@Override
    public ValueSetLink<K, V> getPredecessorInValueSet() {
      return requireNonNull(predecessorInValueSet); // see the comment on the class fields
    }

    @Override
    public ValueSetLink<K, V> getSuccessorInValueSet() {
      return requireNonNull(successorInValueSet); // see the comment on the class fields
    }

    @Override
    public void setPredecessorInValueSet(ValueSetLink<K, V> entry) {

   * unsupported type/method. E.g. "Class.isInstance".
   *
   * <p>As of Guava 20.0, this value is optional. We encourage authors who wish to describe why an
   * API is {@code @GwtIncompatible} to instead leave an implementation comment.
   */
  String value() default "";

    tester.testStaticMethods(PatternFilenameFilter.class, Visibility.PACKAGE); // currently none

    // The reason that we skip this method is discussed in a comment on the method.
    tester.ignore(PatternFilenameFilter.class.getMethod("accept", File.class, String.class));
    tester.testInstanceMethods(new PatternFilenameFilter(".*"), Visibility.PACKAGE);
  }

   * unsupported type/method. E.g. "Class.isInstance".
   *
   * <p>As of Guava 20.0, this value is optional. We encourage authors who wish to describe why an
   * API is {@code @GwtIncompatible} to instead leave an implementation comment.
   */
  String value() default "";

    checkSerialization(Predicates.equalTo(null));
  }

  /**
   * Tests for Predicates.instanceOf(x). TODO: Fix the comment style after fixing annotation
   * stripper to remove comments properly. Currently, all tests before the comments are removed as
   * well.
   */
  @GwtIncompatible // Predicates.instanceOf
  public void testIsInstanceOf_apply() {

    void forceJdk() {
      requireNonNull(impl); // see the comment on the field
      this.impl = new JdkBackedSetBuilderImpl<>(impl);
    }

    final void copyIfNecessary() {
      if (forceCopy) {
        copy();
        forceCopy = false;
      }
    }

    void copy() {
      requireNonNull(impl); // see the comment on the field
      impl = impl.copy();
    }

    @Override

      this.right = null;
    }

    /** Constructor for the header node. */
    AvlNode() {
      this.elem = null;
      this.elemCount = 1;
    }

    // For discussion of pred() and succ(), see the comment on the pred and succ fields.

    private AvlNode<E> pred() {
      return requireNonNull(pred);
    }

    private AvlNode<E> succ() {
      return requireNonNull(succ);
    }

   */
  @CanIgnoreReturnValue
  public static int checkElementIndex(int index, int size, String desc) {
    // Carefully optimized for execution by hotspot (explanatory comment above)
    if (index < 0 || index >= size) {
      throw new IndexOutOfBoundsException(badElementIndex(index, size, desc));
    }
    return index;
  }

  }

  /**
   * These tests fail in JDK 9 and JDK 10 for an unknown reason. It might be the test; it might be
   * the underlying functionality. Fixing this is not a high priority; if you need it to be fixed,
   * please comment on <a href="https://github.com/google/guava/issues/3086">issue 3086</a>.
   */
  private static boolean isJdk9OrHigher() {
    return JAVA_SPECIFICATION_VERSION.value().startsWith("9")

      checkPositive(++successorCount);

      if (orderedNodeConnections != null) {
        orderedNodeConnections.add(new NodeConnection.Succ<>(node));
      }
    }

    // See the comment on the similar cast in removeSuccessor.
    return previousSuccessor == null ? null : (V) previousSuccessor;
  }

  private static boolean isPredecessor(@CheckForNull Object value) {