fix(minifier): drop empty-body IIFE wrapper when called with arguments#22589
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#22589) ## Why `substitute_iife_call` bailed out as soon as the call had any arguments, so `(() => {})(a)` stayed in the output while esbuild emits `a;`. The existing logic (#22349, closing #17480) only handled the zero-args case. Surfaced by rolldown ↔ esbuild compatibility tests for `dce/dce_of_iife` (rolldown/rolldown#8688): ```js // input (() => {})(keepThisButRemoveTheIIFE); // before (oxc DCE) (() => {})(keepThisButRemoveTheIIFE); // after (matches esbuild) keepThisButRemoveTheIIFE; ``` ## Fix Extend `substitute_iife_call` to drop the wrapper when the body is empty, the callee is neither `async` nor a generator, and every named parameter is a bare `BindingIdentifier` with no default. The arguments become a sequence ending in `void 0` (preserving the call's `undefined` result); `remove_unused_expression` strips the tail at statement position. Argument conversion reuses `fold_arguments_into_needed_expressions`, which also drops pure args for free. Two related cases handled in the same path: - Rest parameter binding to a simple identifier (`((...r) => {})(a)` → `a;`). Deliberately looser than the spec `IsSimpleParameterList` (which forbids any rest): the empty body never observes the collected array. - Spread argument (`(() => {})(...a)` → `[...a];`) — converted to a single-spread array literal that preserves the iterator-protocol invocation. Matches esbuild's `--minify` output. Rejected (no behaviour change): destructured params, parameter defaults, `async` / generator callees, destructured rest bindings — each can have observable effects that the empty body would otherwise elide. New positive + negative cases in `test_fold_iife` (`tests/peephole/remove_unused_expression.rs`); full minifier suite (501/0) and `minsize` snapshots unchanged.
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Dunqing
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### 🚀 Features - e857b0c napi/minify: Expose legalComments option and result (#20370) (Boshen) - 661132d parser: More friendly error messages for rest assignment target and rest binding element (#22719) (sapphi-red) - ee659b6 transformer/legacy-decorator: Add `strictNullChecks` option for nullable-union design:type (#22266) (Kyle Cannon) ### 🐛 Bug Fixes - e1d064e transformer/class-properties: Reparent lifted private method helpers (#22716) (Cameron) - 4ac0fca minifier: Preserve `0 && (module.exports = { ... })` cjs-module-lexer hint (#22729) (Dunqing) - 40ff611 minifier: Mark peephole loop changed when dropping dead-after-throw statement (#22722) (Dunqing) - 2f7b210 codegen: Emit pife-arrow/function leading comments inside the wrap (#22720) (Dunqing) - e184f74 parser: Improve invalid `import` property access diagnostic (#22693) (camc314) - 7baed9c transformer/private-method: Clear inherited strict flags (#22508) (camc314) - a9ad27e parser: Keep annotation comments leading without preceding newline (#22711) (Dunqing) - 9ea4d64 minifier: Re-evaluate pure/no-side-effects flags after peephole inlining (#22595) (Dunqing) - 07afbb6 minifier: Drop empty-body IIFE wrapper when called with arguments (#22589) (Dunqing) - fa7c463 semantic: Correct TS enum member symbol spans (#22689) (camc314) - 26b9396 semantic: Resolve parameter decorators outside parameter scope (#22623) (camc314) - b284045 parser: Switch to module goal eagerly on `export` (#22684) (Boshen) - dfa931d semantic: Propagate unresolved auto-increment enum value instead of defaulting to 0 (#22646) (Dunqing) - 69a6ba6 transformer/legacy-decorator: Emit Array for ReadonlyArray<T> in decorator metadata (#22265) (Kyle Cannon) - e421ef0 transformer/legacy-decorator: Return runtime binding for design:type (#22640) (Dunqing) - d61e1d7 codegen: Preserve verbatim text of pure/no-side-effects comments (#22525) (Dunqing) - 702b14e minifier: Preserve IIFE structure in DCE-only mode (#22547) (Dunqing) - 917da24 parser: Apply PURE comment through member-access chains (#22566) (Dunqing) - a069b1c codegen: Preserve quotes for cjs-module-lexer equality strings (#22551) (Dunqing) ### ⚡ Performance - 2f623b0 semantic: Skip unresolved checks for re-exports (#22660) (camc314) - 0d9553d semantic: Early-exit `check_object_expression` for objects with <2 properties (#22668) (Dunqing) - d721ad9 semantic: Use direct grandparent lookup for TS type parameters (#22658) (camc314) - 0aff288 semantic: Reorder numeric literal strict mode checks (#22657) (camc314) - 4d5ddb1 semantic: Reorder binding identifier checks (#22656) (camc314) - e32acd8 semantic: Reorder identifier ambient binding check (#22653) (camc314) - 09fe178 semantic: Reorder ident reference strict mode check (#22652) (camc314) - 4b6add2 semantic: Avoid duplicate ident clone for bindings (#22663) (camc314) - 82f9662 parser: Check identifier kind before context flag (#22662) (camc314) - d7cd951 parser: Fast path identifier parsing and inline operator helpers (#22650) (Boshen) - 7b84314 semantic: Use direct byte access for numeric leading-zero check (#22642) (camc314) - 0345a31 semantic: Pre-size class elements hash map (#22618) (camc314) - 04d3065 minifier: Drop per-call buffers in try_fold_concat (#22596) (Dunqing) - 4f289f1 semantic: Resolve_references_for_current_scope without a temp Vec (#22599) (Dunqing) - e862c15 semantic: Avoid heap alloc for var hoist scope ids (#22603) (Dunqing) - 8ff8674 semantic: Early return if `excess` is `0` in `Stats::increase_by` (#22616) (camc314) - 7a4120e semantic: Pre-reserve unresolved_references using Stats::references (#22580) (Dunqing) Co-authored-by: Dunqing <29533304+Dunqing@users.noreply.github.com>
