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).
29 lines
1.1 KiB
Plaintext
29 lines
1.1 KiB
Plaintext
// Generic `Into(Block)` impl with a `string`-typed arg in the
|
|
// closure signature. The block trampoline declares the param with
|
|
// callconv(.c); without the abi-collapse fix, sx `string` got
|
|
// silently collapsed to `ptr` (the libc `char *` heuristic) and
|
|
// the caller's 16-byte `{ptr, len}` value mismatched the
|
|
// trampoline's 8-byte `ptr` slot. Result: segfault inside the
|
|
// trampoline's first read.
|
|
//
|
|
// The fix lives in `abiCoerceParamTypeEx`: the `string`/`slice` →
|
|
// `ptr` collapse only applies to `is_extern` foreign decls (libc
|
|
// interop). sx-internal `callconv(.c)` keeps the full slice
|
|
// shape, which lands as `[2 x i64]` at the LLVM signature site
|
|
// and matches the caller's two-register pass on AArch64.
|
|
|
|
#import "modules/std.sx";
|
|
#import "modules/std/objc_block.sx";
|
|
|
|
g_s: string = "";
|
|
|
|
main :: () -> s32 {
|
|
cl := (s: string) => { g_s = s; };
|
|
b : Block = xx cl;
|
|
invoke_fn : (*Block, string) -> void callconv(.c) = xx b.invoke;
|
|
invoke_fn(@b, "hello");
|
|
if g_s.len == 0 { print("FAIL: empty\n"); return 1; }
|
|
print("got: <{}>\n", g_s);
|
|
0
|
|
}
|