https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89793
--- Comment #6 from Harald van Dijk <harald at gigawatt dot nl> --- (In reply to Jonathan Wakely from comment #4) > (In reply to Harald van Dijk from comment #1) > > This appears to work the same way in GCC 8 as it does in GCC 7, although it > > is possible that for whatever reason, the GCC 7 version ends up not > > including std::allocator<char> as a base class. > > There was a change in overload resolution between GCC 7 and 8. Ah, sorry, I just realised I was testing a smaller version without -std=c++17 on GCC 7. Yeah, I see the difference between GCC 7 and GCC 8 as well.