Files
sx/examples/1501-vectors-const-lane.sx
agra a491a1bf73 fix(ir): route every comptime-int through the shared evaluator (0083)
Attempts 1–4 fixed the array-dimension paths but the same length-0
fabrication class survived on every other site that resolves a
compile-time integer. Unify them all on the single shared
`program_index.evalConstIntExpr` so they cannot diverge:

- All three Vector lane resolvers (resolveTypeCallWithBindings,
  resolveParameterizedWithBindings, resolveArrayLiteralType) and both
  generic value-param binders (instantiateGenericStruct,
  instantiateTypeFunction) hand-rolled an `else => 0` switch. A
  module-const lane `Vector(N, f32)` fabricated a 0-lane `<0 x float>`
  (LLVM "huge alignment" abort); a value-param `Vec(N, f32)` fabricated
  a 0 binding / wrong mangled name. They now fold through the shared
  evaluator and emit a clean diagnostic + `.unresolved` on a non-const
  operand (resolveVectorLane / resolveValueParamArg) — never 0.
- evalComptimeInt (inline-for bounds) delegated to the shared evaluator,
  so `inline for 0..M` / `0..(M+1)` fold like array dims. The `<pack>.len`
  leaf moved into the shared folder via a new `ctx.lookupPackLen`.
- The unknown-type semantic checker no longer walks a value-param
  position (`Vector(N, …)` / `Vec(N, …)`) as a type name (was reporting
  "unknown type 'N'").
- The parameterized-type-arg parser and the function-body lookahead
  (hasFnBodyAfterArrow) accept a const-EXPRESSION in a value position, so
  `Vector(M + 1, f32)` and `[M + 1]T` parse as a return type too (the
  latter a pre-existing array-dim sibling that the same heuristic broke).

Regressions: examples/1501 (named-const + const-expr lane, direct +
alias, 3/4-lane reads), 1502 (runtime lane clean-halts, exit 1, no LLVM
crash), 0207 (Vec(N)/Vec(M+1) == Vec(3) instantiation), 0610 (inline-for
const bounds). Shared-evaluator unit test extended with the pack-len arm.

zig build && zig build test && bash tests/run_examples.sh: 395 passed,
0 failed.
2026-06-04 11:32:25 +03:00

36 lines
1.5 KiB
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// A `Vector` lane count from a named const or a constant-foldable expression
// resolves to the SAME layout as a literal lane — DIRECT (param / return type)
// and via a type ALIAS. A 3-lane (named const `N`) and a 4-lane (const expr
// `M + 1`) prove the lane VALUE is folded, not fabricated: reading `.w` requires
// the 4-lane vector to actually have four lanes.
//
// Regression (issue 0083): the stateful Vector lane resolvers hand-rolled an
// `else => 0` switch, so a module-const lane (`Vector(N, f32)`) lowered a 0-lane
// `<0 x float>` and died in LLVM verification ("huge alignment values are
// unsupported"); a const-expr lane (`Vector(M + 1, f32)`) was rejected at parse.
// Both now fold through the single shared const-int evaluator
// (`program_index.evalConstIntExpr`) — the same one the array-dimension path
// uses — so a named-const / const-expr lane is identical to a literal lane.
#import "modules/std.sx";
N :: 3;
M :: 3;
LaneAlias :: Vector(N, f32); // ALIAS: 3-lane via named const.
ExprAlias :: Vector(M + 1, f32); // ALIAS: 4-lane via const expression.
mk3 :: () -> Vector(N, f32) { .[1.0, 2.0, 3.0] } // DIRECT named-const lane.
mk4 :: () -> Vector(M + 1, f32) { .[1.0, 2.0, 3.0, 4.0] } // DIRECT const-expr lane.
main :: () {
a := mk3();
print("direct3: {} {} {}\n", a.x, a.y, a.z);
b := mk4();
print("direct4: {} {} {} {}\n", b.x, b.y, b.z, b.w);
c : LaneAlias = .[5.0, 6.0, 7.0];
print("alias3: {}\n", c.z);
d : ExprAlias = .[5.0, 6.0, 7.0, 8.0];
print("alias4: {}\n", d.w);
}