http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58362
--- Comment #9 from Paolo Carlini <paolo.carlini at oracle dot com> --- I sent the simple patch and apparently people would rather prefer fixing location_of to not do t = DECL_CONTEXT (t) for PARM_DECLs, likewise the C front-end of course, in such a way that '+' works and we don't have to pass the DECL_SOURCE_LOCATION. I can't work on this right now.