Annex G (informative) Ill-formed, no diagnostic required [ifndr]

G.10 [temp]: Templates [ifndr.temp]

G.10.6[ifndr:temp.spec.partial.general.partial.reachable]

If a partial specialization is not reachable from a use of a template specialization that would make use of that partial specialization as the result of an implicit or explicit instantiation, the program is ill-formed, no diagnostic required.
[Example 1: template<typename T> class X{ public: void foo(){}; }; template class X<void *>; // IFNDR, explicit instantiation and partial specialization is not reachable template<typename T> class X<T*>{ public: void baz(); }; — end example]