diff --git a/loopy/check.py b/loopy/check.py
index c8a36a5e7d35ae4a052591b0e6baceee810d494b..ce40fbaa70a78570822b2a9f340dfb119e0fcf20 100644
--- a/loopy/check.py
+++ b/loopy/check.py
@@ -53,7 +53,8 @@ def check_identifiers_in_subst_rules(knl):
             raise LoopyError("kernel '%s': substitution rule '%s' refers to "
                     "identifier(s) '%s' which are neither rule arguments nor "
                     "kernel-global identifiers"
-                    % (knl.name, ", ".join(deps-rule_allowed_identifiers)))
+                    % (knl.name, rule.name,
+                       ", ".join(deps-rule_allowed_identifiers)))
 
 # }}}