A macro for constexpr lambdas in C++

constexpr_lambda.cpp

#include <iostream>
#include <type_traits>
#include <utility>

template<class F>
struct wrapper
{
  static_assert(std::is_empty<F>(), "Lambdas must be empty");
  template<class... Ts>
  decltype(auto) operator()(Ts&&... xs) const
  {
    return reinterpret_cast<const F&>(*this)(std::forward<Ts>(xs)...);
  }
};

struct wrapper_factor
{
  template<class F>
  constexpr wrapper<F> operator += (F*)
  {
    return {};
  }
};

struct addr_add
{
  template<class T>
  friend typename std::remove_reference<T>::type *operator+(addr_add, T &&t)
  {
    return &t;
  }
};

#define STATIC_LAMBDA wrapper_factor() += true ? nullptr : addr_add() + []

const constexpr auto add_one = STATIC_LAMBDA(auto x)
{
  return x + 1;
};

int main(void)
{
  // Produces 2
  std::cout << add_one(1) << std::endl;
}