Variadic模板无法编译

Question

#include <stdio.h>


template <typename FuncType, FuncType>
struct TransformFunc;

template <typename Arg, typename... Args, void(*func)(Arg, Args...)>
class TransformFunc<void(*)(Arg, Args...), func>
{
public:
    static void apply(Arg arg, Args... args)
    {
        func(arg, args...);
    }
};


void test1(int x)
{
    printf("test1: int%d\n", x);
}


void test2 (int x, float y)
{
    printf("test2: int%d float%f\n", x, y);
}


int main(int, char **)
{
    TransformFunc<decltype(&test1), &test1>::apply(5);
    TransformFunc<decltype(&test2), &test2>::apply(5, 1.23f); // Error here.

    return 0;
}

1>------ Build started: Project: main, Configuration: Debug x64 ------
1>  main.cpp
1>main.cpp(33): error C2440: 'specialization' : cannot convert from 'void (__cdecl *)(int,float)' to 'void (__cdecl *)(int)'
1>          This conversion requires a reinterpret_cast, a C-style cast or function-style cast
1>          main.cpp(33) : see reference to class template instantiation 'TransformFunc<void (__cdecl *)(int,float),void test2(int,float)>' being compiled
1>main.cpp(33): error C2973: 'TransformFunc<void(__cdecl *)(Arg,Args...),func>' : invalid template argument 'void (__cdecl *)(int,float)'
1>          main.cpp(9) : see declaration of 'TransformFunc<void(__cdecl *)(Arg,Args...),func>'
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

我无法弄清楚为什么test2实例化无法编译。有什么想法吗？