} else {
      return subListUnchecked(fromIndex, toIndex);
    }
  }

  /**
   * Called by the default implementation of {@link #subList} when {@code toIndex - fromIndex > 1},
   * after index validation has already been performed.
   */
  ImmutableList<E> subListUnchecked(int fromIndex, int toIndex) {
    return new SubList(fromIndex, toIndex - fromIndex);
  }

  class SubList extends ImmutableList<E> {

    return tailSetImpl(checkNotNull(fromElement), inclusive);
  }

  /*
   * These methods perform most headSet, subSet, and tailSet logic, besides
   * parameter validation.
   */
  abstract ImmutableSortedSet<E> headSetImpl(E toElement, boolean inclusive);

  abstract ImmutableSortedSet<E> subSetImpl(
      E fromElement, boolean fromInclusive, E toElement, boolean toInclusive);

    return tailSetImpl(checkNotNull(fromElement), inclusive);
  }

  /*
   * These methods perform most headSet, subSet, and tailSet logic, besides parameter validation.
   */
  @SuppressWarnings("MissingOverride") // Supermethod does not exist under GWT.
  abstract ContiguousSet<C> headSetImpl(C toElement, boolean inclusive);

    // The choice of the size() method to call here is arbitrary.  We assume that if any of the Set
    // methods executes the validation check, they all will, and thus we only need to test one of
    // them to ensure that the validation check happens and has the expected behavior.
    assertNodeRemovedFromGraphErrorMessage(
        assertThrows(IllegalStateException.class, n1AdjacentNodes::size));

    // The choice of the size() method to call here is arbitrary.  We assume that if any of the Set
    // methods executes the validation check, they all will, and thus we only need to test one of
    // them to ensure that the validation check happens and has the expected behavior.
    assertNodeRemovedFromGraphErrorMessage(
        assertThrows(IllegalStateException.class, n1AdjacentNodes::size));

    return tailSetImpl(checkNotNull(fromElement), inclusive);
  }

  /*
   * These methods perform most headSet, subSet, and tailSet logic, besides
   * parameter validation.
   */
  abstract ImmutableSortedSet<E> headSetImpl(E toElement, boolean inclusive);

  abstract ImmutableSortedSet<E> subSetImpl(
      E fromElement, boolean fromInclusive, E toElement, boolean toInclusive);

    } else {
      return subListUnchecked(fromIndex, toIndex);
    }
  }

  /**
   * Called by the default implementation of {@link #subList} when {@code toIndex - fromIndex > 1},
   * after index validation has already been performed.
   */
  ImmutableList<E> subListUnchecked(int fromIndex, int toIndex) {
    return new SubList(fromIndex, toIndex - fromIndex);
  }

  class SubList extends ImmutableList<E> {

      render: java
    validations:
      required: true

  - type: textarea
    attributes:
      label: How do you want it to be improved?
    validations:
      required: true

  - type: textarea
    attributes:
      label: Why do we need it to be improved?
    validations:
      required: true

  - type: textarea
    attributes:

      description: Please describe the issue you encountered.
    validations:
      required: true

  - type: textarea
    attributes:
      label: Example
      description: >
        Please provide a [Short, Self Contained, Correct (Compilable), Example](http://sscce.org/)
        demonstrating the bug.
      render: java
    validations:
      required: true

  - type: textarea
    attributes:

    // The choice of the size() method to call here is arbitrary.  We assume that if any of the Set
    // methods executes the validation check, they all will, and thus we only need to test one of
    // them to ensure that the validation check happens and has the expected behavior.
    assertNodeRemovedFromGraphErrorMessage(
        assertThrows(IllegalStateException.class, n1AdjacentNodes::size));