https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126675
--- Comment #7 from Tomasz Kamiński <tkaminsk at gcc dot gnu.org> --- > Existing binaries compiled with -std=c++20 rely on the symbol being exported > by libstdc++ or they will fail to link. libstdc++ users are not aware of this > dependency because the explicit template declaration was not written by them. The exported template has additional unsigned template parameter, and we could decided export an different symbol in C++23, that will be later used if TU is compiled in C++23 mode. What we commited to is that C++20 TU will use symbols with value 1u.
