Goal:
    A : Type  P : list A → A → Type  e : True
  ============================
   (noConfusionHom_All_fold_obligation_2 A P [] (All_fold_nil P)
      (All_fold_nil P)
      (noConfusionHom_All_fold_obligation_1 A P [] 
         (All_fold_nil P) (All_fold_nil P) e) = e)


DEBUG:Going to execute:
match type of H with
           | ?R ?x ?y =>
               let rhs := fresh in
               set (rhs := y) in *; pattern sigma rhs; clearbody rhs;
                destruct H; simpl
           end