{-# LANGUAGE DataKinds, MultiParamTypeClasses, MagicHash, PolyKinds #-}

import GHC.Exts

class UNum r (a :: TYPE r) where
  add :: a -> a -> a

instance UNum IntRep Int# where
  add = (+#)

main :: IO ()
main = print (I# (add 2# 3#))