bdd0e96d78
A block's value is now its last statement ONLY when that statement is a trailing expression with no `;`. A trailing `;` discards the value, leaving the block void. This makes value-vs-statement explicit and lets the compiler reject "this block was supposed to produce a value". Compiler: - Parser records `Block.produces_value` (last stmt is a no-`;` trailing expression) + `Block.discarded_semi` (the `;` that discarded a value), via `expectSemicolonAfter`. A trailing expression before `}` may now omit its `;` (previously a parse error). Match-arm and else-arm bodies are built value-producing regardless of the arm `;` (arms are exempt — the `;` is an arm terminator). - Lowering: `lowerBlockValue` / the block-expr path / `inferExprType` respect `produces_value`. A value-position block that discards its value is a hard error (`lowerValueBody` for function bodies; the value-context `.block` path for if/else branches, `catch` bodies, value bindings, match arms). Pure-failable `-> !` bodies (value rides the error channel) and a value-if whose branches are void are handled without false errors. - `defer`/`onfail` cleanup bodies lower as statements (void), so a trailing `;` there is fine. Migration (behavior-preserving — output unchanged): - stdlib + ~210 examples: dropped the trailing `;` on value-position last expressions. `format` now ends with an explicit `#insert "return result;"` (it relied on `#insert`-as-block-value, which `;` discards). - Two `main :: () -> s32` examples that relied on the old silent default-return got an explicit trailing `0`. - Rejection snapshots 0412 / 1013 regenerated (their quoted source lines lost a `;`); the diagnostics themselves are unchanged. Docs/tests: specs.md "Block values" section; examples 0040 (rules) + 0041 (rejection); 3 parser unit tests. Filed issue 0066 (pre-existing match-arm negated-literal phi-width quirk, surfaced not caused here). Gates: zig build, zig build test, run_examples.sh -> 343 passed, cross_compile.sh -> 7 passed (also refreshed its stale example names).
30 lines
1.2 KiB
Plaintext
30 lines
1.2 KiB
Plaintext
// Regression test for issue-0039 — directory-import scan order.
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//
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// When a directory is imported, the resolver iterates files
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// alphabetically. Inside the directory, `aaa_uses.sx` comes BEFORE
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// `types.sx` but its `make_my` returns `MyEnum` (defined in
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// `types.sx`). The combined directory module must put `aaa_uses.sx`'s
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// transitive imports (which include `MyEnum`) into the global scan
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// stream BEFORE `aaa_uses.sx`'s own decls so the tagged_union for
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// MyEnum is registered before `make_my`'s return type is resolved.
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//
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// Pre-fix, the dir-import implementation appended each file's
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// `own_decls` before its `decls`, which inverted that order and
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// caused `MyEnum` to be registered as a placeholder struct via the
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// `resolveTypeName` fallback. The later `enum_decl` scan then
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// short-circuited via `findByName` and never upgraded the placeholder
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// to the real tagged_union, surfacing as "cannot infer enum type
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// for '.b'" at the `return .b(42)` site.
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#import "modules/std.sx";
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#import "0707-modules-import-dir-scan-order";
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main :: () -> s32 {
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e := make_my();
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if e == {
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case .a: { print("a\n"); }
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case .b: (v) { print("b={}\n", v); }
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}
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0
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}
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