A naive attempt at a refcounted class proxy

[aldanor via Digitalmars-d-learn]

This discussion: 
http://forum.dlang.org/thread/bqtcdpsopxmnfbjyrrzf@forum.dlang.org 
-- led me wondering if it would be possible to create some 
crippled version of a class proxy that is based on RefCounted and 
came up with something like this:

struct Box(T) if (is(T == class)) {
     @disable this();

     this(Args...)(Args args) {
         _payload._refCounted.initialize(new T(args));
     }

     private {
         struct _Box(T) {
             private T _instance;

             ~this() {
                 destroy(_instance);
             }
         }
         RefCounted!(_Box!T) _payload;
     }

     ~this() {
     }

     auto opDispatch(string name, Args...)(Args args) {
         return mixin("_payload._instance.%s(args)".format(name));
     }
}

which lets you create Box!SomeClass(args) and it will be 
refcounted unless you escape references and do other weird stuff.

It actually sort of seems to work at first glance, at least it 
seems like it does... But with my D experience being fairly 
limited I wonder what the potential pitfalls would be?

Full source code with example and stdout:
https://gist.github.com/aldanor/d5fb5e45ddf3dd2cb642