rb_vm_rewrite_cref  254 class.c        	rb_vm_rewrite_cref(me->def->body.iseq.cref, old_klass, new_klass, &new_cref);
rb_vm_rewrite_cref 1069 vm_core.h      void rb_vm_rewrite_cref(rb_cref_t *node, VALUE old_klass, VALUE new_klass, rb_cref_t **new_cref_ptr);