29     static unsigned dtor_called;  member in X
33     ~X() {++dtor_called;}  in ~X()
38 unsigned X::dtor_called = 0;  member in X
44     static unsigned dtor_called;  member in Y
47     ~Y() {++dtor_called;}  in ~Y()
53 unsigned Y::dtor_called = 0;  member in Y
147         assert(X::dtor_called == 0);  in main()
156         X::dtor_called = 0;  in main()
158         assert(X::dtor_called == 1);  in main()
170         X::dtor_called = 0;  in main()
172         assert(X::dtor_called == 1);  in main()
185         X::dtor_called = 0;  in main()
187         assert(X::dtor_called == 1);  // from inside std::swap  in main()
202         assert(Y::dtor_called == 0);  in main()
211         Y::dtor_called = 0;  in main()
213         assert(Y::dtor_called == 1);  in main()
225         Y::dtor_called = 0;  in main()
227         assert(Y::dtor_called == 1);  in main()
240         Y::dtor_called = 0;  in main()
242         assert(Y::dtor_called == 0);  in main()