下面的代码用clang编译好,但不用GCC编译(试过4.1.2,4.5.4和4.7.2):
template <typename T>
struct A
{
struct B { };
};
template <typename T>
bool operator==(typename A<T>::B const& b, T const& t);
enum { BAR };
template <typename T>
bool test()
{
return 0 == BAR;
}
GCC 4.7.2的错误消息是:
a.cpp: In instantiation of ‘struct A<<anonymous enum> >’:
a.cpp:12:6: required by substitution of ‘template<class T> bool operator==(const typename A<T>::B&, const T&) [with T = <anonymous enum>]’
a.cpp:19:17: required from here
a.cpp:6:12: error: ‘<anonymous enum>’ is/uses anonymous type
a.cpp:6:12: …