20 struct B  struct
24     explicit B(int id) : id_(id) {count++;}  in B()  argument
25     B(const B& a) : id_(a.id_) {count++;}  in B()  function
26     ~B() {count--;}  in ~B()  argument
29 int B::count = 0;
32     : B
36     explicit C1(int id) : B(id-2), id_(id) {count++;}  in C1()
37     C1(const C1& a) : B(a.id_-2), id_(a.id_) {count++;}  in C1()
44     : B
48     explicit C2(int id) : B(id-2), id_(id) {count++;}  in C2()
49     C2(const C2& a) : B(a.id_-2), id_(a.id_) {count++;}  in C2()
72     assert(B::count == 0);  in f1()
77     assert(B::count == 2);  in f1()
82     assert(static_cast<B&>(static_cast<C1&>(a)).id_ == 2);  in f1()
83     assert(static_cast<B&>(static_cast<C2&>(a)).id_ == 1);  in f1()
95         assert(B::count == 0);  in f2()
104         assert(static_cast<const B&>(static_cast<const C1&>(a)).id_ == 2);  in f2()
105         assert(static_cast<const B&>(static_cast<const C2&>(a)).id_ == 1);  in f2()
116     catch (const B&)  in f2()
129         assert(B::count == 0);  in f3()
133     catch (const B& a)  // can not catch B (ambiguous base)  in f3()
140         assert(static_cast<const B&>(c1).id_ == 2);  in f3()
156         assert(B::count == 0);  in f4()
160     catch (const B& a)  // can not catch B (ambiguous base)  in f4()
167         assert(static_cast<const B&>(c2).id_ == 1);  in f4()
189     assert(B::count == 0);  in main()