fix(transformer/class-properties): reparent lifted private method helpers by camc314 · Pull Request #22716 · oxc-project/oxc

camc314 · 2026-05-25T10:53:32Z

Summary

Fixes semantic scope metadata for private method helper functions that are lifted out of classes nested inside static field initializers.

The class-properties transform converts a private method into a helper function declaration and emits that helper outside the class. For a nested class inside a static field initializer, current_scope_id() points at the nested class scope, but the helper is actually emitted into the surrounding hoist scope. That made semantic rebuild disagree with the transformed AST.

Before

class Outer {
  static value = class Inner {
    static #method() {}
  };
}

The helper function was reparented as if it still lived under the nested class scope:

flowchart TD
  Program["enclosing hoist scope"] --> Outer["Outer class scope"]
  Outer --> Field["static field initializer"]
  Field --> Inner["Inner class scope"]
  Inner --> Helper["lifted helper function scope"]
  Helper -.-> Problem["incorrect parent + strict-mode source"]

In code, the old logic always used the current scope and current scope flags:

let new_parent_id = ctx.current_scope_id();
ctx.scoping_mut().change_scope_parent_id(scope_id, Some(new_parent_id));
let make_sloppy_mode = !ctx.current_scope_flags().is_strict_mode();

That is correct for normal private methods, but not for private methods inside a class expression that appears in a static field initializer.

After

When the transform is running under a static PropertyDefinitionValue, the helper is parented to the current hoist scope instead:

let new_parent_id = if Self::is_inside_static_property_initializer(ctx) {
    ctx.current_hoist_scope_id()
} else {
    ctx.current_scope_id()
};
ctx.scoping_mut().change_scope_parent_id(scope_id, Some(new_parent_id));
let make_sloppy_mode = !ctx.scoping().scope_flags(new_parent_id).is_strict_mode();

The predicate checks the field is actually static:

matches!(ancestor, Ancestor::PropertyDefinitionValue(property) if *property.r#static())

The resulting scope shape now matches where the helper is emitted:

flowchart TD
  Program["enclosing hoist scope"] --> Helper["lifted helper function scope"]
  Program --> Outer["Outer class scope"]
  Outer --> Field["static field initializer"]
  Field --> Inner["Inner class scope"]

The strict/sloppy adjustment also reads from the selected parent scope, so the helper's flags match the output location rather than the original nested class context.

Validation

just fmt
cargo test -p oxc_transformer
just coverage was run before review. It aborted later with a stack overflow / signal 6 in target/coverage/oxc_coverage; before the abort, the targeted semantic_test262 failures were removed from the generated snapshot output.

AI assistance: Codex was used to cherry-pick, review, test, and draft this PR description.

codspeed-hq · 2026-05-25T10:57:12Z

Merging this PR will not alter performance

✅ 52 untouched benchmarks
⏩ 63 skipped benchmarks¹

_{Comparing camc314:codex/reparent-lifted-private-method-helpers (6182a5b) with main (5774052)²}

63 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩
No successful run was found on main (ebe9373) during the generation of this report, so 5774052 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

Copilot

Pull request overview

Fixes incorrect semantic scope parenting/flags for helper function declarations generated when lifting private methods out of nested classes that appear within class field initializers (notably static field initializers), aligning transformer-produced scope metadata with the rebuilt semantic model.

Changes:

Reparent lifted private-method helper function scopes to the current hoist scope when transforming inside a PropertyDefinitionValue context, and derive strict/sloppy behavior from the selected parent scope.
Update semantic Test262 coverage snapshot to reflect resolved scope parent/flag mismatches for the affected cases.

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

File	Description
crates/oxc_transformer/src/es2022/class_properties/private_method.rs	Adjusts scope reparenting/strictness derivation for lifted private-method helpers using hoist scope when inside a class field initializer.
tasks/coverage/snapshots/semantic_test262.snap	Updates snapshot output to reflect the newly passing semantic scope checks.

