Goal:
  
  A : Type
  P : list A → A → Type
  b : All_fold P []
  e : NoConfusionHom_All_fold A P [] (All_fold_nil P) b
  ============================
   (let H := 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:
CoreTactics.revert_until H
DEBUG LTAC Evaluated term: (let H := 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)