data Foo = MkFoo

instance Eq Foo where
  (==) _ _ = False

instance Ord Foo where
  compare _ _ = LT

instance Num Foo where
  (+) _ _ = MkFoo
  (*) _ _ = MkFoo
  abs _ = MkFoo
  signum _ = MkFoo
  fromInteger _ = MkFoo
  negate _ = MkFoo

main = print $ 2 + 2 == (4 :: Foo)