deps/v8/src/js/promise.js
function PromiseReject(r) {
  if (!IS_RECEIVER(this)) {
    throw MakeTypeError(kCalledOnNonObject, PromiseResolve);
  }
  if (this === GlobalPromise) {
    // Optimized case, avoid extra closure.
    var promise = PromiseCreateAndSet(kRejected, r);
    // The debug event for this would always be an uncaught promise reject,
    // which is usually simply noise. Do not trigger that debug event.
    %PromiseRejectEvent(promise, r, false);
    return promise;
  } else {
    var promiseCapability = NewPromiseCapability(this);
    %_Call(promiseCapability.reject, UNDEFINED, r);
    return promiseCapability.promise;
  }
}
function PromiseReject(r) {
  if (!IS_RECEIVER(this)) {
    throw MakeTypeError(kCalledOnNonObject, PromiseResolve);
  }
  if (this === GlobalPromise) {
    // Optimized case, avoid extra closure.
    var promise = PromiseCreateAndSet(kRejected, r);
    // The debug event for this would always be an uncaught promise reject,
    // which is usually simply noise. Do not trigger that debug event.
    %PromiseRejectEvent(promise, r, false);
    return promise;
  } else {
    var promiseCapability = NewPromiseCapability(this);
    %_Call(promiseCapability.reject, UNDEFINED, r);
    return promiseCapability.promise;
  }
}
ES#sec-promise.reject Promise.reject ( x )