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


DEBUG:Going to execute:
fun tauto_flags X1 X2 id =>
             <coq-core.plugins.tauto::flatten_contravariant_conj@0>