return navigableKeySet();
  }

  @Override
  public NavigableSet<K> descendingKeySet() {
    return descendingMap().navigableKeySet();
  }

  @Override
  public NavigableMap<K, V> descendingMap() {
    return new DescendingMap();
  }

  private final class DescendingMap extends Maps.DescendingMap<K, V> {
    @Override
    NavigableMap<K, V> forward() {
      return AbstractNavigableMap.this;
    }

          ImmutableMap<Range<Integer>, Integer> descendingMap = rangeMap.asDescendingMapOfRanges();
          assertEquals(expectedAsMap, asMap);
          assertEquals(expectedAsMap, descendingMap);
          SerializableTester.reserializeAndAssert(asMap);
          SerializableTester.reserializeAndAssert(descendingMap);
          assertEquals(
              ImmutableList.copyOf(asMap.entrySet()).reverse(),

    return navigableKeySet();
  }

  @Override
  public NavigableSet<K> descendingKeySet() {
    return descendingMap().navigableKeySet();
  }

  @Override
  public NavigableMap<K, V> descendingMap() {
    return new DescendingMap();
  }

  private final class DescendingMap extends Maps.DescendingMap<K, V> {
    @Override
    NavigableMap<K, V> forward() {
      return AbstractNavigableMap.this;
    }

          ImmutableMap<Range<Integer>, Integer> descendingMap = rangeMap.asDescendingMapOfRanges();
          assertEquals(expectedAsMap, asMap);
          assertEquals(expectedAsMap, descendingMap);
          SerializableTester.reserializeAndAssert(asMap);
          SerializableTester.reserializeAndAssert(descendingMap);
          assertEquals(
              ImmutableList.copyOf(asMap.entrySet()).reverse(),

  }

  @Override
  public NavigableSet<K> descendingKeySet() {
    return delegate.descendingKeySet();
  }

  @Override
  public NavigableMap<K, V> descendingMap() {
    return new SafeTreeMap<>(delegate.descendingMap());
  }

  @Override
  public Set<Entry<K, V>> entrySet() {
    return new AbstractSet<Entry<K, V>>() {
      private Set<Entry<K, V>> delegate() {

  }

  @Override
  public NavigableSet<K> descendingKeySet() {
    return delegate.descendingKeySet();
  }

  @Override
  public NavigableMap<K, V> descendingMap() {
    return new SafeTreeMap<>(delegate.descendingMap());
  }

  @Override
  public Set<Entry<K, V>> entrySet() {
    return new AbstractSet<Entry<K, V>>() {
      private Set<Entry<K, V>> delegate() {

      super(delegate);
    }

    @Override
    public NavigableMap<K, V> create(Object... entries) {
      NavigableMap<K, V> map = (NavigableMap<K, V>) delegate.create(entries);
      return map.descendingMap();
    }

    @Override
    public Iterable<Entry<K, V>> order(List<Entry<K, V>> insertionOrder) {
      insertionOrder = castOrCopyToList(delegate.order(insertionOrder));
      reverse(insertionOrder);

      super(delegate);
    }

    @Override
    public NavigableMap<K, V> create(Object... entries) {
      NavigableMap<K, V> map = (NavigableMap<K, V>) delegate.create(entries);
      return map.descendingMap();
    }

    @Override
    public Iterable<Entry<K, V>> order(List<Entry<K, V>> insertionOrder) {
      insertionOrder = castOrCopyToList(delegate.order(insertionOrder));
      reverse(insertionOrder);

  }

  @CollectionSize.Require(SEVERAL)
  public void testDescendingNavigation() {
    List<Entry<K, V>> descending = new ArrayList<>(navigableMap.descendingMap().entrySet());
    Collections.reverse(descending);
    assertEquals(entries, descending);
  }

  @CollectionSize.Require(absent = ZERO)
  public void testHeadMapExclusive() {

    }

    @Override
    public @Nullable Entry<K, V> pollLastEntry() {
      return standardPollLastEntry();
    }

    @Override
    public NavigableMap<K, V> descendingMap() {
      return new StandardDescendingMap();
    }

    @Override
    public NavigableSet<K> navigableKeySet() {
      return new StandardNavigableKeySet();
    }

    @Override