@VisibleForTesting
  // We call the method only after checking that it's present.
  @IgnoreJRERequirement
  @SuppressWarnings({
    "Java8ApiChecker",
    "NewApi",
    // This method is a helper, which we call from a `finally` block, as recommended.
    "ReachabilityFenceUsage",
  })
  static void reachabilityFence(@Nullable Object o) {

    public Double get(int index) {
      checkElementIndex(index, size());
      return array[start + index];
    }

    @Override
    /*
     * This is an override that is not directly visible to callers, so NewApi will catch calls to
     * Collection.spliterator() where necessary.
     */
    @IgnoreJRERequirement
    public Spliterator.OfDouble spliterator() {
      return Spliterators.spliterator(array, start, end, 0);