declare const foo: string[];

declare const doThingWithIndex: (index: number) => void;

foo.forEach((value, index) => { // error: unicorn/no-array-for-each
  console.log(value);
  doThingWithIndex(index);
});

for (const index in foo) { // now triggers new errors: guard-for-in, typescript/no-for-in-array
  const value = foo[index]
  doThingWithIndex(index); // type error, because index is a string
}