在 VS 2013 中使用初始化列表初始化地图映射

I'm trying to initialize map of maps using C++11. My compiler is VS 2013 Express.

unordered_map<EnumType, unordered_map<string, string>> substitutions = {
    {
        Record::BasementType,
        {
            { "0", "" },
            { "1", "Slab or pier" },
            { "2", "Crawl" }
        }
    },
    {
        Record::BuildingStyle,
        {
            { "0", "" },
            { "1", "Ranch" },
            { "2", "Raised ranch" }
        }
    },
    // ... and so on
};

它已编译，但我在 ntdll.dll 中遇到断点.但是此代码的简化版本:

unordered_map<EnumType, unordered_map<string, string>> substitutions = {
    {
        Record::BasementType,
        {
            { "0", "" },
            { "1", "Slab or pier" },
            { "2", "Crawl" }
        }
    },
    // *nothing more*
};