fix(react_compiler): keep imports referenced only by a local re-export by Boshen · Pull Request #23176 · oxc-project/oxc

Boshen · 2026-06-09T17:24:13Z

Problem

When the React Compiler compiles a module, a named import that is only re-exported via a local export { … } clause was dropped from the output, leaving a dangling export { Foo } that references a removed binding — i.e. invalid code.

Minimal repro:

import { Foo } from "./foo";
export { Foo };
export function C() { const x = useState(0); return <div>{x}</div>; }

Before this change, the compiled output emits export { Foo } with no import { Foo }. With the React Compiler disabled the import is kept, so the bug is specific to the compiler's AST round-trip.

Root cause

oxc's parser rewrites a local export's specifier local from IdentifierName to IdentifierReference when there is no source (parse_export_named_specifiers), and semantic analysis only records a reference to the imported binding for an IdentifierReference (binder.rs). The React Compiler's reverse AST conversion (convert_ast_reverse) always rebuilt local as a plain IdentifierName, so no reference was created, and the downstream TypeScript import elision then removed the "unused" import — while leaving the export clause behind.

Fix

Mirror the parser: in convert_export_named_declaration, when the export has no source, build each specifier's local as an IdentifierReference. Re-exports (export { x } from "…") keep an IdentifierName, since there local names an export of the other module.

Verification

Added regression test local_reexport_keeps_its_import_binding; cargo test -p oxc_react_compiler passes (17/17), napi/transform passes (62/62).
Found by differential-testing the React Compiler against babel-plugin-react-compiler across the ecosystem-ci repos. Re-running the 90 affected files with the fix: the invalid-output bucket drops to 0 and 84/90 now match Babel exactly (the rest are pre-existing, benign output-equivalent differences).

Note

The upstream oxc-react-compiler repo carries an identical copy of this conversion code (crates/react_compiler_oxc/src/convert_ast_reverse.rs); the same change should be mirrored there to survive the next vendor sync.

🤖 Generated with Claude Code

codspeed-hq · 2026-06-09T17:28:46Z

Merging this PR will not alter performance

✅ 57 untouched benchmarks
⏩ 14 skipped benchmarks¹

_{Comparing fix-react-compiler-dangling-reexport (2db6e10) with main (d7038de)}

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. ↩

Boshen · 2026-06-09T17:29:15Z

Merge activity

Jun 9, 5:29 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 9, 5:29 PM UTC: Boshen added this pull request to the Graphite merge queue.
Jun 9, 5:34 PM UTC: Merged by the Graphite merge queue.

#23176) ## Problem When the React Compiler compiles a module, a named import that is only re-exported via a local `export { … }` clause was dropped from the output, leaving a dangling `export { Foo }` that references a removed binding — i.e. **invalid code**. Minimal repro: ```tsx import { Foo } from "./foo"; export { Foo }; export function C() { const x = useState(0); return <div>{x}</div>; } ``` Before this change, the compiled output emits `export { Foo }` with **no** `import { Foo }`. With the React Compiler disabled the import is kept, so the bug is specific to the compiler's AST round-trip. ## Root cause oxc's parser rewrites a *local* export's specifier `local` from `IdentifierName` to `IdentifierReference` when there is no `source` (`parse_export_named_specifiers`), and semantic analysis only records a reference to the imported binding for an `IdentifierReference` (`binder.rs`). The React Compiler's reverse AST conversion (`convert_ast_reverse`) always rebuilt `local` as a plain `IdentifierName`, so no reference was created, and the downstream TypeScript import elision then removed the "unused" import — while leaving the export clause behind. ## Fix Mirror the parser: in `convert_export_named_declaration`, when the export has no `source`, build each specifier's `local` as an `IdentifierReference`. Re-exports (`export { x } from "…"`) keep an `IdentifierName`, since there `local` names an export of the other module. ## Verification - Added regression test `local_reexport_keeps_its_import_binding`; `cargo test -p oxc_react_compiler` passes (17/17), `napi/transform` passes (62/62). - Found by differential-testing the React Compiler against `babel-plugin-react-compiler` across the ecosystem-ci repos. Re-running the 90 affected files with the fix: the invalid-output bucket drops to **0** and 84/90 now match Babel exactly (the rest are pre-existing, benign output-equivalent differences). ## Note The upstream `oxc-react-compiler` repo carries an identical copy of this conversion code (`crates/react_compiler_oxc/src/convert_ast_reverse.rs`); the same change should be mirrored there to survive the next vendor sync. 🤖 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>

#23176) ## Problem When the React Compiler compiles a module, a named import that is only re-exported via a local `export { … }` clause was dropped from the output, leaving a dangling `export { Foo }` that references a removed binding — i.e. **invalid code**. Minimal repro: ```tsx import { Foo } from "./foo"; export { Foo }; export function C() { const x = useState(0); return <div>{x}</div>; } ``` Before this change, the compiled output emits `export { Foo }` with **no** `import { Foo }`. With the React Compiler disabled the import is kept, so the bug is specific to the compiler's AST round-trip. ## Root cause oxc's parser rewrites a *local* export's specifier `local` from `IdentifierName` to `IdentifierReference` when there is no `source` (`parse_export_named_specifiers`), and semantic analysis only records a reference to the imported binding for an `IdentifierReference` (`binder.rs`). The React Compiler's reverse AST conversion (`convert_ast_reverse`) always rebuilt `local` as a plain `IdentifierName`, so no reference was created, and the downstream TypeScript import elision then removed the "unused" import — while leaving the export clause behind. ## Fix Mirror the parser: in `convert_export_named_declaration`, when the export has no `source`, build each specifier's `local` as an `IdentifierReference`. Re-exports (`export { x } from "…"`) keep an `IdentifierName`, since there `local` names an export of the other module. ## Verification - Added regression test `local_reexport_keeps_its_import_binding`; `cargo test -p oxc_react_compiler` passes (17/17), `napi/transform` passes (62/62). - Found by differential-testing the React Compiler against `babel-plugin-react-compiler` across the ecosystem-ci repos. Re-running the 90 affected files with the fix: the invalid-output bucket drops to **0** and 84/90 now match Babel exactly (the rest are pre-existing, benign output-equivalent differences). ## Note The upstream `oxc-react-compiler` repo carries an identical copy of this conversion code (`crates/react_compiler_oxc/src/convert_ast_reverse.rs`); the same change should be mirrored there to survive the next vendor sync. 🤖 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>

Boshen added the 0-merge Merge with Graphite Merge Queue label Jun 9, 2026

graphite-app Bot force-pushed the fix-react-compiler-dangling-reexport branch from 2db6e10 to de38a3f Compare June 9, 2026 17:29

graphite-app Bot merged commit de38a3f into main Jun 9, 2026
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graphite-app Bot removed the 0-merge Merge with Graphite Merge Queue label Jun 9, 2026

graphite-app Bot deleted the fix-react-compiler-dangling-reexport branch June 9, 2026 17:34

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

release(crates): oxc v0.136.0 #23443

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fix(react_compiler): keep imports referenced only by a local re-export#23176

fix(react_compiler): keep imports referenced only by a local re-export#23176
graphite-app[bot] merged 1 commit into
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fix-react-compiler-dangling-reexport

Boshen commented Jun 9, 2026

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Boshen commented Jun 9, 2026 •

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Boshen commented Jun 9, 2026

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codspeed-hq Bot commented Jun 9, 2026

Merging this PR will not alter performance

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Boshen commented Jun 9, 2026 •

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