Commit Graph

387 Commits

Author SHA1 Message Date
camc314 853ffabf34 fix(ecmascript): avoid charAt panic on 32-bit (#26244)
## Summary

- Return `OutOfRange` when a `StringCharAt` position cannot fit in `usize`, avoiding a panic on 32-bit targets.
- Cover the `u32` boundary in direct evaluation and minifier constant folding, alongside existing conversion and UTF-16 edge cases.
2026-09-02 09:07:00 +00:00
oxc-guard 894c8f9cd8 release(crates): oxc v0.148.0 (#26198)
### 💥 BREAKING CHANGES

- a31567a allocator: [**BREAKING**] Make `Allocator::cursor_ptr` and `data_end_ptr` private (#26081) (overlookmotel)

### 🚀 Features

- 784e9fa minifier: Invert `!0` and `!1` in place for boolean context to `1` and `0` (#26050) (Armano)
- 1e902cc minifier: Expand fold leading assignments into the var decl (#26142) (Armano)
- 3ed4f6a minifier: Expand de morgan's optimization to allow move of `!` (#25930) (Armano)
- 5672585 parser: Attach all comments to nodes (#25944) (camc314)

### 🐛 Bug Fixes

- 4adfb4c semantic: Validate chained continue labels (#26157) (camc314)
- b874f48 ecmascript: `Math.round` only exact half ties (#26150) (camc314)
- a625378 minifier: Coerce omitted `indexOf` search argument (#26149) (camc314)
- dc7398b ecmascript: Trim trailing whitespace in string to number (#26148) (camc314)
- 243b685 transformer/object-rest: Lower multiple declarators correctly (#26147) (camc314)
- dc09a3a parser: Avoid panic on escaped string export names (#26146) (camc314)
- e412cf2 linter: Clamp invalid JS plugin locations (#26144) (camc314)
- c3dedc9 semantic: Skip function body bindings in parameters (#26099) (Dunqing)
- e74de61 transform-react: Match Babel diagnostic reporting (#26128) (Boshen)
- d5163d0 parser: Correctly classify unapplied pure annotations (#26084) (camc314)
- 8531b9b linter/plugins: Alter method for obtaining mutable `Program` when sending AST to JS plugins (#26077) (overlookmotel)
- 9b51658 regular_expression: Allow oversized decimal escape for Annex B (#26070) (leaysgur)
- c8de4df regular_expression: Reject oversized backreferences (#26055) (camc314)

### ⚡ Performance

- ac4785a diagnostics: Use fixed ANSI styles (#26130) (Boshen)
- 07a0793 packages/codegen: Flatten output in chunks (#26109) (overlookmotel)
- 487427a packages/codegen: Faster string flattening (#26108) (overlookmotel)
- 7785583 packages/codegen: Ensure indent strings are flattened (#26107) (overlookmotel)
- 0dd4db3 packages/codegen: Store mapping positions in an `Int32Array` (#26085) (overlookmotel)
2026-09-01 08:15:07 +00:00
camc314 b874f480c9 fix(ecmascript): Math.round only exact half ties (#26150)
[ECMA-262 §21.3.2.29, `Math.round`](https://tc39.es/ecma262/multipage/numbers-and-dates.html#sec-math.round).

- If `0 < n < 0.5`, return `+0`.
- If `-0.5 ≤ n < -0`, return `-0`.
- Otherwise choose the closest integer, preferring `+∞` only for an actual tie.
2026-08-28 14:26:10 +00:00
camc314 a625378066 fix(minifier): coerce omitted indexOf search argument (#26149)
## Summary

- Apply `ToString(undefined)` when `String.prototype.indexOf` or `lastIndexOf` is called without a search argument.
- Keep folding strings without the resulting `"undefined"` substring to `-1`.
- Add focused helper and minifier regression coverage.

```js
"undefined".indexOf();     // 0
"undefined".lastIndexOf(); // 0
"abcdef".indexOf();        // -1
"abcdef".lastIndexOf();    // -1
```
2026-08-28 14:18:01 +00:00
camc314 dc7398beae fix(ecmascript): trim trailing whitespace in string to number (#26148)
## Summary

`StringToNumber` previously removed ECMAScript whitespace only from the beginning of a string. Legal trailing whitespace therefore remained in the value passed to Rust’s numeric parsers, causing valid JavaScript numeric strings to produce `NaN`.

For example:

```js
"1 " * 2       // incorrectly folded to NaN
"0x10 " - 0    // incorrectly folded to NaN
```

This changes `trim_start_matches` to `trim_matches`, applying the existing ECMAScript whitespace predicate to both ends of the string.

After the change:

```js
"1 " * 2       // folds to 2
"0x10 " - 0    // folds to 16
```

The custom predicate remains important because ECMAScript and Rust define whitespace differently. Tests cover every ECMAScript whitespace character and verify that non-ECMAScript whitespace such as U+0085 is not accepted.
2026-08-28 14:07:56 +00:00
oxc-guard 4e258430cd release(crates): oxc v0.147.0 (#26046)
### 🚀 Features

- b6e9e5e minifier: Fold switch stmt whose parent is not block stmt (#25403) (Armano)

### 🐛 Bug Fixes

- 8a9bdbd estree: Include decorators in `FormalParameterRest ` spans (#26021) (camc314)
- 6f0c7cf minifier: Avoid merging `if` to `for` in sloppy mode when containing function declaration (#25638) (sapphi-red)
- 2cde1f6 rust: Address nightly deprecations (#25998) (Boshen)
- 6c5ad1b codegen: Only add mapping names for `PrivateIdentifier`s which have changed (#25958) (overlookmotel)
- 2dad1e0 parser: Track irregular line terminators in trivia (#25947) (camc314)
- 58ba651 minifier: Avoid merging `if` to `for` when the body contains a function declaration (#25637) (sapphi-red)
- a185ac3 codegen: Print `#` before private identifier in TS signature key (#25938) (overlookmotel)
- af82a07 minifier: Keep unary `+` when the other operand has side effects (#25645) (Kotaro Chikuba)

### ⚡ Performance

- 53f6270 packages/codegen: Eagerly initialize `mapNames` (#25979) (overlookmotel)
- 5b43c60 packages/codegen: Split recording mappings into multiple functions (#25978) (overlookmotel)
- cc947b5 packages/codegen: Reduce property lookups (#25977) (overlookmotel)
- c22a9cc packages/codegen: Combine condition checks (#25976) (overlookmotel)
- 215a6a5 packages/codegen: Add functions for writing/marking unnamed mappings (#25975) (overlookmotel)
- fe444cc codegen: Avoid allocations for single comment anchors (#25598) (camc314)
- a0aee81 minifier: Do not rebuild expression when substituting void to null (#25964) (Armano)
- 1004439 packages/codegen: Merge `mark` and `write` calls in `printImportAttributes` (#25972) (overlookmotel)
- 94c8a34 packages/codegen: Remove `node` param from `printString` and `printNonNegativeFloat` (#25971) (overlookmotel)
- 7e2b4b3 packages/codegen: `printNonNegativeFloat` write mapping directly (#25968) (overlookmotel)
- f09c8ab minifier: Avoid creation of unnecessary conditional expressions (#25931) (Armano)
- 53ff080 packages/codegen: Remove `lastWasPostfixClose` (#25888) (overlookmotel)

### 📚 Documentation

- 07de646 packages/codegen: Fix JSDoc comments on `write*` methods (#25966) (overlookmotel)
- 3b09c04 packages/codegen: Clarify comment (#25959) (overlookmotel)
2026-08-24 11:19:12 +00:00
oxc-guard 0389c4010e release(crates): oxc v0.146.0 (#25912)
### 🚀 Features

- 83cb516 minifier: Improve negation of expressions in boolean context (#25755) (Armano)

### 🐛 Bug Fixes

- 134fb22 isolated-declarations: Preserve unresolved parameter types (#25909) (Dunqing)
- 526c2b3 codegen: Remove deprecated test APIs (#25889) (camc314)
- 344a9b2 codegen: Align enum template sourcemaps (#25872) (camc314)

### ⚡ Performance

- 5ef0c93 minifier: Unwrap all unary exprs without creating dummy expressions (#25891) (Armano)
- 8783524 packages/codegen: Remove loop from `growMappingBuffer` (#25886) (overlookmotel)
- b6b14c0 packages/codegen: Remove redundant branch (#25885) (overlookmotel)
- be6adf0 packages/sourcemap: Make `location` passed to `recordSourceMapping` always a number (#25884) (overlookmotel)
- f720f15 packages/codegen: Take named-mapping only code off hot path in `recordSourceMapping` (#25883) (overlookmotel)
- a734af5 packages/codegen: Remove redundant setting of `last` in `printImportAttributes` and `printIf` (#25882) (overlookmotel)
- c6e44c6 packages/codegen: Combine 2 writes in `printJSXElement` (#25881) (overlookmotel)
- 8801662 packages/codegen: Remove redundant mapping from `printParams` (#25880) (overlookmotel)

### 📚 Documentation

- 5ad330e packages/codegen: Reformat comments (#25876) (overlookmotel)
2026-08-19 08:29:51 +00:00
oxc-guard[bot] 4a4a1fb2e7 release(crates): oxc v0.145.0 (#25865)
### 💥 BREAKING CHANGES

- 365274e packages/codegen: [**BREAKING**] `printSync` return an object
(#25720) (overlookmotel)

### 🚀 Features

- 6a7eb60 packages/codegen: Alter capitalization of `sourceFilename`
option (#25854) (overlookmotel)
- 300763f packages/codegen: Add full source map support (#25585)
(camc314)
- a169e4a napi/minify: Expose property name mangling options (#24741)
(Dunqing)
- 2f5cdb1 minifier: Add property name mangling (#24740) (Dunqing)
- 4922141 mangler: Deduplicate private accessor names (#25601) (camc314)
- 1c4f519 napi: Add Relay transform plugin (#25503) (Boshen)
- a4478e9 codegen: Add `oxc-codegen` package (#25488) (overlookmotel)

### 🐛 Bug Fixes

- 0fbcf64 codegen: Validate sourcemap options (#25860) (camc314)
- 345f981 react_compiler: Skip node_modules by default (#25859) (Boshen)
- ab81f3f minifier: Drop side-effect-free additions (#25639) (Dunqing)
- 241c559 napi/minify: Accept RegExp for property filters (#25827)
(Dunqing)
- 4cc7ea4 codegen: Reject invalid indent options (#25807) (camc314)
- 53f9295 isolated-declarations: Preserve undefined for defaulted any
(#25292) (camc314)
- 8ab883a codegen: Preserve property key annotations (#25766) (Dunqing)
- b13fd48 minifier: Model uninitialized module vars as undefined
(#25497) (Dunqing)
- f6000ac ecmascript: Fold `**` with `Number::exponentiate`, not IEEE
`pow` (#25644) (Kotaro Chikuba)
- b846abc isolated-declarations: Handle ambient expando properties
(#25655) (camc314)
- dec0a86 react-compiler: Standardize diagnostics (#25702) (Boshen)
- fca2e0c parser: Reject initialized lexical declarations in for-in
(#25700) (Boshen)
- ae9be8f parser: Forbid type parameters on quoted constructors (#25696)
(Boshen)
- c5f188a react-compiler: Use Babel v1 validation defaults (#25676)
(Boshen)
- db44651 napi: Disable reuseWorker in browser bindings (#25640)
(leaysgur)
- ce35d47 react_compiler: Preserve JSX import source pragmas (#25592)
(Boshen)
- 059784d semantic: Respect shadowed `Infinity` and `NaN` in enum
evaluation (#25604) (camc314)
- bb5a232 minifier: Keep variable declaration initilized with class when
keepNames is enabled (#25584) (sapphi-red)
- f49229d minifier: Keep side effects when rotating bitwise operands
(#25596) (Kotaro Chikuba)
- e82495b ecmascript: Derive `ToNumber` of `!x` from `ToBoolean`
(#25595) (Kotaro Chikuba)
- 509931b semantic: Classify global references per identifier (#25608)
(camc314)
- 80484ce mangler: Correct base54 safety comment (#25606) (camc314)
- c1369a7 codegen: Resolve private names in class heritage (#25588)
(camc314)
- c002f29 codegen: Escape sources for empty import specifiers (#25586)
(camc314)
- 0c68b7f estree: Emit `decorators` on `FormalParameterRest` (#25582)
(camc314)
- cdf1846 semantic: Allow legacy escapes in JSX attributes (#25576)
(Boshen)
- e75e102 minifier: Preserve block statement in labeled iteration
statements (#25162) (Armano)
- 771d79a mangler: Exclude non-manglable symbols from slot assignment
(#25539) (sapphi-red)
- 76b19f5 minifier: Avoid duplicating large folded strings (#25532)
(Dunqing)
- 59e8895 codegen: Validate starting indent level (#25550) (camc314)
- 88b34f2 clippy: Remove unneeded `unsafe` (#25551) (camc314)
- 23a7ad0 parser: Stop delimited lists at end of file (#25542) (Boshen)
- 73acba9 parser: Preserve fatal errors during await reparse (#25541)
(Boshen)
- c3e99d1 minifier: Avoid invalid octal escapes in template folds
(#25495) (Dunqing)
- b4e6a9e codegen: Output newline after `export default interface`
(#25487) (overlookmotel)
- 5fcf683 minifier: Correct issue with try finally termination (#25185)
(Armano)
- 1645d93 react_compiler: Preserve source spans (#25462) (Boshen)
- 8d7f9cf react_compiler: Honor eslint suppressions (#25394) (Boshen)

