https://gcc.gnu.org/bugzilla/show_bug.cgi?id=12228
S. Davis Herring <herring at lanl dot gov> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |herring at lanl dot gov --- Comment #6 from S. Davis Herring <herring at lanl dot gov> --- CWG399 was resolved by P1787R6 <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p1787r6.html>. All of these definitions of foo are valid, although BT and CA will be found during instantiation only if the template arguments provide them as members.