assertNotSame(builder.contents, prevArray);
      prevArray = builder.contents;
      ImmutableSet<Integer> unused = builder.build();
    }
  }

  @GwtIncompatible // Builder impl
  public void testPresizedBuilderDedups() {
    ImmutableSet.Builder<String> builder = ImmutableSet.builderWithExpectedSize(4);
    builder.add("a");
    assertEquals(1, builder.size);
    builder.add("a");
    assertEquals(1, builder.size);