This discussion is all sorts of wrong. Whoever said that defargs are metadata (Manu?) was right. Therefore it would make sense to implement a general metadata facility for D and use *that* for defargs. C++11 has annotations, so that's the place to start looking at. D has already enough of those pesky special case features, let's not add yet another one at the expense of a more general metadata/annotation mechanism which eventually would be added anyway due to popular demand.