Copilot

Pull request overview

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

Dunqing · 2026-05-26T01:26:40Z

Merge activity

May 26, 1:26 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
May 26, 1:26 AM UTC: Dunqing added this pull request to the Graphite merge queue.
May 26, 1:28 AM UTC: The Graphite merge queue couldn't merge this PR because it failed for an unknown reason (Fast-forward merges are not supported for forked repositories. Please create a branch in the target repository in order to merge).
May 26, 4:50 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
May 26, 4:50 AM UTC: Dunqing added this pull request to the Graphite merge queue.
May 26, 4:52 AM UTC: The Graphite merge queue couldn't merge this PR because it failed for an unknown reason (Fast-forward merges are not supported for forked repositories. Please create a branch in the target repository in order to merge).

Dunqing · 2026-05-26T05:43:23Z

Just noticed that this branch is not created from the Oxc repo, but rather from your fork.

### 🚀 Features - e857b0c napi/minify: Expose legalComments option and result (#20370) (Boshen) - 661132d parser: More friendly error messages for rest assignment target and rest binding element (#22719) (sapphi-red) - ee659b6 transformer/legacy-decorator: Add `strictNullChecks` option for nullable-union design:type (#22266) (Kyle Cannon) ### 🐛 Bug Fixes - e1d064e transformer/class-properties: Reparent lifted private method helpers (#22716) (Cameron) - 4ac0fca minifier: Preserve `0 && (module.exports = { ... })` cjs-module-lexer hint (#22729) (Dunqing) - 40ff611 minifier: Mark peephole loop changed when dropping dead-after-throw statement (#22722) (Dunqing) - 2f7b210 codegen: Emit pife-arrow/function leading comments inside the wrap (#22720) (Dunqing) - e184f74 parser: Improve invalid `import` property access diagnostic (#22693) (camc314) - 7baed9c transformer/private-method: Clear inherited strict flags (#22508) (camc314) - a9ad27e parser: Keep annotation comments leading without preceding newline (#22711) (Dunqing) - 9ea4d64 minifier: Re-evaluate pure/no-side-effects flags after peephole inlining (#22595) (Dunqing) - 07afbb6 minifier: Drop empty-body IIFE wrapper when called with arguments (#22589) (Dunqing) - fa7c463 semantic: Correct TS enum member symbol spans (#22689) (camc314) - 26b9396 semantic: Resolve parameter decorators outside parameter scope (#22623) (camc314) - b284045 parser: Switch to module goal eagerly on `export` (#22684) (Boshen) - dfa931d semantic: Propagate unresolved auto-increment enum value instead of defaulting to 0 (#22646) (Dunqing) - 69a6ba6 transformer/legacy-decorator: Emit Array for ReadonlyArray<T> in decorator metadata (#22265) (Kyle Cannon) - e421ef0 transformer/legacy-decorator: Return runtime binding for design:type (#22640) (Dunqing) - d61e1d7 codegen: Preserve verbatim text of pure/no-side-effects comments (#22525) (Dunqing) - 702b14e minifier: Preserve IIFE structure in DCE-only mode (#22547) (Dunqing) - 917da24 parser: Apply PURE comment through member-access chains (#22566) (Dunqing) - a069b1c codegen: Preserve quotes for cjs-module-lexer equality strings (#22551) (Dunqing) ### ⚡ Performance - 2f623b0 semantic: Skip unresolved checks for re-exports (#22660) (camc314) - 0d9553d semantic: Early-exit `check_object_expression` for objects with <2 properties (#22668) (Dunqing) - d721ad9 semantic: Use direct grandparent lookup for TS type parameters (#22658) (camc314) - 0aff288 semantic: Reorder numeric literal strict mode checks (#22657) (camc314) - 4d5ddb1 semantic: Reorder binding identifier checks (#22656) (camc314) - e32acd8 semantic: Reorder identifier ambient binding check (#22653) (camc314) - 09fe178 semantic: Reorder ident reference strict mode check (#22652) (camc314) - 4b6add2 semantic: Avoid duplicate ident clone for bindings (#22663) (camc314) - 82f9662 parser: Check identifier kind before context flag (#22662) (camc314) - d7cd951 parser: Fast path identifier parsing and inline operator helpers (#22650) (Boshen) - 7b84314 semantic: Use direct byte access for numeric leading-zero check (#22642) (camc314) - 0345a31 semantic: Pre-size class elements hash map (#22618) (camc314) - 04d3065 minifier: Drop per-call buffers in try_fold_concat (#22596) (Dunqing) - 4f289f1 semantic: Resolve_references_for_current_scope without a temp Vec (#22599) (Dunqing) - e862c15 semantic: Avoid heap alloc for var hoist scope ids (#22603) (Dunqing) - 8ff8674 semantic: Early return if `excess` is `0` in `Stats::increase_by` (#22616) (camc314) - 7a4120e semantic: Pre-reserve unresolved_references using Stats::references (#22580) (Dunqing) Co-authored-by: Dunqing <29533304+Dunqing@users.noreply.github.com>

