Goal:
    A : Type  n : nat  hd : A  tl : list A  H : S n < #|hd :: tl|
  ============================
   (n < #|tl|)


DEBUG:Going to execute:
match goal with
           | |- well_founded _ => auto with *
           | |- ?T => match type of T with
                      | Prop => auto
                      end
           end