https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91618
--- Comment #4 from Nathan Sidwell <nathan at gcc dot gnu.org> --- to remind me, bullet 3 that Barry references is: 'if the name of the friend is a qualified-id and a matching function template is found in the specified class or namespace, the friend declaration refers to the deduced specialization of that function template (13.9.2.6), otherwise,'
