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=5.8.2&fileType=.tsx&code=MYewdgzgLgBAtgTwGIFczCgS3DAvDAHgBkBDAIwFMAbGCgDygrABMIZoAnTMAcwD4AFFXLUAXDFKUqASjx8YAbwBQMGKEixhUgEzjJ1PDC3UA3CrXgIIKhQB0VEDyEiq26WYC%2BQA&eslintrc=N4KABGBEBOCuA2BTAzpAXGUEKQAIBcBPABxQGNoBLY-AWhXkoDt8B6Jge1tiacTJTIAhtEK0ipWsRFCAtonyJoqDJCXQO0SODABfELqA&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eAcgK6qoDCAFutAGsylBm3TgwAXxCSgA&tokens=false

Repro Code

const myFunction = <Label extends string>(label: Label) => {
  const label2: Label = label;
  console.log(label2);
}

ESLint Config

module.exports = {
  parser: "@typescript-eslint/parser",
  rules: {
    "@typescript-eslint/no-unnecessary-type-parameters": "error",
  },
};

tsconfig

{
  "compilerOptions": {
    // ...
  }
}

Expected Result

When a type parameter is used only once in the function signature, but also referenced elsewhere in the function, the error should not be thrown.

Actual Result

tseslint doesn't seem to detect the second reference to the type outside the signature.

Additional Info

const label2: Label = label is redundant and has no real world use, but it is the minimum code to reproduce it. I've ran into this error a few times when manipulation objects with a value of type Label[] for example.