模板结构的模板静态成员向量（C ++）

Question

我认为这段代码会比英语更好地解释自己：

namespace SC
{
struct GraphicalDatumBase
{
    struct SwitcherBase
    {
        virtual void switchBuffers(){}
    };

    static std::vector<SwitcherBase*> switchers;

    static void switchBuffers();

    virtual void update(){}
};

template<class Datum>
struct GraphicalDatum: public GraphicalDatumBase
{
    GraphicalDatum(Datum& originalDatum):
        originalDatum(originalDatum)
    {
        for(; doubleBufferIndex < doubleBuffers.size(); ++doubleBufferIndex)
        {
            if(doubleBuffers[doubleBufferIndex].isVacant)
            {
                doubleBuffers[doubleBufferIndex].occupy(originalDatum);
                return;
            }
        }

        doubleBuffers.emplace_back(originalDatum);
    }


    Datum& datum(){ return doubleBuffers[doubleBufferIndex].readBuffer(); }

    void update()
    {
        doubleBuffers[doubleBufferIndex].writeBuffer() = originalDatum;
        doubleBuffersToBeSwitched.push_back(doubleBufferIndex);
    }

private:

    struct DoubleBuffer
    {
        struct
        {
            uint8_t bufferSwitch:   1;
            uint8_t isVacant:       1;
        };

        Datum buffer0;
        Datum buffer1;

        DoubleBuffer(const Datum& original):
            bufferSwitch(0),
            isVacant(0),
            buffer0(original),
            buffer1(original){}

        void occupy(const Datum& original)
        {
            bufferSwitch = 0;
            isVacant = 0;
            buffer0 = original;
        }

        Datum& readBuffer(){ return (bufferSwitch? buffer1 : buffer0); }
        Datum& writeBuffer(){ return (bufferSwitch? buffer0 : buffer1); }

        void switchBuffer(){ bufferSwitch = !bufferSwitch; }
    };

    struct Switcher: public SwitcherBase
    {
        Switcher()
        {
            switchers.emplace_back(this);
        }

        void switchBuffers()
        {
            for(uint32_t d = 0; d < doubleBuffersToBeSwitched.size(); ++d)
            {
                doubleBuffers[doubleBuffersToBeSwitched[d]].switchBuffer();
            }
            doubleBuffersToBeSwitched.clear();
        }
    };

    static Switcher switcher;

    static std::vector<DoubleBuffer> doubleBuffers;
    static std::vector<uint32_t> doubleBuffersToBeSwitched;

    void switchBuffers();

    Datum& originalDatum;

    int32_t doubleBufferIndex = 0;
};

template<class Datum>
std::vector<GraphicalDatum<Datum>::DoubleBuffer> GraphicalDatum<Datum>::doubleBuffers;

...

我尝试定义doubleBuffers的最后一行产生（在gcc中）这些错误：

type/value mismatch at argument 1 in template parameter list for ‘template<class _Tp, class _Alloc> class std::vector’
  expected a type, got ‘SC::GraphicalDatum<Datum>::DoubleBuffer’
template argument 2 is invalid

我的印象是编译器在使用模板作为矢量模板参数时遇到问题。有没有办法解决这个问题？