d8076b9333
Surface rename of the signed integer family: s1..s64 become i1..i64
(u1..u64, usize, isize unchanged). 'string' keeps the s-prefix arm in
name classification; width parsing moves to the i-prefix arm next to
isize.
Internal TypeId tags follow the surface (.s8/.s16/.s32/.s64 ->
.i8/.i16/.i32/.i64), as do mono-key mangle fragments (ptr_i64,
tu_i64_bool) and all display/diagnostic formatting (i{d}).
Migrated in the same sweep: stdlib + examples + issue repros + FFI C
companions (shared symbol names like ffi_id_i64), expected
stdout/stderr/ir snapshots, specs.md, readme.md, CLAUDE.md/AGENTS.md,
implementation_plan.md, docs/, issue writeups. Vendored stb_image and
historical flow state left untouched.
zig build test: 426/426; examples suite: 595/595.
114 lines
4.2 KiB
Markdown
114 lines
4.2 KiB
Markdown
# 0070 — forward alias in top-level global annotation reaches LLVM verifier
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> **RESOLVED.** Root cause: issue 0069's `resolveForwardIdentifierAliases`
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> fixpoint runs at the END of `Lowering.scanDecls`, but the same scan loop
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> resolved top-level `var_decl` global annotations (and typed module-constant
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> annotations) via `self.resolveType(ta)` BEFORE that fixpoint ran — so a forward
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> alias (`A :: B; B :: i32; g : A = 7;`) was still absent from
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> `type_alias_map`, `resolveType` fabricated an empty-struct stub, and the global
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> got a type mismatching its initializer at LLVM verification (the typed-const
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> path silently mistyped the constant instead).
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> Fix: split `scanDecls` into two passes. Pass 1 registers function/type/alias
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> facts; then `resolveForwardIdentifierAliases` converges the aliases; then pass 2
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> registers top-level `var_decl` globals (`registerTopLevelGlobal`) and typed
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> module constants (`registerTypedModuleConst`), so their annotations resolve
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> against the converged alias map. Globals/typed-consts can't be named in a type
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> position, so deferring them past type/alias registration is order-safe; the
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> untyped module-const branch (no annotation to resolve) stays in pass 1.
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> Regression: `examples/0133-types-forward-alias-global.sx`.
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## Symptom
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A forward identifier type alias used as a top-level global's type annotation
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does not resolve before the global is registered, producing an LLVM verifier
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failure instead of compiling as the alias target type.
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Observed:
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```text
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LLVM verification failed: Global variable initializer type does not match global variable type!
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ptr @g
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```
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Expected: `A :: B; B :: i32; g : A = 7;` should type `g` as `i32` and compile/run
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the same way as the ordered alias form.
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## Reproduction
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```sx
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A :: B;
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B :: i32;
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g : A = 7;
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main :: () -> i32 {
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return g;
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}
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```
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Run:
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```sh
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./zig-out/bin/sx run .sx-tmp/probe-0069-forward-alias-global.sx
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```
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The repro is standalone; the inline source above is sufficient to recreate the
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scratch file under `.sx-tmp/`.
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## Investigation prompt
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Fix issue 0070: a forward identifier type alias used in a top-level global
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annotation must resolve before that global's type is registered.
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Context:
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- Issue 0069 (`49a383d`) added `Lowering.resolveForwardIdentifierAliases`, a
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fixpoint post-pass at the end of `scanDecls`, to resolve top-level
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identifier-RHS aliases like `A :: B; B :: i32;`.
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- That works for aliases used later in function bodies because the A2.4
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unknown-type pass and body lowering run after `scanDecls`.
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- But top-level `var_decl` annotations are resolved inside the same `scanDecls`
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loop before `resolveForwardIdentifierAliases(decls)` is called. So
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`g : A = 7;` can be typed while `A` is still absent from
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`ProgramIndex.type_alias_map`.
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- Suspected area: `src/ir/lower.zig`, `Lowering.scanDecls`, especially the
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ordering between `.const_decl` alias collection, the new
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`resolveForwardIdentifierAliases`, and the `.var_decl` branch that calls
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`self.resolveType(ta)`.
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Likely fix:
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- Split the scan ordering so all top-level type declarations and identifier
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aliases converge before any top-level global annotation is resolved.
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- One possible shape: first scan/register function/type/alias facts, run the
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forward-alias fixpoint, then handle top-level `var_decl` global registration
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and literal module constants that require resolved annotation types.
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- Do not reintroduce issue 0068: `NotAType :: 123; v: NotAType` must still emit
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`unknown type 'NotAType'`.
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- Do not fabricate stubs while trying to resolve the forward alias. The alias
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facts should still come from `ProgramIndex.type_alias_map` and real
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`TypeTable.findByName` hits.
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Verification:
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- Add a focused regression, likely in the `01xx` types block:
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```sx
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A :: B;
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B :: i32;
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g : A = 7;
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main :: () -> i32 { return g; }
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```
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- Keep `examples/0132-types-forward-type-alias.sx`,
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`examples/0116-types-type-alias-size-align.sx`,
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`examples/0201-generics-generic-struct.sx`, and
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`examples/1117-diagnostics-value-const-as-type-rejected.sx` green.
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- Run:
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```sh
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zig build
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zig build test
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bash tests/run_examples.sh
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```
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Expected result: the forward-alias global program exits 7, issue 0068 remains
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rejected with a diagnostic, and the full suite passes.
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