final SetBuilderImpl<E> combine(SetBuilderImpl<E> other) {
      SetBuilderImpl<E> result = this;
      for (int i = 0; i < other.distinct; i++) {
        /*
         * requireNonNull is safe because we ensure that the first `distinct` elements have been
         * populated.
         */
        result = result.add(requireNonNull(other.dedupedElements[i]));
      }
      return result;
    }

    }

    @CanIgnoreReturnValue
    Builder<K, V> combine(Builder<K, V> other) {
      checkNotNull(other);
      ensureCapacity(this.size + other.size);
      System.arraycopy(
          other.alternatingKeysAndValues,
          0,
          this.alternatingKeysAndValues,
          this.size * 2,
          other.size * 2);
      this.size += other.size;
      return this;
    }

               * with two implementations, one that contains causeless Cancellation instances and
               * the other of which creates new Cancellation instances each time it's called? Yet
               * another alternative is to fill in a non-null value for each of the fields no matter
               * what and to just not use it if !GENERATE_CANCELLATION_CAUSES.
               */
              : requireNonNull(

    }

    @CanIgnoreReturnValue
    @Override
    Builder<E> combine(ImmutableSet.Builder<E> builder) {
      copyIfNecessary();
      Builder<E> other = (Builder<E>) builder;
      for (int i = 0; i < other.n; i++) {
        add(other.elements[i]);
      }
      return this;
    }

    /**
     * Returns a newly-created {@code ImmutableSortedSet} based on the contents of the {@code

   *
   * <p>If {@code expectedSize} is exactly the number of entries added to the builder before {@link
   * Builder#build} is called, the builder is likely to perform better than an unsized {@link
   * #builder()} would have.
   *
   * <p>It is not specified if any performance benefits apply if {@code expectedSize} is close to,
   * but not exactly, the number of entries added to the builder.

   * {@link TreeSet} or the {@link Map#keySet} of an {@code IdentityHashMap}.
   *
   * <p><b>Note:</b> The returned view performs slightly better when {@code set1} is the smaller of
   * the two sets. If you have reason to believe one of your sets will generally be smaller than the
   * other, pass it first. Unfortunately, since this method sets the generic type of the returned

   *
   * <p><b>Performance note:</b> According to our
   * benchmarking
   * on Open JDK 7, {@link #immutableSortedCopy} generally performs better (in both time and space)
   * than this method, and this method in turn generally performs better than copying the list and
   * calling {@link Collections#sort(List)}.
   */
  // TODO(kevinb): rerun benchmarks including new options

     * LF<? extends @Nullable V>. That might be better: There's currently no difference between the
     * outputs users get when calling this with <Foo> and calling it with <@Nullable Foo>. The only
     * difference is that calling it with <Foo> won't work when an input Future has a @Nullable
     * type. So why even make that error possible by giving callers the choice?
     *

  }

  /**
   * Not supported. Use {@link #naturalOrder}, which offers better type-safety, instead. This method
   * exists only to hide {@link ImmutableMultiset#builder} from consumers of {@code
   * ImmutableSortedMultiset}.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Use {@link ImmutableSortedMultiset#naturalOrder}, which offers better type-safety.
   */
  @DoNotCall("Use naturalOrder.")
  @Deprecated

  public final <T extends @Nullable Object> T[] toArray(T[] other) {
    checkNotNull(other);
    int size = size();

    if (other.length < size) {
      Object[] internal = internalArray();
      if (internal != null) {
        return Platform.copy(internal, internalArrayStart(), internalArrayEnd(), other);
      }
      other = ObjectArrays.newArray(other, size);
    } else if (other.length > size) {
      other[size] = null;
    }