https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103891
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |MOVED See Also| |https://github.com/llvm/llv | |m-project/issues/45614 --- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- This is a known bug (or unfinished feature) in Clang. https://github.com/llvm/llvm-project/issues/45614 We're not going to work around it in libstdc++ because there is no feature test macro that allows us to detect whether clang supports it, see http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2493r0.html for details. If/when GCC bumps the value of __cpp_concepts we can use that to make C++20 support in std::variant conditional on compiler support.