### ⚡ Performance

- 568203e ecmascript: Use binary search for known globals (#25817)
(Boshen)
- c84ede3 estree_tokens: Share JS token update entry point (#25826)
(Boshen)
- 9a6e862 minifier: Move owned statements directly (#25835) (Dunqing)
- 61b2aef minifier: Move owned AST nodes directly (#25837) (Dunqing)
- 673b04b minifier: Replace expressions without take_in dummies (#25836)
(Dunqing)
- 63ff8ef linter: Outline diagnostic construction (#25762) (Boshen)
- 621808e diagnostics: Measure graphemes lazily (#25723) (Boshen)
- f62ed0e diagnostics: Optimize graphical number rendering (#25715)
(Boshen)
- 7152834 diagnostics: Reduce graphical formatting overhead (#25714)
(Boshen)
- 10fc4b7 diagnostics: Reduce graphical rendering allocations (#25711)
(Boshen)
- 9c8abab diagnostics: Batch graphical reports (#25710) (Boshen)
- 757f3d4 mangler: Share allocated names across reused slots (#25605)
(camc314)
- 5444cbf codegen: Skip escaping harmless `<` tokens (#25564) (camc314)

### 📚 Documentation

- 58f7ab9 packages/codegen: Reformat docs and comments (#25848)
(overlookmotel)
- 627466e transform-react: Document all options (#25800) (Boshen)
- ce03ac1 packages/codegen: Fix JSDoc comments for `printSync` (#25722)
(overlookmotel)
- 386a699 packages/codegen: Correct JSDoc comment (#25716)
(overlookmotel)
- 31e571d mangler: Update code example (#25599) (camc314)
- fd62354 codegen: Revamp package readme (#25560) (camc314)
- ffa3153 codegen: Clarify raw transfer Node requirement (#25565)
(camc314)
- c5d4063 codegen: Clarify binary walk allocations (#25562) (camc314)
- 5703d7a codegen: Correct stale printer comments (#25561) (camc314)

Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
2026-08-18 22:26:40 +08:00
Boshen 568203e24f perf(ecmascript): use binary search for known globals (#25817)
Replaces the 639-arm known-global string match with a sorted static table and binary search. The table is guarded for sortedness, uniqueness, and representative lookups.

Release `oxlint`: 12,491,264 → 12,474,736 bytes (−16,528 bytes, −0.13%); `__text` is reduced by 29,252 bytes.

Prepared with AI assistance.
2026-08-18 08:04:34 +00:00
Kotaro Chikuba f6000ac141 fix(ecmascript): fold ** with Number::exponentiate, not IEEE pow (#25644)
`f64::powf` implements IEEE 754 `pow`, which returns `1` for a base of
`1` whatever the exponent.
[`Number::exponentiate`](https://tc39.es/ecma262/#sec-numeric-types-number-exponentiate)
instead returns `NaN` when the exponent is `NaN` (step 1), and when the
base has magnitude `1` and the exponent is infinite (steps 9-10).

Constant folding called `powf` directly, so:

```js
1 ** Infinity      // spec: NaN    oxc folded to: 1
(-1) ** Infinity   // spec: NaN    oxc folded to: 1
1 ** -Infinity     // spec: NaN    oxc folded to: 1
1 ** NaN           // spec: NaN    oxc folded to: 1
```

`1` is truthy and `NaN` is not, so an `if` guarded by such an expression
takes the wrong branch.

The one case the two agree on — an exponent of `0` returning `1`
whatever the base, including `NaN ** 0` and `Infinity ** 0` — is
unchanged, since `powf` already gets it right and the spec checks the
exponent before the base.

`cargo minsize` shows no snapshot change.

Found by the minifier fuzzer (#25594).

---

Written with AI assistance (Claude Code). Reviewed by me, and every
expected value in the added test was checked against Node.js.

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-17 12:21:54 +08:00
Kotaro Chikuba e82495ba54 fix(ecmascript): derive ToNumber of !x from ToBoolean (#25595)
Found by the semantic fuzzer added in #25594 (seed `15979`).

## What

`ToNumber(!x)` was computed from `ToNumber(x)` instead of
`ToBoolean(x)`:

```rust
Expression::UnaryExpression(unary) if unary.operator.is_not() => {
    let number = unary.argument.to_number(ctx)?;
    Some(if number == 0.0 { 1.0 } else { 0.0 })
}
```

`!x` is `ToBoolean(x)` negated, so the two predicates must agree — and
they don't. `NaN` is falsy but does not number to `0`, while `"0"`, `"
"`, `"0.0"` and `[]` all number to `0` yet are truthy.

## Why it was not caught

`minimize_conditional_expression` rewrites `a ? 1 : 0` into `+!!a`. That
rewrite is correct, but when a parent expression evaluated the freshly
built `+!!a` in the same pass, the broken branch flipped the result:

```js
(NaN ? 1 : 0) || 2   // 2, minified to 0
('0' ? 1 : 0) || 2   // 1, minified to 2
([]  ? 1 : 0) || 2   // 1, minified to 2
```

A `!!x` written in the source is folded correctly by `fold_unary_expr`
before any parent observes it, so only pass-generated nodes were
affected. That is why existing tests and the conformance suites pass.

refs https://github.com/oxc-project/oxc/pull/8267

## How

Derive the value from `to_boolean`. This is strictly more conservative:
when `to_boolean` returns `None` the fold is skipped rather than
answered wrongly.

## Testing

- New regression test `test_conditional_to_unary_plus_uses_to_boolean`
covering `NaN`, `"0"`, `" "`, `"0.0"` and `[]`.
- `cargo test -p oxc_minifier -p oxc_ecmascript`, `cargo clippy
--all-targets`, `cargo fmt --check` all pass.
- `just minsize`: no snapshot change, so no size regression.

## AI disclosure

This change was produced with AI assistance (Claude Code). I have
reviewed and understand every line; the root cause and each minimal
reproduction were verified by hand against Node.js.

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-14 00:35:39 +00:00
camc314 88b34f2db2 fix(clippy): remove unneeded unsafe (#25551)
ah lint only runs on linux so this didn't fail previously in CI
2026-08-12 15:11:55 +00:00
CrazyboyQCD 48d5e9e47a refactor(ecmascript): use __jcvt() intrinsic on ARM64 for f64→i32 conversion (#24373)
- Simplify `cfg` by using `cfg_select` macro which is stabilized in 1.95
- Use `__jcvt()` intrinsic which is stabilized in 1.95
- Remove redundant `NAN` check since V8 has a set of test for it, which
claims that it works properly for `NAN` and `Infinity`:
https://github.com/v8/v8/blob/3b58a432df85d51bf1c439c30efcf0752de1076f/test/cctest/test-assembler-arm64.cc#L11416C1-L11468C48

Co-authored-by: Cameron <cameron.clark@hey.com>
2026-08-12 09:15:55 +00:00
oxc-guard b6f1458dec release(crates): oxc v0.144.0 (#25474)
### 💥 BREAKING CHANGES

- a33788e ast: [**BREAKING**] Group class heritage into `ClassHeritage` (#25360) (camc314)
- 5c5cdcd ast: [**BREAKING**] Narrow `TSInterfaceHeritage::expression` to TSTypeName (#24360) (camc314)
- 6be314f ast: [**BREAKING**] Remove duplicated `VariableDeclarator::kind` (#25319) (camc314)
- 44fd320 ast: [**BREAKING**] Split TS external modules & Namespace Declarations (#25284) (camc314)

### 🚀 Features

- 9a37c41 napi: Restructure React transform options (#25326) (Boshen)
- b3c1b30 allocator: Add `ArenaVec::push_mut` (#25338) (overlookmotel)

### 🐛 Bug Fixes

- bbd6ed3 codegen: Wrap string literal in parens after directives (#25435) (overlookmotel)
- d07a293 codegen: Preserve cast parentheses in conditional tests (#25115) (camc314)
- 8b7d441 codegen: Preserve satisfies parentheses before bitwise operators (#25113) (camc314)
- e0fb2d7 minifier: Avoid unsafe return removal in labeled blocks (#25406) (Armano)
- c49f4ce parser: Preserve terminal license comments (#25400) (camc314)
- 9d19ab3 transform_react: Downgrade nonfatal compiler diagnostics (#25418) (Boshen)
- 937825c react_compiler: Disable exhaustive memo validation by default (#25417) (Boshen)
- 12937b3 parser: Reject comma expressions in class fields (#25385) (Cameron)
- 7d8a9b5 react_compiler: Preserve hook spans for React Refresh (#25393) (Boshen)
- 9e93ba6 parser: Reset auto-accessor initializer context (#25384) (camc314)
- cc2e28d parser: Reject trailing tokens in `Parser::parse_expression` (#25371) (camc314)
- 697c629 minifier: Preserve Annex B labeled-function bindings in implicit-return rewrite (#25349) (Armano)
- 4d723ca parser: Report TS1035 for quoted module names (#25305) (camc314)
- 0c9b980 semantic: Report module declaration diagnostics (#25285) (camc314)
- 2a1058a napi: Omit parser header from WASI declarations (#25254) (camc314)

### ⚡ Performance

- dd1430b semantic: Avoid allocation in class overload check (#25440) (camc314)
- e420816 parser: Optimize trailing comma tracking (#25376) (camc314)
- 6529d1a minifier: Short-circuit scope check when alternate already determines result (#25318) (Armano)

### 📚 Documentation

- fe111eb allocator: Improve doc comments for `Arena` methods (#24922) (overlookmotel)
2026-08-10 09:57:10 +00:00
camc314 a33788e13e feat(ast)!: group class heritage into ClassHeritage (#25360)
## Summary

- Groups `Class::super_class` and `Class::super_type_arguments` into `Class::heritage`.
- Introduces `ClassHeritage` containing the superclass expression and its optional TypeScript type arguments.
- Makes superclass type arguments without a superclass expression unrepresentable.

