T defaultConverter = (T) defaultConverter(convertFromType, convertToType);
      return defaultConverter;
    }
    if (type.getRawType().isInterface()) {
      return newDefaultReturningProxy(type);
    }
    return null;
  }

  private <F, T> Converter<F, T> defaultConverter(
      TypeToken<F> convertFromType, TypeToken<T> convertToType) {
    return new Converter<F, T>() {