Visual Studio 2010 - CA1007中的代码分析警告

我已经在规则集中将CA1007打开为错误。然后我写了下面的代码来违反这个规则，但它仍然没有检测到警告或错误。不确定我在哪里犯了错误，是在代码中还是在规则集中?

class Program
{
    public static void Swap(ref object object1, ref object object2)
    {
        object temp = object1;
        object1 = object2;
        object2 = temp;
    }
    static void Main(string[] args)
    {
        string string1 = "Swap";
        string string2 = "It";
        object object1 = (object)string1;
        object object2 = (object)string2;
        Program.Swap(ref object1, ref object2);
        string1 = (string)object1;
        string2 = (string)object2;
        Console.WriteLine("{0} {1}", string1, string2);
        Console.ReadLine();
    }
}

有什么建议吗?谢谢!