<'gc>>,
+    m.force_slot(0, reader, mc)?;
-) -> Result<Value<'gc>> {
+    let list = match m.peek_forced(0).expect::<List>() {
-    let list: Slot<List<'gc>> = force(list).await?;
+        Ok(list) => list,
-    if list.get().inner.borrow().is_empty() {
+        Err(got) => return m.finish_type_err(NixType::List, got),
-        return Ok(Value::new(list.get()));
+    };
-    }
+    if list.inner.borrow().is_empty() {
-    let idx: Slot<i32> = spill(0i32);
+        let val = m.pop();
-    let acc: Slot<List<'gc>> = spill(List::new_gc(mc));
+        let _pred = m.pop();
-    loop {
+        return m.return_from_primop(val, reader);
-        #[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);
     }
+    // prepare stack layout: [ pred list idx acc ]
+    m.push(Value::new(0));
+    m.push(Value::new(List::new_gc(mc)));
+    reader.set_pc(Continuation::PFilterCallPred.ip() as usize);
+    Step::Continue(())
 }
 
-#[handler(name = PAll)]
+pub fn filter_call_pred<'gc, M: Machine<'gc>>(
-fn all<'gc>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
     mc: &Mutation<'gc>,
-    pred: Slot<Value<'gc>>,
+) -> Step {
-    list: Slot<Value<'gc>>,
+    m.force_slot(3, reader, mc)?;
-) -> Result<Value<'gc>> {
+    let pred = m.peek_forced(3);
-    let list: Slot<List<'gc>> = force(list).await?;
+    #[allow(clippy::unwrap_used)]
-    if list.get().inner.borrow().is_empty() {
+    let idx = m.peek(1).downcast::<i32>().unwrap();
-        return Ok(Value::new(true));
+    #[allow(clippy::unwrap_used)]
-    }
+    let elem = m.peek_forced(2).downcast::<List>().unwrap().inner.borrow()[idx as usize];
-    let idx: Slot<i32> = spill(0i32);
+    m.push(pred.relax());
-    loop {
+    m.call(reader, mc, elem, Continuation::PFilterCheck.ip() as usize)
-        #[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)]
+pub fn filter_check<'gc, M: Machine<'gc>>(
-fn any<'gc>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
     mc: &Mutation<'gc>,
-    pred: Slot<Value<'gc>>,
+) -> Step {
-    list: Slot<Value<'gc>>,
+    let ret = m.force_and_retry::<bool>(reader, mc)?;
-) -> Result<Value<'gc>> {
+    #[allow(clippy::unwrap_used)]
-    let list: Slot<List<'gc>> = force(list).await?;
+    let idx = m.peek(1).downcast::<i32>().unwrap();
-    if list.get().inner.borrow().is_empty() {
+    #[allow(clippy::unwrap_used)]
-        return Ok(Value::new(false));
+    let list = m.peek_forced(2).downcast::<List>().unwrap();
+    let list = list.inner.borrow();
+    #[allow(clippy::unwrap_used)]
+    let acc = m.peek_forced(0).downcast::<List>().unwrap();
+    if ret {
+        let mut acc = acc.unlock(mc).borrow_mut();
+        acc.push(list[idx as usize]);
     }
-    let idx: Slot<i32> = spill(0i32);
+    if idx as usize == list.len() - 1 {
-    loop {
+        let acc = m.pop();
-        #[expect(
+        let _ = m.pop(); // idx
-            clippy::indexing_slicing,
+        let _ = m.pop(); // list
-            reason = "idx is a non-negative loop counter in 0..list.len(), so it indexes the list in bounds"
+        let _ = m.pop(); // pred
-        )]
+        return m.return_from_primop(acc, reader);
-        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);
     }
+    m.replace(1, Value::new(idx + 1));
+    reader.set_pc(Continuation::PFilterCallPred.ip() as usize);
+    Step::Continue(())
 }
 
