Goal:
    A : Type  P : list A → A → Type
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in
    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) I) = I)


DEBUG:Going to execute:
match goal with
           | |- let _ := CoreTactics.block in ?T =>
                 match T with
                 | context [ CoreTactics.block ] =>
                     change T; CoreTactics.intros_until_block
                 end
           | _ => CoreTactics.unblock_goal
           end