perf(parser): peek once for the static modifier disambiguation by Boshen · Pull Request #23079 · oxc-project/oxc

Boshen · 2026-06-07T14:02:56Z

In try_parse_modifier, a static token was peeked twice at the same offset: once for peek_token().kind() == LCurly (the static {} block check) and again inside next_token_can_follow_modifier (reached via parse_any_contextual_modifier). peek_token is not cached, so this re-lexed the token after static twice for every static class member.

Pull static into its own branch, peek the next token once, and reuse it for all three checks (static block / repeated static / static used as a property name). The non-static modifier path still goes through parse_any_contextual_modifier unchanged.

Behavior-preserving:

cargo coverage -- parser — snapshots byte-identical (no .snap changes).
just allocs — unchanged.
Full parser output byte-identical to baseline on a static class fixture (static block, fields, methods, static as name, repeated static, TS modifier combos) in .ts and .js.

🤖 Generated with Claude Code

codspeed-hq · 2026-06-07T14:10:28Z

Merging this PR will not alter performance

✅ 57 untouched benchmarks
⏩ 14 skipped benchmarks¹

_{Comparing perf/parser-static-modifier-single-peek (af32bfe) with main (e7e07a3)²}

14 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩
No successful run was found on main (0c19c0e) during the generation of this report, so e7e07a3 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

Boshen · 2026-06-08T15:24:04Z

Merge activity

Jun 8, 3:24 PM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Jun 8, 3:27 PM UTC: Boshen added this pull request to the Graphite merge queue.
Jun 8, 3:32 PM UTC: Merged by the Graphite merge queue.

In `try_parse_modifier`, a `static` token was peeked twice at the same offset: once for `peek_token().kind() == LCurly` (the `static {}` block check) and again inside `next_token_can_follow_modifier` (reached via `parse_any_contextual_modifier`). `peek_token` is not cached, so this re-lexed the token after `static` twice for every `static` class member. Pull `static` into its own branch, peek the next token once, and reuse it for all three checks (static block / repeated `static` / `static` used as a property name). The non-`static` modifier path still goes through `parse_any_contextual_modifier` unchanged. Behavior-preserving: - `cargo coverage -- parser` — snapshots byte-identical (no `.snap` changes). - `just allocs` — unchanged. - Full parser output byte-identical to baseline on a `static` class fixture (static block, fields, methods, `static` as name, repeated `static`, TS modifier combos) in `.ts` and `.js`. 🤖 Generated with [Claude Code](https://claude.com/claude-code)

