loc_after (Loc ll) = Loc $ loc_after_ ll
    where
        loc_after_ (l:[]) = [l+1]
        loc_after_ (l:ll) = l:(loc_after_ ll)
loc_after (Loc ll) = Loc $ loc_after_ ll
    where
        loc_after_ (l:[]) = [l+1]
        loc_after_ (l:ll) = l:(loc_after_ ll)
loc_after (Loc ll) = Loc $ loc_after_ ll
    where
        loc_after_ (l:[]) = [l+1]
        loc_after_ (l:ll) = l:(loc_after_ ll)