@NotNull
  @Override
  public DfReferenceType dropNullability() {
    // Nullable constant is not constant anymore
    return new DfGenericObjectType(
      Set.of(), myConstraint, DfaNullability.UNKNOWN, myMutability, myJvmSpecialField, mySpecialFieldType, false);
  }
@NotNull
  @Override
  public DfReferenceType dropNullability()