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).
35 lines
1.2 KiB
Plaintext
35 lines
1.2 KiB
Plaintext
// Compound type literals in expression position — `size_of` /
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// `align_of` accept pointer (`*T`), optional (`?T`), array (`[N]T`),
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// function (`(A) -> B`), and tuple (`(A, B)`) types directly. Also
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// const-decl RHS aliases through the same forms (`Ptr :: *u8;` etc).
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// Same shape as the existing `size_of(s32)` baseline path.
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#import "modules/std.sx";
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// Unambiguous type-form const-decl aliases.
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Ptr :: *u8;
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Maybe :: ?u8;
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Arr :: [3]u8;
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Cb :: (s32) -> s32;
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main :: () -> s32 {
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// Direct: parser fix for *T, ?T + existing [N]T path.
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print("size_of(*u8) = {}\n", size_of(*u8));
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print("align_of(*u8) = {}\n", align_of(*u8));
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print("size_of(?u8) = {}\n", size_of(?u8));
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print("size_of([3]u8) = {}\n", size_of([3]u8));
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// Function-type literal in expression position.
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print("size_of((s32)->s32) = {}\n", size_of((s32) -> s32));
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// Tuple literal reinterpreted as tuple type at the type-demanding site.
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print("size_of((s32, s32)) = {}\n", size_of((s32, s32)));
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// Aliases.
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print("size_of(Ptr) = {}\n", size_of(Ptr));
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print("size_of(Maybe) = {}\n", size_of(Maybe));
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print("size_of(Arr) = {}\n", size_of(Arr));
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print("size_of(Cb) = {}\n", size_of(Cb));
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0
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}
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