Is it possible to prevent stack allocation of an object and only allow it to be instantiated with 'new'?

Question

Is it possible to prevent stack allocation of an object and only allow it to be instiated with \'new\' on the heap?

Answer 1

This should be possible in C++20 using a destroying operator delete, see p0722r3.

#include 

class C
{
private:
  ~C() = default;
public:
  void operator delete(C *c, std::destroying_delete_t)
  {
    c->~C();
    ::operator delete(c);
  }
};

Note that the private destructor prevents it from being used for anything else than dynamic storage duration. But the destroying operator delete allows it to be destroyed via a delete expression (as the delete expression does not implicitly call the destructor in this case).