https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65848
--- Comment #4 from Andrew Sutton <andrew.n.sutton at gmail dot com> --- > I think that is actually not so unfortunate. Statically asserting > concept models has helped me find numerous issues in my own code. > I'm glad to hear the proposal is being extended to cover this. Unfortunate in the sense that we missed the features that would allow that usage. But to be fair, it wasn't exactly a primary use case when we were considering the design.