unsafePerformIO exists, though. I suppose Safe Haskell might provide what you want, but (as someone mentioned elsewhere), the point of evaluating a pure functio

unsafePerformIO exists, though. I suppose Safe Haskell might provide what you want, but (as someone mentioned elsewhere), the point of evaluating a pure function is to use its result somehow; a pure function that is supposed to look up a bitcoin address in a Map, but is changed to always return a constant one, could be just as bad of a backdoor.