I’m not as sure, several optimizations are only possible if we know that they can’t/won’t have side effects, and while the compiler can see it after inlining, h

I’m not as sure, several optimizations are only possible if we know that they can’t/won’t have side effects, and while the compiler can see it after inlining, having it part of the signature does help. Haskell is quite impressive on the performance front.