@GwtIncompatible
    Object writeReplace() {
    return super.writeReplace();
  }

  // This class is never actually serialized directly, but we have to make the
  // warning go away (and suppressing would suppress for all nested classes too)
  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

    static final Comparator<byte[]> BEST_COMPARATOR = getBestComparator();

    @SuppressWarnings({
      // b/345822163
      "SunApi",
      "deprecation",
      // The `deprecation` suppression is for Unsafe APIs that aren't deprecated under some versions
      "UnnecessaryJavacSuppressWarnings"
    })
    @VisibleForTesting
    enum UnsafeComparator implements LexicographicalComparator {
      INSTANCE;

            .createTestSuite());
    suite.addTest(
        ListTestSuiteBuilder.using(new UnhashableElementsImmutableListGenerator())
            .suppressing(ListHashCodeTester.getHashCodeMethod())
            .named("ImmutableList, unhashable values")
            .withFeatures(CollectionSize.ANY, ALLOWS_NULL_QUERIES)
            .createTestSuite());
    return suite;
  }

  @GwtIncompatible
    Object writeReplace() {
    return super.writeReplace();
  }

  // This class is never actually serialized directly, but we have to make the
  // warning go away (and suppressing would suppress for all nested classes too)
  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

  private static final class FailedService extends Throwable {
    FailedService(Service service) {
      super(
          service.toString(),
          service.failureCause(),
          false /* don't enable suppression */,
          false /* don't calculate a stack trace. */);
    }
  }

            .createTestSuite());
    suite.addTest(
        ListTestSuiteBuilder.using(new UnhashableElementsImmutableListGenerator())
            .suppressing(ListHashCodeTester.getHashCodeMethod())
            .named("ImmutableList, unhashable values")
            .withFeatures(CollectionSize.ANY, ALLOWS_NULL_QUERIES)
            .createTestSuite());
    return suite;
  }

           * populated.
           */
          return of(requireNonNull(dedupedElements[0]));
        default:
          /*
           * The suppression is safe because we ensure that the first `distinct` elements have been
           * populated.
           */
          @SuppressWarnings("nullness")
          Object[] elements =

     * ImmutableSortedSet#orderedBy}.
     */
    /*
     * TODO(cpovirk): use Object[] instead of E[] in the mainline? (The backport is different and
     * doesn't need this suppression, but we keep it to minimize diffs.) Generally be more clear
     * about when we have an Object[] vs. a Comparable[] or other array type in internalArray? If we

                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    suite.addTest(
        NavigableSetTestSuiteBuilder.using(new ImmutableSortedSetUnhashableGenerator())
            .suppressing(SetHashCodeTester.getHashCodeMethods())
            .named(ImmutableSortedSetTest.class.getName() + ", unhashable")
            .withFeatures(
                CollectionSize.ANY,

        E onlyElement = (E) requireNonNull(elements[0]);
        return of(onlyElement);
      default:
        /*
         * The suppression is safe because the callers promise to put non-null objects in the first
         * `length` array elements.
         */
        @SuppressWarnings("nullness")
        Object[] elementsWithoutTrailingNulls =