### 💥 BREAKING CHANGES - 7a24911 codegen: [**BREAKING**] Borrow sourcemaps from codegen (#23422) (Boshen) - bb0ed44 transformer: [**BREAKING**] Disable styled-components transpileTemplateLiterals by default (#23171) (Boshen) ### 🚀 Features - 1490a0a linter/react: Implement react-compiler rule (#23202) (Boshen) - 6c0bdf0 transformer/react-refresh: Support `module.property.useHook()` (#23190) (Dunqing) - 47991bd semantic: Report TS1228 for invalid type predicates (#23174) (camc314) - 1d3af58 parser: Add TS2398 parameter property diagnostic (#23216) (camc314) - 44313da semantic: Add `scope_is_descendant_of` api (#22313) (camc314) - e5050c0 parser: Improve diagnostic for rest initializer (#23205) (camc314) - ec266bb transformer: Run React Compiler as a feature-gated transform pass (#23201) (Boshen) - e7374fe parser: Report error for `const` modifier on interface type parameter (#23173) (camc314) - a7c1c9b parser: Report ambient definite variable assertions (#23165) (camc314) - d169fcd parser: Report invalid class definite assertions (#23164) (camc314) - 00244d8 parser: Report definite property initializer errors (#23160) (camc314) ### 🐛 Bug Fixes - 52d0c31 transformer: Replace ambient dot defines (#23231) (camc314) - 2c28748 transformer/class: Parent generated constructors to class scope (#23222) (camc314) - 8edd234 parser: Report accessor definite assertion on token (#23203) (camc314) - de38a3f react_compiler: Keep imports referenced only by a local re-export (#23176) (Boshen) - f5721c2 codegen: Preserve parentheses around `intrinsic` type reference (#23156) (Boshen) - e89f81d parser: Don't emit TS1477 for parenthesized instantiation expression (#23147) (Boshen) - 8a04149 parser: Reject module-referencing imports/exports in a namespace body (#22829) (Boshen) ### ⚡ Performance - 2783295 parser: Table-driven operator precedence lookup (#23346) (Boshen) - 231d5de parser: Single-match member expression dispatch (#23347) (Boshen) - e89729b codegen: Accept one-shot wrap closures (#23265) (camc314) - a6c11fa parser: Force-inline read_non_decimal to fold per-digit number dispatch (#23157) (Boshen) - d74964c parser: Store class definite assertion offset (#23170) (camc314) - f0fda4d parser: Shrink-wrap cold diagnostic tails out of hot frames (#23159) (Boshen) - a082180 parser: Store definite assertion offset (#23167) (camc314) - 534f9c6 oxc: Conditionally rebuild semantic in compiler pipeline (#23153) (Boshen) - b435c6a parser: Skip checkpoint for `infer T extends U` constraint in disallow context (#23128) (Boshen) - 7464dce parser: Peek instead of checkpoint/rewind for `export default` modifier (#23124) (Boshen) - 80a9a32 parser: Fast-path single-keyword TS declarations (#23083) (Boshen) - da1a6c6 diagnostics: Migrate to allocation-optimized oxc-miette (#23094) (Boshen) - b7b08ce parser: Peek once for the static modifier disambiguation (#23079) (Boshen) - e7e07a3 parser: Fold unary dispatch into a single match (#23076) (Boshen) ### 📚 Documentation - d241add semantic: Add `AGENTS.md` test guidance for agents (#23441) (camc314) - 026f1ae parser: Add `AGENTS.md` test guidance for agents (#23440) (camc314) - 09755ac transformer: Add `AGENTS.md` test guidance for agents (#23439) (camc314) - e6bdfd4 lexer: Correct reference link for `byte_handlers!` (#23313) (Dunqing) - 65b6d7a allocator: Fix memory leaks in `Arena` examples (#23257) (overlookmotel) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>

In `try_parse_modifier`, a `static` token was peeked twice at the same offset: once for `peek_token().kind() == LCurly` (the `static {}` block check) and again inside `next_token_can_follow_modifier` (reached via `parse_any_contextual_modifier`). `peek_token` is not cached, so this re-lexed the token after `static` twice for every `static` class member. Pull `static` into its own branch, peek the next token once, and reuse it for all three checks (static block / repeated `static` / `static` used as a property name). The non-`static` modifier path still goes through `parse_any_contextual_modifier` unchanged. Behavior-preserving: - `cargo coverage -- parser` — snapshots byte-identical (no `.snap` changes). - `just allocs` — unchanged. - Full parser output byte-identical to baseline on a `static` class fixture (static block, fields, methods, `static` as name, repeated `static`, TS modifier combos) in `.ts` and `.js`. 🤖 Generated with [Claude Code](https://claude.com/claude-code)

