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).
67 lines
2.1 KiB
Plaintext
67 lines
2.1 KiB
Plaintext
// ffi-objc-arc-03 — #property(weak) on sx-defined class.
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//
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// Weak contract:
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// - setter calls objc_storeWeak — does NOT retain.
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// - getter calls objc_loadWeakRetained + autorelease — auto-nils
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// if the target has been deallocated.
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// - -dealloc calls objc_destroyWeak on each weak ivar.
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//
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// Observation: assign a target to the weak property. Drop the
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// caller's strong reference. Read back via the weak getter — should
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// be `null` (the target deallocated when its last strong ref
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// dropped, and the weak slot auto-niled).
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//
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// Pre-M4.B: setter just stores the pointer (no storeWeak); getter
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// reads the raw pointer (no loadWeakRetained). After target's
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// release, the slot points at freed memory — the read returns the
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// stale pointer (not null). The test catches this by comparing the
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// read result to null.
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#import "modules/std.sx";
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#import "modules/allocators.sx";
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#import "modules/std/objc.sx";
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#import "modules/compiler.sx";
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SxWeakTarget :: #objc_class("SxWeakTarget") {
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#extends NSObject;
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tag: s32;
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alloc :: () -> *SxWeakTarget;
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}
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SxWeakHolder :: #objc_class("SxWeakHolder") {
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#extends NSObject;
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target: *SxWeakTarget #property(weak);
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alloc :: () -> *SxWeakHolder;
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}
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main :: () -> s32 {
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inline if OS == .macos {
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gpa := GPA.init();
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tracker := TrackingAllocator.init(xx gpa);
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push Context.{ allocator = xx tracker, data = null } {
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holder := SxWeakHolder.alloc();
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target := SxWeakTarget.alloc();
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holder.target = target;
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target.release();
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// After release: target's refcount → 0 → target deallocates.
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// With weak: holder.target should read as null (auto-niled).
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// Without weak: holder.target reads as the stale pointer.
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read_back := holder.target;
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if read_back != null {
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print("FAIL: weak property didn't auto-nil after target dealloc\n");
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return 1;
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}
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holder.release();
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}
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print("weak property: ok\n");
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}
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inline if OS != .macos {
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print("skipped (not macos)\n");
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}
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0
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}
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