Before You File a Bug Report Please Confirm You Have Done The Following...

• 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.

Playground Link

https://typescript-eslint.io/play/#ts=5.8.3&fileType=.tsx&code=C4TwDgpgBAQghgJygXigbwFBSgbQNZQCWAdlAM7AIkDmAugNwYC%2BjQA&eslintrc=N4KABGBEBOCuA2BTAzpAXGUEKQAIBcBPABxQGNoBLY-AWhXkoDt8B6MgeyeUuX0Ra1mAE0QAPRMNocARgCtEZOn0JJ0URNGgdokcGAC%2BIA0A&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eAcgK6qoDCAFutAGsylBm3TgwAXxCSgA&tokens=false

Repro Code

// the following seems to be valid syntax and is parsable:
type Bar = {
  [k in string];
};

// it gets auto-fixed into the following syntax error
type Bar = Record<string, type Bar = {
  [k in string];
};
>;

ESLint Config

module.exports = {
  parser: "@typescript-eslint/parser",
  rules: {
    "@typescript-eslint/consistent-indexed-object-style": "error",
  },
};

tsconfig

{
  "compilerOptions": {
    "strictNullChecks": true
  }
}

Expected Result

I expected the rule to either not have an auto-fix for this special-case, or auto-fix it into the following Record:

type Bar = Record<string, any>;

Actual Result

The rule auto-fixes this into invalid syntax:

type Bar = Record<string, type Bar = {
  [k in string];
};
>;

Additional Info

TSMappedType‘s type annotation can be undefined (source).

I noticed this while trying to add missing coverage in #11177.