Goal:
  
  A : Type
  B : Type
  R : nat → A → B → Type
  n : nat
  l0 : list A
  l : list B
  a : All2i R n l0 l
  b : All2i R n l0 l
  H : NoConfusionHom_All2i A B R n l0 l a b
  ============================
   (a = b)


DEBUG:Going to execute:
match goal with
           | H:_ = _ |- _ = _ => try solve_noconf_hom_inv_equiv
           | H:_ = _ |- _ => try solve_noconf_prf
           | |- _ = _ => try solve_noconf_hom_inv
           end