https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86491
--- Comment #2 from Jason Vas Dias <jason.vas.dias at gmail dot com> --- Created attachment 44384 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44384&action=edit More readable (diff -ur) patch against 6.4.1's cp/decl2.c Here is a more readable version of the patch to print out information on the exact component of the base class structure which GCC thinks uses the anonymous namespace. In this case, it is of not much use, but does inform the user that GCC thinks the whole structure declaration somehow uses the anonymous namespace, which obviously it does not, so does signal the existence of this GCC bug to the user.