builder.add(-1);
    Object[] prevArray = null;
    for (int i = 0; i < 10; i++) {
      builder.add(i);
      assertNotSame(builder.contents, prevArray);
      prevArray = builder.contents;
      ImmutableSet<Integer> unused = builder.build();
    }
  }

  @GwtIncompatible("Builder impl")
  public void testPresizedBuilderDedups() {

   *
   * <p>A collection is considered immutable if:
   *
   * <ol>
   *   <li>All its mutation methods result in UnsupportedOperationException, and do not change the
   *       underlying contents.
   *   <li>All methods that return objects that can indirectly mutate the collection throw
   *       UnsupportedOperationException when those mutators are called.
   * </ol>
   *

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRetainAllIgnoresCount() {
    initThreeCopies();
    List<E> contents = Helpers.copyToList(getMultiset());
    assertFalse(getMultiset().retainAll(Collections.singleton(e0())));
    expectContents(contents);
  }

  /**
   * Returns {@link Method} instances for the remove tests that assume multisets support duplicates

   * the set is the same as the ordering of the given contents.
   */
  private static <E> void verifyLinkedHashSetContents(
      LinkedHashSet<E> set, Collection<E> contents) {
    assertEquals(
        "LinkedHashSet should have preserved order for iteration",
        new ArrayList<E>(set),
        new ArrayList<E>(contents));
    verifySetContents(set, contents);
  }

  /**

   * detected. This implementation may replace the entries in entryArray with its own entry objects
   * (though they will have the same key/value contents), and will take ownership of entryArray.
   */
  static <K, V> ImmutableMap<K, V> create(
      int n, @Nullable Entry<K, V>[] entryArray, boolean throwIfDuplicateKeys) {

import java.util.function.Function;
import java.util.stream.Collector;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link RangeMap} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * @author Louis Wasserman
 * @since 14.0
 */
@GwtIncompatible // NavigableMap
@ElementTypesAreNonnullByDefault

    throwIfUnchecked(throwable);
    throw new RuntimeException(throwable);
  }

  /**
   * Returns the innermost cause of {@code throwable}. The first throwable in a chain provides
   * context from when the error or exception was initially detected. Example usage:
   *
   * <pre>
   * assertEquals("Unable to assign a customer id", Throwables.getRootCause(e).getMessage());
   * </pre>
   *

   * PermittedMetaException}.
   */
  protected final class MultiExceptionListIterator implements ListIterator<E> {
    // TODO: track seen elements when order isn't guaranteed
    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**

    throwIfUnchecked(throwable);
    throw new RuntimeException(throwable);
  }

  /**
   * Returns the innermost cause of {@code throwable}. The first throwable in a chain provides
   * context from when the error or exception was initially detected. Example usage:
   *
   * <pre>
   * assertEquals("Unable to assign a customer id", Throwables.getRootCause(e).getMessage());
   * </pre>
   *

  }

  /**
   * Converts an iterable into a collection. If the iterable is already a collection, it is
   * returned. Otherwise, an {@link java.util.ArrayList} is created with the contents of the
   * iterable in the same iteration order.
   */
  private static <E extends @Nullable Object> Collection<E> castOrCopyToCollection(
      Iterable<E> iterable) {
    return (iterable instanceof Collection)