perf(semantic): mark checker::check as inline(always)

[camc314]

the reasoning here is:

1. check is a big function with a big match arm
2. if we inline it into leave_node
3. and inline leave_node into it's caller
4. the match will be flattened, as the compiler knows what varient of the kind it is, this means all the other match arms can be dropped, as well as the match it's self, just leaving the call into the check fn (if needed) <- if this works correctly, it also means this change will hardly have any impact on binary size

[camc314]

• perf(semantic): mark all diagnostic functions as #[cold] #17487
• perf(transformer): mark all diagnostic functions as #[cold] #17486
• perf(semantic): mark checker::check as inline(always) #17459 👈 (View in Graphite)
• main

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[codspeed-hq]

CodSpeed Performance Report

Merging #17459 will improve performance by 10.13%

_{Comparing c/12-29-perf_semantic_test (f448e31) with main (68b2e54)}

Summary

⚡ 4 improvements
✅ 38 untouched
⏩ 3 skipped¹

Benchmarks breakdown

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	semantic[binder.ts]	4 ms	3.7 ms	+6.45%
⚡	Simulation	semantic[RadixUIAdoptionSection.jsx]	74 µs	67.2 µs	+10.13%
⚡	Simulation	semantic[cal.com.tsx]	25.8 ms	23.9 ms	+7.97%
⚡	Simulation	semantic[react.development.js]	1.6 ms	1.5 ms	+6.34%

Footnotes

1. 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. ↩

[Boshen]

Add two inline comments to these two #[inline(always)] and we should be good to go!

[Copilot]

Pull request overview

This PR applies a performance optimization by marking two functions with #[inline(always)] to enable compile-time match arm elimination. The strategy relies on inlining both checker::check and SemanticBuilder::leave_node so that when each visit_* method calls leave_node with a statically known AstKind variant, the compiler can constant-fold the large match statement in checker::check, eliminating all non-matching arms and reducing both execution time and potentially binary size.

• Adds #[inline(always)] to checker::check with comprehensive documentation
• Adds #[inline(always)] to SemanticBuilder::leave_node with explanatory comments
• Both use #[expect(clippy::inline_always)] with clear reasoning for the optimization

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
crates/oxc_semantic/src/checker/mod.rs	Adds documentation and #[inline(always)] attribute to the check function to enable compile-time match elimination
crates/oxc_semantic/src/builder.rs	Adds documentation and #[inline(always)] attribute to the leave_node method to complete the inlining chain

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[graphite-app]

Merge activity

• Dec 30, 11:39 AM UTC: Boshen added this pull request to the Graphite merge queue.
• Dec 30, 11:46 AM UTC: Merged by the Graphite merge queue.