fix(linter/no-unused-vars): handle loop-carried self-reassignments

[camc314]

fixes #20456

[camc314]

• fix(linter/no-unused-vars): handle loop-carried self-reassignments #20457 👈 (View in Graphite)
• main

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[Copilot]

Pull request overview

Fixes a no-unused-vars false positive by treating loop-carried self-reassignments (e.g. chain = chain.extend() inside a loop body) as real usages, aligning behavior with ESLint and addressing #20456.

Changes:

• Update is_self_reassignment logic to treat self-reassignments inside loop bodies as usages (not ignorable self-updates).
• Add new regression test cases for loop-carried self-reassignment (pass) vs single self-reassignment (fail).
• Update the snapshot for the self-use test suite to include the new failing case output.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
crates/oxc_linter/src/rules/eslint/no_unused_vars/usage.rs	Adds loop-body detection to avoid classifying loop-carried self-reassignments as “unused”.
crates/oxc_linter/src/rules/eslint/no_unused_vars/tests/oxc.rs	Introduces new pass/fail cases covering the reported scenario.
crates/oxc_linter/src/snapshots/eslint_no_unused_vars@oxc-vars-self-use.snap	Updates expected diagnostics to reflect the new failing case.

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[graphite-app]

Merge activity

• Mar 17, 2:38 PM UTC: camc314 added this pull request to the Graphite merge queue.
• Mar 17, 2:44 PM UTC: Merged by the Graphite merge queue.

[codspeed-hq]

Merging this PR will not alter performance

✅ 4 untouched benchmarks
⏩ 52 skipped benchmarks¹

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_{Comparing c/03-17-fix_linter_no-unused-vars_handle_loop-carried_self-reassignments (d78c55d) with main (71628e6)²}

Footnotes

1. 52 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. ↩

2. No successful run was found on main (d78c55d) during the generation of this report, so 71628e6 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