## Breaking Change

The Rust AST changes from:

```rust
pub struct Class<'a> {
    pub node_id: Cell<NodeId>,
    pub span: Span,
    pub r#type: ClassType,
    pub decorators: Vec<'a, Decorator<'a>>,
    pub id: Option<BindingIdentifier<'a>>,
    #[ts]
    pub type_parameters: Option<Box<'a, TSTypeParameterDeclaration<'a>>>,
    pub super_class: Option<Expression<'a>>,
    #[ts]
    pub super_type_arguments: Option<Box<'a, TSTypeParameterInstantiation<'a>>>,
    #[ts]
    pub implements: Vec<'a, TSClassImplements<'a>>,
    pub body: Box<'a, ClassBody<'a>>,
    #[ts]
    pub r#abstract: bool,
    #[ts]
    pub declare: bool,
    pub scope_id: Cell<Option<ScopeId>>,
}
```

to:

```rust
pub struct Class<'a> {
    pub node_id: Cell<NodeId>,
    pub span: Span,
    pub r#type: ClassType,
    pub decorators: Vec<'a, Decorator<'a>>,
    pub id: Option<BindingIdentifier<'a>>,
    #[ts]
    pub type_parameters: Option<Box<'a, TSTypeParameterDeclaration<'a>>>,
    pub heritage: Option<ClassHeritage<'a>>,
    #[ts]
    pub implements: Vec<'a, TSClassImplements<'a>>,
    pub body: Box<'a, ClassBody<'a>>,
    #[ts]
    pub r#abstract: bool,
    #[ts]
    pub declare: bool,
    pub scope_id: Cell<Option<ScopeId>>,
}

pub struct ClassHeritage<'a> {
    pub expression: Expression<'a>,
    #[ts]
    pub type_arguments: Option<Box<'a, TSTypeParameterInstantiation<'a>>>,
}
```

## Why?

ECMAScript defines the complete `extends` clause as `ClassHeritage`:

```text
ClassHeritage : extends LeftHandSideExpression
```

TypeScript additionally permits type arguments on the heritage expression:

```ts
class Derived extends Base<T> {}
```

Previously, the AST stored the expression and type arguments independently:

```text
Class {
    super_class: Some(Base),
    super_type_arguments: Some(<T>),
    ...
}
```

This allowed an invalid state to be constructed:

```text
Class {
    super_class: None,
    super_type_arguments: Some(<T>),
    ...
}
```

Superclass type arguments cannot exist without an `extends` expression.

The parser already treated these fields as a pair. It parsed a class heritage entry and then split its expression and type arguments into two independent fields. Builders and transforms therefore had to preserve their relationship manually.

Grouping them into `ClassHeritage` makes the syntactic dependency explicit and prevents consumers from observing or constructing contradictory class heritage.

## Class heritage forms

A class without an `extends` clause has no heritage:

```js
class Base {}
```

```text
Class {
    heritage: None,
    ...
}
```

A class extending an expression has heritage without type arguments:

```js
class Derived extends Base {}
```

```text
Class {
    heritage: Some(ClassHeritage {
        expression: Base,
        type_arguments: None,
    }),
    ...
}
```

TypeScript type arguments belong to the same heritage structure:

```ts
class Derived extends Base<T> {}
```

```text
Class {
    heritage: Some(ClassHeritage {
        expression: Base,
        type_arguments: Some(<T>),
    }),
    ...
}
```

The heritage expression may be any valid class heritage expression:

```js
class Derived extends mixin(Base) {}
class NullDerived extends null {}
```

## How to migrate

Code that previously accessed the superclass expression directly:

```rust
if let Some(super_class) = &class.super_class {
    // ...
}
```

can use the compatibility accessor:

```rust
if let Some(super_class) = class.super_class() {
    // ...
}
```

Code that needs both parts should access the grouped heritage:

```rust
if let Some(heritage) = &class.heritage {
    let expression = &heritage.expression;
    let type_arguments = heritage.type_arguments.as_deref();
}
```

Mutating consumers should update the nested fields:

```rust
if let Some(heritage) = &mut class.heritage {
    heritage.type_arguments = None;
}
```

Common migrations:

| Previous representation | New representation |
| --- | --- |
| `class.super_class` | `class.heritage.as_ref().map(\|h\| &h.expression)` or `class.super_class()` |
| `class.super_type_arguments` | `class.heritage.as_ref()?.type_arguments` or `class.super_type_arguments()` |
| `class.super_class.is_some()` | `class.heritage.is_some()` |
| Mutate `class.super_class` | Mutate `class.heritage.expression` |
| Clear `class.super_type_arguments` | Clear `class.heritage.type_arguments` |
| Pass superclass and type arguments separately to a `Class` builder | Construct and pass `ClassHeritage` |
| Clone both fields independently | Clone `class.heritage` |

```ts
superClass: Expression | null;
superTypeArguments?: TSTypeParameterInstantiation | null;
```

No `heritage` property or `ClassHeritage` node is added to the ESTree output.

fixes https://github.com/oxc-project/backlog/issues/216
2026-08-07 14:18:59 +00:00
camc314 44fd320324 feat(ast)!: split TS external modules & Namespace Declarations (#25284)
## Summary

- Splits `TSModuleDeclaration` into two dedicated declaration nodes:
  - `TSExternalModuleDeclaration` for string-literal modules and module augmentations.
  - `TSNamespaceDeclaration` for identifier-based `module` and `namespace` declarations.
- Removes `TSModuleDeclaration`, `TSModuleDeclarationName`, `TSModuleDeclarationBody`, and `TSModuleDeclarationKind`.
- Makes invalid combinations of names, bodies, and declaration kinds unrepresentable.
- Ensures only namespace declarations introduce a normal binding.
- Updates all AST consumers, generators, traversal, formatting, code generation, semantic analysis, lint rules, transforms, and serialization.
- Keeps normal and eager-raw ESTree output compatible: both declarations remain `TSModuleDeclaration` nodes.
- Allows experimental lazy raw deserialization to expose the two new node types directly.

## Breaking Change

The Rust AST changes from:

```rust
pub enum Declaration<'a> {
    VariableDeclaration(Box<'a, VariableDeclaration<'a>>) = 32,
    FunctionDeclaration(Box<'a, Function<'a>>) = 33,
    ClassDeclaration(Box<'a, Class<'a>>) = 34,

    TSTypeAliasDeclaration(Box<'a, TSTypeAliasDeclaration<'a>>) = 35,
    TSInterfaceDeclaration(Box<'a, TSInterfaceDeclaration<'a>>) = 36,
    TSEnumDeclaration(Box<'a, TSEnumDeclaration<'a>>) = 37,
    TSModuleDeclaration(Box<'a, TSModuleDeclaration<'a>>) = 38,
    TSGlobalDeclaration(Box<'a, TSGlobalDeclaration<'a>>) = 39,
    TSImportEqualsDeclaration(Box<'a, TSImportEqualsDeclaration<'a>>) = 40,
}

pub struct TSModuleDeclaration<'a> {
    pub node_id: Cell<NodeId>,
    pub span: Span,
    pub id: TSModuleDeclarationName<'a>,
    pub body: Option<TSModuleDeclarationBody<'a>>,
    pub kind: TSModuleDeclarationKind,
    pub declare: bool,
    pub scope_id: Cell<Option<ScopeId>>,
}
```

to:

```rust
pub enum Declaration<'a> {
    VariableDeclaration(Box<'a, VariableDeclaration<'a>>) = 32,
    FunctionDeclaration(Box<'a, Function<'a>>) = 33,
    ClassDeclaration(Box<'a, Class<'a>>) = 34,

    TSTypeAliasDeclaration(Box<'a, TSTypeAliasDeclaration<'a>>) = 35,
    TSInterfaceDeclaration(Box<'a, TSInterfaceDeclaration<'a>>) = 36,
    TSEnumDeclaration(Box<'a, TSEnumDeclaration<'a>>) = 37,
    TSExternalModuleDeclaration(Box<'a, TSExternalModuleDeclaration<'a>>) = 38,
    TSNamespaceDeclaration(Box<'a, TSNamespaceDeclaration<'a>>) = 39,
    TSGlobalDeclaration(Box<'a, TSGlobalDeclaration<'a>>) = 40,
    TSImportEqualsDeclaration(Box<'a, TSImportEqualsDeclaration<'a>>) = 41,
}

pub struct TSExternalModuleDeclaration<'a> {
    pub node_id: Cell<NodeId>,
    pub span: Span,
    pub id: StringLiteral<'a>,
    pub body: Option<Box<'a, TSModuleBlock<'a>>>,
    pub declare: bool,
    pub scope_id: Cell<Option<ScopeId>>,
}

pub struct TSNamespaceDeclaration<'a> {
    pub node_id: Cell<NodeId>,
    pub span: Span,
    pub id: BindingIdentifier<'a>,
    pub body: TSNamespaceDeclarationBody<'a>,
    pub kind: TSNamespaceDeclarationKind,
    pub declare: bool,
    pub scope_id: Cell<Option<ScopeId>>,
}

pub enum TSNamespaceDeclarationBody<'a> {
    TSNamespaceDeclaration(Box<'a, TSNamespaceDeclaration<'a>>) = 0,
    TSModuleBlock(Box<'a, TSModuleBlock<'a>>) = 1,
}

pub enum TSNamespaceDeclarationKind {
    Module = 0,
    Namespace = 1,
}
```

The corresponding inherited `Statement` variants, `AstKind` variants, builders, and visitor methods have also changed.

## Why?

`TSModuleDeclaration` previously represented two declaration families with different syntax and semantics:

```ts
declare module "foo" {}
declare module "*.css";

module Foo {}
namespace Foo {}
namespace Foo.Bar {}
```

The shared representation allowed invalid states such as:

- A namespace with a string-literal name.
- An external module with an identifier name.
- An identifier namespace without a body.
- A dotted external module.
- An external module containing another module declaration as its body.
- A declaration whose `kind` disagreed with its name.

Consumers also had to inspect `id` before determining whether the node introduced a binding or represented an external module.

The two declaration families have stronger independent invariants:

### External modules

- Always have a string-literal name.
- Never introduce a normal binding identifier.
- May omit their body.
- Cannot use dotted names.
- Use module-body import and export rules.

### Namespace declarations

- Always have a binding identifier.
- Always have a body.
- May contain nested namespace declarations for dotted names.
- Explicitly preserve the `module` or `namespace` spelling.
- Introduce a namespace/module symbol.
- Use namespace-body restrictions.

Dedicated nodes encode these differences directly.

## Declaration forms

External modules use `TSExternalModuleDeclaration`:

```ts
declare module "foo" {}
declare module "*.css";
module "foo" {}
```

Identifier-based declarations use `TSNamespaceDeclaration`:

```ts
module Foo {}
namespace Foo {}
```

Dotted namespaces are represented as nested namespace declarations:

```ts
namespace Foo.Bar {}
```

```rust
TSNamespaceDeclaration {
    id: Foo,
    body: TSNamespaceDeclarationBody::TSNamespaceDeclaration(
        TSNamespaceDeclaration {
            id: Bar,
            body: TSNamespaceDeclarationBody::TSModuleBlock(...),
            // ...
        }
    ),
    // ...
}
```

Only `TSExternalModuleDeclaration::body` is optional.

## ESTree compatibility

Normal serialization and eager raw deserialization continue to emit the existing ESTree shape:

```ts
interface TSModuleDeclaration {
  type: "TSModuleDeclaration";
  id: BindingIdentifier | StringLiteral | TSQualifiedName;
  body: TSModuleBlock | null;
  kind: "module" | "namespace";
  declare: boolean;
  global: false;
}
```

Dotted namespaces continue to serialize as a single `TSModuleDeclaration` with a `TSQualifiedName`.

Experimental lazy raw deserialization is not compatibility-preserving. It now exposes `TSExternalModuleDeclaration` and `TSNamespaceDeclaration` directly, with separate constructors, layouts, and visitor type IDs.

