C++20 variadics with abbreviated function template

Today, when working with my stripped C++ Win32 library – after the frustration with Rust’s long compile times in WinSafe –, I was trying to implement an overloaded variadic method, in order to get rid of initializer_list. Then I stumbled upon a great article which introduced me to the abbreviated function template feature of C++20, which I’m using.

This is an example:

int foo(std::wstring n)
{
	OutputDebugStringW(n.data());
	OutputDebugStringW(L"\n");
	return 43;
}

int foo(std::wstring n, std::convertible_to<std::wstring> auto... nn)
{
	foo(n);
	return foo(nn...);
}

The convertible_to concept is particularly interesting in narrowing the template type.