fix(noUnusedPrivateClassMembers): ignore all TS `private` members if a `this[computed]` is found #7419

Conaclos · 2025-09-06T16:38:19Z

Summary

Fixes #7323

The rule now considers as used all TS private members if a computed access on this is found.

Test Plan

I added two tests:

A test that demonstrates that TS private members are no longer reported when a computed access on this is found.
A test that demonstrates that unused #member are still reported even if a computed access on this is found.

Docs

I added a Caveat section describing the new behavior.

changeset-bot · 2025-09-06T16:38:23Z

🦋 Changeset detected

Latest commit: 8e57294

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

Name	Type
@biomejs/biome	Patch
@biomejs/cli-win32-x64	Patch
@biomejs/cli-win32-arm64	Patch
@biomejs/cli-darwin-x64	Patch
@biomejs/cli-darwin-arm64	Patch
@biomejs/cli-linux-x64	Patch
@biomejs/cli-linux-arm64	Patch
@biomejs/cli-linux-x64-musl	Patch
@biomejs/cli-linux-arm64-musl	Patch
@biomejs/wasm-web	Patch
@biomejs/wasm-bundler	Patch
@biomejs/wasm-nodejs	Patch
@biomejs/backend-jsonrpc	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

coderabbitai · 2025-09-06T16:38:25Z

Walkthrough

The noUnusedPrivateClassMembers lint was changed to treat computed/bracket access on this (e.g. this[name]) as usage for TypeScript-style private members. Traversal was refactored to use descendants iteration, adding ts_private_count and early-exit logic. A new AnyMember::is_private_sharp() helper distinguishes ES private (#) members. On detecting computed this[...] access the code marks TS-private members as used (retaining only ES private-sharp members). Two tests (valid/invalid dynamic access) and a changeset documenting the fix were added.

Assessment against linked issues

Objective	Addressed	Explanation
Detect bracket/computed access to private members as usage to avoid false positives (#7323)	✅
Cover reproduce case: private members assigned in constructor, invoked via thisaction with "add" \| "remove" (#7323)	✅
Use type information to resolve computed property expression types (string literal unions) and only mark matching private members as used; preserve conservative behaviour when unresolved (#7323)	❓	Implementation treats any computed this[...] as using TS-private members without using type-checker resolution; no evidence of literal-union resolution logic.

Suggested labels

A-Type-Inference

Suggested reviewers

ematipico
vladimir-ivanov
dyc3

✨ Finishing Touches

📝 Generate Docstrings

🧪 Generate unit tests

Create PR with unit tests
Post copyable unit tests in a comment
Commit unit tests in branch conaclos/noUnusedPrivateClassMembers-omputed-access-7323

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

codspeed-hq · 2025-09-06T16:52:14Z

CodSpeed Performance Report

Merging #7419 will not alter performance

_{Comparing conaclos/noUnusedPrivateClassMembers-omputed-access-7323 (8e57294) with main (53ff5ae)}

Summary

✅ 133 untouched benchmarks

ematipico

Tests are failing

crates/biome_js_analyze/src/lint/correctness/no_unused_private_class_members.rs

…computed access is found

coderabbitai

Actionable comments posted: 0

♻️ Duplicate comments (1)

crates/biome_js_analyze/src/lint/correctness/no_unused_private_class_members.rs (1)

445-456: Good helper; docstring matches prior suggestion.

Accurately distinguishes ES private # members.

🧹 Nitpick comments (3)

crates/biome_js_analyze/src/lint/correctness/no_unused_private_class_members.rs (3)
68-82: Clarify caveat scope (‘this[…]’ only) and highlight ES-# exception.

Tighten wording so readers don’t infer we also handle arbitrary bracket access or optional chaining.
-    /// The rule currently considers that all TypeScript private members are used if it encounters a computed access.
+    /// The rule treats all TypeScript private members as used when it encounters a computed access on `this` (`this[...]`).
+    /// ES private members declared with `#` are not affected by this caveat and are still analysed normally.
252-258: Polish the comment for readability.

