(* Recursive factorial and a simple property *)
(* Outer comment
   (* nested comment *)
*)
module Factorial

let rec fact (n:nat) : Tot nat =
  if n = 0 then 1
  else n * fact (n - 1)

// Winged-comment syntax per trait table
let banner = "fact 5 = "
let fact5_is_120 : Lemma (fact 5 == 120) = ()
