Goal:
  
  A : Type
  P : list A → list A → A → A → Type
  d : A
  Γ : list A
  H : All2_fold P Γ Γ
  p : P Γ Γ d d
  IHAll2_fold : ∀ (H := CoreTactics.block) (Γ0 : list A),
                  {| pr1 := Γ0; pr2 := Γ0 |} = {| pr1 := Γ; pr2 := Γ |}
                  → let H0 := CoreTactics.block in
                    let H1 := CoreTactics.block in
                    All_fold (λ (Γ : list A) (d : A), P Γ Γ d d) Γ0
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in
    All_fold (λ (Γ : list A) (d : A), P Γ Γ d d) (d :: Γ))


DEBUG:Going to execute:
cbn beta in hyp; eqns_specialize_eqs_block hyp;
            cbn[eq_rect_r eq_rect] in hyp