diff --git a/src/userfunc.c b/src/userfunc.c
index 2bae9ef..cc41eed 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -574,6 +574,7 @@
     {
 	if (types_optional)
 	    ga_clear_strings(&argtypes);
+	ga_clear_strings(&newargs);
 	return white_error ? FAIL : NOTDONE;
     }
     *arg = s;