Let test_stack_unification_interaction_with_delta A
: (if negb _ then true else false) = if orb false (negb A) then true else false
:= eq_refl.
(* Test patterns unification *)
(* Feature introduced June 2011 *)

Lemma l7 : forall x (P:nat->Prop), (forall f, P (f x)) -> P (x+x).