private @Nullable AvlNode<E> firstNode() {
    AvlNode<E> root = rootReference.get();
    if (root == null) {
      return null;
    }
    AvlNode<E> node;
    if (range.hasLowerBound()) {
      // The cast is safe because of the hasLowerBound check.
      E endpoint = uncheckedCastNullableTToT(range.getLowerEndpoint());
      node = root.ceiling(comparator(), endpoint);
      if (node == null) {
        return null;
      }

  private @Nullable AvlNode<E> firstNode() {
    AvlNode<E> root = rootReference.get();
    if (root == null) {
      return null;
    }
    AvlNode<E> node;
    if (range.hasLowerBound()) {
      // The cast is safe because of the hasLowerBound check.
      E endpoint = uncheckedCastNullableTToT(range.getLowerEndpoint());
      node = root.ceiling(comparator(), endpoint);
      if (node == null) {
        return null;
      }

    private final boolean positiveBoundedAbove;

    private final int size;

    ComplementRanges(ImmutableList<Range<C>> ranges) {
      this.ranges = ranges;
      this.positiveBoundedBelow = ranges.get(0).hasLowerBound();
      this.positiveBoundedAbove = Iterables.getLast(ranges).hasUpperBound();

      int size = ranges.size() - 1;
      if (positiveBoundedBelow) {
        size++;
      }

    }
  }

  /** Returns {@code true} if this range has a lower endpoint. */
  public boolean hasLowerBound() {
    return lowerBound != Cut.belowAll();
  }

  /**
   * Returns the lower endpoint of this range.
   *
   * @throws IllegalStateException if this range is unbounded below (that is, {@link
   *     #hasLowerBound()} returns {@code false})
   */
  public C lowerEndpoint() {
    return lowerBound.endpoint();

        && set.comparator() != Ordering.natural()
        && range.hasLowerBound()
        && range.hasUpperBound()) {
      checkArgument(
          set.comparator().compare(range.lowerEndpoint(), range.upperEndpoint()) <= 0,
          "set is using a custom comparator which is inconsistent with the natural ordering.");
    }
    if (range.hasLowerBound() && range.hasUpperBound()) {
      return set.subSet(

        && map.comparator() != Ordering.natural()
        && range.hasLowerBound()
        && range.hasUpperBound()) {
      checkArgument(
          map.comparator().compare(range.lowerEndpoint(), range.upperEndpoint()) <= 0,
          "map is using a custom comparator which is inconsistent with the natural ordering.");
    }
    if (range.hasLowerBound() && range.hasUpperBound()) {
      return map.subMap(

        && map.comparator() != Ordering.natural()
        && range.hasLowerBound()
        && range.hasUpperBound()) {
      checkArgument(
          map.comparator().compare(range.lowerEndpoint(), range.upperEndpoint()) <= 0,
          "map is using a custom comparator which is inconsistent with the natural ordering.");
    }
    if (range.hasLowerBound() && range.hasUpperBound()) {
      return map.subMap(