523 struct ConstructorTracker {  struct
524   static size_t constructor_called;
525   static size_t copy_constructor_called;
526   static size_t move_constructor_called;
527   static size_t copy_assignment_called;
528   static size_t move_assignment_called;
531   ConstructorTracker(T&& string) : string(string) {  in ConstructorTracker()  function
535   ConstructorTracker(const ConstructorTracker& ct) {  in ConstructorTracker()  function
539   ConstructorTracker(ConstructorTracker&& ct) noexcept {  in ConstructorTracker()  argument
543   ConstructorTracker& operator=(const ConstructorTracker& ct) {  in operator =()
548   ConstructorTracker& operator=(ConstructorTracker&& ct) noexcept {  in operator =()
554   std::string string;