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).
33 lines
1.1 KiB
Plaintext
33 lines
1.1 KiB
Plaintext
// Phase 1 step 1.16 (PLAN-FFI.md): two `#jni_call` sites against the
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// same (class, method, sig) tuple. Today each site emits its own
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// `GetObjectClass` + `GetMethodID` call (no caching yet); after 1.17
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// the lowering collapses to one cached `jmethodID` per unique
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// (class, method, sig).
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//
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// Runtime: unreachable. The JNI dispatch is all indirect through
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// `*env` — no external symbol declarations — so the IR loads cleanly
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// into the host JIT, and the dereferences never execute because the
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// guarding `g_should_call` global stays false. A plain `if false`
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// would get constant-folded, taking the `unused_jni` body out of the
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// IR with it; the runtime-readable global keeps the call alive so
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// the JNI lowering is visible to the IR snapshot.
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#import "modules/std.sx";
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g_should_call : bool = false;
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unused_jni :: (env: *void, target: *void) {
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#jni_env(env) {
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#jni_call(void)(target, "noop", "()V");
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#jni_call(void)(target, "noop", "()V");
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}
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}
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main :: () -> s32 {
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if g_should_call {
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unused_jni(null, null);
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}
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print("ok\n");
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0
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}
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