https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105584
--- Comment #1 from cqwrteur <unlvsur at live dot com> --- [clang] Implement the using_if_exists attribute https://github.com/llvm/llvm-project/commit/369c64839946d89cf5697550b6feeea031b2f270 This shows how the attribute works. Hope GCC could add it. Also probably need __clang__::__using_if_exists__ too to avoid name collisions.
