C++20 parameter pack perfect capture

gistfile1.txt

#include <iostream>
#include <string>

template <class T, class...Args>
auto ftemplate(T& t) {
  auto thunk = [&t](auto& f, Args&&... args) {
    auto post = [&t, &f, ... args = std::forward<Args>(args)] {
      f(t, std::forward<decltype(args)>(args)...);
    };

    return post;
  };

  return thunk;
}

auto fauto(int& t) {
  auto thunk = [&t](auto& f, auto&&... args) {
    auto post = [&t, &f, ... args = std::forward<decltype(args)>(args)] {
      f(t, std::forward<decltype(args)>(args)...);
    };

    return post;
  };

  return thunk;
}

template<typename T>
auto ftemplate_auto(T& i) {
  auto thunk = [&i](auto& f, auto&&... args) {
    // this capture fails
    auto post = [&f, ... args = std::forward<decltype(args)>(args)] {
      f(std::forward<decltype(args)>(args)...);
    };

    return post;
  };

  return thunk;

}

int main(int, char**) {

  int i=5;

  auto f = [](auto&&... args) {
    (std::cout << ... << std::forward<decltype(args)>(args)) << "\n";
  };

  auto t = ftemplate<int, int, int, std::string>(i);
  t(f, 1, 4, "string")();


  auto t2 = fauto(i);
  t2(f, 2,5,"string")();

// comment this and it will build
  auto t3 = ftemplate_auto(i);
  t3(f, 2,5,"string")();

  return EXIT_SUCCESS;
}