The compiler does not yet implement the resolution to core issue 1804 involving template friend declarations applying to specializations of a class template. In the following code sample, a member of class C is inaccessible through a template friend declaration when the associated class template is a specialization. class C_; // Class template template<class T> struct A_ {   int f(const C_&);   struct D {     int g() { return 8; }   }; }; // Specialization template<> struct A_<int> {   int f(const C_&);   struct D {     int g() { return 18; }   }; }; class C_ {   template<class T> friend int A_<T>::f(const C_&); // friend declaration   int member; public:   C_(int i) : member(i) { } }; template<class U> int A_<U>::f(const C_& c)   { return c.member; } // Not specialized, C::member is accessible int A_<int>::f(const C_& c)   { return 10+c.member; } // Specialized, C::member is inaccessible