In the Reddit thread they have also linked this paper, "Precise Garbage Collection for C", by Jon Rafkind, Adam Wick, John Regehr and Matthew Flatt:
http://www.cs.utah.edu/~regehr/papers/ismm15-rafkind.pdf It contains some ideas (and it seems my idea of a standard optioanl onGC() method for unions/structs/classes is not so bad). Bye, bearophile
