// prms-id: 807 extern "C" int printf(const char*, ...); class B; class AX { protected: int x; public: operator B(); }; class B { private: int x; public: B(const AX&); }; int foo(B& b); // ERROR - referenced below int main() { AX a; foo(a); // ERROR - Ambiguous B(a) or a.operator B() // See ARM 12.3.2 }