Goal:
  
  A : Type
  B : Type
  R : A → B → Type
  R' : ∀ (a : A) (b : B), R a b → Type
  xs : list A
  ys : list B
  a : All2 R xs ys
  a0 : All2_dep R' a
  b : All2_dep R' a
  e : NoConfusionHom_All2_dep A B R R' xs ys a a0 b
  ============================
   (noConfusionHom_All2_dep_obligation_2 A B R R' xs ys a a0 b
      (noConfusionHom_All2_dep_obligation_1 A B R R' xs ys a a0 b e) = e)


DEBUG:Going to execute:
match goal with
           | |- ?f ?a ?b _ = _ => solve_noconf_hom_inv_eq a b
           | |- ?R ?a ?b =>
                 CoreTactics.destruct_sigma a; CoreTactics.destruct_sigma b;
                  destruct a; DepElim.depelim b; simpl in * |-;
                  CoreTactics.on_last_hyp
                   ltac:(fun id =>
                           hnf in id;
                            CoreTactics.destruct_tele_eq id ||
                              DepElim.depelim id); (solve
                  [ constructor || DepElim.simpl_equations; constructor ])
           end