feat(lint): implement useConsistentMethodSignatures from typescript-eslint

[Bertie690]

Summary

Works towards implementing #8780

Implements a new nursery rule useConsistentMethodSignatures with the same semantics as its parent TSEslint counterpart.

No code fix is currently implemented, so the issue is left open for someone else to try their hand.

Test Plan

4 new spec test files, plus around 1-2 dozen doctests.

Docs

see above

[changeset-bot]

🦋 Changeset detected

Latest commit: 6fe58c5

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]

Walkthrough

Adds a nursery linter rule useConsistentMethodSignatures that enforces a configured method-signature style (property or method) for TypeScript interfaces and type aliases. Implements the rule and its state (InconsistentMethodSignatureState), a public union AnyTsMethodSignatureLike with get_signature_style, and options types (UseConsistentMethodSignaturesOptions and MethodSignatureStyle). Adds tests and JSON configs for valid and invalid cases. The rule emits diagnostics when a node's signature style differs from the configured style and provides no automatic fixes.

Suggested reviewers

• ematipico
• dyc3

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: implementing a new lint rule useConsistentMethodSignatures from typescript-eslint.
Description check	✅ Passed	The description clearly relates to the changeset, explaining the implementation of a nursery rule with test plan and deferred autofix work.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

---

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[coderabbitai]

Actionable comments posted: 4

🤖 Fix all issues with AI agents

In @.changeset/shiny-hands-care.md:
- Line 24: The file .changeset/shiny-hands-care.md is missing a trailing
newline; open that markdown file and add a single newline character at the end
so the file ends with exactly one trailing newline (ensure no extra blank lines
are appended).

In
`@crates/biome_js_analyze/src/lint/nursery/use_consistent_method_signatures.rs`:
- Around line 240-245: Fix the typo in the doc comment for the
declare_node_union! block that defines AnyTsMethodSignatureLike: change the
string "orinterface" to "or interface" in the comment above the macro invocation
so the sentence reads "within a type alias or interface." Leave the macro name
declare_node_union! and the union members (TsMethodSignatureTypeMember |
TsPropertySignatureTypeMember) unchanged.
- Line 56: The documentation comment in use_consistent_method_signatures.rs
contains an incomplete sentence: "any `Event`s passed to the  `SpecialEvent`s" —
update the doc string for the rule (near the comment mentioning `Event` and
`SpecialEvent`) to complete the thought and clarify the relationship (for
example: "any `Event`s passed to the `SpecialEvent` handlers" or "any `Event`s
passed to `SpecialEvent`-typed parameters"), ensuring the sentence reads
grammatically and consistently references `Event` and `SpecialEvent`.
- Around line 114-118: The doctest in use_consistent_method_signatures.rs
contains invalid TypeScript syntax for the property type `genericProp<T, U>:
(arg: T) => U`; update the example so the property is typed as a generic
function type instead of placing type parameters on the property name (i.e.,
make `genericProp` have a type that declares `<T, U>` on the function itself and
then `(arg: T) => U`). Modify the snippet in the doctest for the `genericProp`
property accordingly so it is valid TypeScript.

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing Bertie690:method-signature-style (6fe58c5) with main (871b45e)}

Summary

✅ 58 untouched benchmarks
⏩ 95 skipped benchmarks¹

Footnotes

1. 95 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. ↩

[coderabbitai]

Actionable comments posted: 2

🤖 Fix all issues with AI agents

In
`@crates/biome_js_analyze/src/lint/nursery/use_consistent_method_signatures.rs`:
- Around line 248-253: Doc comment contains a typo "annotatation" — update the
comment inside the declare_node_union for AnyTsMethodSignatureLike (the union of
TsMethodSignatureTypeMember and TsPropertySignatureTypeMember) to correct
"annotatation" to "annotation" so the documentation reads properly.
- Around line 149-155: The JSON example in the doc comment for the rule
use_consistent_method_signatures contains an invalid trailing comma after
"method"; remove that trailing comma so the snippet becomes valid JSON (update
the docblock showing the "options" example in
use_consistent_method_signatures.rs to have "style": "method" without a
following comma).

🧹 Nitpick comments (1)

crates/biome_js_analyze/src/lint/nursery/use_consistent_method_signatures.rs (1)

188-192: Convert comment to rustdoc.

Per coding guidelines, use inline rustdoc documentation. The current comment uses // instead of ///.

Proposed fix

-// Struct containing info about an inconsistent method signature diagnostic.
+/// Struct containing info about an inconsistent method signature diagnostic.
 pub struct InconsistentMethodSignatureState {
     target_style: MethodSignatureStyle,
     node_style: MethodSignatureStyle,
 }

[ematipico]

Since the rule isn't finished (code fix missing), add issue_number to the rule metadata (check the contribution guide). You'll have to update the snapshots.

Then, update the PR description so that it doesn't close the relative issue

[Bertie690]

... how did merging into next break formatting

[Bertie690]

@dyc3 Rebased onto main as requested.

[dyc3]

There's still some CI failures

[Bertie690]

wow, these diagnostics are very helpful (not)

[Bertie690]

@dyc3
On second glance, it appears the problems arise from the doctest parser not recognizing code highlight ranges from Starlight and promptly erroring out.

The goal was to highlight lines 2-3 and 4-6 of the codeblock on the website, but it appears this will have to be shelved until the doctest code learns to ignore such patterns.

[dyc3]

That's fine, we can remove the syntax causing the error