diff --git a/src/errors.h b/src/errors.h
index 6596199..c76afbc 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -256,4 +256,6 @@
 	INIT(= N_("E1115: assert_fails() fourth argument must be a number"));
 EXTERN char e_assert_fails_fifth_argument[]
 	INIT(= N_("E1116: assert_fails() fifth argument must be a string"));
+EXTERN char e_cannot_use_bang_with_nested_def[]
+	INIT(= N_("E1117: Cannot use ! with nested :def"));
 #endif