Files
sx/examples/1129-diagnostics-array-dim-not-const.sx
agra cd39316f5e fix(ir): evaluate constant-expression array dimensions (0083)
A constant-FOLDABLE expression array dimension (`[M + 1]`, `[M * N]`,
`[N - M]`, nested `[M + N - 1]`, parenthesised `[(M + 1) * 2]`, mixing
untyped and typed module consts) was wrongly rejected as "not a
compile-time integer constant" even though every operand is
compile-time-known. Attempts 1-3 resolved only a bare named-const dim or
a literal; an expression dim must be EVALUATED, not rejected.

Fix: the shared dim resolver now routes the dimension through a single
constant integer-expression evaluator (`program_index.evalConstIntExpr`)
that folds integer `+ - * / %` and unary negate over literals and
named/typed module consts, recursively (parentheses carry no AST node).
The leaf-name lookup is delegated via `ctx.lookupDimName`, so the
stateful body-lowering path (`Lowering`, which also sees comptime
constants and generic `$N` values) and the stateless registration path
(`type_bridge.StatelessInner`, module consts only) share the EXACT SAME
folding logic and cannot diverge — an expression dim via a type alias
resolves identically to the direct form.

No-fabrication discipline unchanged: a genuinely non-comptime dimension
(runtime local, non-comptime call, unbound name) or arithmetic that
overflows / divides by zero still yields null -> `.unresolved` -> the
same clean compile-halting diagnostic, never a fabricated length.

- examples/0144-types-const-expr-array-dim.sx: every expression form,
  direct vs alias, scalar / string / struct element types (fails on the
  pre-fix compiler, passes after).
- examples/1129 re-pointed at a genuinely non-const dimension
  (`[get()]s64`, a runtime call) so it still proves the stateless
  clean-halt (a foldable expression is no longer an error).
- program_index.test.zig: unit test for evalConstIntExpr folding and
  clean-halt-on-non-const.
2026-06-04 10:38:21 +03:00

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// An array dimension that is not a compile-time integer constant is a hard
// error, not a silently-fabricated 0-length array. Here a type alias's
// dimension is a runtime function call (`get()`), which is genuinely not
// compile-time-known — the registration-time resolver cannot evaluate it.
//
// (A const-FOLDABLE expression dimension such as `[M + 1]` is NOT an error — it
// folds; see examples/0144-types-const-expr-array-dim.sx. Only a dimension with
// a genuinely runtime operand halts here.)
//
// Regression (issue 0083): the stateless resolver printed a non-fatal warning
// and fabricated length 0, then let compilation continue — producing a 0-byte
// alloca and corrupt element access. It now yields the `.unresolved` sentinel,
// which the alias registration surfaces as this diagnostic, aborting the build
// with a non-zero exit.
#import "modules/std.sx";
get :: () -> s64 { return 5; }
BadArr :: [get()]s64;
main :: () {
a : BadArr = ---;
a[0] = 7;
print("a0={}\n", a[0]);
}