That doesn't seem so bad to my eye, though. In Haskell terms it just means that any overloaded operators on Optional have to respect parametricity. If you need

That doesn't seem so bad to my eye, though. In Haskell terms it just means that any overloaded operators on Optional have to respect parametricity. If you need something more specifically typed then you can just use a new name. Is there a particular use case?