fix(lint/noShadow): ignore parameters in function type signatures

[sudabg]

Summary

Fixes #9482

The noShadow rule incorrectly flags parameter names in function type signatures as shadowing outer variables. For example:

function fn(options: unknown, callback: (options: unknown) => void) {}
//                                     ^^^^^^^^ incorrectly flagged

Function type parameters are type-only and don't create runtime bindings — they should not trigger shadowing warnings.

Changes

• Added is_inside_function_type() helper that checks if a binding is inside a TsFunctionType ancestor
• Extended the existing function parameter type-only check in evaluate_shadowing() to also skip bindings inside function types

This follows the same pattern as the existing is_inside_type_parameter() and is_inside_type_member() checks.

Test plan

• The reproduction case from 💅 nusery/noShadow should not flag parameter names of function types #9482 should no longer produce a diagnostic
• Existing overload signature handling (added for 💅 nursery/noShadow: implement ignoreTypeValueShadow option from source rule #7812) should continue to work

[changeset-bot]

🦋 Changeset detected

Latest commit: 9baba0d

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

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 76c514a and 9baba0d.

📒 Files selected for processing (2)

• .changeset/fix-no-shadow-function-types.md
• crates/biome_js_analyze/src/lint/nursery/no_shadow.rs

✅ Files skipped from review due to trivial changes (1)

• .changeset/fix-no-shadow-function-types.md

🚧 Files skipped from review as they are similar to previous changes (1)

• crates/biome_js_analyze/src/lint/nursery/no_shadow.rs

---

Walkthrough

This PR updates the no_shadow nursery lint to skip reporting bindings that appear as parameter identifiers inside TypeScript TsFunctionType signatures. It adds is_inside_function_type(binding: &Binding) -> bool which walks syntax ancestors to detect TsFunctionType, and extends the early-exit logic that already excluded TsTypeParameter and TsPropertySignatureTypeMember contexts. A changeset records the patch release and links the fix to issue #9482.

Possibly related PRs

• fix(noShadow): ts overloads #9360: Modifies the same crates/biome_js_analyze/src/lint/nursery/no_shadow.rs to exclude type-only parameter contexts (handles function-type parameters and overload signatures).

Suggested reviewers

• ematipico

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: fixing the noShadow rule to ignore parameters in function type signatures, which is the primary objective of this PR.
Description check	✅ Passed	The description is clearly related to the changeset, explaining the issue, the rationale, and the implementation approach with a concrete example.
Linked Issues check	✅ Passed	The PR successfully addresses issue #9482 by adding the is_inside_function_type() helper and extending evaluate_shadowing() to exclude bindings in TsFunctionType, directly meeting the core requirement.
Out of Scope Changes check	✅ Passed	All changes are scoped to the noShadow rule fix and the changeset entry. No unrelated modifications are present; the implementation follows the established pattern used for type-only parameter checks.

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🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[dyc3]

Needs a changeset

[dyc3]

nit: the pointer is misaligned

[codspeed-hq]

Merging this PR will not alter performance

✅ 58 untouched benchmarks
⏩ 156 skipped benchmarks¹

---

_{Comparing sudabg:fix/no-shadow-function-type (9baba0d) with main (1710cf1)²}

Footnotes

1. 156 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 (cd51722) during the generation of this report, so 1710cf1 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[dyc3]

Actually, looking at the snapshot diff, I'm not convinced this is a complete fix

[ematipico]

That's a bot, I'll close the PR