1 files changed, 1 insertions, 1 deletions
diff --git a/object.c b/object.c
index a0783e9ef7..26ced2c8d8 100644
--- a/object.c
+++ b/object.c
@@ -120,7 +120,7 @@ rb_obj_reveal(VALUE obj, VALUE klass)
 VALUE
 rb_obj_setup(VALUE obj, VALUE klass, VALUE type)
 {
-    VALUE ignored_flags = RUBY_FL_PROMOTED;
+    VALUE ignored_flags = RUBY_FL_PROMOTED | RUBY_FL_SEEN_OBJ_ID;
     RBASIC(obj)->flags = (type & ~ignored_flags) | (RBASIC(obj)->flags & ignored_flags);
     RBASIC_SET_CLASS(obj, klass);
     return obj;