Review

14

com/google/javascript/jscomp/ConcreteType.java

createForTypes(Collection)

class ConcreteType {
  protected static ConcreteType createForTypes(Collection<ConcreteType> types) {
    if (types == null || types.size() == 0) {
      return NONE;
    } else if (types.size() == 1) {
      return types.iterator().next();
    } else {
      return new ConcreteUnionType(Sets.newHashSet(types));
    }
  }

}