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


DEBUG:Going to execute:
match goal with
           | |- let _ := CoreTactics.block in _ => intros _
           | |- _ => try (intro; CoreTactics.intros_until_block)
           end