Files
sx/examples/1143-diagnostics-typed-module-const-mismatch.sx
agra 156edf8e28 fix(ir): reject typed module const whose initializer mismatches annotation [F0.7]
A typed module-level constant whose initializer did not match its
annotation was silently accepted: `N : string : 4` compiled, then
`print(N)` segfaulted (an integer emitted as a `string` const → a bogus
pointer) and `[N]s64` folded `N` to 4 as an integer count. Issue 0088.

Root cause: `registerTypedModuleConst` stored the annotation type but never
validated the initializer literal against it, and
`program_index.moduleConstInt` folded a const into a count by inspecting
the initializer node alone, ignoring `ModuleConstInfo.ty`.

Fix at the declaration (kills both symptoms):
- lower.zig: `registerTypedModuleConst` now validates the initializer via
  `typedConstInitFits` (arms mirror `emitModuleConst`'s faithful-emit
  precondition: int→int/float, float→float, bool→bool, string→string,
  null→pointer/optional, `---`→any). A mismatch emits a `type mismatch`
  diagnostic at the initializer span and does not register the const (also
  evicting the pass-0 placeholder). Not routed through
  `coercionResolver().classify`: that runtime-coercion planner is unsound
  here (null's natural type is void → false-rejects `*T`; bool is 1 bit →
  false-accepts s64).
- program_index.zig: `moduleConstInt` now takes the `TypeTable` and gates
  the fold on `isCountableConstType(ci.ty)` (integer of any width, or a
  float), so a non-numeric typed const can never fold into a count off its
  initializer node. Callers in lower.zig and type_bridge.zig updated.

Regression:
- examples/1143-diagnostics-typed-module-const-mismatch.sx (negative, exit 1)
- examples/0162-types-typed-module-const-roundtrip.sx (positive)
- program_index.test.zig: gate-on-declared-type unit test

Docs: specs.md §3 Constant Binding + readme.md note the compatibility rule.
2026-06-05 07:17:20 +03:00

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// A typed module-level constant whose initializer does not match its
// annotation is a compile-time type error — not a silently-accepted const.
// Each declaration below pairs a literal with an incompatible annotation, so
// the compiler must emit a `type mismatch` diagnostic at the initializer and
// abort (exit 1) rather than registering a usable const.
//
// Regression (issue 0088): `N : string : 4` was accepted; `print(N)` then
// segfaulted (an integer emitted as a `string` const → a bogus pointer) and
// `[N]s64` folded `N` to 4. The fix rejects the declaration at the root.
#import "modules/std.sx";
N : string : 4; // integer literal where a string is annotated
F : s64 : "x"; // string literal where an integer is annotated
B : s64 : true; // boolean literal where an integer is annotated
G : s64 : 1.5; // float literal where an integer is annotated
main :: () {
print("unreachable\n");
}