## How to migrate

Code that previously matched all forms through one variant:

```rust
if let Declaration::TSModuleDeclaration(declaration) = declaration {
    // ...
}
```

should now match the required declaration family:

```rust
match declaration {
    Declaration::TSExternalModuleDeclaration(declaration) => {
        // String-literal external module
    }
    Declaration::TSNamespaceDeclaration(declaration) => {
        // Identifier-based module or namespace
    }
    _ => {}
}
```

The same applies to `Statement` and `AstKind`:

```rust
Statement::TSExternalModuleDeclaration(declaration)
Statement::TSNamespaceDeclaration(declaration)

AstKind::TSExternalModuleDeclaration(declaration)
AstKind::TSNamespaceDeclaration(declaration)
```

Common field migrations:

| Previous representation | New representation |
| --- | --- |
| `TSModuleDeclarationName::StringLiteral(id)` | `TSExternalModuleDeclaration::id` |
| `TSModuleDeclarationName::Identifier(id)` | `TSNamespaceDeclaration::id` |
| `body: None` | Only valid on `TSExternalModuleDeclaration` |
| `TSModuleDeclarationBody::TSModuleBlock` | External `body` or `TSNamespaceDeclarationBody::TSModuleBlock` |
| `TSModuleDeclarationBody::TSModuleDeclaration` | `TSNamespaceDeclarationBody::TSNamespaceDeclaration` |
| `TSModuleDeclarationKind::Module` | External module, or `TSNamespaceDeclarationKind::Module` |
| `TSModuleDeclarationKind::Namespace` | `TSNamespaceDeclarationKind::Namespace` |
| Inspect `id` to determine binding behavior | Match `TSNamespaceDeclaration` |
| `declaration.id()` for string modules | Now returns `None` |
| `visit_ts_module_declaration` | `visit_ts_external_module_declaration` or `visit_ts_namespace_declaration` |

When constructing nodes, use the generated `TSExternalModuleDeclaration` or `TSNamespaceDeclaration` builders rather than recreating the previous shared representation.

fixes https://github.com/oxc-project/backlog/issues/218
2026-08-05 14:37:35 +00:00
oxc-guard 45a17c25d1 release(crates): oxc v0.143.0 (#25250)
### 💥 BREAKING CHANGES

- 4120da0 semantic: [**BREAKING**] Return borrowed JSDoc so the parse cache works (#25186) (Connor Shea)
- f0a41c8 allocator: [**BREAKING**] Remove `ArenaBox::dangling` method (#25236) (overlookmotel)
- 067da8c ast: [**BREAKING**] Store single parameter in `TSIndexSignature::parameter` (#25154) (camc314)
- a0c7788 ast: [**BREAKING**] Change `TSIndexSignatureName::name` to `Ident` (#25150) (camc314)
- 1bdedd1 ast: [**BREAKING**] Introduce `ExportDeclaration`, `ExportFromDeclaration` (#25095) (camc314)
- c917f20 ast: [**BREAKING**] Introduce `ArrowFunctionBody` enum (#24987) (camc314)
- 7e1199c ast: [**BREAKING**] Remove conversion to `Box` from AST builder methods (#25038) (overlookmotel)

### 🚀 Features

- 3c8312e allocator: Make `Box` `Send` + `Sync` when the type it contains is (#25242) (overlookmotel)
- cb5bc08 ast: Derive `GetSpan` for `Comment` (#25147) (leaysgur)
- 8541e18 ast_tools: Generate minifier scope collector (#25088) (camc314)
- 5acdae2 ecmascript: Skip transparent TS expressions (#25072) (camc314)
- 85d0f4d napi: Add React Compiler transform binding (#24934) (Boshen)
- 70d6ece minifier: Fold safe integer exponentiation (#25009) (Dunqing)
- 73fc747 minifier: Enable termination statement optimization for do while (#24921) (Armano)
- 5eadfdb minifier: Fold safe integer division and remainder (#24981) (Dunqing)

### 🐛 Bug Fixes

- 6c9ee14 minifier: Preserve if-chain idempotency and correct side effects when alternate should not be moved (#25041) (Armano)
- 8a47ff3 ecmascript: Do not treat lone-surrogate strings as constants (#25084) (Dunqing)
- 468b970 isolated-declarations: Strip re-export attributes (#25090) (camc314)
- a70035d parser: Report export imports in namespaces (#25086) (camc314)
- 5d8ccf5 react_compiler: Preserve nonfatal diagnostics (#25066) (Boshen)
- d349e4a react_compiler: Match eslint suppression gating (#25068) (Boshen)
- 0dc16ba react_compiler: Track catch block declarations (#25067) (Boshen)
- e6734a5 minifier: Fold typeof comparisons with known object strings (#25017) (Dunqing)
- 3a9d5a5 minifier: Keep `typeof foo == ['object']` as-is (#24941) (sapphi-red)
- 10ec276 ast: Custom AST builder methods take `IntoIn<ArenaBox>` where child method does (#25033) (overlookmotel)
- fbe8d31 minifier: Respect targets when folding RegExp source (#24790) (Dunqing)

### ⚡ Performance

- fb402b0 minifier: Stop re-deriving printed numeric spellings (#25103) (Dunqing)
- 7251e52 react_compiler: Avoid large types on stack (#25037) (overlookmotel)
- e07718f isolated_declarations: Avoid large types on stack (#25036) (overlookmotel)
- 9fb1e3e transformer: Avoid large types on stack (#25035) (overlookmotel)
- 8b80f8b parser: Avoid large types on stack (#25034) (overlookmotel)

### 📚 Documentation

- 2ea0aa9 ast: Correct grammar in AST builder methods doc comments (#25173) (overlookmotel)
2026-08-03 11:07:37 +00:00
camc314 1bdedd11ca feat(ast)!: introduce ExportDeclaration, ExportFromDeclaration (#25095)
## Summary

Split the overloaded Rust `ExportNamedDeclaration` into syntax-specific AST nodes:

- `ExportDeclaration` for exported declarations
- `ExportNamedDeclaration` for local exports
- `ExportFromDeclaration` for re-exports

## Breaking Change

The Rust AST changes from:

```rust
pub struct ExportNamedDeclaration<'a> {
    pub node_id: Cell<NodeId>,
    pub span: Span,
    pub declaration: Option<Declaration<'a>>,
    pub specifiers: Vec<'a, ExportSpecifier<'a>>,
    pub source: Option<StringLiteral<'a>>,
    pub export_kind: ImportOrExportKind,
    pub with_clause: Option<Box<'a, WithClause<'a>>>,
}

pub enum ModuleDeclaration<'a> {
    // ...
    ExportNamedDeclaration(Box<'a, ExportNamedDeclaration<'a>>),
    // ...
}
```

to:

```rust
pub struct ExportDeclaration<'a> {
    pub node_id: Cell<NodeId>,
    pub span: Span,
    pub declaration: Declaration<'a>,
}

pub struct ExportNamedDeclaration<'a> {
    pub node_id: Cell<NodeId>,
    pub span: Span,
    pub specifiers: Vec<'a, ExportSpecifier<'a>>,
    pub export_kind: ImportOrExportKind,
}

pub struct ExportFromDeclaration<'a> {
    pub node_id: Cell<NodeId>,
    pub span: Span,
    pub specifiers: Vec<'a, ExportSpecifier<'a>>,
    pub source: StringLiteral<'a>,
    pub export_kind: ImportOrExportKind,
    pub with_clause: Option<Box<'a, WithClause<'a>>>,
}

pub enum ModuleDeclaration<'a> {
    // ...
    ExportDeclaration(Box<'a, ExportDeclaration<'a>>),
    ExportNamedDeclaration(Box<'a, ExportNamedDeclaration<'a>>),
    ExportFromDeclaration(Box<'a, ExportFromDeclaration<'a>>),
    // ...
}
```

## Why?

The previous node represented three distinct syntax forms through optional and mutually exclusive fields:

```text
export const value = 1;       -> ExportDeclaration
export { value };             -> ExportNamedDeclaration
export { value } from "mod";  -> ExportFromDeclaration
```

This allowed invalid combinations such as declarations with specifiers or sources, and import attributes without a source. The new nodes make these states unrepresentable and remove repeated `declaration`/`source` branching from consumers.

## How to migrate

Match the syntax-specific `ModuleDeclaration`, `Statement`, or `AstKind` variant instead of inspecting optional fields. Generated builders, visitors, traversal ancestors, and formatter wrappers now expose corresponding APIs for all three nodes.

Common field migrations:

| Previous representation | New representation |
| --- | --- |
| `declaration: Some(declaration)` | `ExportDeclaration { declaration }` |
| `declaration.as_ref()` | `&export.declaration` |
| `source.is_none()` for local exports | Match `ExportNamedDeclaration` |
| `source: Some(source)` | `ExportFromDeclaration { source }` |
| `source.as_ref().unwrap()` | `&export.source` |
| `with_clause` | Only available on `ExportFromDeclaration` |
| Stored `export_kind` on exported declarations | `ExportDeclaration::export_kind()` |
| `ExportNamedDeclaration::boxed_plain_declaration(...)` | `ExportDeclaration::boxed(...)` |
| `ExportNamedDeclaration::boxed(..., None, specifiers, None, ...)` | `ExportNamedDeclaration::boxed(..., specifiers, ...)` |
| `ExportNamedDeclaration::boxed(..., None, specifiers, Some(source), ...)` | `ExportFromDeclaration::boxed(..., specifiers, source, ...)` |

closes https://github.com/oxc-project/backlog/issues/219
2026-07-31 10:25:47 +00:00
Dunqing 8a47ff3743 fix(ecmascript): do not treat lone-surrogate strings as constants (#25084)
The value of a StringLiteral and the cooked value of a template quasi encode lone surrogates with `\u{FFFD}` escapes and mark the node with a `lone_surrogates` flag. ToJsString and constant evaluation returned the encoded text, and consumers materialized it into new string literals without the flag, printing the escape encoding as literal text: `"\ud800" + "y"` folded to a string containing a literal `d800`.

Return `None` for such strings and template quasis so folds keep the original nodes.

```js
// source
console.log("\ud800" + "y");  // node prints: �y

// before (miscompiled)
console.log(`�d800y`);         // node prints: �d800y

// after
console.log(`\ud800`+`y`);     // node prints: �y
```
2026-07-30 10:52:55 +00:00
camc314 c917f204a7 feat(ast)!: introduce ArrowFunctionBody enum (#24987)
## Summary

- Introduces `ArrowFunctionBody` to represent concise expression and block bodies explicitly.
- Removes the `ArrowFunctionExpression::expression` boolean.
- Makes invalid arrow body combinations unrepresentable.

## Breaking Change

The Rust AST changes from:

```rust
pub struct ArrowFunctionExpression<'a> {
    pub expression: bool,
    pub body: Box<'a, FunctionBody<'a>>,
}
```

to:

```rust
pub enum ArrowFunctionBody<'a> {
    FunctionBody(Box<'a, FunctionBody<'a>>) = 64,
    INHERIT(Expression<'a>),
}

pub struct ArrowFunctionExpression<'a> {
    pub body: ArrowFunctionBody<'a>,
}
```

Concise arrow bodies are now stored directly as expressions instead of synthetic `FunctionBody` and `ExpressionStatement` nodes. Block bodies continue to use `FunctionBody`.

## Why?

The previous representation required consumers to maintain this implicit invariant:

```text
expression == true
→ no directives
→ exactly one statement
→ that statement is an ExpressionStatement
```

Invalid combinations could cause panics, skipped work, or fallback behavior. The enum encodes the grammar directly and makes those invalid states unrepresentable.

Concise expressions also now have `ArrowFunctionExpression` as their direct traversal ancestor, without synthetic `FunctionBody` or `ExpressionStatement` nodes.

## How to migrate

Use the arrow body accessors or match on `ArrowFunctionBody` rather than inspecting `expression` and synthetic statements.

Common field migrations:

| Previous representation | New representation |
| --- | --- |
| `arrow.expression` | `arrow.is_expression()` |
| `arrow.get_expression()` | `arrow.get_expression()` |
| `&arrow.body.statements` | `arrow.get_function_body().map(\|body\| &body.statements)` |
| `&mut arrow.body.statements` | `arrow.get_function_body_mut().map(\|body\| &mut body.statements)` |
| Synthetic expression statement in `arrow.body` | Direct `ArrowFunctionBody` expression variant |
| `arrow.body = function_body` | `arrow.body = ArrowFunctionBody::FunctionBody(function_body)` |
| Expression-to-block conversion | Create a `FunctionBody` containing a return statement |
| Block-to-expression conversion | Assign the expression directly to `arrow.body` |
| Builder `(expression, body)` arguments | Pass a single `ArrowFunctionBody` |

closes https://github.com/oxc-project/backlog/issues/211
2026-07-29 13:32:32 +00:00
camc314 3f36b16556 refactor(ecmascript): impl MayHaveSideEffects for SequenceExpression (#25074)
simple refactor to extract out `SequenceExpression` side effects such that it now implements `MayHaveSideEffects` to allow us to call `SequenceExpression::may_have_side_effects`
2026-07-29 10:30:44 +00:00
camc314 5acdae22cb feat(ecmascript): skip transparent TS expressions (#25072)
This will be used by the linter.
2026-07-29 10:06:13 +00:00
Dunqing fbe8d318ff fix(minifier): respect targets when folding RegExp source (#24790)
RegExp literal `.source` folding used a hard-coded approximation of ES2015 support. It rejected syntax that configured targets support, such as the `u` flag for ES2015, while allowing newer syntax without checking the configured engines.

