[C++] Non-capturing C++ lambdas can be converted to a pointer to function, but what about the calling convention?

Non-capturing C++ lambdas can be converted to a pointer to function, but what about the calling convention?

void ContainingClass::SomeMethod()
{
 class AnonymousClass$0
 {
 public:
  AnonymousClass$0()  { }
  operator int (__cdecl *)(int k) { return cdecl_static_function; }
  operator int (__stdcall *)(int k) { return stdcall_static_function; }
  operator int (__fastcall *)(int k) { return fastcall_static_function; }
  int operator(int k) { return cdecl_static_function(k); }
 private:
  static int __cdecl cdecl_static_function(int k) { return calc(k + 42); }
  static int __stdcall stdcall_static_function(int k) { return calc(k + 42); }
  static int __fastcall fastcall_static_function(int k) { return calc(k + 42); }
 };

 auto f = AnonymousClass$0();
 ...
}