https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80670
TC <rs2740 at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |rs2740 at gmail dot com --- Comment #2 from TC <rs2740 at gmail dot com> --- namespace A { template<class> class X { struct P; }; } namespace B { using Y = A::X<int>; } namespace A { template<> struct B::Y::P {}; } main.cpp:10:29: error: declaration of 'struct A::X<int>::P' in namespace 'A' which does not enclose 'using Y = class A::X<int>' template<> struct B::Y::P {};