Goal:
    A : Type  P : list A → A → Type  b : All_fold P []
  ============================
   (∀ (H := CoreTactics.block) (e : NoConfusionHom_All_fold A P []
                                      (All_fold_nil P) b),
      let H0 := CoreTactics.block in
      noConfusionHom_All_fold_obligation_2 A P [] 
        (All_fold_nil P) b
        (noConfusionHom_All_fold_obligation_1 A P [] (All_fold_nil P) b e) =
      e)


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