diff --git a/pl/errors.yap b/pl/errors.yap
index e77cc76ab..4d2af19a9 100644
--- a/pl/errors.yap
+++ b/pl/errors.yap
@@ -494,11 +494,11 @@ print_message(Level, Mss) :-
 	'$format'(user_error," ~s ", [S]).
 '$dump_error_token'(string(S)) :- !,
 	'$format'(user_error," ""~s""", [S]).
-'$dump_error_token'('(') :-
+'$dump_error_token'('(') :- !,
 	'$format'(user_error,"(", []).
-'$dump_error_token'(')') :-
+'$dump_error_token'(')') :- !,
 	'$format'(user_error," )", []).
-'$dump_error_token'(',') :-
+'$dump_error_token'(',') :- !,
 	'$format'(user_error," ,", []).
 '$dump_error_token'(A) :-
 	'$format'(user_error," ~a", [A]).