perf(semantic): move check for function declaration out of `is_function_part_of_if_statement` by overlookmotel · Pull Request #18292 · oxc-project/oxc

overlookmotel · 2026-01-20T12:26:48Z

Small optimization. After #18291, one of the callers of is_function_part_of_if_statement has already done the check for whether the Function is a declaration. So move that repeated check out of is_function_part_of_if_statement.

As that function now only applies to function declarations, rename it to is_function_decl_part_of_if_statement.

overlookmotel · 2026-01-20T12:27:03Z

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codspeed-hq · 2026-01-20T12:32:29Z

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing om/01-20-perf_semantic_move_check_for_function_declaration_out_of_is_function_part_of_if_statement_ (953be9e) with main (f675eb4)¹}

Summary

✅ 42 untouched benchmarks
⏩ 3 skipped benchmarks²

No successful run was found on main (31bbe39) during the generation of this report, so f675eb4 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩
3 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. ↩

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Pull request overview

This PR optimizes the semantic checker by moving a redundant check for function declarations out of a helper function. Following PR #18291, one caller already performs the is_declaration() check, so this change eliminates duplicate work.

Changes:

Renamed is_function_part_of_if_statement to is_function_decl_part_of_if_statement to reflect that it now only applies to function declarations
Replaced the runtime check with a debug assertion inside the function
Updated both call sites to check is_declaration() before calling the renamed function

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
crates/oxc_semantic/src/checker/mod.rs	Updated public export to use the renamed function
crates/oxc_semantic/src/checker/javascript.rs	Renamed function and replaced runtime check with debug assertion; updated call site that already had the check
crates/oxc_semantic/src/binder.rs	Updated import and added `is_declaration()` check before calling the renamed function

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graphite-app · 2026-01-20T14:02:47Z

Merge activity

Jan 20, 2:02 PM UTC: Boshen added this pull request to the Graphite merge queue.
Jan 20, 2:16 PM UTC: The Graphite merge queue removed this pull request due to downstack failures on PR #18290.
Jan 21, 1:10 AM UTC: Dunqing added this pull request to the Graphite merge queue.
Jan 21, 1:18 AM UTC: The Graphite merge queue couldn't merge this PR because it had merge conflicts.
Jan 21, 2:02 AM UTC: Dunqing added this pull request to the Graphite merge queue.
Jan 21, 2:08 AM UTC: Merged by the Graphite merge queue.

…on_part_of_if_statement` (#18292) Small optimization. After #18291, one of the callers of `is_function_part_of_if_statement` has already done the check for whether the `Function` is a declaration. So move that repeated check out of `is_function_part_of_if_statement`. As that function now only applies to function declarations, rename it to `is_function_decl_part_of_if_statement`.

### 💥 BREAKING CHANGES - 22dec6a semantic: [**BREAKING**] Remove `Scoping::scope_build_child_ids` and all related APIs (#18362) (Dunqing) - 30a4899 oxc: [**BREAKING**] Remove `CompilerInterface::semantic_child_scope_ids` (#18361) (Dunqing) - 777fc40 ast: [**BREAKING**] Add `Ident` type (#18354) (Boshen) - af0ca46 span: [**BREAKING**] Use `ModuleKind::CommonJS` for `SourceType::cjs()` (#18276) (sapphi-red) ### 🚀 Features - 0a02026 semantic: Add TS1499 code to diagnostic (#18557) (camc314) - 8b4618f parser: Add TS1500 code to diagnostic (#18547) (camc314) - 866b6b3 parser: Add TS1048 code to diagnostic (#18546) (camc314) - 1117c44 parser: Add TS1054 code to diagnostic (#18541) (camc314) - e4fcdde semantic: Add TS1053 code to diagnostic (#18539) (camc314) - bcbf396 semantic: Add TS1052 code to diagnostic (#18538) (camc314) - 8155edf semantic: Add TS1049 code to diagnostic (#18535) (camc314) - 51d3b3f parser: Add TS1502 code to diagnostic (#18534) (camc314) - 00854e8 semantic: Add TS2337 error code to super call diagnostic (#18531) (camc314) - 993fd2b parser: Parse unambiguous await with better error messages (#18480) (Boshen) - 8db0e78 linter/plugins: Handle BOMs (#18376) (overlookmotel) - 6ac09e2 linter/plugins: Support source text not being at start of buffer (#18375) (overlookmotel) - 2ef5647 ast: Add escape_raw parameter to template_element builders (#18121) (Boshen) ### 🐛 Bug Fixes - 74d0998 semantic: Update error msg for multiple `default` cases in switch stmt (#18526) (camc314) - c205b0d ast: Remove `ThisExpression` from `TSModuleReference` (#18489) (Boshen) - aed3669 parser: Parse HTML-like comments in unambiguous mode (#18442) (Boshen) - c4132fb parser: Validate accessor parameters in interface method signatures (#18391) (Boshen) - b0cd74d semantic: Allow `var` and `function` with same name in static blocks (#18358) (Boshen) - 6037995 semantic: Allow `new.target` in class field initializers (#18349) (Boshen) - 9a15c6a semantic: Do not rely on spans for node comparison in `Function::bind` (#18296) (overlookmotel) ### ⚡ Performance - 6b600c4 semantic: Skip parent lookup for function declarations in `Function::bind` (#18293) (overlookmotel) - c27ad2d semantic: Move check for function declaration out of `is_function_part_of_if_statement` (#18292) (overlookmotel) - 63eb89e semantic: Skip checking redeclarations for function expressions (#18291) (overlookmotel) - 7c12743 semantic: Skip checking unresolved exports in CommonJS files (#18250) (overlookmotel) - 2349031 allocator: Increase initial chunk size from 512B to 16KB (#18234) (Boshen) ### 📚 Documentation - 8ccd853 npm: Update package homepage URLs and add keywords (#18509) (Boshen) - 9b3165f napi/parser: Clarify when to use `parseAsync` vs `parseSync` (#18486) (Boshen) - 1b59f63 napi/parser: Correct typo in README (#18251) (overlookmotel) - 00ff75f mangler: Fix `top_level` option in example (#18233) (overlookmotel) - 2ddc073 semantic: Fix typo in comment (#18238) (overlookmotel) Co-authored-by: Boshen <[email protected]>

