That’s an interesting reference! Although I doubt that a storeless approach will actually need less space than a … storeful machine with a garbage collector. Furthermore, by storing all heap bindings on the stack, it’s quite complicated to reclaim dead bindings. Well, you could copy collect the whole stack or relink stack frames… But the fundamental problem with space leaks is that some thunk retains a huge working set – nothing about moving the heap into the stack will change that.