### 💥 BREAKING CHANGES - 7a24911 codegen: [**BREAKING**] Borrow sourcemaps from codegen (#23422) (Boshen) - bb0ed44 transformer: [**BREAKING**] Disable styled-components transpileTemplateLiterals by default (#23171) (Boshen) ### 🚀 Features - 1490a0a linter/react: Implement react-compiler rule (#23202) (Boshen) - 6c0bdf0 transformer/react-refresh: Support `module.property.useHook()` (#23190) (Dunqing) - 47991bd semantic: Report TS1228 for invalid type predicates (#23174) (camc314) - 1d3af58 parser: Add TS2398 parameter property diagnostic (#23216) (camc314) - 44313da semantic: Add `scope_is_descendant_of` api (#22313) (camc314) - e5050c0 parser: Improve diagnostic for rest initializer (#23205) (camc314) - ec266bb transformer: Run React Compiler as a feature-gated transform pass (#23201) (Boshen) - e7374fe parser: Report error for `const` modifier on interface type parameter (#23173) (camc314) - a7c1c9b parser: Report ambient definite variable assertions (#23165) (camc314) - d169fcd parser: Report invalid class definite assertions (#23164) (camc314) - 00244d8 parser: Report definite property initializer errors (#23160) (camc314) ### 🐛 Bug Fixes - 52d0c31 transformer: Replace ambient dot defines (#23231) (camc314) - 2c28748 transformer/class: Parent generated constructors to class scope (#23222) (camc314) - 8edd234 parser: Report accessor definite assertion on token (#23203) (camc314) - de38a3f react_compiler: Keep imports referenced only by a local re-export (#23176) (Boshen) - f5721c2 codegen: Preserve parentheses around `intrinsic` type reference (#23156) (Boshen) - e89f81d parser: Don't emit TS1477 for parenthesized instantiation expression (#23147) (Boshen) - 8a04149 parser: Reject module-referencing imports/exports in a namespace body (#22829) (Boshen) ### ⚡ Performance - 2783295 parser: Table-driven operator precedence lookup (#23346) (Boshen) - 231d5de parser: Single-match member expression dispatch (#23347) (Boshen) - e89729b codegen: Accept one-shot wrap closures (#23265) (camc314) - a6c11fa parser: Force-inline read_non_decimal to fold per-digit number dispatch (#23157) (Boshen) - d74964c parser: Store class definite assertion offset (#23170) (camc314) - f0fda4d parser: Shrink-wrap cold diagnostic tails out of hot frames (#23159) (Boshen) - a082180 parser: Store definite assertion offset (#23167) (camc314) - 534f9c6 oxc: Conditionally rebuild semantic in compiler pipeline (#23153) (Boshen) - b435c6a parser: Skip checkpoint for `infer T extends U` constraint in disallow context (#23128) (Boshen) - 7464dce parser: Peek instead of checkpoint/rewind for `export default` modifier (#23124) (Boshen) - 80a9a32 parser: Fast-path single-keyword TS declarations (#23083) (Boshen) - da1a6c6 diagnostics: Migrate to allocation-optimized oxc-miette (#23094) (Boshen) - b7b08ce parser: Peek once for the static modifier disambiguation (#23079) (Boshen) - e7e07a3 parser: Fold unary dispatch into a single match (#23076) (Boshen) ### 📚 Documentation - d241add semantic: Add `AGENTS.md` test guidance for agents (#23441) (camc314) - 026f1ae parser: Add `AGENTS.md` test guidance for agents (#23440) (camc314) - 09755ac transformer: Add `AGENTS.md` test guidance for agents (#23439) (camc314) - e6bdfd4 lexer: Correct reference link for `byte_handlers!` (#23313) (Dunqing) - 65b6d7a allocator: Fix memory leaks in `Arena` examples (#23257) (overlookmotel) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>

github-actions Bot added the A-parser Area - Parser label Jun 7, 2026

Boshen self-assigned this Jun 7, 2026

Boshen marked this pull request as draft June 7, 2026 14:59

Boshen force-pushed the perf/parser-static-modifier-single-peek branch from 7c5a30d to b275ca1 Compare June 8, 2026 15:13

Boshen marked this pull request as ready for review June 8, 2026 15:18

Boshen force-pushed the perf/parser-static-modifier-single-peek branch 2 times, most recently from 660a979 to af32bfe Compare June 8, 2026 15:21

Boshen added the 0-merge Merge with Graphite Merge Queue label Jun 8, 2026

graphite-app Bot force-pushed the perf/parser-static-modifier-single-peek branch from af32bfe to b7b08ce Compare June 8, 2026 15:27

graphite-app Bot merged commit b7b08ce into main Jun 8, 2026
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graphite-app Bot removed the 0-merge Merge with Graphite Merge Queue label Jun 8, 2026

graphite-app Bot deleted the perf/parser-static-modifier-single-peek branch June 8, 2026 15:32

Boshen mentioned this pull request Jun 10, 2026

perf(parser): cache peeked token and replay it when advancing #23191

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oxc-guard Bot mentioned this pull request Jun 15, 2026

release(crates): oxc v0.136.0 #23443

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perf(parser): peek once for the static modifier disambiguation#23079

perf(parser): peek once for the static modifier disambiguation#23079
graphite-app[bot] merged 1 commit into
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perf/parser-static-modifier-single-peek

Boshen commented Jun 7, 2026

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Boshen commented Jun 7, 2026

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Merging this PR will not alter performance

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codspeed-hq Bot commented Jun 7, 2026 •

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