(* 1st-order unification did not work when in competition with pattern unif. *)
Set Implicit Arguments.

Lemma test : forall
(A : Type)
(B : Type)
(f : A -> B)
(S : B -> Prop)
(EV : forall y (f':A->B), (forall x', S (f' x')) -> S (f y))
(HS : forall x', S (f x'))
(x : A),
S (f x).