Small grammar tweak; variable name is fine, but consider remaining_ts_privates for self‑documentation.
-    // `true` is at least one member is a TypeScript private member like `private member`.
-    // The other private members are sharp members `#member`.
+    // At least one member is a TypeScript-style private (e.g. `private member`).
+    // The remaining private members are ES private-sharp (e.g. `#member`).
288-299: Exclude this[…] in nested classes when clearing TS-private usage
 for node in syntax.descendants() {
+    // Prevent a nested class’s `this[…]` from clearing outer private-member diagnostics
+    if node
+        .ancestors()
+        .any(|anc| anc.kind() == JsSyntaxKind::JS_CLASS_DECLARATION && !is_node_equal(&anc, syntax))
+    {
+        continue;
+    }
     // …existing computed-member handling…
 }
Add a test demonstrating a nested class with this[action] does not suppress diagnostics for the outer class’s unused privates.

📜 Review details

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 476f2b2 and 8e57294.

⛔ Files ignored due to path filters (2)

crates/biome_js_analyze/tests/specs/correctness/noUnusedPrivateClassMembers/invalid_dynamic_access.ts.snap is excluded by !**/*.snap and included by **
crates/biome_js_analyze/tests/specs/correctness/noUnusedPrivateClassMembers/valid_dynamic_access.ts.snap is excluded by !**/*.snap and included by **

📒 Files selected for processing (4)

.changeset/little-heads-divide.md (1 hunks)
crates/biome_js_analyze/src/lint/correctness/no_unused_private_class_members.rs (4 hunks)
crates/biome_js_analyze/tests/specs/correctness/noUnusedPrivateClassMembers/invalid_dynamic_access.ts (1 hunks)
crates/biome_js_analyze/tests/specs/correctness/noUnusedPrivateClassMembers/valid_dynamic_access.ts (1 hunks)

🚧 Files skipped from review as they are similar to previous changes (3)

crates/biome_js_analyze/tests/specs/correctness/noUnusedPrivateClassMembers/invalid_dynamic_access.ts
crates/biome_js_analyze/tests/specs/correctness/noUnusedPrivateClassMembers/valid_dynamic_access.ts
.changeset/little-heads-divide.md

🧰 Additional context used

📓 Path-based instructions (3)

**/*.{rs,toml}

📄 CodeRabbit inference engine (CONTRIBUTING.md)

Format Rust and TOML files before committing (use just f/just format).

Files:

crates/biome_js_analyze/src/lint/correctness/no_unused_private_class_members.rs

crates/biome_*_{syntax,parser,formatter,analyze,factory,semantic}/**

📄 CodeRabbit inference engine (CLAUDE.md)

Maintain the per-language crate structure: biome_{lang}_{syntax,parser,formatter,analyze,factory,semantic}

Files:

crates/biome_js_analyze/src/lint/correctness/no_unused_private_class_members.rs

crates/biome_*/**

📄 CodeRabbit inference engine (CLAUDE.md)

Place core crates under /crates/biome_*/

Files:

crates/biome_js_analyze/src/lint/correctness/no_unused_private_class_members.rs

🧬 Code graph analysis (1)

crates/biome_js_analyze/src/lint/correctness/no_unused_private_class_members.rs (1)

crates/biome_js_syntax/src/expr_ext.rs (4)

member (1590-1595)

object (1569-1574)

object (1610-1615)

object (1672-1678)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (24)

GitHub Check: Bench (biome_module_graph)
GitHub Check: Bench (biome_configuration)
GitHub Check: Bench (biome_css_analyze)
GitHub Check: Bench (biome_package)
GitHub Check: Bench (biome_graphql_formatter)
GitHub Check: Bench (biome_json_analyze)
GitHub Check: Bench (biome_js_analyze)
GitHub Check: Bench (biome_html_parser)
GitHub Check: Bench (biome_html_formatter)
GitHub Check: Bench (biome_graphql_parser)
GitHub Check: Bench (biome_css_parser)
GitHub Check: Bench (biome_json_formatter)
GitHub Check: Bench (biome_json_parser)
GitHub Check: Bench (biome_css_formatter)
GitHub Check: Bench (biome_js_parser)
GitHub Check: Bench (biome_js_formatter)
GitHub Check: Documentation
GitHub Check: Test Node.js API
GitHub Check: Lint project (depot-windows-2022)
GitHub Check: Test (depot-ubuntu-24.04-arm-16)
GitHub Check: Test (depot-windows-2022-16)
GitHub Check: Lint project (depot-ubuntu-24.04-arm-16)
GitHub Check: Check Dependencies
GitHub Check: autofix

🔇 Additional comments (2)

crates/biome_js_analyze/src/lint/correctness/no_unused_private_class_members.rs (2)

13-16: Imports wired up correctly for computed access.

The new imports are used (computed member and expression checks; formal parameter).

259-287: Name-based usage pruning looks sound.

