I would like us to declare that C++20 is no longer experimental and change the default dialect to gnu++20. Last time we changed the default was over 5 years ago in GCC 11: <https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=0801f419440c14f6772b28f763ad7d40f7f7a580> and before that in 2015 in GCC 6.1, so this happens roughly every 5 years.
I had been hoping to move to C++20 in GCC 15 (see bug 113920), but at that time libstdc++ still had incomplete C++20 support and the compiler had issues to iron out (mangling of concepts, modules work, etc.). Are we ready now? Is anyone aware of any blockers? Presumably we still wouldn't enable Modules by default. I'm willing to do the work if we decide that it's time to switch the default C++ dialect (that includes updating cxx-status.html and adding a new caveat to changes.html). Marek
