diff --git a/otherlibs/systhreads/pervasives.ml b/otherlibs/systhreads/pervasives.ml
index cd4063f4b..a86f44d72 100644
--- a/otherlibs/systhreads/pervasives.ml
+++ b/otherlibs/systhreads/pervasives.ml
@@ -24,7 +24,7 @@ let failwith s = raise(Failure s)
 let invalid_arg s = raise(Invalid_argument s)
 
 exception Exit
-exception Assert_failure of string * int * int
+exception Assert_failure of (string * int * int)
 
 (* Comparisons *)
 
diff --git a/otherlibs/threads/pervasives.ml b/otherlibs/threads/pervasives.ml
index 1b501d83a..c9c4f32ab 100644
--- a/otherlibs/threads/pervasives.ml
+++ b/otherlibs/threads/pervasives.ml
@@ -25,7 +25,7 @@ let failwith s = raise(Failure s)
 let invalid_arg s = raise(Invalid_argument s)
 
 exception Exit
-exception Assert_failure of string * int * int
+exception Assert_failure of (string * int * int)
 
 (* Comparisons *)