-#[handler(name = PFoldlStrict)]
+// foldl' op nul list
-fn foldl_strict<'gc>(
+//
+// Stack layouts across phases:
+//   Entry:  [op, nul, list]
+//   Empty:  [op, nul]
+//   Call1:  [op, list, idx, acc]
+//   Call2:  [op, list, idx, acc, intermediate]
+//   Update: [op, list, idx, acc, result]
+pub fn foldl_strict_entry<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
     mc: &Mutation<'gc>,
-    op: Slot<Value<'gc>>,
+) -> Step {
-    nul: Slot<Value<'gc>>,
+    m.force_slot(0, reader, mc)?;
-    list: Slot<Value<'gc>>,
+    let list_val = m.peek_forced(0);
-) -> Result<Value<'gc>> {
+    let Some(list) = list_val.downcast::<List>() else {
-    let list: Slot<List<'gc>> = force(list).await?;
+        return m.finish_type_err(NixType::List, list_val.ty());
-    if list.get().inner.borrow().is_empty() {
+    };
-        return Ok(nul.get());
+    if list.inner.borrow().is_empty() {
-    }
+        let _ = m.pop(); // list
-    let idx: Slot<i32> = spill(0i32);
+        reader.set_pc(Continuation::PFoldlStrictEmpty.ip() as usize);
-    let acc = spill(nul.get());
+        return Step::Continue(());
-    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);
     }
+    let list_val = m.pop();
+    let nul_val = m.pop();
+    m.push(list_val);
+    m.push(Value::new(0i32));
+    m.push(nul_val);
+    reader.set_pc(Continuation::PFoldlStrictCall1.ip() as usize);
+    Step::Continue(())
+}
+
+pub fn foldl_strict_empty<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    let nul = m.force_and_retry::<StrictValue>(reader, mc)?;
+    let _ = m.pop(); // op
+    m.return_from_primop(nul.relax(), reader)
+}
+
+pub fn foldl_strict_call1<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    m.force_slot(3, reader, mc)?;
+    let op = m.peek_forced(3);
+    let acc = m.peek(0);
+    m.push(op.relax());
+    m.call(
+        reader,
+        mc,
+        acc,
+        Continuation::PFoldlStrictCall2.ip() as usize,
+    )
+}
+
+pub fn foldl_strict_call2<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    #[allow(clippy::unwrap_used)]
+    let idx = m.peek(2).downcast::<i32>().unwrap();
+    #[allow(clippy::unwrap_used)]
+    let list = m.peek_forced(3).downcast::<List>().unwrap();
+    let elem = list.inner.borrow()[idx as usize];
+    m.call(
+        reader,
+        mc,
+        elem,
+        Continuation::PFoldlStrictUpdate.ip() as usize,
+    )
+}
+
+pub fn foldl_strict_update<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    _mc: &Mutation<'gc>,
+) -> Step {
+    let result = m.pop();
+    m.replace(0, result);
+    #[allow(clippy::unwrap_used)]
+    let idx = m.peek(1).downcast::<i32>().unwrap();
+    #[allow(clippy::unwrap_used)]
+    let list = m.peek_forced(2).downcast::<List>().unwrap();
+    let len = list.inner.borrow().len();
+    if (idx as usize) + 1 == len {
+        let acc = m.pop();
+        let _ = m.pop(); // idx
+        let _ = m.pop(); // list
+        let _ = m.pop(); // op
+        return m.return_from_primop(acc, reader);
+    }
+    m.replace(1, Value::new(idx + 1));
+    reader.set_pc(Continuation::PFoldlStrictCall1.ip() as usize);
+    Step::Continue(())
+}
+
+pub fn all_entry<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    m.force_slot(0, reader, mc)?;
+    let list = match m.peek_forced(0).expect::<List>() {
+        Ok(list) => list,
+        Err(got) => return m.finish_type_err(NixType::List, got),
+    };
+    // FIXME: force callable
+    m.force_slot(1, reader, mc)?;
+    if list.inner.borrow().is_empty() {
+        let _list = m.pop();
+        let _pred = m.pop();
+        return m.return_from_primop(Value::new(true), reader);
+    }
+    // prepare stack layout: [ pred list idx ]
+    m.push(Value::new(0));
+    reader.set_pc(Continuation::PAllCallPred.ip() as usize);
+    Step::Continue(())
+}
+
+pub fn all_call_pred<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    let pred = m.peek_forced(2);
+    #[allow(clippy::unwrap_used)]
+    let idx = m.peek(0).downcast::<i32>().unwrap();
+    #[allow(clippy::unwrap_used)]
+    let elem = m.peek_forced(1).downcast::<List>().unwrap().inner.borrow()[idx as usize];
+    m.push(pred.relax());
+    m.call(reader, mc, elem, Continuation::PAllCheck.ip() as usize)
+}
+
+pub fn all_check<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    let ret = m.force_and_retry::<bool>(reader, mc)?;
+    #[allow(clippy::unwrap_used)]
+    let idx = m.peek(0).downcast::<i32>().unwrap();
+    #[allow(clippy::unwrap_used)]
+    let list = m.peek_forced(1).downcast::<List>().unwrap();
+    let list = list.inner.borrow();
+    if idx as usize == list.len() - 1 || !ret {
+        let _ = m.pop(); // idx
+        let _ = m.pop(); // list
+        let _ = m.pop(); // pred
+        return m.return_from_primop(Value::new(ret), reader);
+    }
+    m.replace(0, Value::new(idx + 1));
+    reader.set_pc(Continuation::PAllCallPred.ip() as usize);
+    Step::Continue(())
+}
+
+pub fn any_entry<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    m.force_slot(0, reader, mc)?;
+    let list = match m.peek_forced(0).expect::<List>() {
+        Ok(list) => list,
+        Err(got) => return m.finish_type_err(NixType::List, got),
+    };
+    // FIXME: force callable
+    m.force_slot(1, reader, mc)?;
+    if list.inner.borrow().is_empty() {
+        let _list = m.pop();
+        let _pred = m.pop();
+        return m.return_from_primop(Value::new(false), reader);
+    }
+    // prepare stack layout: [ pred list idx ]
+    m.push(Value::new(0));
+    reader.set_pc(Continuation::PAnyCallPred.ip() as usize);
+    Step::Continue(())
+}
+
+pub fn any_call_pred<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    let pred = m.peek_forced(2);
+    #[allow(clippy::unwrap_used)]
+    let idx = m.peek(0).downcast::<i32>().unwrap();
+    #[allow(clippy::unwrap_used)]
+    let elem = m.peek_forced(1).downcast::<List>().unwrap().inner.borrow()[idx as usize];
+    m.push(pred.relax());
+    m.call(reader, mc, elem, Continuation::PAnyCheck.ip() as usize)
+}
+
+pub fn any_check<'gc, M: Machine<'gc>>(
+    m: &mut M,
+    reader: &mut BytecodeReader<'_>,
+    mc: &Mutation<'gc>,
+) -> Step {
+    let ret = m.force_and_retry::<bool>(reader, mc)?;
+    #[allow(clippy::unwrap_used)]
+    let idx = m.peek(0).downcast::<i32>().unwrap();
+    #[allow(clippy::unwrap_used)]
+    let list = m.peek_forced(1).downcast::<List>().unwrap();
+    let list = list.inner.borrow();
+    if idx as usize == list.len() - 1 || ret {
+        let _ = m.pop(); // idx
+        let _ = m.pop(); // list
+        let _ = m.pop(); // pred
+        return m.return_from_primop(Value::new(ret), reader);
+    }
+    m.replace(0, Value::new(idx + 1));
+    reader.set_pc(Continuation::PAnyCallPred.ip() as usize);
+    Step::Continue(())
 }

