diff --git a/scripts/tracetool b/scripts/tracetool
index a279c2c58b07b9dec275a9d28bece55e93329f91..5e77aa243d25539764491b3968ee19ae210b8808 100755
--- a/scripts/tracetool
+++ b/scripts/tracetool
@@ -506,10 +506,12 @@ EOF
     i=1
     for arg in $arglist
     do
-        # 'limit' is a reserved keyword
-        if [ "$arg" = "limit" ]; then
-          arg="_limit"
-        fi
+        # postfix reserved words with '_'
+        case "$arg" in
+            limit|in|next|self)
+                arg="${arg}_"
+                ;;
+        esac
         cat <<EOF
   $arg = \$arg$i;
 EOF