https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106223
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Nimrod from comment #4) > https://timsong-cpp.github.io/cppwp/n4659/func.require#3 > "...A forwarding call wrapper is a call wrapper that can be called with an This is irrelevant, std::forward isn't a call wrapper. Anyway, specializing any function template from namespace std is explicitly forbidden since C++20, because it's not necessary or sensible to do it.