docs: private void assertTypeUniqueness(GraphQLType type, Map<String, GraphQLType> result) {
          GraphQLType existingType = result.get(type.getName());
          // do we have an existing definition
          if (existingType != null) {
              // type references are ok
              if (!(existingType instanceof GraphQLTypeReference || type instanceof GraphQLTypeReference))
                  // object comparison here is deliberate
                  if (existingType != type) {
                      throw new AssertException(format("All types within a GraphQL schema must have unique names. No two provided types may have the same name.\n" +
                                      "No provided type may have a name which conflicts with any built in types (including Scalar and Introspection types).\n" +
                                      "You have redefined the type '%s' from being a '%s' to a '%s'",
                              type.getName(), existingType.getClass().getSimpleName(), type.getClass().getSimpleName()));
                  }
          }
      }