https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93821
--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> --- No. C++20 support in GCC 10 is missing a number of features, so it would be misleading/incorrect to define it to 202002L. https://gcc.gnu.org/projects/cxx-status.html#cxx20 You can just test for > 201703L if you want to know if partial C++20 support is present. Or use the feature test macros for individual features.