The same target compatibility mapping already exists in `oxc_ecmascript` for RegExp constructor analysis. Expose one parsed-syntax predicate from that layer and reuse it for `.source` folding. This removes the duplicate policy and the minifier's direct `oxc_regular_expression` dependency. An unspecified target remains conservative, while an explicit supporting target unlocks the fold.

Covered by `test_fold_regex_source` with adjacent unsupported and supported targets for `y`, `u`, `s`, `d`, `v`, named groups, Unicode property escapes, lookbehind, duplicate named groups, and pattern modifiers.

Verified with `cargo test -p oxc_ecmascript --features side_effects`, `cargo test -p oxc_minifier` (631 passed, 42 ignored), `just minsize` (no minsize or allocation snapshot changes), affected-crate clippy with warnings denied, and `just fmt`.

Follow-up to #24712 and [its non-blocking review](https://github.com/oxc-project/oxc/pull/24712#discussion_r3619967432).

Implemented with AI assistance (OpenAI Codex and Claude). The contributor remains responsible for reviewing, understanding, and submitting these changes under the repository AI usage policy.
2026-07-28 03:37:44 +00:00
oxc-guard[bot] fc702c1fa9 release(crates): oxc v0.142.0 (#24977)
### 💥 BREAKING CHANGES

- 1ac5ac7 ast: [**BREAKING**] Tighten bound on `AstBuild` trait (#24925)
(overlookmotel)

### 🚀 Features

- c7c5696 minifier: Fold parenthesized boolean ternary tests (#24968)
(Dunqing)
- 82c5806 minifier: Fold sequence branches in boolean ternaries (#24943)
(Dunqing)
- cc623d9 ast_visit: Add VisitJsMut visitor (#24828) (Boshen)
- b31713a minifier: Add new IsTerminated trait and use it in exit-point
optimization (#24950) (Armano)
- e9e0f24 minifier: Shorten integer zero comparisons (#24933) (Dunqing)
- 34f5559 minifier: Convert switch with one case to if statement
(#24611) (Armano)
- 9107e74 str: Add `static_str!` macro (#24887) (overlookmotel)
- 4d6f623 parser: Emit error for type args in JS files (#24896)
(camc314)
- ec08afc ast: Re-export `Ident` from `oxc_ast` crate (#24861)
(overlookmotel)
- 73cfdfa oxc: Re-export `oxc_str` types from `oxc` crate (#24860)
(overlookmotel)
- 11f5d1f ast_visit: Add `Utf8ToUtf16::convert_program_and_comments`
(#24859) (overlookmotel)

### 🐛 Bug Fixes

- cb5acfb minifier: Optimize termination statements in labeled
statements (#24813) (Armano)
- 4618300 minifier: Avoid longer numeric constant folds (#24875)
(Dunqing)
- f7971f1 minifier: Keep side effects in typeof comparisons (#24940)
(sapphi-red)
- 4597d6f minifier: Keep side effects when compressing `== true` to `==
1` (#24939) (sapphi-red)
- c3a48df minifier: Keep side effects values in template literals
(#24938) (sapphi-red)
- e19f183 minifier: Keep side effects when folding `Number` call
(#24937) (sapphi-red)
- 9d7745a react-compiler: Preserve warning bailouts (#24935) (Boshen)
- 0126aba codegen: Preserve orphaned file coverage comments (#24815)
(Dunqing)
- 9fbbaf8 parser: Clarify return in class static blocks (#24899)
(camc314)
- e7d5c78 str: Fix hygiene of `format_ident!` and `format_str!` macros
(#24886) (overlookmotel)
- 07e9acc ecmascript: Keep side effects in parent of `toString` calls
(#24846) (sapphi-red)
- 16a40ad ecmascript: Detect side effects in unused arguments to
`charCodeAt` (#24845) (sapphi-red)
- 5b4ae54 parser: Use specific for-await diagnostic (#24856) (camc314)
- ffcc33a parser: Report for-await in non-async functions (#24855)
(camc314)
- df230d0 minifier: Avoid reordering this in nested class keys (#24785)
(Dunqing)
- d24b76b minifier: Isolate derived constructor this state (#24784)
(Dunqing)
- 582805d parser: Parse unary conditional after satisfies (#24807)
(Boshen)
- 23b904f minifier: Preserve default parameter side effects (#24791)
(Dunqing)
- 3048594 parser: Use correct diagnostic for `await using` in bare
switch case (#24798) (camc314)
- e80574f estree: Handle empty spans serializing `ImportMeta` and
`NewTarget` (#24775) (overlookmotel)
- 4b12840 minifier: Do not fold a `-0` ternary branch to `+a` (loses the
sign) (#23637) (Jerry Zhao)
- 133bb35 ecmascript: Detect side effects of `foo().#bar` correctly when
PropertyReadSideEffects::None (#24769) (sapphi-red)

### ⚡ Performance

- a086d91 ecmascript: Avoid number literal allocations (#24889)
(Dunqing)
- 98f2ecb react_compiler: Compare value set pointers before probing in
state merge (#24805) (Marius Schulz)
- b287f29 estree: Avoid ident hash calculations when serializing
(#24774) (overlookmotel)

### 📚 Documentation

- 4d2e2bf ast: Fix incorrect return value in `common_js_require` docs
(#24945) (connorshea)
- b539e74 estree: Document custom serializers for `ImportMeta` and
`NewTarget` (#24777) (overlookmotel)

Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
2026-07-27 23:07:40 +08:00
Dunqing a086d91c83 perf(ecmascript): avoid number literal allocations (#24889)
The shared number-literal serializer can be called repeatedly by consumers that only need the emitted length. Its existing `Cow<str>` implementation allocates candidate strings for some hexadecimal and exponent forms, which would add avoidable allocation traffic to those callers.

Build candidates in an inline stack string while preserving the callback API and generated output. In allocation tracking, the unoptimized consumer added 56 system allocations for `antd.js` and 129 for `kitchen-sink.tsx`; this version removes those increases.

This PR depends on #24876. #24875 adds the minifier consumer.

Verified with `cargo test -p oxc_ecmascript -p oxc_codegen`, Clippy, formatting, and `just allocs` with no standalone snapshot changes.

AI assistance: Codex was used to implement and verify this change.
2026-07-26 12:11:48 +00:00
Dunqing dba374912a refactor(ecmascript): share number literal serialization (#24876)
Codegen is not the only consumer that needs the exact emitted form of a number, but the serializer currently lives in the codegen crate. Other consumers would otherwise need to duplicate its formatting policy or depend on codegen.

Move the callback helper extracted in #24888 from `oxc_codegen` to `oxc_ecmascript`, then reuse it from codegen. The serialization algorithm is unchanged; this PR only makes the helper public and relocates its dependencies.

This PR depends on #24888. #24889 handles allocation-free candidate construction, and #24875 adds the minifier consumer.

Verified independently with `cargo test -p oxc_ecmascript -p oxc_codegen`, Clippy, and formatting.

AI assistance: Codex was used to implement and verify this change.
2026-07-26 12:11:47 +00:00
sapphi-red 07e9acca08 fix(ecmascript): keep side effects in parent of toString calls (#24846)
Detect the side effect of`f()` in `(f(), 5).toString()`.
2026-07-24 01:16:58 +00:00
sapphi-red 16a40ad48c fix(ecmascript): detect side effects in unused arguments to charCodeAt (#24845)
Detect the side effect of`f()` in `'abcde'.charCodeAt(0, f())`.
2026-07-24 01:16:57 +00:00
sapphi-red 133bb35dee fix(ecmascript): detect side effects of foo().#bar correctly when PropertyReadSideEffects::None (#24769)
Side effects of`foo().#bar` was not detected correctly when PropertyReadSideEffects::None is used.

Repro: https://stackblitz.com/edit/oxc-project-website-l6tidw4j?file=src%2Fmain.js

refs https://github.com/oxc-project/oxc/pull/24707#discussion_r3614105531
2026-07-21 23:33:45 +00:00
Boshen baf022d74d refactor(ast)!: remove old AstBuilder methods (#24563)
Closes the migration tracked in #23043.

The new builder API (methods on the AST types themselves) has been in place for a while, all Oxc crates are migrated, and every crate which uses `AstBuilder` already enables `disable_old_builder` in its tests. The module docs said "after a few weeks, we will remove `AstBuilder`'s own methods entirely" — this does that.

## What's removed

- `crates/oxc_ast/src/generated/ast_builder.rs` and `builder/methods.rs` — `AstBuilder`'s own node and primitive constructors.
- `AstBuilderGenerator`, which produced the former.
- The `disable_old_builder` Cargo feature, plus the dev-dependency hacks it required across 33 manifests. Eight crates depended on `oxc_ast` *purely* to turn the feature on; those deps and their `cargo-shear` ignore entries are gone too.

## One thing worth reviewing

`AstBuilderGenerator` owned the `#[builder(default)]` / `#[builder(skip)]` attr registration that `BuilderMethodsGenerator` only *reads* — its doc comment said as much. Deleting it naively would have silently dropped `skip`/`default` handling for the 12 AST types using those attrs, so `attrs()` and `parse_attr()` move to `BuilderMethodsGenerator`.

The evidence this was faithful: after regenerating, `builder_methods.rs` and every other generated file are **byte-identical**. The only generated change in the diff is the deletion.

## Breaking changes

- `AstBuilder`'s own methods are gone. Use the AST type methods: `Statement::new_expression_statement(span, expr, &builder)` instead of `builder.statement_expression(span, expr)`.
- `AstBuilder` is no longer `Copy`/`Clone`, and its `allocator` field is private — use the `allocator` method from `GetAllocator`.
- `AstBuilder` and `NONE` are no longer re-exported from the crate root; import them from `oxc_ast::builder`. (The `disable_old_builder` feature already gated these off, so nothing in-tree used the root path.)
- The `disable_old_builder` feature no longer exists — remove it from any manifest that sets it.

A migration note covering all of the above is in `crates/oxc_ast/src/builder/mod.rs`.

---

Implemented with AI assistance (Claude Code); design, review, and verification driven by the author per the repo AI-usage policy.
2026-07-21 15:22:46 +00:00
oxc-guard[bot] 14533a3dc1 release(crates): oxc v0.141.0 (#24714)
### 💥 BREAKING CHANGES

- 54cc121 ast: [**BREAKING**] Split `MetaProperty` into `ImportMeta` and
`NewTarget` (#24557) (camc314)

### 🚀 Features

- 4c71560 parser: More friendly error for spread element in dynamic
imports (#24705) (sapphi-red)
- 7b045cd minfier: Drop last break from last switch case (#24673)
(Armano)
- 7d3c178 minifier: Remove unreachable recursive functions (#24125)
(Dunqing)
- 94f99b3 ast: Allow `NONE` to be passed to AST builder methods where
`Option<ArenaVec>` is expected (#24629) (overlookmotel)
- 77230c5 ast: Accept arrays for `ArenaVec` params of AST builder
methods (#24621) (overlookmotel)
- f08b152 allocator: Implement `FromIn` for array to `Vec` conversion
(#24620) (overlookmotel)
- 2338c13 track-memory-allocations: Track heap deallocs, alloc bytes,
and peak growth (#24619) (Boshen)
- 7aa4739 syntax,transformer: Move JSX entity decoder to `oxc_syntax`
(#24617) (camc314)
- 2b097c4 str: Export `Str` as `ArenaStr` (#24604) (overlookmotel)
- 3acf4c1 minifier: Expand switch optimiation to remove empty cases
(#24520) (Armano)
- 129b759 parser: Improve diagnostics for unparenthesized LHS on
exponential expr (#24569) (camc314)
- 4d0c601 minifier: Fold arithmetic over undefined and null operands
(#24485) (Dunqing)
- 91541dd minifier: Drop empty switch statements  (#24527) (Armano)
- d05224d ast_visit: Generate VisitJs visitor that skips TypeScript
type-space (#24499) (Boshen)
- 3d22307 parser: Add `ParseOptions::enable_ident_hashes` (#24491)
(Boshen)

