ImmutableSortedSet<E> set = headSet(e, true);
    return !set.isEmpty() ? set.last() : null;
  }

  public ImmutableSortedSet<E> headSet(E toElement, boolean inclusive) {
    checkNotNull(toElement);
    if (inclusive) {
      E tmp = higher(toElement);
      if (tmp == null) {
        return this;
      }
      toElement = tmp;
    }
    return headSet(toElement);
  }

        // Of course, we have to use binary search to find the precise
        // breakpoint...
        int lower = foundIndex;
        int upper = list.size() - 1;
        // Everything between lower and upper inclusive compares at >= 0.
        while (lower < upper) {
          int middle = (lower + upper + 1) >>> 1;
          int c = comparator.compare(list.get(middle), key);
          if (c > 0) {
            upper = middle - 1;

      derivedSuites.add(createSubmapSuite(parentBuilder, Bound.NO_BOUND, Bound.EXCLUSIVE));
      derivedSuites.add(createSubmapSuite(parentBuilder, Bound.INCLUSIVE, Bound.NO_BOUND));
      derivedSuites.add(createSubmapSuite(parentBuilder, Bound.INCLUSIVE, Bound.EXCLUSIVE));
    }

    return derivedSuites;
  }

  @Override
  protected SetTestSuiteBuilder<K> createDerivedKeySetSuite(TestSetGenerator<K> keySetGenerator) {

    }

    @Override
    public NavigableMap<K, V> headMap(@ParametricNullness K toKey, boolean inclusive) {
      return asMap(set.headSet(toKey, inclusive), function);
    }

    @Override
    public NavigableMap<K, V> tailMap(@ParametricNullness K fromKey, boolean inclusive) {
      return asMap(set.tailSet(fromKey, inclusive), function);
    }

    @Override

    }

    @Override
    public NavigableMap<K, V> headMap(@ParametricNullness K toKey, boolean inclusive) {
      return asMap(set.headSet(toKey, inclusive), function);
    }

    @Override
    public NavigableMap<K, V> tailMap(@ParametricNullness K fromKey, boolean inclusive) {
      return asMap(set.tailSet(fromKey, inclusive), function);
    }

    @Override

  public ImmutableSortedMap<K, V> headMap(K toKey) {
    checkNotNull(toKey);
    return newView(sortedDelegate.headMap(toKey));
  }

  ImmutableSortedMap<K, V> headMap(K toKey, boolean inclusive) {
    checkNotNull(toKey);
    if (inclusive) {
      K tmp = higher(toKey);
      if (tmp == null) {
        return this;
      }
      toKey = tmp;
    }
    return headMap(toKey);
  }

  @Override

   * value} is greater than {@code max}, {@code max} is returned.
   *
   * @param value the {@code short} value to constrain
   * @param min the lower bound (inclusive) of the range to constrain {@code value} to
   * @param max the upper bound (inclusive) of the range to constrain {@code value} to
   * @throws IllegalArgumentException if {@code min > max}
   * @since 21.0
   */

   * value} is greater than {@code max}, {@code max} is returned.
   *
   * @param value the {@code char} value to constrain
   * @param min the lower bound (inclusive) of the range to constrain {@code value} to
   * @param max the upper bound (inclusive) of the range to constrain {@code value} to
   * @throws IllegalArgumentException if {@code min > max}
   * @since 21.0
   */

   * value} is greater than {@code max}, {@code max} is returned.
   *
   * @param value the {@code short} value to constrain
   * @param min the lower bound (inclusive) of the range to constrain {@code value} to
   * @param max the upper bound (inclusive) of the range to constrain {@code value} to
   * @throws IllegalArgumentException if {@code min > max}
   * @since 21.0
   */

    @Override
    public NavigableSet<E> headSet(@ParametricNullness E toElement, boolean inclusive) {
      return filter(unfiltered().headSet(toElement, inclusive), predicate);
    }

    @Override
    public NavigableSet<E> tailSet(@ParametricNullness E fromElement, boolean inclusive) {
      return filter(unfiltered().tailSet(fromElement, inclusive), predicate);
    }
  }

  /**