Goal:
  
  A : Type
  P : list A → A → Type
  d : A
  Γ : list A
  a : All_fold P Γ
  p : P Γ d
  b : All_fold P (d :: Γ)
  ============================
   (∀ e : NoConfusionHom_All_fold A P (d :: Γ) (All_fold_cons P a p) b,
      let H := CoreTactics.block in
      noConfusionHom_All_fold_obligation_2 A P (d :: Γ) 
        (All_fold_cons P a p) b
        (noConfusionHom_All_fold_obligation_1 A P 
           (d :: Γ) (All_fold_cons P a p) b e) = e)


DEBUG:Going to execute:
match goal with
           | |- ?T => change (let _ := CoreTactics.block in T)
           end