This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 118e. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2025-11-05

708. Partial specialization of member templates of class templates

The Standard does not appear to specify clearly the effect of a partial specialization of a member template of a class template. For example:

 template<class T> struct B { template<class U> struct A { // #1 void h() {} }; template<class U> struct A<U*> { // #2 void f() {} }; }; template<> template<class U> struct B<int>::A { // #3 void g() {} }; void q(B<int>::A<char*>& p) { p.f(); // #4 } 

The explicit specialization at #3 replaces the primary member template #1 of B<int>; however, it is not clear whether the partial specialization #2 should be considered to apply to the explicitly-specialized member template of A<int> (thus allowing the call to p.f() at #4) or whether the partial specialization will be used only for specializations of B that are implicitly instantiated (meaning that #4 could call p.g() but not p.f()).