https://gcc.gnu.org/bugzilla/show_bug.cgi?id=17314
--- Comment #23 from Anthony Sharp <anthonysharp15 at gmail dot com> --- The patch is now on the mailing list (https://gcc.gnu.org/pipermail/gcc-patches/2021-January/562835.html). Please take my last comment with a pinch of salt ... I was mainly trying to sum up what has already been said. There are plenty of people here who have much more knowledge than I do and if they say that something is the case, it probably is. Also just to be clear when I said that no-one uses virtual private inheritance, that obviously isn't strictly true. What I meant to say was that no one would realistically use a virtual private inheritance, and then try to derive another class from it, which is what the problem is.