feat(linter/react): implement react-compiler rule

[Boshen]

Adds a nursery react/react-compiler rule that runs the React Compiler (oxc_react_compiler) in lint-only mode and reports Rules of React violations: conditional hook calls, setState during render, ref access during render, mutation errors, etc.

Rule

• run_once rule calling oxc_react_compiler::lint() on the program; the compiler's own prefilter skips files with no React-like functions.
• Lints with the same compiler options as eslint-plugin-react-compiler (COMPILER_OPTIONS in its RunReactCompiler.ts): lint output mode plus the validations the plugin force-enables (impure functions, capitalized calls, JSX in try, static components, setState in effects, etc.).
• Reports only error-severity violations by default. Compiler bail-outs (skipped optimizations, e.g. unsupported syntax) are opt-in via reportAllBailouts.
• Flow suppressions are handled like the eslint plugin: diagnostics whose primary location sits directly below a $FlowFixMe[react-rule-hook] / $FlowFixMe[react-rule-unsafe-ref] comment are dropped, while other diagnostics in the same function still surface.

Tests

All test cases from eslint-plugin-react-compiler/__tests__ (MIT) are ported, covering hooks order, capitalized calls, impure calls in render, JSX in try/catch, ref access in render, useMemo diagnostics, useState mutation (TS), 'use memo'/'use no forget' directives, and Flow suppressions. The only case not ported is "Basic example with component syntax", which uses Flow's experimental component declaration syntax that oxc does not parse. RustBackendComparison-test.ts replicates the same cases for backend comparison, so it adds no new ones. Every diagnostic message and location in the snapshot matches the upstream assertions.

Diagnostics

oxc_react_compiler diagnostics previously had no spans. They now carry labeled spans built from the compiler's source locations (byte offsets flow through from oxc spans): detail.loc → sub-detail locations with their messages (e.g. "Found setState() in render") → enclosing function as fallback. Long descriptions moved from the message into help. This makes code frames and oxlint-disable directives work.

Example output:

⚠ react(react-compiler): RenderSetState: Cannot call setState during render
   ╭─[App.tsx:3:17]
 2 │                 const [state, setState] = useState(0);
 3 │                 setState(1);
   ·                 ────┬───
   ·                     ╰── Found setState() in render
 4 │                 return <div>{state}</div>;
   ╰────
  help: Calling setState during render may trigger an infinite loop.

🤖 Generated with Claude Code

[codspeed-hq]

Merging this PR will degrade performance by 73.33%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

❌ 2 regressed benchmarks
✅ 60 untouched benchmarks
⏩ 9 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	linter[RadixUIAdoptionSection.jsx]	885.6 µs	10,306.7 µs	-91.41%
❌	Simulation	linter[App.tsx]	174.1 ms	210.4 ms	-17.25%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing feat/linter-react-compiler-rule (e0cd81e) with main (d6d1189)}

Footnotes

1. 9 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. ↩

[camc314]

nice!

I've marked it explicitly as experimental so that I can make some more changes to it when time allows over the next few weeks.

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Allow React Compiler options to flow through

For projects that intentionally allowlist an uppercase helper call via React Compiler's validateNoCapitalizedCalls config, this hard-coded empty allowlist still reports CapitalizedCalls, and the rule's config type only accepts reportAllBailouts with deny_unknown_fields. That makes the diagnostic's suggested “allowlist it via the compiler config” path impossible in oxlint, so these legitimate cases become unfixable false positives unless users disable the whole rule.

Useful? React with 👍 / 👎.

[Stybo]

Waited for this!