sorry and please forget the name and what it is meaning for.
just look at in syntax aspect

the error : "parse error on input `|'
Failed, modules loaded: none."

linerFind :: [Int] -> Int -> MaxSA -> MaxSA   --MaxSA is  MaximumSubarray
linerFind xs len  ms1@(MaxSA l h m)             -- (MaxSA leftPosition rightPosition maxsum)
  | h<len = keepFind ms1                             
                where keepFind ms'@(MaxSA l' h' m')=
                    let ms2@(MaxSA l2 h2 m2)= find' xs l' (h'+1) in
                    if m < m2 then linerFind xs len ms2
                    else keepFind ms2                                 
  |otherwise = ms1                                      --compiler say error is in  this line