### 🐛 Bug Fixes

- 64c2241 minifier: Align class heritage removal with assumptions
(#24533) (Dunqing)
- 48b59f4 parser: Span ambient generator diagnostics (#24711) (camc314)
- e750a82 ecmascript: Fix false negative for may_have_side_effects on
dynamic property access (#24709) (sapphi-red)
- f145d73 minifier: Guard reordered identifier reads (#24698) (Dunqing)
- a2ef382 isolated-declarations: Reject `window.Symbol` as global symbol
reference (#24689) (camc314)
- b1bcf72 minifier: Invalidate facts for redeclared bindings (#24658)
(Dunqing)
- 921b834 minifier: Don't treat a conditionally-assigned var as
write-once (#24650) (Dunqing)
- 061af1f minifier: Avoid stale pure function summaries (#24636)
(Dunqing)
- 40c2f43 allocator: `Vec::from_array_in` do not allocate zero-length
array (#24628) (overlookmotel)
- 70994ae codegen: Preserve comments before expression operands (#24510)
(Dunqing)
- 7b4baff parser: Reject new import member access (#23459) (camc314)
- 128b385 minifier: Clippy warning with no-debug-assertions (#24547)
(camc314)
- 8421feb parser: Use first `as` span for imported name (#24537)
(leaysgur)
- c517aa0 parser: Reject invalid accessor assertions (#24504) (camc314)

### ⚡ Performance

- 884d9eb parser: Pre-size cover-grammar assignment target buffers
(#24683) (Boshen)
- d3f07a0 diagnostics: Box OxcDiagnosticInner to reduce binary size
(#24665) (Boshen)
- bcc9de0 parser: Defer diagnostic creation until parse exit (#24663)
(Boshen)
- c35d8ab allocator: Mark `ReplaceWith` panic path cold (#24515)
(camc314)
- ba65790 semantic, allocator: Branchless `clone_in` for semantic IDs
(#24564) (overlookmotel)
- 747feec parser: Build AST nodes with the AST builder instead of
cloning (#24540) (Boshen)
- ba35a0d react_compiler: Use IndexVec for dense id-keyed maps (#24549)
(Boshen)
- b685062 react_compiler: Keep small hot-path collections inline
(#24514) (Marius Schulz)
- a149e95 transformer: Outline rare expression exits (#24512) (camc314)
- 7808a6e react_compiler: Make aliasing effects cheap to intern and
clone (#24506) (Marius Schulz)
- 3a36f2a react_compiler: Store AbstractValue reasons as a u16 bitmask
(#24480) (Boshen)
- 1c96753 react_compiler: Use FxHashMap for the lookup-only aliasing
node map (#24490) (Boshen)

Co-authored-by: Cameron <cameron.clark@hey.com>
2026-07-21 16:09:41 +01:00
Armano 9a59e1961d refactor(minifier): reuse is_typed_array_constructor from ecma (#24765)
refactor/reuse of `is_typed_array_constructor` from `oxc_ecmascript`
instead of redefining it it `oxc_minifier` as `is_typed_array_name`
2026-07-21 22:41:28 +08:00
Dunqing 79e6d775fb fix(minifier): preserve RegExp feature detection (#24712)
> **PR stack (3 of 3)**
> 1. #24739
> 2. #24742
> 3. **#24712 (this PR)**
>
> Review #24739 and #24742 first. This PR is based on #24742, so GitHub shows only the RegExp behavior change.

Stacked on #24742, which exposes strict engine-target capabilities to side-effect analysis.

RegExp constructor calls used for engine feature detection were removed by DCE when their pattern was valid according to the current Oxc RegExp parser. A pattern can be valid at build time but still throw a `SyntaxError` on the configured runtime, so removing the call changes the result of surrounding `try`/`catch` checks.

RegExp purity now requires both syntactic validity and support from every configured target. Consumers without concrete targets remain conservative, while an explicit target allows the minifier to remove constructors known to be safe for those engines.

Target-independent flag validation and pattern compatibility checks now live in `oxc_regular_expression`; side-effect analysis only maps target support to unsupported flags and patterns. String patterns, modern flags, named groups, property escapes, lookbehind, modifiers, invalid flags, and lone-surrogate strings are covered. A RegExp literal with replacement flags is removable only when the target supports both those flags and the dedicated `ES2015RegExpConstructorCanAlterFlags` compatibility feature. Explicitly targeting `esnext` opts into current features.

## Example

Input:

```js
export function supportsUnicodeRegExp() {
  try {
    new RegExp("\\p{Ll}", "u");
    return true;
  } catch {
    return false;
  }
}
```

Before:

```js
export function supportsUnicodeRegExp() {
  try {
    return true;
  } catch {
    return false;
  }
}
```

After:

```js
export function supportsUnicodeRegExp() {
  try {
    new RegExp("\\p{Ll}", "u");
    return true;
  } catch {
    return false;
  }
}
```

Verified with all `oxc_regular_expression`, `oxc_compat`, `oxc_ecmascript`, and `oxc_minifier` tests; the no-feature/`side_effects`/`constant_evaluation` `oxc_ecmascript` matrix; affected-crate clippy; formatting; and diff checks.

Fixes rolldown/rolldown#10279.

Implemented with AI assistance (OpenAI Codex and Claude). The contributor remains responsible for reviewing, understanding, and submitting these changes under the repository AI usage policy.
2026-07-21 14:15:24 +00:00
Dunqing 01c3611d9b refactor(ecmascript): expose engine targets to side effects (#24742)
> **PR stack (2 of 3)**
> 1. #24739
> 2. **#24742 (this PR)**
> 3. #24712
>
> Review #24739 first. This PR is based on its branch, so GitHub shows only the engine-target plumbing.

Stacked on #24739, which introduces the `side_effects` and `constant_evaluation` feature boundary for `oxc_ecmascript`.

Side-effect analysis sometimes needs to know whether runtime syntax is supported by every configured engine. `MayHaveSideEffectsContext` currently has no access to target information, while `EngineTargets::has_feature` is intentionally permissive about missing compatibility data because it answers whether a transformation is needed.

`MayHaveSideEffectsContext::engine_targets()` exposes the configured targets through a general-purpose accessor. Its default is `None`, so consumers without target information remain conservative, while the minifier supplies its existing `CompressOptions::target`.

`EngineTargets::supports_es_feature` provides the corresponding strict capability query. Every configured engine must have compatibility data and meet the required version; empty targets and missing rows are not treated as proof of support. The existing transformation-oriented `has_feature` behavior remains unchanged.

Because `oxc_linter` enables `side_effects`, this also adds `oxc_compat` to the oxlint and language-server build graphs. It does not change side-effect decisions by itself; #24712 consumes the new capability for target-aware RegExp validation.

Verified with all `oxc_compat` tests, the no-feature/`side_effects`/`constant_evaluation` `oxc_ecmascript` matrix, a minifier check, formatting, and Clippy.

Implemented with AI assistance (OpenAI Codex and Claude). The contributor remains responsible for reviewing, understanding, and maintaining these changes.
2026-07-21 14:15:23 +00:00
Dunqing 9a48d2308f refactor(ecmascript)!: gate analysis APIs (#24739)
> **PR stack (1 of 3)**
> 1. **#24739 (this PR)**
> 2. #24742
> 3. #24712
>
> Review and merge in this order.

The `oxc_ecmascript` crate currently compiles constant evaluation and side-effect analysis for every consumer, even when a consumer only needs the small shared ECMAScript value primitives. This makes optional analysis code and its dependencies part of unrelated builds.

This introduces two explicit features:

- `side_effects` enables side-effect analysis and its RegExp support.
- `constant_evaluation` enables constant evaluation and implies `side_effects`, because side-effect analysis uses constant folding for several purity decisions.

`ConstantValue`, `ValueType`, and `DetermineValueType` move to feature-independent root modules so `GlobalContext` remains available without either analysis feature. Existing paths through `constant_evaluation` remain re-exported when that feature is enabled.

This is a prerequisite for #24742, which exposes engine targets to side-effect analysis without making compatibility data part of every `oxc_ecmascript` consumer.

This is a breaking Cargo feature change for direct consumers of `oxc_ecmascript`: code using side-effect analysis or constant evaluation must enable the corresponding feature.

Verified locally with the no-feature, `side_effects`, and `constant_evaluation` configurations, crate tests, dependent linter and minifier tests, rustdoc with warnings denied, and `just ready`. The release oxlint binary on this commit is 13,350,096 bytes.

Implemented with AI assistance (OpenAI Codex and Claude). The contributor remains responsible for reviewing, understanding, and maintaining these changes.
2026-07-21 14:15:23 +00:00
sapphi-red e750a8243a fix(ecmascript): fix false negative for may_have_side_effects on dynamic property access (#24709)
``[][`length${foo()}`]`` was treated as side effect free. But `foo()` can have side effects.
2026-07-20 09:13:59 +00:00
camc314 54cc121250 feat(ast)!: split MetaProperty into ImportMeta and NewTarget (#24557)
## Summary
- replace the generic Rust MetaProperty AST node with dedicated ImportMeta and NewTarget nodes
- preserve the ESTree MetaProperty shape and generated public TypeScript types
- update parser, formatter, codegen, lint, transform, minifier, traversal, and React compiler consumers

## Summary

Remove `MetaProperty` AST node, in favour of two separate nodes (`ImportMeta` and `NewTarget`)

## Breaking Change

The Rust AST field changes from:

```rust
pub struct MetaProperty<'a> {
    pub node_id: Cell<NodeId>,
    pub span: Span,
    pub meta: IdentifierName<'a>,
    pub property: IdentifierName<'a>,
}
```

to:

```rust
/// /// `import.meta` in `console.log(import.meta);`.
pub struct ImportMeta {
    pub node_id: Cell<NodeId>,
    pub span: Span,
}

/// `new.target` in `function F() { return new.target; }`.
pub struct NewTarget {
    pub node_id: Cell<NodeId>,
    pub span: Span,
}
```

## Why?

The current AST could represent shapes such as:

```
foo.bar
```

By constructing the node manually. However this doesn't make sense, and is invalid.

## How to migrate?

1. Replace any `Expression::MetaProperty` matches/checks with the dedicated `Expression::ImportMeta` and `Expression::NewTarget` varients
2. Replace any `new_meta_property` construction with the new `new_import_meta` or `new_new_target` APIs.
3. Inspecting the `meta`/`property` identifier names is no longer required.
2026-07-15 14:48:32 +00:00
oxc-guard[bot] 8e0ed2ebb9 release(crates): oxc v0.140.0 (#24453)
### 🚀 Features

- 616bfa2 minifier: Remove unreachable code after terminating statements
(#24441) (Dunqing)
- ddab89a data_structures: Add `likely` and `unlikely` functions
(#24368) (overlookmotel)
- a3a39f9 react_compiler: Implement enableEmitHookGuards codegen
(#24329) (Boshen)
- b79eef7 minifier: Apply De Morgan's law to negated comparison chains
in jump guards and loop tests (#24279) (Dunqing)
- 34ff7b4 minifier: Drop write-only property assignments to unused local
bindings by default (#24112) (Dunqing)
- 1b829d8 semantic: Record const enums in EnumData (#24268) (Dunqing)
- ba0944c semantic: Add `Scoping::set_symbol_span` (#24221) (camc314)

### 🐛 Bug Fixes

- 7d33363 minifier: Preserve guaranteed throws from class heritage
evaluation (#24349) (Dunqing)
- 058a62f semantic: Track ambient contexts in `SemanticBuilder` (#24327)
(camc314)
- 721eb0b transformer/decorator: Scope accessor class binding (#24330)
(camc314)
- 1ebdce3 semantic: Allow reserved keywords in ambient declaration types
(#24325) (camc314)
- 460176a track-memory-allocations: Exclude arena chunks from Sys allocs
(#24292) (Dunqing)
- af4922b transformer: Clear lowered namespace redeclarations (#24300)
(camc314)
- ffd2765 semantic: Mark declared computed `MethodDefinition`s as type
references (#24296) (camc314)
- f17514b isolated-declarations: Emit const readonly fields as types
(#24288) (camc314)
- 40f769d minifier: Make `__proto__` write tracking execution-order
independent (#24280) (Dunqing)
- 6371fed transformer: Remove stale enum member bindings (#24272)
(camc314)
- f05dfab transformer: Correct symbol flags for lowered namespaces
(#24271) (Dunqing)
- 84eeb55 transformer: Correct symbol flags for lowered enums (#24269)
(Dunqing)
- c3057da transformer: Preserve generated class binding spans (#24220)
(camc314)
- 8260096 transformer: Correct span for lowered namespace symbol
(#24222) (camc314)
- 42d00d3 semantic: Mark declared class heritage as type references
(#24237) (camc314)
- 588d997 semantic: Mark TS `PropertyDefinition`s computed fields as
type references (#24233) (camc314)
- 9b95632 semantic: Mark computed method keys in `TSMethodSignature`s as
type references (#24232) (camc314)

