Goal:
  
  ============================
   (∀ (A : Type) (l : list A) (n0 : {n : nat | n < #|l|}) 
      (hd : A) (tl : list A),
      hd :: tl = l → ∀ n : nat, S n = proj1_sig n0 → n < #|tl|)


DEBUG:Going to execute:
intros