Well if get rid of not just the heap, but the stack too... turn all variables into global ones, then it will be safe. This means we lose thread safety and func

Well if get rid of not just the heap, but the stack too... turn all variables into global ones, then it will be safe. This means we lose thread safety and functions become non-reentrant (but easy to prove safe - make sure graph of A-calls-B is a acyclical).