As I said, it's about making costs explicit. Otherwise, you're relying on the compiler's escape analysis to choose whether to allocate something on the heap or

As I said, it's about making costs explicit. Otherwise, you're relying on the compiler's escape analysis to choose whether to allocate something on the heap or the stack. A programmer might not realize that something escapes, and thus, there is a heap allocation that the programmer thought was a stack allocation. It's worth something to be able to say, "put this on the stack dammit" and if it can't go on the stack safely, require that the compiler yell at you.