https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66844
Andrew Sutton <andrew.n.sutton at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |andrew.n.sutton at gmail dot com --- Comment #4 from Andrew Sutton <andrew.n.sutton at gmail dot com> --- The parameter list of a requires clause should have the same restrictions as that of a function's, unless WG21 decides to relax this later. The concepts-cxx2a branch disallows void parameters, making both examples ill-formed. A (void) parameter-list is still permitted and is equivalent to ().