Eq :: Eq a => (a -> a) -> a -> a
fixEq f = go where
  go x | x == x'   = x'
       | otherwise = go x'
       where x' = f x
{-#
fixEq :: Eq a => (a -> a) -> a -> a
fixEq f = go where
  go x | x == x'   = x'
       | otherwise = go x'
       where x' = f x

fixEq f = go where
  go x | x == x'   = x'
       | otherwise = go x'
       where x' = f x
