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fix(ir): complete const-float evaluator — resolve float-const leaves too [F0.11]

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Completes issue 0095: a non-integral float→int narrowing via a FLOAT-const
leaf (`F : f64 : 2.5; y : s64 = F + 0.25` = 2.75) silently truncated to 2.
`evalConstFloatExpr` delegated only INTEGER leaves to `evalConstIntExpr` and
had no float-const leaf arm, so the unified rule never saw the value.

- program_index.zig: add `moduleConstFloat`/`moduleConstFloatFramed` — the f64
  twin of `moduleConstInt` (same `isCountableConstType` gate, same cyclic-
  definition frame), recovering a numeric module const's value via
  `evalConstFloatExpr`. Add `lookupFloatName` to `ModuleConstCtx` and the
  `.identifier`/`.type_expr` leaf arms to `evalConstFloatExpr` that call it.
  Integer / integral-float leaves keep resolving through the existing
  `evalConstIntExpr` delegation, so the unified rule now applies to ANY
  compile-time-constant float expression — literal, int-const leaf, float-const
  leaf, and combinations — at every binding site.
- lower.zig: add `Lowering.lookupFloatName` delegating to `moduleConstFloat`.
  Route `typedConstInitFits`' integral-fold check through `evalConstFloatExpr` +
  `floatToIntExact` (the SAME facility `foldComptimeFloatInit` uses) instead of
  the int-only `evalComptimeInt`, which folded leaf-by-leaf in i64 and so
  rejected an integral SUM built from a non-integral float leaf
  (`K : s64 : F + 1.5` = 4.0 now folds; `K : s64 : F + 0.25` errors).

A LOCAL `::` const leaf is a scope ref (not in the const tables) so neither
the int nor float evaluator folds it — float now matches int exactly there.

Regression: examples/1146 (negative) + 0168 (positive) extended with
float-const-leaf cases at local/field/param/const; unit test in
program_index.test.zig covers the leaf resolution (F→2.5, F+0.25→2.75,
F+1.5→4.0). specs.md + readme.md state the rule covers any compile-time-const
float expression incl. float-typed const leaves. issues/0095 banner updated.

Gate: zig build + zig build test green; 447 examples pass, 0 failed.
This commit is contained in:
agra
2026-06-05 17:00:12 +03:00
parent 43d44fff75
commit b6d66d9c56
10 changed files with 229 additions and 76 deletions
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10
examples/expected/0168-types-integral-float-to-int.stdout
View File

@@ -1,6 +1,6 @@
local=4 localExpr=4
local=4 localExpr=4 localFlt=4
neg=-2
field=4 fieldExpr=4
param=6
const=8 len=8
xx=4 cast=1 xxExpr=2
field=4 fieldExpr=4 fieldFlt=4
param=6 paramFlt=4
const=8 constFlt=4 len=8
xx=4 cast=1 xxExpr=2 xxFlt=2

44
examples/expected/1146-diagnostics-nonintegral-float-to-int.stderr
View File

@@ -1,35 +1,53 @@
error: cannot implicitly narrow non-integral float '1.5' to 's64'; use an explicit cast (`xx`/`cast`)
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:29:16
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:34:16
|
29 | y : s64 = 1.5; // non-integral float LITERAL local → error
34 | y : s64 = 1.5; // non-integral float LITERAL local → error
| ^^^
error: cannot implicitly narrow non-integral float '2.5' to 's64'; use an explicit cast (`xx`/`cast`)
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:30:16
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:35:16
|
30 | ye : s64 = M + 0.5; // non-integral const-EXPRESSION local → error
35 | ye : s64 = M + 0.5; // non-integral int-const-EXPRESSION local → error
| ^^^^^^^
error: cannot implicitly narrow non-integral float '2.75' to 's64'; use an explicit cast (`xx`/`cast`)
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:36:16
|
36 | yf : s64 = F + 0.25; // non-integral float-const-LEAF local → error
| ^^^^^^^^
error: cannot implicitly narrow non-integral float '3.5' to 's64'; use an explicit cast (`xx`/`cast`)
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:21:16
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:24:16
|
21 | f : s64 = 3.5; // non-integral float LITERAL field default → error
24 | f : s64 = 3.5; // non-integral float LITERAL field default → error
| ^^^
error: cannot implicitly narrow non-integral float '2.5' to 's64'; use an explicit cast (`xx`/`cast`)
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:22:16
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:25:16
|
22 | fe : s64 = M + 0.5; // non-integral const-EXPRESSION field default → error
25 | fe : s64 = M + 0.5; // non-integral int-const-EXPR field default → error
| ^^^^^^^
error: cannot implicitly narrow non-integral float '2.5' to 's64'; use an explicit cast (`xx`/`cast`)
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:25:23
error: cannot implicitly narrow non-integral float '2.75' to 's64'; use an explicit cast (`xx`/`cast`)
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:26:16
|
25 | badLit :: (x : s64 = 2.5) -> s64 { return x; } // non-integral LITERAL param default → error
26 | ff : s64 = F + 0.25; // non-integral float-const-LEAF field default → error
| ^^^^^^^^
error: cannot implicitly narrow non-integral float '2.5' to 's64'; use an explicit cast (`xx`/`cast`)
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:29:23
|
29 | badLit :: (x : s64 = 2.5) -> s64 { return x; } // non-integral LITERAL param default → error
| ^^^
error: cannot implicitly narrow non-integral float '2.5' to 's64'; use an explicit cast (`xx`/`cast`)
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:26:23
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:30:23
|
26 | badExpr :: (x : s64 = M + 0.5) -> s64 { return x; } // non-integral const-EXPR param default → error
30 | badExpr :: (x : s64 = M + 0.5) -> s64 { return x; } // non-integral int-const-EXPR param default → error
| ^^^^^^^
error: cannot implicitly narrow non-integral float '2.75' to 's64'; use an explicit cast (`xx`/`cast`)
--> examples/1146-diagnostics-nonintegral-float-to-int.sx:31:23
|
31 | badFlt :: (x : s64 = F + 0.25) -> s64 { return x; } // non-integral float-const-LEAF param default → error
| ^^^^^^^^