Currently my company has thousands of static / non-static member function pairs, the static function exists purely to call its non-static member function through an instance pointer passed as a member of the parameter. I have been working on a neat templated replacement for all of these static functions, since the parameters are always the same. My solution is a templated static member function that takes a pointer-to-member, and calls it via std::invoke(). However, you do not seem to be able to instantiate the function pointer, through list initialization - but if you cast it or set it directly, it works fine! See the following code and the line that does not compile (commented as such):

#include <iostream>
#include <functional>

struct widget_data;

typedef void(MY_FUNC)(widget_data*);

struct widget_data
{
    void* instance;
    MY_FUNC* func;
};

template <class CLASSNAME>
class widget_base
{
public:
    virtual ~widget_base() {};

    static CLASSNAME* get_instance(widget_data* data)
    {
        return static_cast<CLASSNAME*>(data->instance);
    }

    template<void(CLASSNAME::*f)(widget_data*)>
    static void mem_wrap(widget_data*d)
    {
         std::invoke(f, get_instance(d), d);
    }
};

class widget_derived : public widget_base<widget_derived>
{
private:
    widget_data m_widget;

    void my_member_func(widget_data*)
    {
        std::cout << "Hello world" << '\n';
        std::cin.get();
};

public:
    widget_derived()
    {
        m_widget.instance = this;

        // This works and prints "Hello world"
        m_widget.func = mem_wrap<&widget_derived::my_member_func>;
        std::invoke(m_widget.func, &m_widget);

        // This fails to compile, with "cannot convert from 'void (__cdecl *)(widget_data *)' to 'MY_FUNC (__cdecl *)'"
        //m_widget = { this, mem_wrap<&widget_derived::my_member_func> };

        // This compiles fine, and prints "Hello world"
        m_widget = { this, static_cast<MY_FUNC*>(mem_wrap<&widget_derived::my_member_func>) };
        std::invoke(m_widget.func, &m_widget);
}
};


int main(int /*argc*/, char* /*argv*/[])
{
    widget_derived();
}