[Bug c++/83533] error: no type named 'X' in 'using = ...'

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83533

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This was a bug in GCC 4.7.x which is fixed in GCC 4.8.0

We already fixed it, and do not support GCC 4.7 (or anything older than GCC 6),
so there's nothing more we can do. Either use the workaround or use a newer
version of GCC.