Goal:
    A : Type  B : Type  R : nat → A → B → Type  n : nat
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in
    noConfusionHom_All2i_obligation_1 A B R n [] [] All2i_nil All2i_nil
      (noConfusionHom_All2i_obligation_2 A B R n [] [] All2i_nil All2i_nil
         eq_refl) = eq_refl)


DEBUG:Going to execute:
match T with
           | context [ CoreTactics.block ] =>
               change T; CoreTactics.intros_until_block
           end