fix-vm/src/primops/mod.rs

@@ -5,7 +5,6 @@ mod eq;
 mod io;
 mod list;
 mod path;
-mod stubs;
 
 pub use context::*;
 pub use control::*;
@@ -19,6 +18,7 @@ pub use io::*;
 pub use list::*;
 pub use path::*;
 
+#[allow(clippy::too_many_lines)]
 pub fn dispatch_cont<'gc, M: Machine<'gc>>(
     m: &mut M,
     ctx: &mut impl VmRuntimeCtx,
@@ -33,18 +33,28 @@ pub fn dispatch_cont<'gc, M: Machine<'gc>>(
     match cont {
         PAbort => abort(m, ctx, reader, mc),
 
-        PAll0 | PAll1 | PAll2 | PAll3 => all(m, reader, mc, cont),
+        PAll => all_entry(m, reader, mc),
-        PAny0 | PAny1 | PAny2 | PAny3 => any(m, reader, mc, cont),
+        PAllCallPred => all_call_pred(m, reader, mc),
-        PDeepSeq0 | PDeepSeq1 | PDeepSeq2 | PDeepSeq3 | PDeepSeq4 | PDeepSeq5 => {
+        PAllCheck => all_check(m, reader, mc),
-            deep_seq(m, reader, mc, cont)
-        }
-        PSeq0 | PSeq1 => seq(m, reader, mc, cont),
 
-        PFilter0 | PFilter1 | PFilter2 | PFilter3 | PFilter4 => filter(m, reader, mc, cont),
+        PAny => any_entry(m, reader, mc),
+        PAnyCallPred => any_call_pred(m, reader, mc),
+        PAnyCheck => any_check(m, reader, mc),
 
