> Umm, that's part of the operational definition of a value based cache
> - it needs to keep things alive, so that if a different instance shows
> up with the same value, it will still get a cache hit.

If it only kept the return value alive, that wouldn't be a problem, it's indeed intuitively obvious that it has to do that in order to work. But what many people miss to notice is that it also keeps any arguments that were passed to the function alive. This is not intuitive, and as I demonstrated with my patch, not even necessary, so I think it might be worthwhile to at least mention this little implementation quirk.