C++ weird compilation error on removing a variable

Question

Following code doesn't compile ^{g++ 4.8.1}

struct Layers
{
    typedef struct Widgets { } Widgets;

    virtual void fun(void) 
    {
        struct Widgets w;
    }

    Widgets w, x, y, z ;
};

However, if I just use Widgets w, x, y ; //Remove variable z it compiles !

Why is this happening ? What am I missing here ?