# loadt "Library/words.ml";;
  ...

  # `word_join (word 10:int64) (word 20:int64)`;;
  Warning: inventing type variables
  val it : term =
    `(word_join:(64)word->(64)word->(?194629)word) (word 10) (word 20)`
  # `word_join (word 10:int64) (word 20:int64):int128`;;
  val it : term = `word_join (word 10) (word 20)`

  # print_types_of_subterms := 0;;
  val it : unit = ()
  # `word_join (word 10:int64) (word 20:int64)`;;
  Warning: inventing type variables
  val it : term = `word_join (word 10) (word 20)`
  # `word_join (word 10:int64) (word 20:int64):int128`;;
  val it : term = `word_join (word 10) (word 20)`

  # print_types_of_subterms := 2;;
  val it : unit = ()
  # `word_join (word 10:int64) (word 20:int64)`;;
  Warning: inventing type variables
  val it : term =
    `(word_join:(64)word->(64)word->(?194609)word) ((word:num->(64)word) 10)
    ((word:num->(64)word) 20)`
  # `word_join (word 10:int64) (word 20:int64):int128`;;
  val it : term =
    `(word_join:(64)word->(64)word->(128)word) ((word:num->(64)word) 10)
    ((word:num->(64)word) 20)`