assertEquals(ImmutableSortedMap.of(2, 0), Maps.subMap(map, Range.open(0, 4)));
    assertEquals(ImmutableSortedMap.of(4, 0), Maps.subMap(map, Range.open(2, 6)));
    assertEquals(ImmutableSortedMap.of(4, 0, 6, 0), Maps.subMap(map, Range.open(3, 7)));
    assertEquals(empty, Maps.subMap(map, Range.open(20, 30)));

    assertEquals(map, Maps.subMap(map, Range.openClosed(0, 12)));

    assertEquals(ImmutableSortedMap.of(2, 0), Maps.subMap(map, Range.open(0, 4)));
    assertEquals(ImmutableSortedMap.of(4, 0), Maps.subMap(map, Range.open(2, 6)));
    assertEquals(ImmutableSortedMap.of(4, 0, 6, 0), Maps.subMap(map, Range.open(3, 7)));
    assertEquals(empty, Maps.subMap(map, Range.open(20, 30)));

    assertEquals(map, Maps.subMap(map, Range.openClosed(0, 12)));

    List<Feature<?>> features = new ArrayList<>();
    features.add(NoRecurse.SUBMAP);
    features.addAll(parentBuilder.getFeatures());

    return newBuilderUsing(delegate, to, from)
        .named(parentBuilder.getName() + " subMap " + from + "-" + to)
        .withFeatures(features)
        .suppressing(parentBuilder.getSuppressedTests())

      } else if (from == Bound.EXCLUSIVE && to == Bound.EXCLUSIVE) {
        return map.subMap(firstExclusive, false, lastExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.INCLUSIVE) {
        return map.subMap(firstExclusive, false, lastInclusive, true);
      } else if (from == Bound.INCLUSIVE && to == Bound.INCLUSIVE) {
        return map.subMap(firstInclusive, true, lastInclusive, true);
      } else {

    /**
     * Usually the same as map, but smaller for the headMap(), tailMap(), or subMap() of a
     * SortedAsMap.
     */
    final transient Map<K, Collection<V>> submap;

    AsMap(Map<K, Collection<V>> submap) {
      this.submap = submap;
    }

    @Override
    protected Set<Entry<K, Collection<V>>> createEntrySet() {
      return new AsMapEntries();

    return descendingMap().navigableKeySet();
  }

  /**
   * A sensible definition of {@link #subMap(Object, Object)} in terms of {@link #subMap(Object,
   * boolean, Object, boolean)}. If you override {@code subMap(K, boolean, K, boolean)}, you may
   * wish to override {@code subMap} to forward to this implementation.
   */
  @Override
  protected SortedMap<K, V> standardSubMap(

   * This method returns a {@code ImmutableSortedMap}, consisting of the entries whose keys ranges
   * from {@code fromKey}, inclusive, to {@code toKey}, exclusive.
   *
   * <p>The {@link SortedMap#subMap} documentation states that a submap of a submap throws an {@link
   * IllegalArgumentException} if passed a {@code fromKey} less than an earlier {@code fromKey}.
   * However, this method doesn't throw an exception in that situation, but instead keeps the

    List<Feature<?>> features = new ArrayList<>();
    features.add(NoRecurse.SUBMAP);
    features.addAll(parentBuilder.getFeatures());

    return newBuilderUsing(delegate, to, from)
        .named(parentBuilder.getName() + " subMap " + from + "-" + to)
        .withFeatures(features)
        .suppressing(parentBuilder.getSuppressedTests())

    return Maps.keyOrNull(higherEntry(key));
  }

  abstract Iterator<Entry<K, V>> descendingEntryIterator();

  @Override
  public SortedMap<K, V> subMap(@ParametricNullness K fromKey, @ParametricNullness K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  @Override
  public SortedMap<K, V> headMap(@ParametricNullness K toKey) {
    return headMap(toKey, false);
  }

  @Override

      } else if (from == Bound.EXCLUSIVE && to == Bound.EXCLUSIVE) {
        return map.subMap(firstExclusive, false, lastExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.INCLUSIVE) {
        return map.subMap(firstExclusive, false, lastInclusive, true);
      } else if (from == Bound.INCLUSIVE && to == Bound.INCLUSIVE) {
        return map.subMap(firstInclusive, true, lastInclusive, true);
      } else {