[Haskell-beginners] Type inference question

Given the following two function definitions: let func4 l = map (\y -> y+2) (filter (\z -> z `elem` [1..10]) (5:l)) let func4_pf = map (+2) . filter (`elem` [1..10]) . (5 :) which are equivalent, why does the first one have a type of func4 :: (Num a, Enum a) => [a] -> [a] while the second one has a type of func4_pf :: [Integer] -> [Integer] Shouldn't the types be the same?