I wonder how this behaves in combination with __attribute__((cleanup(...))). Especially if the to be cleaned variable is passed into the tail function as parameter.
You get an error that tail call can't be performed which is kind of the point of tailcall attribute. Same thing with regular c++ destructors or dozen other language features which interfere with tail calls, no need for extensions like __attribute__((cleanup()).
https://godbolt.org/z/Yex74Wjz7