1 files changed, 1 insertions, 0 deletions
diff --git a/object.c b/object.c
index fda6410274..174d8ccfc0 100644
--- a/object.c
+++ b/object.c
@@ -1662,6 +1662,7 @@ Init_Object()
     rb_define_method(rb_cClass, "allocate", rb_obj_alloc, 0);
     rb_define_method(rb_cClass, "new", rb_class_new_instance, -1);
     rb_define_method(rb_cClass, "initialize", rb_class_initialize, -1);
+    rb_define_method(rb_cClass, "initialize_copy", rb_class_init_copy, 1);
     rb_define_method(rb_cClass, "superclass", rb_class_superclass, 0);
     rb_define_alloc_func(rb_cClass, rb_class_s_alloc);
     rb_undef_method(rb_cClass, "extend_object");