copy and assignment operator autogeneration

copies.c++

class A {};

class B {
 public:
  B() = default;
  B(B const&) = delete;
};

class C {
 public:
  C() = default;
  C(C const&) = delete;
  C& operator=(C const&) = delete;
};

class D {
 public:
  D() = default;
  D& operator=(D const&) = delete;
};

int main() {
  A a1;
  A a2(a1);
  A a3; a3 = a1;
  B b1;
  //B b2(b1);       // nope
  B b3; b3 = b1;
  C c1;
  //C c2(c1);       // nope
  //C c3; c3 = c1;  // nope
  D d1;
  D d2(d1);
  //D d3; d3 = d1;  // nope
  return 0;
}