https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115196
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Halalaluyafail3 from comment #0) > This note doesn't seem to be very helpful, it mentions adding an extra > '#include<memory>' when one is already present. A better error message here > would be to omit the note, or to make it mention changing the selected C++ > standard version. If you'd tried gcc trunk on godbolt you'd have seen that's exactly what happens: <source>:3:10: note: 'std::to_address' is only available from C++20 onwards There was just a typo which made gcc think std::to_address is part of <memory> in C++11, so if it wasn't declared in your program then it must be because you didn't include <memory>. After the fix it correctly suggests using at least C++20.
