TS6205

All type parameters are unused.

Broken Code ❌

function identity<T, U>(value: T): T {
  return value;
}

This error occurs because the type parameter U is declared but not used anywhere in the function definition.

Fixed Code ✔️

Remove the unused type parameter to resolve the error:

function identity<T>(value: T): T {
  return value;
}

Alternatively, if U is necessary for future implementation, you can use it properly in the function:

function pair<T, U>(first: T, second: U): [T, U] {
  return [first, second];
}

This approach ensures all declared type parameters are actively used in the function.