Well, yes, but those don't seem objectively superior. They all have problems to do with it being too easy to accidentally introduce space leaks or time leaks...

Well, yes, but those don't seem objectively superior. They all have problems to do with it being too easy to accidentally introduce space leaks or time leaks... (At least as far as I recall. If there's some documentation/papers that suggest otherwise, please link!) EDIT: I should say: FRPNow! seems to have cracked a bit of this puzzle and Neel Krishnaswami had a recent-ish (2014?) paper on avoiding both space and time leaks with static checking, but I don't think we have anything approaching the mainstream, unfortunately.