下列:
template< typename >
struct S;
template< typename T >
S< T >& f (S< T >& s) {
const typename S< T >::nested ignore;
return s;
}
template S< char >& f (S< char >&);
template< typename >
struct S {
struct nested { };
};
用gcc编译,但不用clang编译:
$ clang -c /tmp/t.cpp
/tmp/t.cpp:6:20: error: implicit instantiation of undefined template 'S<char>'
const typename S< T >::nested ignore;
^
/tmp/t.cpp:10:21: note: in instantiation of function template specialization 'f<char>' requested here
template S< …