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globalInitValue had no unary_op arm, so g : s64 = -1; fell into the catch-all 'must be initialized by a compile-time constant' even though constExprValue already folds negate(literal) for the module-const identifier route. The new arm routes through constExprValue and applies the direct-literal rules to the folded value: checkIntLiteralFits on ints (g : s8 = -300 gets the range diagnostic), and a negated float at an integer global narrows only when integral (-4.0 folds to -4, -4.5 errors). Binary-op initializers keep the specific non-constant diagnostic. Regression: examples/0175-types-negative-literal-global.sx.
78 lines
3.4 KiB
Markdown
78 lines
3.4 KiB
Markdown
# RESOLVED — 0113: negative-literal global initializer rejected as "not a compile-time constant"
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**Root cause:** `globalInitValue` (src/ir/lower/decl.zig) had no `.unary_op`
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arm, so a negated literal fell into the catch-all "must be initialized by a
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compile-time constant" — even though `constExprValue` already folds
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`negate(int/float literal)` for the module-const identifier route.
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**Fix:** a `.unary_op` arm routes the initializer through `constExprValue`;
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the folded value follows the direct-literal rules — `checkIntLiteralFits` on
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ints (`g : s8 = -300;` gets the range diagnostic, not "non-constant"), and a
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negated float at an integer global narrows only when integral
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(`g : s64 = -4.0;` → -4; `-4.5` errors). Binary-op initializers
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(`g : s32 = 2 + 3;`) remain unsupported and keep the specific
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"must be initialized by a compile-time constant" diagnostic — const-expr
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folding for those is a separate feature if ever wanted.
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**Regression test:** `examples/0175-types-negative-literal-global.sx`
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(prints `-1 -4 -128`; failed "non-constant" pre-fix).
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---
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# 0113 — negative-literal global initializer rejected as "not a compile-time constant"
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**Symptom.** A top-level global initialized with a negated literal fails to
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compile: `g : s64 = -1;` errors
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`global 'g' must be initialized by a compile-time constant`. Expected: a
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negated literal is a compile-time constant; the global serializes to -1.
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Positive literals work (`g : s64 = 1;`). Locals are unaffected
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(`x : s64 = -1;` inside a function is fine — lowerExpr folds the negate).
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## Reproduction
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```sx
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#import "modules/std.sx";
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g : s64 = -1;
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main :: () {
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print("{}\n", g);
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}
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```
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- **Observed**: `error: global 'g' must be initialized by a compile-time
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constant` at the initializer.
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- **Expected**: compiles; prints `-1`.
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Repro co-located: `issues/0113-negative-literal-global-initializer-rejected.sx`.
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## Root cause (suspected area)
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`src/ir/lower/decl.zig` `globalInitValue` (~973): the initializer switch has
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arms for `.int_literal` / `.float_literal` / `.bool_literal` / etc., but a
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negated literal is a `.unary_op` node, which falls into the catch-all
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`else => "must be initialized by a compile-time constant"`. The identifier
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arm already routes module-const values through `constExprValue` (~1013) —
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the direct `.unary_op` / `.binary_op` initializer shapes never get that
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chance.
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## Investigation prompt (paste into a fresh session)
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> Fix issue 0113: `g : s64 = -1;` (and const-expression initializers like
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> `g : s64 = 2 + 3;`) are rejected as non-constant globals. In
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> `src/ir/lower/decl.zig` `globalInitValue`, route `.unary_op` and
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> `.binary_op` initializers through the same const-expression evaluation the
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> `.identifier` arm uses (`constExprValue`, or the
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> `program_index.evalConstFloatExpr`-family used by `typedConstInitFits`
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> ~878) before falling into the catch-all diagnostic. Apply the int-literal
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> fits-check (`checkIntLiteralFits`) to the folded value against the
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> global's type — `g : s8 = -300;` must produce the range diagnostic, not a
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> wrap and not "non-constant". Negative bounds in `typedConstInitFits`
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> already admit unary_op shapes; keep both checks consistent.
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>
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> Verify: the repro prints -1; `g2 : s8 = -300;` errors with the range
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> message; `g3 : s32 = 2 + 3;` initializes to 5 (or, if expression globals
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> are deliberately unsupported, keeps a SPECIFIC diagnostic saying so).
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> `zig build && zig build test && bash tests/run_examples.sh`. Promote the
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> repro per the resolution flow.
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