return -1;
  }

  @Override
  public UnmodifiableIterator<C> iterator() {
    return emptyIterator();
  }

  @GwtIncompatible // NavigableSet
  @Override
  public UnmodifiableIterator<C> descendingIterator() {
    return emptyIterator();
  }

  @Override
  boolean isPartialView() {
    return false;
  }

  @Override
  public boolean isEmpty() {
    return true;
  }

  }

  @CollectionSize.Require(SEVERAL)
  public void testDescendingNavigation() {
    List<E> descending = new ArrayList<>();
    for (Iterator<E> i = navigableSet.descendingIterator(); i.hasNext(); ) {
      descending.add(i.next());
    }
    Collections.reverse(descending);
    assertEquals(values, descending);
  }

  public void testEmptySubSet() {

            }
          }
          return elemItr.next();
        }
      };
    }

    @Override
    @GwtIncompatible("NavigableSet")
    public UnmodifiableIterator<C> descendingIterator() {
      return new AbstractIterator<C>() {
        final Iterator<Range<C>> rangeItr = ranges.reverse().iterator();
        Iterator<C> elemItr = emptyIterator();

        @Override

        return equalsOrThrow(previous, last) ? null : domain.next(previous);
      }
    };
  }

  @GwtIncompatible // NavigableSet
  @Override
  public UnmodifiableIterator<C> descendingIterator() {
    return new AbstractSequentialIterator<C>(last()) {
      final C first = first();

      @Override
      protected @Nullable C computeNext(C previous) {

  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return elements.iterator();
  }

  @GwtIncompatible // NavigableSet
  @Override
  public UnmodifiableIterator<E> descendingIterator() {
    return elements.reverse().iterator();
  }

  @Override
  public Spliterator<E> spliterator() {
    return asList().spliterator();
  }

  @Override

  }

  @CollectionSize.Require(SEVERAL)
  public void testDescendingNavigation() {
    List<E> descending = new ArrayList<>();
    for (Iterator<E> i = navigableSet.descendingIterator(); i.hasNext(); ) {
      descending.add(i.next());
    }
    Collections.reverse(descending);
    assertEquals(values, descending);
  }

  public void testEmptySubSet() {

    public @Nullable E ceiling(E e) {
      synchronized (mutex) {
        return delegate().ceiling(e);
      }
    }

    @Override
    public Iterator<E> descendingIterator() {
      return delegate().descendingIterator(); // manually synchronized
    }

    transient @Nullable NavigableSet<E> descendingSet;

    @Override
    public NavigableSet<E> descendingSet() {

    public @Nullable E ceiling(E e) {
      synchronized (mutex) {
        return delegate().ceiling(e);
      }
    }

    @Override
    public Iterator<E> descendingIterator() {
      return delegate().descendingIterator(); // manually synchronized
    }

    transient @Nullable NavigableSet<E> descendingSet;

    @Override
    public NavigableSet<E> descendingSet() {

Lokio/internal/_BufferKt;
Lokio/internal/_ByteStringKt;
Lokio/internal/_PathKt;
PLandroidx/arch/core/internal/SafeIterableMap$DescendingIterator;-><init>(Landroidx/arch/core/internal/SafeIterableMap$Entry;Landroidx/arch/core/internal/SafeIterableMap$Entry;)V
PLandroidx/arch/core/internal/SafeIterableMap$DescendingIterator;->forward(Landroidx/arch/core/internal/SafeIterableMap$Entry;)Landroidx/arch/core/internal/SafeIterableMap$Entry;

    }

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

    @Override
    public Iterator<K> descendingIterator() {
      return descendingSet().iterator();
    }

    @Override
    public NavigableSet<K> subSet(
        @ParametricNullness K fromElement,
        boolean fromInclusive,