save nullptr

nullptr.cpp

class my_nullptr_t
{
public:
  template<class T>
  operator T*() const noexcept
  {
    return reinterpret_cast<T*>(0);
  }
} my_nullptr;

class Dummy
{
};

int main()
{
  auto dummy = new Dummy;
  if (dummy == my_nullptr)
  {
    // is null
  }

  return 0;
}