Goal:
  
  A : Type
  P : list A → list A → A → A → Type
  Γ : list A
  H : All2_fold P Γ Γ
  ============================
   (All_fold (λ (Γ : list A) (d : A), P Γ Γ d d) Γ)


DEBUG:Going to execute:
(DepElim.is_introduced H; CoreTactics.block_goal;
             CoreTactics.revert_until H; CoreTactics.block_goal) ||
             (let H' := fresh H in
              intros until H'; CoreTactics.block_goal) ||
               (intros; CoreTactics.block_goal)