Goal:
  
  A : Type
  B : Type
  P : B → A → A → Type
  Q : B → A → Type
  i : list B
  l : list A
  l' : list A
  ============================
   (All2 Q i l
    → OnOne2All P i l l'
      → OnOne2All (λ (i : B) (x y : A), P i x y × Q i x) i l l')


DEBUG:Going to execute:
intros a; induction 1; constructor; try inv a