Goal:
    A : Type  B : Type  R : nat → A → B → Type  n : nat  b : All2i R n [] []
  ============================
   (∀ (H := CoreTactics.block) (e : NoConfusionHom_All2i A B R n [] []
                                      All2i_nil b),
      let H0 := CoreTactics.block in
      noConfusionHom_All2i_obligation_2 A B R n [] [] All2i_nil b
        (noConfusionHom_All2i_obligation_1 A B R n [] [] All2i_nil b e) = e)


DEBUG:Going to execute:
fun id =>
             DepElim.generalize_sig id
              ltac:(fun id id' => DepElim.decompose_exists id id')