Dyn doesn't have to lose the fact that it once held (Int -> Int). If you have a function that is (Dyn -> Dyn), then it's true that you can't get (Int -> Int) o

Dyn doesn't have to lose the fact that it once held (Int -> Int). If you have a function that is (Dyn -> Dyn), then it's true that you can't get (Int -> Int) out of that, but you don't actually have one of those so that shouldn't be surprising.