https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92034
--- Comment #4 from Alisdair Meredith <alisdairm at me dot com> --- (In reply to Jonathan Wakely from comment #3) > I'm not sure if a diagnostic is required. The standard doesn't specifically > say it's ill-formed to do this. By my reading it's undefined, and so > silently accepting it is a conforming (but unhelpful) implementation. My reading of [intro.compliance]p1 is that this would be a diagnosable error, but navigating core wording is hard if you do not know all of the exact places that contribute, and could easily have missed a clarification?
