lsubst n new (LCon lv t cn args) = let args' = map (lsubst n new) args in
                                       LCon lv t cn args'
lsubst n new (LCon lv t cn args) = let args' = map (lsubst n new) args in
                                       LCon lv t cn args'
lsubst n new (LCon lv t cn args) = let args' = map (lsubst n new) args in
                                       LCon lv t cn args'