-        PFoldlStrict0 | PFoldlStrict1 | PFoldlStrict2 | PFoldlStrict3 | PFoldlStrict4 | PFoldlStrict5 => {
+        PDeepSeq => deep_seq_force_top(m, reader, mc),
-            foldl_strict(m, reader, mc, cont)
+        PDeepSeqPush => deep_seq_push(m, reader, mc),
-        }
+        PDeepSeqLoop => deep_seq_loop(m, reader, mc),
+        PSeq => seq(m, reader, mc),
+
+        PFilterForceList => filter_force_list(m, reader, mc),
+        PFilterCallPred => filter_call_pred(m, reader, mc),
+        PFilterCheck => filter_check(m, reader, mc),
+
+        PFoldlStrict => foldl_strict_entry(m, reader, mc),
+        PFoldlStrictEmpty => foldl_strict_empty(m, reader, mc),
+        PFoldlStrictCall1 => foldl_strict_call1(m, reader, mc),
+        PFoldlStrictCall2 => foldl_strict_call2(m, reader, mc),
+        PFoldlStrictUpdate => foldl_strict_update(m, reader, mc),
 
         ForceResultShallow => force_result_shallow(m, ctx, reader, mc),
         ForceResultShallowPush => force_result_shallow_push(m, ctx, reader, mc),

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/Cargo.toml

@@ -48,9 +48,5 @@ 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

fix/benches/utils.rs

@@ -1,5 +1,4 @@
-#![allow(clippy::allow_attributes_without_reason)]
+#![allow(dead_code)]
-#![allow(dead_code, clippy::unwrap_used, clippy::unwrap_in_result)]
 
 use fix::Evaluator;
 use fix_error::{Result, Source};

fix/src/lib.rs

@@ -1,3 +1,6 @@
+#![warn(clippy::unwrap_used)]
+#![allow(dead_code)]
+
 use fix_bytecode::InstructionPtr;
 use fix_bytecode::disassembler::{Disassembler, DisassemblerContext};
 use fix_compiler::{CodeState, ExtraScope};
@@ -8,6 +11,7 @@ use fix_vm::Vm;
 use hashbrown::{HashMap, HashSet};
 use string_interner::{DefaultStringInterner, Symbol as _};
 
+mod derivation;
 pub mod logging;
 
 #[global_allocator]
@@ -97,12 +101,12 @@ impl VmRuntimeCtx for RuntimeState {
         StringId(self.strings.get_or_intern(s))
     }
     fn resolve_string(&self, id: StringId) -> &str {
-        self.strings
+        #[allow(clippy::unwrap_used)]
-            .resolve(id.0)
+        self.strings.resolve(id.0).unwrap()
-            .expect("interned string id must resolve")
     }
     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)
@@ -141,9 +145,9 @@ impl DisassemblerContext for Evaluator {
         &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)
+        let id = string_interner::symbol::SymbolU32::try_from_usize(id as usize).unwrap();
-            .expect("invalid string id");
+        self.runtime.strings.resolve(id).unwrap()
-        self.runtime.strings.resolve(id).expect("invalid string id")
     }
 }

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 {
+    let src = if let Some(expr) = src.expr {
-        ExprSource::Expr(expr) => Source::new_eval(expr)?,
+        Source::new_eval(expr)?
-        ExprSource::File(file) => Source::new_file(file)?,
+    } 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 {
+    let src = if let Some(expr) = src.expr {
-        ExprSource::Expr(expr) => Source::new_eval(expr)?,
+        Source::new_eval(expr)?
-        ExprSource::File(file) => Source::new_file(file)?,
+    } 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()) {
+                let _ = rl.add_history_entry(line.as_str());
-                    eprintln!("[WARN] Failed to add history entry: {err}");
-                }
                 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::Compile { source, silent } => run_compile(&mut eval, source, silent),
-        Command::Eval { source } => run_eval(&mut eval, source.into()),
+        Command::Eval { source } => run_eval(&mut eval, source),
         Command::Repl => run_repl(&mut eval),
     }
 }

fix/tests/tests/derivation.rs

@@ -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

@@ -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

@@ -5,7 +5,6 @@ use std::path::PathBuf;
 use fix::Evaluator;
 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!(
+    eval_okay_test!(getenv, || {
-        #[serial(env)]
-        getenv,
-        || {
-            // SAFETY: guarded with #[serial_test::serial]
         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!(
+    eval_okay_test!(path_string_interpolation, || {
-        #[serial(env)]
-        path_string_interpolation,
-        || {
-            // SAFETY: guarded with #[serial_test::serial]
         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

