Goal:
  
  A : Type
  B : Type
  C : Type
  R : A → B → C → Type
  l0 : list A
  l1 : list B
  l : list C
  a : All3 R l0 l1 l
  b : All3 R l0 l1 l
  e : a = b
  ============================
   (noConfusionHom_All3_obligation_1 A B C R l0 l1 l a b
      (noConfusionHom_All3_obligation_2 A B C R l0 l1 l a b e) = e)


DEBUG:Going to execute:
intros; CoreTactics.on_last_hyp ltac:(fun id => destruct id);
            CoreTactics.on_last_hyp
             ltac:(fun id =>
                     CoreTactics.destruct_sigma id; DepElim.depelim id);
            simpl