[Caml-list] Problem with the compiler 3.12.1

[Claire Dross <claire.dross@lri.fr>]

Hello,

I am new to caml-list, so sorry in advance if it is not the right place 
to make this post. In a quite important piece of ocaml code, I have a 
function:

let matching_term terms env uf id (pats, subst) (seen, forms) =
     match pats, subst with
       | _, [] | [], _ -> seen, forms
       | t :: pats, _ -> fprintf fmt "   %a@." T.print t;
         let acc = matchpats env terms uf (subst, seen, id+1) t in
         let acc, seen, _ = List.fold_left (matchpats env env.fils uf)
           acc pats in
         seen, List.rev_append acc forms

Removing the print in the second case of the match changes the result of 
the compiled file (compiler 3.12.1) on one of my tests. T.print does not 
have side effects, it recursively prints a hashconsed term structure.

Do you have any idea of what the problem is ?

Thanks a lot,

Claire Dross