feat: add types to ESLint Scope

[fasttime]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request?

Add built-in types to ESLint Scope

What changes did you make? (Give an overview)

• Copied and updated types and tests from DefinitelyTyped
  • Added addGlobals() to ScopeManager
  • Marked globalScope in ScopeManager as nullable
  • Moved implicit from Scope to GlobalScope and added implicit.variables
  • Added missing Scope subclasses
  • Added @deprecated tag to deprecated members per https://github.com/eslint/eslint/blob/v10.0.0-alpha.0/docs/src/extend/scope-manager-interface.md
  • functionExpressionScope set to true or false depending on whether the Scope is FunctionExpressionNameScope
  • isArgumentsMaterialized() and isThisMaterialized() return true for Scope subclasses except FunctionScope
  • Fixed resolve() in Scope (the definition in @types/eslint-scope is very different, possibly unrelated)
  • Fixed several inconsistencies in PatternVisitor
• Enabled type checking for source files in packages/eslint-scope/lib to verify they match the type declarations
• Added npm scripts to test types
• Added "Are the types wrong?" CI job (currently for eslint-scope and espree)
• Linting *.ts and *.cts files
• Minor fixes in the logic:
  • Reference#isStatic() now always returns a boolean even when resolved is not set
  • ScopeManager#isImpliedStrict() now always returns a boolean even when the impliedStrict option is not set

Related Issues

fixes #708

Is there anything you'd like reviewers to focus on?

[fasttime]

Adapting the DefinitelyTyped types should be fine in terms of licensing, although I think it doesn't quite align with this project's guidelines:

js/packages/eslint-scope/CONTRIBUTING.md

Line 3 in 2ecfb8b

- You will only Submit Contributions where You have authored 100% of the content.

[Copilot]

Pull request overview

This PR adds built-in TypeScript type definitions to the ESLint Scope package, eliminating the need for separate @types/eslint-scope packages. The types were adapted from DefinitelyTyped with enhancements including nullable global scope, additional scope subclasses, deprecated member tags, and improved type safety through type checking of JavaScript source files.

Key changes:

• Added TypeScript declaration files (index.d.ts, index.d.cts) with comprehensive type definitions
• Enabled type checking for JavaScript source files using JSDoc annotations
• Added type testing infrastructure with npm scripts and CI workflow

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
packages/eslint-scope/tsconfig.json	TypeScript configuration for type-checking JavaScript source files
packages/eslint-scope/tests/types/tsconfig.json	TypeScript configuration for type test files
packages/eslint-scope/tests/types/types.test.ts	Comprehensive type tests covering all exported APIs
packages/eslint-scope/tests/types/cjs-import.test.cts	CommonJS import type test
packages/eslint-scope/package.json	Added type exports, dependencies, and scripts
packages/eslint-scope/lib/*.js	Added JSDoc type annotations to source files
packages/eslint-scope/lib/index.d.ts	ESM type declaration file (re-exports from .cts)
packages/eslint-scope/lib/index.d.cts	Main CommonJS type declaration file
eslint.config.js	Added TypeScript file linting configuration
package.json	Added TypeScript parser and expect-type plugin
.github/workflows/ci.yml	Added "Are the types wrong?" CI job

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[mdjermanovic]

This can also be JSXIdentifier.

[fasttime]

It's true, but we need to update the base interface Scope.Reference in ESLint first, because we can't broaden the type of the identifier member in the implementing class.

js/packages/eslint-scope/lib/index.d.cts

Line 568 in c6d38b2

export class Reference implements eslint.Scope.Reference {

[fasttime]

Now that the Reference type no longer extends ESLint'sScope.Reference, and the type test that checks Scope.reference is satisfied is temporarily disabled, I've updated identifier so it can be also JSXIdentifier now (ef22a28).

js/packages/eslint-scope/lib/index.d.cts

Line 617 in f5f0808

export class Reference {

js/packages/eslint-scope/tests/types/types.test.ts

Lines 492 to 493 in f5f0808

	// @ts-ignore -- needs update in ESLint types
	(reference: eslintScope.Reference) => reference satisfies eslint.Scope.Reference;

It should be possible to re-enable the type test once the current changes in the ESLint repo are released.

[github-actions]

Hi everyone, it looks like we lost track of this pull request. Please review and see what the next steps are. This pull request will auto-close in 7 days without an update.

[lumirlumir]

This looks like a good start!

I've left some comments throughout, especially regarding documentation updates.

[fasttime]

Okay, I think I've addressed all the feedback now.

[lumirlumir]

Thanks for all the hard work on the reviews!

I think I've gone through almost every file so far. I've left some more comments throughout.