private MapperConfiguration(MapperPrism mapperPrism) {
    this.mapperPrism = mapperPrism;

    if (mapperPrism.values.config() != null) {
      // TODO #737 Only a declared type makes sense here; Validate and raise graceful error;
      // Also validate that @MapperConfig is present
      this.config = (DeclaredType) mapperPrism.config();
      this.mapperConfigPrism = MapperConfigPrism.getInstanceOn(config.asElement());
    } else {
      this.config = null;
      this.mapperConfigPrism = null;
    }
  }