Retains write-only/update usages and removes confirmed reads; early-exit on empty set is helpful.

…a `this[computed]` is found (biomejs#7419)

github-actions bot added A-Linter Area: linter L-JavaScript Language: JavaScript and super languages labels Sep 6, 2025

Conaclos force-pushed the conaclos/noUnusedPrivateClassMembers-omputed-access-7323 branch 2 times, most recently from f28f207 to 0772609 Compare September 6, 2025 16:42

This comment was marked as resolved.

Sign in to view

Conaclos requested review from a team September 6, 2025 16:49

Conaclos force-pushed the conaclos/noUnusedPrivateClassMembers-omputed-access-7323 branch from 0772609 to 476f2b2 Compare September 6, 2025 16:50

Conaclos changed the title ~~fix(noUnusedPrivateClassMembers): ignore all TS private members if a this[access] is found~~ fix(noUnusedPrivateClassMembers): ignore all TS private members if a this[computed] is found Sep 6, 2025

ematipico approved these changes Sep 6, 2025

View reviewed changes

crates/biome_js_analyze/src/lint/correctness/no_unused_private_class_members.rs Outdated Show resolved Hide resolved

Conaclos force-pushed the conaclos/noUnusedPrivateClassMembers-omputed-access-7323 branch from 476f2b2 to 8e57294 Compare September 6, 2025 23:01

fix(noUnusedPrivateClassMembers): ignore all TS private members if a …

8e57294

…computed access is found

coderabbitai bot reviewed Sep 6, 2025

View reviewed changes

Conaclos merged commit 576baf4 into main Sep 6, 2025
30 checks passed

Conaclos deleted the conaclos/noUnusedPrivateClassMembers-omputed-access-7323 branch September 6, 2025 23:24

github-actions bot mentioned this pull request Sep 6, 2025

ci: release #7413

Merged

coderabbitai bot mentioned this pull request Sep 15, 2025

feat(biome-js-analyze): adjusts members update assignments to be marked as valid in noUnusedPrivateClassMembers #7500

Closed

kedevked pushed a commit to kedevked/biome that referenced this pull request Sep 22, 2025

fix(noUnusedPrivateClassMembers): ignore all TS private members if …

4bec7a8

…a `this[computed]` is found (biomejs#7419)

coderabbitai bot mentioned this pull request Sep 29, 2025

feat(biome_js_analyze): align no_unused_private_class_members_with_semantic_class #7610

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Uh oh!

fix(noUnusedPrivateClassMembers): ignore all TS `private` members if a `this[computed]` is found #7419

fix(noUnusedPrivateClassMembers): ignore all TS `private` members if a `this[computed]` is found #7419

Uh oh!

Conaclos commented Sep 6, 2025 •

edited

Loading

Uh oh!

changeset-bot bot commented Sep 6, 2025 •

edited

Loading

Uh oh!

coderabbitai bot commented Sep 6, 2025 •

edited

Loading

Uh oh!

This comment was marked as resolved.

Uh oh!

codspeed-hq bot commented Sep 6, 2025 •

edited

Loading

Uh oh!

ematipico left a comment

Uh oh!

Uh oh!

coderabbitai bot left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

fix(noUnusedPrivateClassMembers): ignore all TS private members if a this[computed] is found #7419

fix(noUnusedPrivateClassMembers): ignore all TS private members if a this[computed] is found #7419

Uh oh!

Conversation

Conaclos commented Sep 6, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Test Plan

Docs

Uh oh!

changeset-bot bot commented Sep 6, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

🦋 Changeset detected

Uh oh!

coderabbitai bot commented Sep 6, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Walkthrough

Assessment against linked issues

Suggested labels

Suggested reviewers

Uh oh!

This comment was marked as resolved.

Uh oh!

codspeed-hq bot commented Sep 6, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

CodSpeed Performance Report

Merging #7419 will not alter performance

Summary

Uh oh!

ematipico left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

coderabbitai bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

fix(noUnusedPrivateClassMembers): ignore all TS `private` members if a `this[computed]` is found #7419

fix(noUnusedPrivateClassMembers): ignore all TS `private` members if a `this[computed]` is found #7419

Conaclos commented Sep 6, 2025 •

edited

Loading

changeset-bot bot commented Sep 6, 2025 •

edited

Loading

coderabbitai bot commented Sep 6, 2025 •

edited

Loading

codspeed-hq bot commented Sep 6, 2025 •

edited

Loading