deprecated: ISO-Latin1 characters in identifiers, plus Illegal character

"[email protected] [ocaml_beginners]" <[email protected]> 26 Apr 2015 23:22:55 -0700

Newsgroups	gmane.comp.lang.ocaml.beginners
Message-ID	<[email protected]>

Something strange happens when I experiment with the get_intf.ml file from the Gen package at https://opam.ocaml.org/packages/gen/gen.0.2.4/

  If I select the whole content of the file and copy/paste it into my interpreter, everything executes fine.
  If, however, I use the #use directive, I get a warning plus an error message :

 #use??"gen_intf.ml";;;
Warning 3: deprecated: ISO-Latin1 characters in identifiers
Error: Illegal character (?)

  I don’t understand why using « ISO-Latin1 characters« in identifiers is wrong. Isn’t the ISO-Latin1 a very basic alphabet ?
 Also, the error message gives me no clue as to where the Illegal character is ?

   
 I’m using OCaml 4.02 on Yosemite, by the way.

Ewan