camc314 assigned Dunqing May 25, 2026

camc314 added A-isolated-declarations Isolated Declarations A-transformer Area - Transformer / Transpiler and removed A-isolated-declarations Isolated Declarations labels May 25, 2026

camc314 marked this pull request as ready for review May 25, 2026 10:59

camc314 requested a review from overlookmotel as a code owner May 25, 2026 10:59

Copilot AI review requested due to automatic review settings May 25, 2026 10:59

camc314 requested a review from Dunqing as a code owner May 25, 2026 10:59

Copilot started reviewing on behalf of camc314 May 25, 2026 11:00 View session

Copilot AI reviewed May 25, 2026

View reviewed changes

Comment thread crates/oxc_transformer/src/es2022/class_properties/private_method.rs Outdated

camc314 requested a review from Copilot May 25, 2026 17:20

Copilot started reviewing on behalf of camc314 May 25, 2026 17:20 View session

Copilot AI reviewed May 25, 2026

View reviewed changes

Comment thread crates/oxc_transformer/src/es2022/class_properties/private_method.rs

camc314 force-pushed the codex/reparent-lifted-private-method-helpers branch from 8b18c62 to 5fcc3c4 Compare May 25, 2026 17:23

Dunqing approved these changes May 26, 2026

View reviewed changes

Dunqing added the 0-merge Merge with Graphite Merge Queue label May 26, 2026

graphite-app Bot removed the 0-merge Merge with Graphite Merge Queue label May 26, 2026

camc314 added 2 commits May 26, 2026 12:50

fix(transformer): reparent lifted private method helpers

a74e184

fix(transformer): narrow static initializer check

6182a5b

Dunqing force-pushed the codex/reparent-lifted-private-method-helpers branch from 5fcc3c4 to 6182a5b Compare May 26, 2026 04:50

Dunqing added the 0-merge Merge with Graphite Merge Queue label May 26, 2026

graphite-app Bot removed the 0-merge Merge with Graphite Merge Queue label May 26, 2026

Dunqing changed the title ~~fix(transformer): reparent lifted private method helpers~~ fix(transformer/class-properties): reparent lifted private method helpers May 26, 2026

Dunqing merged commit e1d064e into oxc-project:main May 26, 2026
39 checks passed

oxc-guard Bot mentioned this pull request May 26, 2026

release(crates): oxc v0.133.0 #22734

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

fix(transformer/class-properties): reparent lifted private method helpers#22716

fix(transformer/class-properties): reparent lifted private method helpers#22716
Dunqing merged 2 commits into
oxc-project:mainfrom
camc314:codex/reparent-lifted-private-method-helpers

camc314 commented May 25, 2026 •

edited

Loading

Uh oh!

codspeed-hq Bot commented May 25, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Dunqing commented May 26, 2026 •

edited by graphite-app Bot

Loading

Uh oh!

Dunqing commented May 26, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Uh oh!

Conversation

camc314 commented May 25, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Before

After

Validation

Uh oh!

codspeed-hq Bot commented May 25, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Merging this PR will not alter performance

Footnotes

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Uh oh!

Dunqing commented May 26, 2026 • edited by graphite-app Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Merge activity

Uh oh!

Dunqing commented May 26, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

camc314 commented May 25, 2026 •

edited

Loading

codspeed-hq Bot commented May 25, 2026 •

edited

Loading

Dunqing commented May 26, 2026 •

edited by graphite-app Bot

Loading