oxc-project/oxc - CodSpeed

oxc

Performance History

Latest Results

fix(mangler): prevent slot reuse for block-scoped functions in sloppy mode In sloppy mode JavaScript, function declarations inside blocks (if, try, switch, {}) have Annex B.3.2.1 semantics: they create an implicit var-like assignment in the enclosing function scope at block exit. The mangler was treating these as purely block-scoped (like let/const), allowing slot reuse with outer var bindings. When both got the same mangled name, the Annex B assignment would overwrite the outer variable at runtime, changing program behavior. The fix has two parts: 1. Annex B function declarations in sloppy block scopes are partitioned to the end of bindings and always get fresh slots (never reuse existing ones) 2. Their slot liveness is extended upward to the enclosing var-scope, preventing sibling scopes from reusing their slots either Strict mode and ES modules are unaffected (no Annex B, no size regression). Fixes #20610 Fixes #14316 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

fix/mangler-annex-b-block-scoped-function

43 minutes ago

feat(parser): mark pure comments that cannot be applied (#20687) ## Summary Adds `CommentContent::PureNotApplied` variant to flag `#__PURE__` / `@__PURE__` annotations that cannot be applied, aligning with [Rollup's behavior](https://rollupjs.org/configuration-options/#pure) for invalid pure comment positions. ### Changes - `set_pure_on_call_or_new_expr` now returns `bool` so callers detect when the annotation couldn't be applied - Track the specific pure comment index (`Option<usize>`) instead of a boolean flag, fixing a bug where the wrong comment could be retagged when multiple pure comments exist (e.g. `/*#__PURE__*/ foo + /*#__PURE__*/ bar()`) - Mark pure comments as `PureNotApplied` in three contexts: - **Expression-level**: annotation not before a call/new expression (e.g. `/* #__PURE__ */ a().b`) - **Statement-level**: annotation before non-expression statements (e.g. `/* #__PURE__ */ function foo() {}`) - **Variable declarator**: annotation before `=` (e.g. `const foo /* #__PURE__ */ = bar()`) - Downstream consumers (codegen, minifier, Rolldown) can check for `PureNotApplied` to warn or strip Closes #20334 Rolldown will add custom logic to emit the comments that are `PureNotApplied` so it does not affect the rest of the compiler pipeline. ## Test plan - [x] Unit tests for all `PureNotApplied` cases (expression, statement, variable declarator) - [x] Regression test for correct comment targeting with multiple pure comments - [x] Codegen integration tests updated - [x] `cargo test -p oxc_parser -p oxc_codegen` passes 🤖 Generated with [Claude Code](https://claude.com/claude-code)

main

1 hour ago

feat: support warning about non-expression and pure comment before `=`

boshen/pure-comment-not-applied

2 hours ago

[autofix.ci] apply automated fixes

boshen/pure-comment-not-applied

2 hours ago

fix(codegen): preserve coverage comments before `ConditionalExpression` alternate and between `SwitchCase`s (#20718) ## Summary - Print leading coverage ignore comments (e.g. `/* istanbul ignore next */`) before `ConditionalExpression`'s alternate expression - Print leading coverage ignore comments before `case`/`default` keywords in `SwitchStatement` Closes #20549 🤖 Generated with [Claude Code](https://claude.com/claude-code)

main

2 hours ago

fix(codegen): preserve coverage comments before `ConditionalExpression` alternate and between `SwitchCase`s Print leading coverage ignore comments (e.g. `/* istanbul ignore next */`) in two previously unsupported positions: - Before the alternate expression in ternary operators (`? : /* comment */ expr`) - Before `case`/`default` keywords in switch statements Closes #20549 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

fix/codegen-preserve-coverage-comments

2 hours ago

fix/codegen-preserve-coverage-comments

3 hours ago

fix/codegen-preserve-coverage-comments

3 hours ago

Latest Branches

fix(mangler): prevent slot reuse for block-scoped functions in sloppy mode#20705

11 hours ago

9d7cb62

fix/mangler-annex-b-block-scoped-function

feat(parser): mark pure comments that cannot be applied#20687

2 hours ago

5a821b7

boshen/pure-comment-not-applied

fix(codegen): preserve coverage comments before `ConditionalExpression` alternate and between `SwitchCase`s#20718

3 hours ago

c6a5b0a

fix/codegen-preserve-coverage-comments

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