Ltac do_map_arg :=
match goal with |- ?a = ?b =>
match a with context [map ?x _] =>
match b with context [map ?y _] => replace y with x; auto end end end.

Lemma resource_at_joins2:
forall phi1 phi2,
level phi1 = level phi2 ->
(forall loc, constructive_joins (phi1 @ loc) (phi2 @ loc)) ->
joins phi1 phi2.