https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67650
--- Comment #26 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Vincent from comment #25) > Oh, it used to be the case. I think that must be due to some additional > artefact of more recent compilers. I'll try to find another way to show it. I tried 5.1.0 and 5.2.0 and several other previous releases, they all link the program successfully, with just this warning: main.cpp:53:8: warning: 'I' has a field 'I::_e' whose type uses the anonymous namespace
