Being able to make recursive functions use the heap would be great. I assume it would need to be opt-in since you'll change performance characteristics, but I a

Being able to make recursive functions use the heap would be great. I assume it would need to be opt-in since you'll change performance characteristics, but I almost always rearrange recursive algorithms to use a loop and a heap allocated stack structure instead. There's no reason the compiler couldn't help do that for me.