Goal:
  
  A : Type
  P : nat → A → Type
  Q : nat → A → Type
  n : nat
  hd : A
  tl : list A
  p : P n hd
  X : Alli P (S n) tl
  X0 : ∀ (n : nat) (x : A), P n x → Q n x
  X1 : Alli Q (S n) tl
  ============================
   (Q n hd)


DEBUG:Going to execute:
match goal with
           | |- _ → _ => intro; t_tauto_intuit
           | |- _ => t_reduce; t_solver
           end