1 files changed, 1 insertions, 0 deletions
diff --git a/vm_core.h b/vm_core.h
index df186a0b58..c22621864e 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -221,6 +221,7 @@ struct rb_iseq_struct {
     int arg_size;
     VALUE *arg_opt_table;
     int arg_keyword;
+    int arg_keyword_check; /* if this is true, raise an ArgumentError when unknown keyword argument is passed */
     int arg_keywords;
     ID *arg_keyword_table;