1 files changed, 1 insertions, 0 deletions
diff --git a/object.c b/object.c
index 3574c6f23a..cfc1f125c6 100644
--- a/object.c
+++ b/object.c
@@ -113,6 +113,7 @@ rb_obj_dup(obj)
     }
     if (!SPECIAL_CONST_P(dup)) {
 	OBJSETUP(dup, rb_obj_type(obj), BUILTIN_TYPE(obj));
+	OBJ_INFECT(dup, obj);
     }
     return dup;
 }