interface PromiseFulfilledResult<T> {
  status: 'fulfilled';
  value: T;
}

interface PromiseRejectedResult {
  status: 'rejected';
  reason: any;
}

type PromiseSettledResult<T> = PromiseFulfilledResult<T> | PromiseRejectedResult;

interface PromiseConstructor {
  /**
   * Creates a Promise that is resolved with an array of results when all
   * of the provided Promises resolve or reject.
   * @param values An array of Promises.
   * @returns A new Promise.
   */
  allSettled<T extends readonly unknown[] | readonly [unknown]>(values: T):
      Promise<{ -readonly [P in keyof T]: PromiseSettledResult<T[P] extends PromiseLike<infer U> ? U : T[P]> }>;

  /**
   * Creates a Promise that is resolved with an array of results when all
   * of the provided Promises resolve or reject.
   * @param values An array of Promises.
   * @returns A new Promise.
   */
  allSettled<T>(values: Iterable<T>): Promise<PromiseSettledResult<T extends PromiseLike<infer U> ? U : T>[]>;
}