Files
sx/examples/expected
agra 43d44fff75 fix(ir): narrow non-integral const-float EXPRESSIONS at typed local/field/param; align const message [F0.11]
Completes issue 0095 (attempt 2). The attempt-1 coerce arm only caught a direct
`const_float` literal, so a non-integral const-folded float EXPRESSION still
truncated silently at a typed local / field default / param default:

  M :: 2;
  local : s64 = M + 0.5;   // → 2  (silent truncation — BUG; now ERRORS)
  fld   : s64 = M + 0.5;   // field default — same
  take(x : s64 = M + 0.5)  // param default — same

while the typed-CONST site already errored. The integral expression
(`M + 2.0` → 4) folded but the runtime/explicit-cast paths must stay untouched.

Fix:
- New `program_index.evalConstFloatExpr` — the f64 counterpart to
  `evalConstIntExpr`, delegating every integer subtree back to it (no parallel
  integer logic) and adding only the float literal / unary-negate / `+ - * /`
  arms. Pure (no diagnostics, no resolution side effects).
- `Lowering.foldComptimeFloatInit` applies the unified rule to a typed-binding
  initializer EXPRESSION: an integral comptime float folds to its `constInt`, a
  non-integral one errors, a genuine runtime float / `xx`-cast falls through to
  the normal path. It runs `evalConstFloatExpr` FIRST (pure) so a `$pack[i]`
  argument is never spuriously type-resolved outside an active binding, then
  gates on `isFloat(inferExprType)` so a plain comptime int is left alone.
  Wired into the typed-local path, the three struct field-default sites (via a
  shared `lowerCoercedDefault`), and the call-argument loop (covers expanded
  param defaults).
- One `Lowering.diagNonIntegralNarrow` now emits the narrowing wording at all
  five sites (coerce arm, global init, const-expr value, the typed-binding
  sites, and the typed-const path). The typed-CONST non-integral diagnostic
  therefore reads "cannot implicitly narrow non-integral float …" instead of
  the stale "initializer is a float literal / floating-point expression".

Tests: examples/1146 (negative) extended with non-integral const-EXPRESSION
cases at local/field/param; examples/0168 (positive) extended with integral
const-EXPRESSION folds and `xx (M + 0.5)` truncation; examples/1143 reconciled
to the aligned const message (G/BAD/BAD2 stay errors); unit test
`evalConstFloatExpr folds comptime float expressions`. Full gate green (447).
2026-06-05 16:28:12 +03:00
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