}
  }

  @SuppressWarnings("unchecked")
  private RangeMap<K, V> emptySubRangeMap() {
    return (RangeMap<K, V>) (RangeMap<?, ?>) EMPTY_SUB_RANGE_MAP;
  }

  @SuppressWarnings("ConstantCaseForConstants") // This RangeMap is immutable.
  private static final RangeMap<Comparable<?>, Object> EMPTY_SUB_RANGE_MAP =
      new RangeMap<Comparable<?>, Object>() {
        @Override

    }
  }

  @SuppressWarnings("unchecked")
  private RangeMap<K, V> emptySubRangeMap() {
    return (RangeMap<K, V>) (RangeMap<?, ?>) EMPTY_SUB_RANGE_MAP;
  }

  @SuppressWarnings("ConstantCaseForConstants") // This RangeMap is immutable.
  private static final RangeMap<Comparable<?>, Object> EMPTY_SUB_RANGE_MAP =
      new RangeMap<Comparable<?>, Object>() {
        @Override

@SuppressWarnings({
  // We call threadUnexpectedException, which does the right thing for errors.
  "AssertionFailureIgnored",
  // We're following the upstream naming to reduce diffs.
  "IdentifierName",
  "ConstantCaseForConstants",
})
@NullUnmarked
abstract class JSR166TestCase extends TestCase {
  protected static final boolean expensiveTests = Boolean.getBoolean("jsr166.expensiveTests");

  /**