c++ - Call member method of a variadic class template with a member field

I learned a bit about variadic templates and searched over the Internet for some samples and now trying to write some tricky code to call member a method of a variadic class template with one of its fields. I can't understand why it doesn't work. Please, help.

Here is sample classes:

class BarBase
{
public:
    BarBase() = default;


    virtual void call() = 0;
};

template
class Bar
    : public BarBase
{
public:
    Bar(O* o, M m, A&&... a)

        : BarBase()
        , m_o(o), m_m(m), m_a(std::forward(a)...)
    { }

    void call() override final
    {
        callInnerWithArgsInside();
    }

private:

    void callInnerWithArgsInside()
    {
        (m_o->*m_m)(m_a); // Some errors happends here
    }

    O* m_o;
    M m_m;
    std::tuple::type...> m_a;
};


template
BarBase* crateBar(O* o, M m, A&&... a)
{
    return new Bar(o, m, std::forward(a)...);
}

And call from main:

struct Foo

{
    void foo(int ii, float ff, std::string ss)
    {
        std::cout << "called" << std::endl;
    }
};

int main()
{
    Foo f;

    int i = 10;
    float ff = 20.2f;
    std::string s = "Hello";

    BarBase* bar = crateBar(&f, &Foo::foo, i, ff, s);
    bar->call();
}

Errors:

main.cpp

1>d:\drafts_tests\main.cpp(203): error C2198: 'void (__thiscall Foo::* )(int,float,std::string)' : too few arguments for call

1> d:\drafts_tests\main.cpp(202) : while compiling class template member function 'void Bar::callInnerWithArgsInside(void)'

1> with

1> [

1> O=Foo

1> , M=void (__thiscall Foo::* )(int,float,std::string)

1> ]

1> d:\drafts_tests\main.cpp(197) : see reference to function template instantiation 'void Bar::callInnerWithArgsInside(void)' being compiled

1> with

1> [

1> O=Foo

1> , M=void (__thiscall Foo::* )(int,float,std::string)

1> ]

1> d:\drafts_tests\main.cpp(214) : see reference to class template instantiation 'Bar' being compiled

1> with

1> [

1> O=Foo

1> , M=void (__thiscall Foo::* )(int,float,std::string)

1> ]

1> d:\drafts_tests\main.cpp(225) : see reference to function template instantiation 'BarBase *crateBar(O *,M,int &,float &,std::string &)' being compiled

1> with

1> [

1> O=Foo

1> , M=void (__thiscall Foo::* )(int,float,std::string)

1> ]

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