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• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have searched for related issues and found none that matched my issue.
• I have read the FAQ and my problem is not listed.

Relevant Package

eslint-plugin

Playground Link

No response

Repro Code

// not applicable

ESLint Config

module.exports = {
  parser: "@typescript-eslint/parser",
  rules: {},
};

tsconfig

{
  "compilerOptions": {
    "allowArbitraryExtensions": true,
  }
}

Expected Result

I expected isDefinitionFile to return true for file names like .d.css.ts (or the more general form of {file basename}.d.{extension}.ts) when allowArbitraryExtensions is enabled.

Actual Result

The utility function doesn't seem to consider allowArbitraryExtensions.

Additional Info

This is a follow-up to the discussion in #10714 (comment).

TypeScript v5.0 added support for allowArbitraryExtensions. This seems to affect several rules that use the isDefinitionFile utility:

• no-empty-interface
• no-namespace
• no-shadow
• no-unused-vars
• no-useless-empty-export

Versions