tyHitMap :: HitMap
emptyHitMap = M.fromList
  [ (tRational, S.singleton tInteger)
  , (tInteger,  S.empty)
  ] where
  tRational = typeOf (undefined :: Rational)
  tInteger  = typeOf (undefined :: Integer )

i
emptyHitMap :: HitMap
emptyHitMap = M.fromList
  [ (tRational, S.singleton tInteger)
  , (tInteger,  S.empty)
  ] where
  tRational = typeOf (undefined :: Rational)
  tInteger  = typeOf (undefined :: Integer )
emptyHitMap = M.fromList
  [ (tRational, S.singleton tInteger)
  , (tInteger,  S.empty)
  ] where
  tRational = typeOf (undefined :: Rational)
  tInteger  = typeOf (undefined :: Integer )