github-actions bot added the A-semantic Area - Semantic label Jan 20, 2026

This was referenced Jan 20, 2026

test(semantic): add test cases for function redeclaration check #18288

Merged

refactor(semantic): simplify checking if function is part of if statement #18290

Merged

github-actions bot added the C-performance Category - Solution not expected to change functional behavior, only performance label Jan 20, 2026

overlookmotel mentioned this pull request Jan 20, 2026

perf(semantic): skip checking redeclarations for function expressions #18291

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overlookmotel marked this pull request as ready for review January 20, 2026 12:39

overlookmotel requested a review from Dunqing as a code owner January 20, 2026 12:39

Copilot AI review requested due to automatic review settings January 20, 2026 12:39

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This was referenced Jan 20, 2026

perf(semantic): skip parent lookup for function declarations in Function::bind #18293

Merged

refactor(semantic): move code into if block #18294

Merged

overlookmotel assigned Dunqing Jan 20, 2026

This was referenced Jan 20, 2026

perf(semantic): single call to Function::bind for functions #18295

Closed

fix(semantic): do not rely on spans for node comparison in Function::bind #18296

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graphite-app bot added the 0-merge Merge with Graphite Merge Queue label Jan 20, 2026

graphite-app bot force-pushed the om/01-20-perf_semantic_skip_checking_redeclarations_for_function_expressions branch from df3236a to b02673e Compare January 20, 2026 14:10

graphite-app bot force-pushed the om/01-20-perf_semantic_move_check_for_function_declaration_out_of_is_function_part_of_if_statement_ branch from c9cc4ad to 8dccef1 Compare January 20, 2026 14:10

graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Jan 20, 2026

Dunqing approved these changes Jan 21, 2026

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graphite-app bot changed the base branch from om/01-20-perf_semantic_skip_checking_redeclarations_for_function_expressions to graphite-base/18292 January 21, 2026 01:09

graphite-app bot added 0-merge Merge with Graphite Merge Queue and removed 0-merge Merge with Graphite Merge Queue labels Jan 21, 2026

graphite-app bot changed the base branch from graphite-base/18292 to main January 21, 2026 01:16

graphite-app bot added the 0-merge Merge with Graphite Merge Queue label Jan 21, 2026

graphite-app bot force-pushed the om/01-20-perf_semantic_move_check_for_function_declaration_out_of_is_function_part_of_if_statement_ branch from 953be9e to c27ad2d Compare January 21, 2026 02:02

graphite-app bot merged commit c27ad2d into main Jan 21, 2026
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graphite-app bot deleted the om/01-20-perf_semantic_move_check_for_function_declaration_out_of_is_function_part_of_if_statement_ branch January 21, 2026 02:08

graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Jan 21, 2026

Boshen mentioned this pull request Jan 26, 2026

release(crates): oxc v0.111.0 #18572

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perf(semantic): move check for function declaration out of `is_function_part_of_if_statement`#18292

perf(semantic): move check for function declaration out of `is_function_part_of_if_statement`#18292
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