diff --git a/ChangeLog b/ChangeLog
index cc55005ce2..5fdf2d789c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Dec  2 07:20:21 2014  Eric Wong  <e@80x24.org>
+
+	* iseq.c (iseq_data_to_ary): keep hidden variables
+	  Thanks to wanabe [ruby-core:66566]
+
 Tue Dec  2 06:46:57 2014  Aaron Patterson <aaron@tenderlovemaking.com>
 
 	* ext/psych/lib/psych.rb: bumping version
diff --git a/iseq.c b/iseq.c
index fd0cbd8cd2..8a658d17f1 100644
--- a/iseq.c
+++ b/iseq.c
@@ -1717,7 +1717,12 @@ iseq_data_to_ary(rb_iseq_t *iseq)
     for (i=0; i<iseq->local_table_size; i++) {
 	ID lid = iseq->local_table[i];
 	if (lid) {
-	    if (rb_id2str(lid)) rb_ary_push(locals, ID2SYM(lid));
+	    if (rb_id2str(lid)) {
+		rb_ary_push(locals, ID2SYM(lid));
+	    }
+	    else { /* hidden variable from id_internal() */
+		rb_ary_push(locals, ULONG2NUM(lid));
+	    }
 	}
 	else {
 	    rb_ary_push(locals, ID2SYM(rb_intern("#arg_rest")));