如何解决ActionScript 3(AS3)中的闭包问题

var obj:Object = { prop: "value" };
var func:Function = function():void {
    trace(obj.prop);
};
func = func.weakReference();

var obj:Object = { prop: "value" };
var func:Function = function(prop:String):void {
    trace(prop);
};
func = func.bind(null, obj.prop);

var dict:Dictionary = new Dictionary();
dict["obj"] = { prop: "value" };
var func:Function = function():void {
    trace(dict["obj"].prop);
};

var obj:Object = { prop: "value" };
var proxy:Proxy = new Proxy(obj, {});
var func:Function = function():void {
    trace(proxy.prop);
};