Require Eqdep_dec.
(* Check the behaviour of Injection *)
(* Check that Injection tries Intro until *)
Unset Structural Injection.
injection 1.
apply n_Sn.
Qed.
injection H.
intros.
apply (n_Sn x H0).
Qed.
intros x y H.
injection H.
exact (fun H => H).
Qed.
intros.
injection H.
exact (fun H => H).
Qed.
Set Structural Injection.
(* Test injection as *)

Lemma l5 : forall x y z t : nat, (x,y) = (z,t) -> x=z.