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feat(parser): support `turbopack` magic comments

kane50613:main

14 minutes ago

fix(minifier): avoid illegal `var;` when folding unused arguments copy loop (#21421) ## Summary When peephole-folding the classic `arguments` copy loop, we could end up with an empty `VariableDeclaration` initializer (`for (var; …)`), which prints as invalid `var;` and can confuse downstream folding (e.g. `try_fold_for` hoisting). ## Changes - Only build the `[...arguments]` / `.slice(offset)` array initializer when there is a binding pattern for the copy result (`r_id_pat`). - If there is **no** binding pattern, clear `for_stmt.init` instead of emitting an empty `VariableDeclaration`, so the loop becomes `for (; 0;)` and dead-code elimination can remove it cleanly. ## Tests - Added a regression in `crates/oxc_minifier/tests/peephole/substitute_alternate_syntax.rs` covering unused copy result + consequent (must not become illegal `var;`). ## AI usage This change was developed with assistance from Cursor; I reviewed the diff and tests locally before opening this PR. Co-authored-by: 进新 <zhengxubei.zx@alibaba-inc.com>

main

51 minutes ago

fix(minifier): preserve `var` inside `catch` with same-named parameter (#21366) ## Summary - Block inlining of `var` declarators whose symbol has the `CatchVariable` flag, preventing loss of function-scoped hoisting - Check `symbol_redeclarations` before removing catch parameters, preventing semantic changes when the catch body contains a `var` redeclaration - Uses existing semantic data (`CatchVariable` flag and `symbol_redeclarations`) instead of manual AST walks Closes #17307 ## Test plan - [x] `cargo test -p oxc_minifier` — 476 tests pass - [x] Verified minified output matches original JS semantics via `node` 🤖 Generated with [Claude Code](https://claude.com/claude-code)

main

1 hour ago

Merge branch 'main' into fix/minifier-rewrite-arguments-copy-loop

fazba:fix/minifier-rewrite-arguments-copy-loop

2 hours ago

fix(transformer/typescript): preserve execution order for accessor with `useDefineForClassFields: false` (#21369) ## Summary When `useDefineForClassFields: false` (`setPublicClassFields` assumption), the TypeScript transform moves public/TS-private field initializers into the constructor. However, private field initializers (including `accessor` backing fields from the legacy decorator transform) were left as class field declarations, causing them to execute **before** the constructor body. This broke execution order when the initializer depended on other fields that were already moved to the constructor. **Input:** ```ts class Hello { private input = { foo }; accessor util = this.input.foo(); } ``` **Before (broken):** `this.input.foo()` runs before `this.input = { foo }` ```js class Hello { constructor() { this.input = { foo }; } #_util_accessor_storage = this.input.foo(); // ← runs BEFORE constructor } ``` **After (fixed):** all instance initializers in the constructor, in source order ```js class Hello { constructor() { this.input = { foo }; this.#_util_accessor_storage = this.input.foo(); } #_util_accessor_storage; } ``` ### Approach Matches TypeScript's [`WillHoistInitializersToConstructor`](https://github.com/microsoft/TypeScript/blob/7b8cb3bdf82f400642b73173f941335775d6f730/src/compiler/transformers/classFields.ts#L339) logic in [`shouldTransformAutoAccessorsInCurrentClass`](https://github.com/microsoft/TypeScript/blob/7b8cb3bdf82f400642b73173f941335775d6f730/src/compiler/transformers/classFields.ts#L1069-L1073): - Pre-scan the class body to check if any non-private instance field has an initializer that will be hoisted - When hoisting occurs, include **all** instance fields (including `#` private) in the hoisting to preserve execution order - When no public fields are being hoisted, private fields stay as class field declarations No changes needed to the decorator/legacy transform — the fix is entirely in `transform_class_fields`. Fixes #21365 ## Test plan - [x] Added test fixture: `accessor-use-define-for-class-fields` (with hoisted + non-hoisted cases) - [x] Updated `use-define-for-class-fields-without-class-properties` expected output to match TypeScript behavior - [x] `cargo test -p oxc_transformer` — all pass - [x] `cargo run -p oxc_transform_conformance` — no regressions, previously failing test now passes 🤖 Generated with [Claude Code](https://claude.ai/code)

main

3 hours ago

fix(formatter): Preserve more `intrinsic` parens (#21449) Follow up on #21410 Added more test cases and fixes.

main

3 hours ago

fix(formatter): preserve parens around `intrinsic` in type alias annotation (#21410) ## Summary Fixes #20205 — `type t = (intrinsic);` was losing its parentheses during formatting, changing the AST on re-parse or producing unparseable TypeScript. ## Why this happens The parser treats a leading `intrinsic` identifier in a type alias annotation as `TSIntrinsicKeyword`: - `type t = intrinsic;` → `TSIntrinsicKeyword` - `type t = (intrinsic);` → `TSParenthesizedType(TSTypeReference(IdentifierReference))` `oxc_formatter` runs the parser with `preserve_parens: false`, which drops the `TSParenthesizedType` wrapper. Without re-emitting the parens: | Input | Naive output | Re-parses as | |-------|-------------|--------------| | `type t = (intrinsic);` | `type t = intrinsic;` | `TSIntrinsicKeyword` (different AST) | | `type t = (intrinsic) \| string;` | `type t = intrinsic \| string;` | **Syntax error** — oxc and TypeScript both reject it | | `type t = (intrinsic) & string;` | `type t = intrinsic & string;` | **Syntax error** | Prettier has the same bug and emits the broken outputs; we intentionally diverge to produce correct, round-trippable TypeScript. ## Fix In `FormatWrite<TSTypeReference>::write`, detect when the reference is a bare `intrinsic` identifier AND is the leftmost descendant of a `TSTypeAliasDeclaration` (directly, or through leftmost members of union/intersection types). When so, wrap the output in parens. Any other `intrinsic` position (right arm of union, array element, object property, type arguments, etc.) is unambiguous and is left alone. Fast-pathed on the name check so non-`intrinsic` references pay only a hash-prefixed string compare. ## Test plan - [x] New fixture `crates/oxc_formatter/tests/fixtures/ts/parenthesis/intrinsic.ts` covers direct, leftmost-union, leftmost-intersection, right-arm, tuple, object property, and type-argument positions - [x] Output round-trips through `oxc_parser` - [x] `cargo test -p oxc_formatter` — 269/269 passing - [x] `cargo run -p oxc_prettier_conformance` — js 746/753, ts 591/601 (no delta)

main

3 hours ago

fix(formatter): Follow up on #21410

04-15-fix_formatter_follow_up_on_21410

3 hours ago

Latest Branches

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feat(parser): support `turbopack` magic comments#20803

19 days ago

6a0e43f

kane50613:main

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fix(minifier): avoid illegal `var;` when folding unused arguments copy loop#21421

18 hours ago

3a2cd88

fazba:fix/minifier-rewrite-arguments-copy-loop

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fix(formatter): Preserve more `intrinsic` parens#21449

3 hours ago

8559776

04-15-fix_formatter_follow_up_on_21410

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