[Haskell-cafe] Type problem

Why? Shouldn't this work for any type a? Michael ========== f :: [a] -> [a] f l = do x <- l          return x ========== *Main> :r [1 of 1] Compiling Main             ( test.hs, interpreted ) Ok, modules loaded: Main. *Main> f "abcde" "abcde" *Main> f [1,2,3,4,5] [1,2,3,4,5] *Main> "abcde" >>= f <interactive>:1:12:     Couldn't match expected type `Char' against inferred type `m b'     In the second argument of `(>>=)', namely `f'     In the expression: "abcde" >>= f     In the definition of `it': it = "abcde" >>= f *Main>