https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89913
Andrew Sutton <andrew.n.sutton at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |andrew.n.sutton at gmail dot com --- Comment #3 from Andrew Sutton <andrew.n.sutton at gmail dot com> --- This isn't strictly related to concepts. Resolution posted here: https://gcc.gnu.org/ml/gcc-patches/2019-11/msg01429.html The tests target C++20, but this could be extended back to C++11. However, the diagnostic is different for pre-C++20.