@@ -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

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 use fix::Evaluator;
 use fix_error::{Result, Source};
 use fix_lang::Value;

flake.lock

@@ -1,5 +1,63 @@
 {
   "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"
+        ],
+        "nixpkgs": [
+          "llm-agents",
+          "nixpkgs"
+        ],
+        "systems": [
+          "llm-agents",
+          "systems"
+        ],
+        "treefmt-nix": [
+          "llm-agents",
+          "treefmt-nix"
+        ]
+      },
+      "locked": {
+        "lastModified": 1778446047,
+        "narHash": "sha256-oQvcadh2BCkrog+SGrG6YffKJrveYpjj3TdQJWaKhaM=",
+        "owner": "nix-community",
+        "repo": "bun2nix",
+        "rev": "f2bc12af1a6369648aac41041ceeaa0b866599c6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "bun2nix",
+        "type": "github"
+      }
+    },
     "fenix": {
       "inputs": {
         "nixpkgs": [
@@ -8,11 +66,11 @@
         "rust-analyzer-src": "rust-analyzer-src"
       },
       "locked": {
-        "lastModified": 1784017020,
+        "lastModified": 1781343250,
-        "narHash": "sha256-49WO85egjNtN1vMgJ3zUjDh5IqO+ou4zZY80WQ6EKGg=",
+        "narHash": "sha256-KBJktAwDG9+10j2wMfvOVkBEhZr3yS769xoqqdFI62s=",
         "owner": "nix-community",
         "repo": "fenix",
-        "rev": "fa2a0be0f712d7147d1677d33d15ea7b0589cdb4",
+        "rev": "aad7d8bb6936d473c2b9d1a5846a1fe1bc92767a",
         "type": "github"
       },
       "original": {
@@ -35,13 +93,59 @@
         "url": "https://git.lix.systems/lix-project/flake-compat/archive/main.tar.gz"
       }
     },
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "llm-agents",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1778716662,
+        "narHash": "sha256-m1Yf0wZ8j1OHjTc2UwHwyQRSnNeSgLJOd7q5Y45hzi4=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "f7c1a2d347e4c52d5fb8d10cb4d94b5884e546fb",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "llm-agents": {
+      "inputs": {
+        "blueprint": "blueprint",
+        "bun2nix": "bun2nix",
+        "flake-parts": "flake-parts",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "systems": "systems",
+        "treefmt-nix": "treefmt-nix"
+      },
+      "locked": {
+        "lastModified": 1781330261,
+        "narHash": "sha256-2fFAGel2VVXr5mwrTXldqXva2ng3T3HHxyuBKRIxauI=",
+        "owner": "numtide",
+        "repo": "llm-agents.nix",
+        "rev": "24ec6b7b1ddf8896ac8df3b65dc564575e0a1928",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "llm-agents.nix",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1784007870,
+        "lastModified": 1781074563,
-        "narHash": "sha256-djcLt/JJphyNt4eDY9XTly+/WbCK5lqWq9lSgCmJkkQ=",
+        "narHash": "sha256-md8WlXOlfnIeHeOScMTTHFyf2d6iaTwPl2apR5EQ3P4=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "18b9261cb3294b6d2a06d03f96872827b8fe2698",
+        "rev": "9ae611a455b90cf061d8f332b977e387bda8e1ca",
         "type": "github"
       },
       "original": {
@@ -55,17 +159,18 @@
       "inputs": {
         "fenix": "fenix",
         "flake-compat": "flake-compat",
+        "llm-agents": "llm-agents",
         "nixpkgs": "nixpkgs"
       }
     },
     "rust-analyzer-src": {
       "flake": false,
       "locked": {
-        "lastModified": 1783975201,
+        "lastModified": 1781294997,
-        "narHash": "sha256-oyHWTfKWk06nTynCO8ByEAx/KEARvOOyTVnwinOmK3Q=",
+        "narHash": "sha256-XjCyIvJw4JtcwItTKRdQz5h1pLF9hr8ZSYeMP+/1d3A=",
         "owner": "rust-lang",
         "repo": "rust-analyzer",
-        "rev": "63a6f0d4bcfd3bbcf36383fcbcbcd93456ed1653",
+        "rev": "3f92cd1612268995d5667bd04fa03ba2916413d9",
         "type": "github"
       },
       "original": {
@@ -74,6 +179,42 @@
         "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": 1780220602,
+        "narHash": "sha256-eynAfOmbmxJnkp7YewvCEbShNnnYJ9gLLqkzsYtBPeM=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "db947814a175b7ca6ded66e21383d938df01c227",
+        "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 +24,37 @@
           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
+              tombi
+
+              # llm-agents.codex
+              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