Bug#1050684:
According to https://packages.debian.org/trixie/clang it was bumped to clang-16 and this bug is fixed and can be closed. Thank you!
Bug#1050684: /usr/lib/llvm-14/bin/clang: Default clang++ -std=c++20 does not work with default libstdc++ on trixie
Package: clang-14 Version: 1:14.0.6-13 Severity: important File: /usr/lib/llvm-14/bin/clang Dear Maintainer, The default clang++ version on trixie and sid is 14. However, this version of clang++ does not go well with C++20 and the default libstdc++ (version 13). It would be good to bump the defa