checkNonNegative(--successorCount);

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

    /*
     * TODO(cpovirk): `return (V) removedValue` once our checker permits that.
     *
     * (We promoted a class of warnings into errors because sometimes they indicate real problems.

        .forAllPublicStaticMethods(Suppliers.class)
        .testNulls();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  @AndroidIncompatible // TODO(cpovirk): ClassNotFoundException: com.google.common.base.Function
  public void testSuppliersSerializable() throws Exception {
    new ClassSanityTester()
        .setDefault(Duration.class, Duration.ofSeconds(1))

 * #dispatch} is expected to be called concurrently, it is idempotent.
 */
@J2ktIncompatible
@GwtIncompatible
final class ListenerCallQueue<L> {
  // TODO(cpovirk): consider using the logger associated with listener.getClass().
  private static final LazyLogger logger = new LazyLogger(ListenerCallQueue.class);

  // TODO(chrisn): promote AppendOnlyCollection for use here.

    new ClassSanityTester().forAllPublicStaticMethods(Functions.class).testNulls();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  @AndroidIncompatible // TODO(cpovirk): ClassNotFoundException: com.google.common.base.Function
  // (I suspect that this and the other similar failures happen with ArbitraryInstances proxies.)
  public void testEqualsAndSerializable() throws Exception {

    actsLikeIteratorHelper(emptyList());
  }

  public void testPeekingIteratorBehavesLikeIteratorOnSingletonIterable() {
    actsLikeIteratorHelper(singletonList(new Object()));
  }

  // TODO(cpovirk): instead of skipping, use a smaller number of steps
  @GwtIncompatible // works but takes 5 minutes to run
  public void testPeekingIteratorBehavesLikeIteratorOnThreeElementIterable() {

   * process it; all should produce the same answer, the only difference should be the number of
   * process()/processRemaining() invocations, due to alignment.
   */
  @AndroidIncompatible // slow. TODO(cpovirk): Maybe just reduce iterations under Android.
  public void testExhaustive() throws Exception {
    Random random = new Random(0); // will iteratively make more debuggable, each time it breaks

    return !tooLow(t) && !tooHigh(t);
  }

  /**
   * Returns the intersection of the two ranges, or an empty range if their intersection is empty.
   */
  @SuppressWarnings("nullness") // TODO(cpovirk): Add casts as needed. Will be noisy and annoying...
  GeneralRange<T> intersect(GeneralRange<T> other) {
    checkNotNull(other);
    checkArgument(comparator.equals(other.comparator));

    if (elements.isEmpty()) {
      // We avoid allocating anything.
      return of();
    }
    // Collection<E>.toArray() is required to contain only E instances, and all we do is read them.
    // TODO(cpovirk): Consider using Object[] anyway.
    @SuppressWarnings("unchecked")
    E[] array = (E[]) elements.toArray();
    /*
     * For a Set, we guess that it contains no duplicates. That's just a guess for purpose of

    return !tooLow(t) && !tooHigh(t);
  }

  /**
   * Returns the intersection of the two ranges, or an empty range if their intersection is empty.
   */
  @SuppressWarnings("nullness") // TODO(cpovirk): Add casts as needed. Will be noisy and annoying...
  GeneralRange<T> intersect(GeneralRange<T> other) {
    checkNotNull(other);
    checkArgument(comparator.equals(other.comparator));

   */
  private void assertSuppressed(Suppression... expected) {
    assertEquals(ImmutableList.copyOf(expected), suppressor.suppressions);
  }

  // TODO(cpovirk): Just use addSuppressed+getSuppressed now that we can rely on it.
  /** Suppressor that records suppressions. */
  private static class TestSuppressor implements Closer.Suppressor {