ghci will (usually) tell you:

    phil@arod:~$ ghci
    GHCi, version 7.6.3: http://www.haskell.org/ghc/  :? for help
    Loading package ghc-prim ... linking ... done.
    Loading package integer-gmp ... linking ... done.
    Loading package base ... linking ... done.
    Prelude> :t take 5 . filter (\ _ -> True) . drop 3
    take 5 . filter (\ _ -> True) . drop 3 :: [a] -> [a]

So it’s a function from List of a to List of a