Goal:
  
  A : Type
  P : A → Prop
  p : A → bool
  q : A → bool
  H : ∀ x : A, P x → p x = q x
  ============================
   (true = true)


DEBUG:Going to execute:
match goal with
           | |- ?X1 → ?X2 => intro
           | |- ¬ _ => unfold not at 1; intro
           end