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## Summary - Bump oxc Rust crates and `@oxc-project/*` / `oxc-*` npm packages from `0.132.0` to `0.133.0`. ~~Bump `oxc_resolver` / `oxc_resolver_napi` from `11.19.1` to `11.19.2`.~~ - Regenerate `embedded_helpers.rs` to point at `@oxc-project+runtime@0.133.0` (version string only — no helper-content drift). - Handle two new oxc fields surfaced by `cargo check`: - `oxc::transformer::DecoratorOptions.strict_null_checks` — hardcoded to `true` in the `From` impl (matches oxc's default). Exposing it through rolldown's wrapper would be a separate API change. - `oxc_minify_napi::CodegenOptions.legal_comments` — set to `None`. - Extend `DecoratorOptionSchema` and `CodegenOptionsSchema` in `validator.ts` to mirror the new optional fields. - Refresh 32 snapshots driven by upstream oxc PR [#22547](oxc-project/oxc#22547) ("fix(minifier): preserve IIFE structure in DCE-only mode"). In DCE-only mode (rolldown's per-module preprocess via `Compressor::dead_code_elimination_with_scoping`), oxc no longer inlines `(() => …)()` IIFEs that carry — or could carry — `/*#__PURE__*/` annotations, so downstream tree-shaking can see them. Empty-IIFE elision still fires. Side effects: `property_read_side_effects` now correctly tree-shakes `/*#__PURE__*/ test().a.b.c;` lines and drops the previously spurious `INVALID_ANNOTATION` warnings; TS class `(() => new Foo())()` patterns and `Symbol((() => Math.random() < 0.5)() ? …)` calls are preserved as the sources actually wrote them; `dce_of_iife/diff.md` divergence vs esbuild shrunk. ## Issues fixed Pulled in from upstream oxc fixes between 0.132.0 and 0.133.0: - Fixes #9437 — Pure-annotated IIFE returning an array is inlined (via oxc [#22547](oxc-project/oxc#22547)) - Fixes #9494 — Cross-module enum inlining mis-folds auto-increment member to 0 (via oxc [#22646](oxc-project/oxc#22646)) - Fixes #9408 — Rolldown drops `@preserve` from `/* #__PURE__ -- @preserve */` comments (via oxc [#22525](oxc-project/oxc#22525) "preserve verbatim text of pure/no-side-effects comments") - Partially addresses #8688 — `dce/dce_of_iife` esbuild divergence shrunk (via oxc [#22589](oxc-project/oxc#22589) "drop empty-body IIFE wrapper when called with arguments") Also relevant: oxc [#22566](oxc-project/oxc#22566) reduces false-positive `PureNotApplied` warnings (the warnings system landed in rolldown #9381) by applying PURE through member-access chains. ## Test plan - [x] `cargo check --workspace --all-targets` - [x] `just update-generated-code` - [x] `just test-update` - [x] `just ued` - [x] `just roll` — 32 Rust suites pass (0 failed), 1212 node tests pass (0 failed), TS lint+types clean on 804 files --------- Co-authored-by: shulaoda <165626830+shulaoda@users.noreply.github.com>
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Why
substitute_iife_callbailed out as soon as the call had any arguments, so(() => {})(a)stayed in the output while esbuild emitsa;. The existing logic (#22349, closing #17480) only handled the zero-args case.Surfaced by rolldown ↔ esbuild compatibility tests for
dce/dce_of_iife(rolldown/rolldown#8688):Fix
Extend
substitute_iife_callto drop the wrapper when the body is empty, the callee is neitherasyncnor a generator, and every named parameter is a bareBindingIdentifierwith no default. The arguments become a sequence ending invoid 0(preserving the call'sundefinedresult);remove_unused_expressionstrips the tail at statement position. Argument conversion reusesfold_arguments_into_needed_expressions, which also drops pure args for free.Two related cases handled in the same path:
((...r) => {})(a)→a;). Deliberately looser than the specIsSimpleParameterList(which forbids any rest): the empty body never observes the collected array.(() => {})(...a)→[...a];) — converted to a single-spread array literal that preserves the iterator-protocol invocation. Matches esbuild's--minifyoutput.Rejected (no behaviour change): destructured params, parameter defaults,
async/ generator callees, destructured rest bindings — each can have observable effects that the empty body would otherwise elide.New positive + negative cases in
test_fold_iife(tests/peephole/remove_unused_expression.rs); full minifier suite (501/0) andminsizesnapshots unchanged.