Base: type = {
  operator=: (out this) = { }
  operator=: (out this, that)       = std::cout << "(out this, that)\n";
  operator=: (implicit out this, _) = std::cout << "(implicit out this, _)\n";
}

Derived: type = {
  this: Base            = ();
  operator=: (out this) = { }
  operator=: (out this, that)   = { }
  operator=: (inout this, move that) = { }
}

main: () = {
  d  := Derived();
  d2 := d;
  d2 = d;
}