class BaseA
{
    public:
    void DoSomething()
    {
    };
};

class BaseB
{
    public:
    virtual void DoSomething() = 0;
};

class Derived : public BaseA, public BaseB
{
    public:
    void BaseB::DoSomething();
};

void Derived::DoSomething()
{
}

int _cdecl main()
{
    Derived d;
    return 0;
}