Fix 4.04 warnings

1 files changed, 5 insertions, 1 deletions

diff --git a/pretyping/reductionops.ml b/pretyping/reductionops.ml
index da3add2e5a..52f424f751 100644
--- a/pretyping/reductionops.ml
+++ b/pretyping/reductionops.ml
@@ -239,6 +239,9 @@ sig
   | Shift of int
   | Update of 'a
   and 'a t = 'a member list
+
+  exception IncompatibleFold2
+
   val pr : ('a -> Pp.std_ppcmds) -> 'a t -> Pp.std_ppcmds
   val empty : 'a t
   val is_empty : 'a t -> bool
@@ -413,6 +416,7 @@ struct
       | (_,_) -> false in
     compare_rec 0 stk1 stk2
 
+  exception IncompatibleFold2
   let fold2 f o sk1 sk2 =
     let rec aux o lft1 sk1 lft2 sk2 =
       let fold_array =
@@ -442,7 +446,7 @@ struct
 	  aux o lft1 (List.rev params1) lft2 (List.rev params2)
 	in aux o' lft1' q1 lft2' q2
       | (((Update _|App _|Case _|Proj _|Fix _| Cst _) :: _|[]), _) ->
-	raise (Invalid_argument "Reductionops.Stack.fold2")
+	raise IncompatibleFold2
     in aux o 0 (List.rev sk1) 0 (List.rev sk2)
 
   let rec map f x = List.map (function