https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65575
--- Comment #4 from Andrew Sutton <andrew.n.sutton at gmail dot com> --- Apparently I do not understand declarators. The attached patch searches through the declarator structure to filter out declarator structures to which a requires-clause cannot be attached. I updated the pr665575.C test to include more examples (positive and negative), but that's not reflected in the attached patch. I haven't been able to test as thoroughly as I'd like because I'm at the airport, but this seems like the right thing to do.
