prop_foldl xs n f x0 = n > 0 ==>
 runner1 (enumSpecial xs n (Iter.foldl f x0)) == P.foldl f x0 xs
  where types = (xs :: [Int], x0 :: Int)
prop_foldl xs n f x0 = n > 0 ==>
 runner1 (enumSpecial xs n (Iter.foldl f x0)) == P.foldl f x0 xs
  where types = (xs :: [Int], x0 :: Int)
prop_foldl xs n f x0 = n > 0 ==>
 runner1 (enumSpecial xs n (Iter.foldl f x0)) == P.foldl f x0 xs
  where types = (xs :: [Int], x0 :: Int)