Check return expressions against the function's declared return type #59

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opened 2026-09-10 22:14:01 +00:00 by jacksonopp · 1 comment

jacksonopp commented

2026-09-10 22:14:01 +00:00

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Type-check Expr::Return's optional value against the enclosing function's declared return type (or Unit when the value is absent), extending #3's return-type checking to early returns, not just a function body's trailing expression.

jacksonopp added this to the Step 2: Core Type Checker milestone

2026-09-10 22:14:01 +00:00

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2026-09-10 22:14:01 +00:00

jacksonopp added this to the twill project

2026-09-10 22:19:56 +00:00

jacksonopp referenced this issue from a pull request that will close it,

2026-10-04 02:17:58 +00:00

check return expressions against the enclosing function's return type #78

jacksonopp commented

2026-10-04 02:18:03 +00:00

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Resolved in #78: a new check_return checks Expr::Return's optional value against the enclosing function's declared return type (Scope::current_fn_return, set/restored around check_fn's body check), with bare return checked against Unit. Reuses ReturnTypeMismatch/NoTypeProduced, mirrors the -> type carve-out, and defers return-outside-a-function same as break-outside-a-loop.

Resolved in #78: a new `check_return` checks `Expr::Return`'s optional value against the enclosing function's declared return type (`Scope::current_fn_return`, set/restored around `check_fn`'s body check), with bare `return` checked against `Unit`. Reuses `ReturnTypeMismatch`/`NoTypeProduced`, mirrors the `-> type` carve-out, and defers `return`-outside-a-function same as `break`-outside-a-loop.

jacksonopp closed this issue

2026-10-04 02:18:04 +00:00

jacksonopp removed this from the twill project

2026-10-04 02:28:22 +00:00