// @lib: es2015

// test fix for #18112, type guard predicates should narrow returned element
function isNumber(x: any): x is number {
  return typeof x === "number";
}

const arrayOfStringsNumbersAndBooleans = ["string", false, 0, "strung", 1, true];
const foundNumber: number | undefined = arrayOfStringsNumbersAndBooleans.find(isNumber);

const readonlyArrayOfStringsNumbersAndBooleans = arrayOfStringsNumbersAndBooleans as ReadonlyArray<string | number | boolean>;
const readonlyFoundNumber: number | undefined = readonlyArrayOfStringsNumbersAndBooleans.find(isNumber);