filter function overload broken into multiple lines

core.ts

export function filter<T, U extends T>(
    array: T[],
    f: (x: T) => x is U
  ) : U[];
export function filter<T>(
    array: T[],
    f: (x: T) => boolean
  ) : T[];
export function filter<T, U extends T>(
    array: ReadonlyArray<T>,
    f: (x: T) => x is U
  ): ReadonlyArray<U>;
export function filter<T, U extends T>(
    array: ReadonlyArray<T>,
    f: (x: T) => boolean
  ): ReadonlyArray<T>;
export function filter<T>(
    array: T[],
    f: (x: T) => boolean
  ): T[] {