C++ same name for non-virtual function in derived class conflicts with `final` specifier

This has the feeling of a complete newbie question, but why does the following code not compile when the final specifier is used for B::operator()?

struct A
{
    virtual void operator()() const = 0;
};

// the CRTP-component is not really necessary here
// but it possibly makes more sense in that it could be applied like this in reality
//
template<typename Derived>
struct B : A
{
    virtual void operator()() const override final
    {
        static_cast<Derived const&>(*this).operator()();
    }
};

struct C : B<C>
{
    void operator()() const
    {
        //do something
    }
};

int main()
{
    C()();
}

G++ prints the following error message:

main.cpp:17:14: error: virtual function 'virtual void C::operator()() const'
         void operator()() const
              ^
main.cpp:9:22: error: overriding final function 'void B<Derived>::operator()() const [with Derived = C]'
         virtual void operator()() const override final
                      ^

I would have thought it works as the non-virtual C::operator() does not override the virtual functions in its base classes? How can I bring this to work (--without changing the name of C::operator())?

EDIT: As pointed out by several users, the answer is simply that the virtual-keyword in the derived class is redundant (whereas I thought leaving it out would prevent from inheriting). However, the goal I had in asking this -- namely a consistent interface throughout the dynamic and static inheritance hierarchy -- can be solved by using a non-virtual operator[] throughout and couple classes A and B by a virtual function apply:

struct A
{
    void operator()() const
    {
        this->apply();
    }

protected:
    virtual void apply() const = 0;
};

template<typename Derived>
struct B : A
{
    void operator()() const
    {
        static_cast<Derived const&>(*this).operator()();
    }

protected:
    virtual void apply() const override final
    {
        this->operator()();
    }
};

struct C : B<C>
{
    void operator()() const
    {
        //do something
    }
};

int main()
{
    C()();
}