Perhaps, but I always have spaces on either side when it's function composition.  Isn't there already an ambiguity?

-- I bet there's a quicker way to do this ...
module M where data M a = M a deriving (Show)
                            data T a = T a deriving (Show)
module M.T where f = (+1)
 
import M
import qualified M.T

f = (*2)
v1 = M . T . f $ 5
v2 = M.T.f $ 5

main = do { print v1; print v2; return () }