fix(transformer/explicit-resource-management): align lexical binding scopes#22320
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Pull request overview
Aligns semantic scope/binding metadata with the AST shape produced by the ES2026 explicit resource management (using/await using) transform, reducing semantic mismatches in conformance/coverage runs (part of #9699).
Changes:
- Adjust the
explicit_resource_managementfunction-body transform to move block-scoped bindings into the newly insertedtry-body scope. - Add
Scoping::move_bindings_ifto support bulk moving bindings between scopes while updating symbol scope ownership. - Update conformance/coverage snapshots reflecting improved pass counts and fewer scope/binding mismatches for the transform.
Reviewed changes
Copilot reviewed 4 out of 7 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| crates/oxc_transformer/src/es2026/explicit_resource_management.rs | Moves relevant bindings from the function-body scope into the generated try block scope to match the transformed AST. |
| crates/oxc_semantic/src/scoping.rs | Introduces move_bindings_if to move bindings between scopes and update symbol scope IDs. |
| tasks/transform_conformance/snapshots/oxc.snap.md | Snapshot updated for improved explicit-resource-management conformance results. |
| tasks/transform_conformance/snapshots/babel.snap.md | Snapshot updated for improved explicit-resource-management conformance results. |
| tasks/coverage/snapshots/semantic_typescript.snap | Snapshot updated showing fewer semantic mismatches / improved pass count. |
| tasks/coverage/snapshots/semantic_test262.snap | Snapshot updated showing fewer semantic mismatches / improved pass count. |
| tasks/coverage/snapshots/semantic_babel.snap | Snapshot updated showing fewer semantic mismatches / improved pass count. |
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## Summary Adds `Scoping::move_binding_by_symbol_id(from, to, symbol_id)` that bundles `move_binding` + `set_symbol_scope_id`, looking up the symbol's name internally. Every existing call to `move_binding` is paired with `set_symbol_scope_id` to keep `symbol_scope_ids` consistent with the binding map. Folding them into one call also lets callers move a binding without holding an arena-lifetime `Ident` across the `&mut Scoping` access — useful when the only name source is `Scoping`'s own binding map (the next step in the ERM scope-binding fix in #22320). The 6 existing pair sites are migrated: - `oxc_semantic/src/binder.rs` (var-hoist Annex B) - `oxc_transformer/src/common/arrow_function_converter.rs` (`adjust_binding_scope`) - `oxc_transformer/src/es2017/async_to_generator.rs` (`BindingMover`) - `oxc_transformer/src/es2018/object_rest_spread.rs` (for-init bindings) - `oxc_transformer/src/es2026/explicit_resource_management.rs` x3 (for-of init, static block, try statement) ## Notes - The helper updates `symbol_scope_ids` unconditionally — matching the pre-existing pair behavior, which always set the scope id even when `move_binding` was a silent no-op. - The internal `remove_entry(&name)` lookup uses `Ident`'s precomputed hash via `IdentBuildHasher::write_u64`, skipping the byte-by-byte hash path that `name.as_str()` would take. - No new tests: each migrated call site is exercised by transformer Babel/conformance and `semantic_*` coverage; snapshots are unchanged.
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### 🚀 Features - bc91a17 codegen: Expose `Codegen::with_source_type` method (#22432) (camc314) ### 🐛 Bug Fixes - 5ac7e79 minifier: Drop unused-var-init pure IIFEs and preserve annotation for downstream (#22349) (Dunqing) - 4ab57eb allocator: Fixed-size allocators use `VirtualAlloc` on Windows (#22124) (overlookmotel) - 66d77eb allocator: Fix segfault on Linux MUSL with fixed-size allocators (#22388) (overlookmotel) - b8fbc1f transformer/object-rest-spread: Correct scope id when moving bindings (#22419) (camc314) - 18edc2c codegen: Keep `Object.defineProperty` property name as plain string in minify (#22400) (Dunqing) - dda33de transformer/explicit-resource-management: Align lexical binding scopes (#22320) (camc314) - 8e79de8 transformer: Preserve for-await statement bodies (#22361) (camc314) - 0cba210 transformer/class: Replace `new.target` in static blocks (#22360) (camc314) - 67ab1c9 transformer/es2018/for-await: Hoist for-await generated bindings (#22355) (camc314) - c3ceb4a transformer/object-rest-spread: Use hoisted scope for `for-of` temp refs (#22347) (camc314) ### ⚡ Performance - 73a9043 allocator/bitset: Avoid temp heap `String` allocation (#22403) (camc314) - 8b2f4f9 transformer/object-rest-spread: Collect `Vec<SymbolId` over `Vec<BindingIdentifier>` (#22418) (camc314) - 83679ea parser: Split TriviaBuilder::handle_token hot/cold paths (#22415) (Boshen) - 2c7d781 codegen: Inline identifier-name accessors (#22411) (Boshen) - 618bc76 diagnostics: Inline `OxcDiagnosticInner` to avoid heap allocation (#22406) (Boshen) - 0b4e158 parser: Reserve cap `2` for sequence expressions vec (#22374) (camc314) - 5f3bdd0 codegen: Add `#[inline]` to `code`, `code_len` (#22373) (camc314) Co-authored-by: overlookmotel <557937+overlookmotel@users.noreply.github.com>

Part of #9699