https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58040
--- Comment #5 from Matt Whitlock <gcc at mattwhitlock dot name> --- FYI, this is still a problem in G++ 5.3.0.
[Bug c++/58040] Cannot take address-of public using-declaration of member from protected base class
gcc at mattwhitlock dot name Fri, 25 Dec 2015 12:16:12 -0800