### ⚡ Performance

- 5b26643 transformer_plugins: Dispatch global defines by trailing name
(#23666) (Boshen)
- dce0f29 react_compiler: Replace all compiled functions in a single AST
walk (#24403) (Boshen)
- f85f0d8 ast: Delegate inherited enum variants in clone_in and estree
derives (#23555) (Boshen)
- 3ff0234 allocator: Remove `unwrap` from `ReplaceWith` (#24365)
(overlookmotel)
- ab22e80 transformer: Fix Rust 1.97 performance regression (#24354)
(camc314)
- b47585c parser: Use `ReplaceWith` instead of `TakeIn` (#24018)
(overlookmotel)
- b227a06 minifier: Use `ReplaceWith` instead of `TakeIn` (#24017)
(overlookmotel)

Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
2026-07-14 15:02:22 +08:00
oxc-guard[bot] 69b2dfc181 release(crates): oxc v0.139.0 (#24218)
### 🚀 Features

- 260425f semantic/examples: Include unresolved references (#24214)
(camc314)
- 2d9b0b3 minifier: Fold boolean-literal ternary branches in value
contexts (#24110) (Dunqing)
- 61fbf10 ast: Implement `ReplaceWith` on all AST types (#24013)
(overlookmotel)
- 7db7a29 allocator: Add `ReplaceWith` trait (#24012) (overlookmotel)
- 4eb074e mangler: Add `reserved` option for names that must not be
mangled (#24041) (Dunqing)
- 2e62012 data_structures: Add `StringExt` trait (#24006)
(overlookmotel)
- 60e7160 minifier: Drop side-effect-free IIFEs whose result is unused
(#23967) (Dunqing)
- 26dd9e2 ast: Add method to widen inherited enum ref to parent ref
(#23961) (overlookmotel)

### 🐛 Bug Fixes

- e8b50ee transformer: Clean up semantics for stripped TypeScript syntax
(#24180) (camc314)
- d966d0b react_compiler: Remove clippy allows (#24168) (Boshen)
- 854ef8d react_compiler: Compile generic functions instead of
over-bailing on type-param hoisting (#24158) (Boshen)
- 093586c react_compiler: Align memoization cache-slot allocation with
Babel (#24157) (Boshen)
- 09c8f59 react_compiler: Normalize snapshot fixture paths (#24142)
(camc314)
- f13df97 react_compiler: Drop stray empty statement from catch bindings
(#24133) (Boshen)
- cb2a505 react_compiler: Codegen destructuring reassignment targets
(#24131) (Boshen)
- b82c394 react_compiler: Propagate codegen invariants instead of
emitting empty bodies (#24128) (Boshen)
- 5771982 react_compiler: Render unchanged programs as source in fixture
snapshots (#24129) (Boshen)
- 4b16e1a transformer/async-to-generator: Preserve direct eval scope
flags (#24136) (camc314)
- 4e9194f react_compiler: Lower `delete obj.prop` to
Property/ComputedDelete (#24123) (Boshen)
- 0b25582 ast: Type binding node `typeAnnotation` as `TSTypeAnnotation |
null` (#23113) (Boshen)
- 018c0e5 transformer: Hoist lowered async declarations (#22770)
(camc314)
- 652fbaf mangler: Keep names of destructured exported bindings (#24036)
(Dunqing)
- e274415 minifier: Don't drop global calls that throw despite pure
arguments (#23917) (Dunqing)
- 59abb30 minifier: Only merge string literals in `try_fold_add` when
the inner operator is `+` (#23622) (Jerry Zhao)

### ⚡ Performance

- c5ca77b transformer: Avoid cloning refresh options (#24191) (camc314)
- bf1a151 react_compiler: Compile out debug printers (#24184) (Boshen)
- abb44a0 transformer: Build fixed object-rest arguments (#24190)
(camc314)
- a4db731 isolated_declarations: Use `ReplaceWith` instead of `TakeIn`
(#24016) (overlookmotel)
- ff10855 transformer: Use `ReplaceWith` instead of `TakeIn` (#24015)
(overlookmotel)
- bd49aff ecmascript: Avoid heap-allocating Math.min/max/imul operands
(#23941) (Lawrence Lin)
- e4b708b react_compiler: Skip compiled files before prefilters (#24171)
(Boshen)
- c59f2fe rust: Return impl ExactSizeIterator from slice-backed
accessors (#24144) (Boshen)
- 5d6d04a codegen: SWAR-skip boring byte runs in sourcemap line/column
scan (#24023) (Boshen)
- a55e0be traverse: Reduce string operations in `get_var_name_from_node`
(#24007) (overlookmotel)
- e6d48e1 transformer/nullish_coalescing: Move cold path into separate
function (#23989) (overlookmotel)
- c4e35b5 transformer/object_rest_spread: Pre-allocate capacity in `Vec`
(#23988) (overlookmotel)
- 527b8e5 transformer/decorators: Narrow type earlier (#23987)
(overlookmotel)

### 📚 Documentation

- 30d17f5 allocator: Clarify docs for `TakeIn::take_in_box` (#24093)
(overlookmotel)
- 675e6a8 ast: Correct doc comment for `PrivateFieldExpression` (#24008)
(overlookmotel)
- e4c30e6 minifier: Explain what `dce` mode means (#23994) (Dunqing)
- 37cbf88 ast_macros: Document fields of `StructDetails` (#23959)
(overlookmotel)
- 4de3e54 ast: Correct doc comment (#23948) (overlookmotel)

Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
2026-07-06 23:26:26 +08:00
Lawrence Lin bd49aff795 perf(ecmascript): avoid heap-allocating Math.min/max/imul operands (#23941)
## Summary

`try_fold_math_variadic` constant-folds `Math.min` / `Math.max` /
`Math.imul(...)` by
collecting the operand values into a `Vec<f64>`. That is a **system
allocation on every
foldable call**, on the minifier's constant-folding hot path.

The evaluation context already exposes the arena
(`ConstantEvaluationCtx: GetAllocator`,
and the module already imports `ArenaVec`), so collect into an
`ArenaVec` instead. The
list is transient and only iterated / indexed (`.iter()`, `.first()`,
`.get()`), so the
change is behaviour-identical — the system allocation is simply gone.

## Results — `cargo allocs` (minifier system allocations)

| fixture | before | after |
| --- | ---: | ---: |
| kitchen-sink.tsx | 2576 | **2312** (−264) |
| antd.js | 1040 | **870** (−170) |
| pdf.mjs | 2569 | **2476** (−93) |
| App.tsx | 78 | 72 |

## Tests

- `cargo test -p oxc_ecmascript --lib --tests` — pass
- `cargo test -p oxc_minifier --lib --tests` — 539 pass

## AI disclosure

Prepared with AI assistance (Claude). I located the hotspot with a
per-call-site allocation
profile across real files, confirmed the list is
transient/iterated-only, and verified the
reduction with `cargo allocs` plus the test suites.

---------

Co-authored-by: Cameron <cameron.clark@hey.com>
2026-07-05 14:21:15 +01:00
Dunqing e2744150c1 fix(minifier): don't drop global calls that throw despite pure arguments (#23917)
## What

`is_pure_global_method_call` (and the bare-global path) in `CallExpression::may_have_side_effects` treated a call as side-effect-free whenever its arguments were, ignoring that several of these functions **throw** at runtime. Unused calls that throw were therefore dropped as dead code. terser and esbuild both keep them.

Guard the cases oxc can prove:

| Call | Throws | Before | After |
| --- | --- | --- | --- |
| `String.raw()`, `Symbol.keyFor()`, `Symbol.keyFor(42)` | `TypeError` (missing/invalid required arg) | dropped | kept |
| `URL.canParse()` | `TypeError` (required first arg) | dropped | kept |
| `String.fromCodePoint(-1 / 1.5 / 0x110000)` | `RangeError` (code point outside `[0, 0x10FFFF]`) | dropped | kept |
| `Math.abs(10n)`, `Date.UTC(10n)`, `String.fromCharCode(10n)`, `isNaN(10n)`, … | `TypeError` (`ToNumber(BigInt)`) | dropped | kept |

Safe optimizations are preserved — `URL.canParse("x")`, `String.fromCodePoint(65)`, `String.fromCharCode(65)`, `Math.abs(1)` still drop. `String.raw` / `Symbol.keyFor` are removed from the pure-method list (never provably safe); the rest get argument guards.

### A Symbol argument is left droppable, on purpose

A Symbol argument also throws (`ToString` / `ToNumber` on a Symbol), but oxc has no `ValueType::Symbol` and `to_primitive` never resolves a pure expression to `Symbol`, so a Symbol throw is **never provable**. Guarding it would mean keeping every `Math.abs(x)` / `parseInt(x)` on an undetermined argument — a large minification regression. esbuild makes the same trade-off (it drops `Math.abs(Symbol.iterator)` too), so only the provable cases are guarded.

oxc already guards exactly this for the `Number` / `Symbol` / `BigInt` / `Error` constructors; this brings the method-call path in line. The assumption (including the non-provable-Symbol carve-out) is documented in `crates/oxc_minifier/docs/ASSUMPTIONS.md`.

Covered by `test_throwing_global_calls` in `crates/oxc_minifier/tests/ecmascript/may_have_side_effects.rs`; cross-checked against terser and esbuild; `minsize` unchanged.

---

Stacked on #23916.
2026-07-02 02:02:14 +00:00
Dunqing 60e716087d feat(minifier): drop side-effect-free IIFEs whose result is unused (#23967)
## Summary

- `CallExpression::may_have_side_effects` now looks through an IIFE — a call whose callee is a function/arrow literal: it is side-effect-free when its arguments, parameters, and every body statement are. Previously every such call was assumed effectful, so the minifier kept dead wrappers like `var unused = (function () { function test() {} return test })()`. Closes #23777.
- This is a plain improvement to side-effect detection in `oxc_ecmascript` — no DCE awareness there. The "preserve IIFE structure in DCE-only mode" policy (match Rollup / esbuild `--tree-shaking=true`, see `preserve_iife_in_dce_mode`) lives in the minifier, in one helper (`has_side_effects_or_preserved_iife`) shared by every unused-removal site that can face an IIFE call, so only full minification actually drops it.
- Conservative — skips `async`/generator callees (different invocation semantics) and any non-identifier parameter (defaults run user code, destructuring reads properties / drives the iterator protocol).
- Covered by `remove_unused_expression.rs::test_remove_side_effect_free_iife` (full-mode positive + negative) and `dead_code_elimination.rs::preserve_iife_in_dce_mode` (DCE-mode preservation: bare, unused-binding, sequence, and `for`-init positions). `minsize` unchanged, `allocs` slightly down.

