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 *)
(* Example submitted for Zenon *)

Axiom zenon_noteq : forall T : Type, forall t : T, ((t <> t) -> False).
Axiom zenon_notall : forall T : Type, forall P : T -> Prop,
(forall z : T, (~(P z) -> False)) -> (~(forall x : T, (P x)) -> False).