## Example

```js
// input
var unused = (function () {
  function test() {}
  return test
})()
```

```js
// full minify, before — kept as a bare expression statement
(function () {
  function test() {}
  return test;
})();

// full minify, after
// (empty)
```

In dce-only / tree-shaking mode the IIFE structure is preserved (matches Rollup / esbuild `--tree-shaking=true`).
2026-07-01 03:36:07 +00:00
oxc-guard[bot] 8bf69a3076 release(crates): oxc v0.138.0 (#23934)
### 💥 BREAKING CHANGES

- 94fbacb ast: [**BREAKING**] Only export `AstBuilder` and `NONE` in
`builder` module (#23876) (overlookmotel)
- 8de5122 ecmascript: [**BREAKING**] Switch to new `AstBuilder` (#23834)
(overlookmotel)
- dc0ef38 transformer: [**BREAKING**] Switch to new `AstBuilder`
(#23831) (overlookmotel)
- 88f4455 str: [**BREAKING**] `Str` and `Ident` methods take
`&GetAllocator` (#23781) (overlookmotel)
- 36009dd allocator: [**BREAKING**] `GetAllocator::allocator` take
`&self` (#23676) (overlookmotel)
- bd74f9d allocator: [**BREAKING**] Rename `AllocatorAccessor` trait to
`GetAllocator` (#23675) (overlookmotel)

### 🚀 Features

- 326fe25 transformer_plugins: Support `typeof` `define` keys (#23605)
(Alexander Lichter)
- f2091b3 ast: Unify old and new `AstBuilder`s (#23875) (overlookmotel)
- cd1fd12 codegen: Expose `Codegen::print_string` API (#23785) (camc314)
- 785461b ast: Add custom builder methods to AST types (#23651)
(overlookmotel)
- 05d1357 ast: Add AST creation methods to AST types (#23650)
(overlookmotel)
- 2580eda str: Add `Str::from_str_in` and `Ident::from_str_in` methods
(#23767) (overlookmotel)
- 6883fcf minifier: Fold write-once falsy var to false in boolean
context (#23540) (Dunqing)
- fcbf993 allocator: Add `Vec::from_value_in` method (#23718)
(overlookmotel)
- 989ddb7 allocator: Add `Vec::from_box_in` method (#23717)
(overlookmotel)
- 9d1aa7f allocator: Improve `PartialEq` for `Vec` (#23716)
(overlookmotel)

### 🐛 Bug Fixes

- da0e5bf minifier: Don't reorder a closed-over TDZ read when inlining a
var (#23771) (Dunqing)
- 0b3021f allocator: Remove `Vec::from_box_in` (#23873) (overlookmotel)
- 0ab64ec ast: Silence deprecation warnings within files defining
deprecated `AstBuilder` methods (#23889) (overlookmotel)
- 8c07cad all: Enable `disable_old_builder` Cargo feature for `oxc_ast`
crate in tests (#23888) (overlookmotel)
- 3800f01 ast: Legacy `AstBuilder` methods take `self` not `&self`
(#23891) (overlookmotel)
- 869ac20 semantic/cfg: Connect for update exit to loop test (#23791)
(camc314)
- d3e92d5 semantic/cfg: Connect while branches from condition exit
(#23790) (camc314)
- 025045d ast: `ExportNamedDeclaration` plain builder methods return
boxed nodes (#23783) (overlookmotel)
- 7537c58 ast: Fix name of `AstBuilder` method for
`Expression::V8IntrinsicExpression` (#23766) (overlookmotel)
- 3f574f5 traverse: Fix unsoundness in `Traverse` walk functions
(#23745) (overlookmotel)
- 585760f parser: String in AST reference arena (#23721) (overlookmotel)
- 7231d55 allocator: Fix unsound lifetime extension in `Box::new_in`
(#23685) (overlookmotel)

### ⚡ Performance

- d5c916a semantic: Flatten hoisting_variables to avoid per-scope map
allocation (#23927) (Lawrence Lin)
- e71609d minifier: Bail member-expr folding before the side-effect walk
(#23924) (Lawrence Lin)
- e1f89ab minifier: Reduce string allocations folding addition (#23846)
(overlookmotel)
- 9f6ee3b isolated-declarations: Pool scope maps to avoid per-scope
alloc/rehash (#23761) (Boshen)
- 0b07c4c semantic: Avoid heap alloc for catch-clause binding ids
(#23911) (Lawrence Lin)
- c5eef8b regular_expression: Skip capturing-group pre-parse when
pattern has no `(` (#23908) (Lawrence Lin)
- b4f5b4b isolated_declarations: Remove redundant clone of formal
parameter pattern (#23912) (Lawrence Lin)
- 53d083f isolated_declarations: Use `TakeIn` not `CloneIn` (#23847)
(overlookmotel)
- 3ea9304 react_compiler: Use faster API to arena allocate strings
(#23849) (overlookmotel)
- a6d8e45 parser: Avoid span lookup for arrow expression body (#23788)
(camc314)
- e1886a0 transformer, minifier: Use `static_ident!` macro to create
static `Ident`s (#23727) (overlookmotel)
- 5527bef transformer/object-rest-spread: Reduce iteration (#23720)
(overlookmotel)
- 680ffbc transformer: Allocate AST nodes in arena directly (#23711)
(overlookmotel)
- 1c63c66 parser: Allocate AST nodes in arena directly (#23712)
(overlookmotel)
- 3855f0c minifier: Allocate AST nodes in arena directly (#23710)
(overlookmotel)
- d025887 isolated_declarations: Allocate AST nodes in arena directly
(#23709) (overlookmotel)
- 10b96c6 parser: Remove string search from parsing JSX element name
(#23713) (overlookmotel)

### 📚 Documentation

- 3d61dea all: Correct capitalization in comments (#23887)
(overlookmotel)
- aa1ad74 ast: Add `#[deprecated]` to legacy `AstBuilder` methods
(#23877) (overlookmotel)
- a4676db ast: Correct doc comment for `NONE` (#23765) (overlookmotel)
- 419ec80 syntax: Fix typo in doc comment (#23674) (overlookmotel)

### 🛡️ Security

- 3cdd18f deps: Update npm packages (#23690) (renovate[bot])

Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
Co-authored-by: Cameron <cameron.clark@hey.com>
2026-06-29 20:11:00 +01:00
Dunqing dcc9a73b12 fix(minifier): treat Object.isExtensible/isFrozen/isSealed as pure (#23916)
## What

`Object.isExtensible`, `Object.isFrozen`, and `Object.isSealed` were grouped with the throwing introspection methods (`Object.keys`, `getOwnPropertyDescriptor`, …) in `CallExpression::may_have_side_effects`, so a call with a missing / `null` / `undefined` argument was conservatively kept.

Unlike those methods, the three `is*` methods never `ToObject` their target — per [spec](https://tc39.es/ecma262/#sec-object.isextensible) a non-object receiver returns a primitive (`false` / `true`) instead of throwing, so the call is side-effect-free and an unused one can be dropped.

```js
// in
Object.isExtensible();
Object.isFrozen(x);
Object.isSealed();
Object.keys();

// out
Object.isFrozen(x), Object.keys();
```

`isExtensible()` / `isSealed()` drop (pure); `isFrozen(x)` stays — an undetermined target could be a `Proxy`, whose `[[IsExtensible]]` / `[[OwnPropertyKeys]]` traps are observable — and `keys()` stays (it throws on the `undefined` receiver).

Covered by new cases in `crates/oxc_minifier/tests/ecmascript/may_have_side_effects.rs`; `minsize` unchanged.

Closes #23779
2026-06-29 13:51:39 +00:00
overlookmotel 3d61dea7e2 docs(all): correct capitalization in comments (#23887)
Just fix capitalization in comments.
2026-06-28 12:13:18 +00:00
overlookmotel f2091b3846 feat(ast): unify old and new AstBuilders (#23875)
Part of #23043.

Recent PRs have introduced a new `AstBuilder` type, and migrated all Oxc's crates over to it.

To allow downstream consumers to incrementally migrate from old `AstBuilder` to new one, unify the two implementations into a single `AstBuilder` type.

Remove the `builder_new` Cargo feature and instead add a new feature `disable_old_builder`. When enabled, this feature removes all the methods from `AstBuilder`, and makes `AstBuilder` non-`Copy`. Consumers should migrate, and then enable this feature to ensure later changes don't use the methods which are slated for removal.

Enable the `disable_old_builder` feature in all Oxc crates which use `AstBuilder` _in tests_. This ensures we don't go back to using the deprecated methods, while not forcing the feature on consumers (e.g. Rolldown) who use e.g. `oxc_transformer` but also use `AstBuilder` directly.
2026-06-27 20:37:38 +00:00
overlookmotel 8de5122230 feat(ecmascript)!: switch to new AstBuilder (#23834)
Part of #23043. Migrate `oxc_ecmascript` over to new `AstBuilder`.

This is a breaking change for users of `oxc_ecmascript` crate. `ConstantEvaluationCtx` no longer has an `ast` method to get an `AstBuilder`. Instead, any type that implements `ConstantEvaluationCtx` must also implement `oxc_allocator::GetAllocator` and `oxc_ast::builder::GetAstBuilder` - the latter proving a `builder` method which returns a `&AstBuilder`.

I'll aim to fix this to remove the breaking change in a follow-on PR (before next release).
2026-06-26 18:17:30 +00:00
overlookmotel f65d8e5291 refactor(all): shorten redundant std::vec::Vec (#23748)
Pure refactor.

#23748 made all usages of arena-allocated `Vec` be named `ArenaVec`. This makes plain `Vec` unambiguously refer to heap-allocated `Vec` from standard library.

Shorten `std::vec::Vec` to just `Vec` in various places.
2026-06-24 01:21:41 +00:00
overlookmotel d1f18cda21 refactor(all): import arena Box and Vec as ArenaBox / ArenaVec (#23747)
Pure refactor.

Use `ArenaBox` and `ArenaVec` everywhere for the arena-allocated types from `oxc_allocator`, instead of plain `Box` and `Vec`.

This disambiguates when `Vec` is `oxc_allocator::Vec` and when it's `std::vec::Vec`, making code clearer to follow.

Previously it was easy to confuse the two, and such confusion led to UB in `Traverse` (fixed in #23745).

Ditto other arena types - `ArenaHashMap`, `ArenaHashSet`, `ArenaStringBuilder`.

The only exceptions are:

1. Inside `oxc_allocator` crate itself.
2. AST type definitions.
3. Generated code (migrated separately in #23749).
2026-06-24 01:21:41 +00:00
oxc-guard[bot] 6d56d57535 release(crates): oxc v0.137.0 (#23591)
### 💥 BREAKING CHANGES

- 7a76cd3 estree: [**BREAKING**] Make whether to include TS fields a
runtime option (#23574) (overlookmotel)
- e7b6b68 estree: [**BREAKING**] `ESTree` config use methods not consts
(#23573) (overlookmotel)

### 🚀 Features

- 556cc6d data_structures: Add `CodeBuffer::as_str` method (#23571)
(overlookmotel)
- 38c4b06 parser: Add friendly error for adjacent JSX elements (#23378)
(sapphi-red)
- 53509a8 minifier: Treeshake pure typed arrays and Set/Map array
literals (#23469) (Dunqing)
- 09762d9 minifier: Inline const value for read-only vars (#22593)
(Dunqing)

### 🐛 Bug Fixes

- 20375f9 react_compiler: Keep imports referenced only by a computed key
(#23586) (Boshen)
- 31bfd9b minifier: Keep Object introspection calls on a possible Proxy
(#23483) (Dunqing)
- 837a395 parser: Treat a line comment after ':' as leading, not
trailing (#23515) (Dunqing)
- e409fe0 minifier: Keep `new Map`/`WeakSet`/`WeakMap` with a string
argument (#23470) (Dunqing)
- ae02b4e ci/parser: Use `minimal` for vitest reporter (#23457)
(camc314)

### ⚡ Performance

- cf24329 mangler: Compile slot sort once instead of per CAPACITY
(#23577) (Boshen)
- 4058a6a parser: Reduce code bloat from verify_modifiers
monomorphization (#23576) (Boshen)
- 053b0c1 estree: Remove pointless `mem::take` (#23572) (overlookmotel)
- dfb52b6 transformer: Pre-size statement vecs in TS enum & namespace
lowering (#23516) (Yunfei He)
- 970e09a minifier: Compute template-literal inline checks in a single
pass (#23467) (Yunfei He)
- 3170c0e semantic,mangler,minifier: Fix `Semantic::stats` node count
and reuse stats in mangler builds (#23352) (Boshen)
- d1fa6e0 minifier: Evaluate ternary branches once in
minimize_conditional_expression (#23479) (Yunfei He)
- 3fa8051 transformer: Pre-size JSX props vec to attribute count
(#23466) (Yunfei He)
- 488b382 react_compiler: Borrow binding names in prefilter instead of
allocating (#23471) (Yunfei He)
- bcb3894 minifier: Incremental scoping refresh, delete
LiveUsageCollector (#23197) (Dunqing)

### 📚 Documentation

- f68641e data_structures: Improve docs on safety contract (#23575)
(overlookmotel)

Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
2026-06-18 17:31:57 +08:00