https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68711
--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> --- The patch in comment #1 fixes it. Unfortunately, there are other expressions that cause the same problem even in prior versions of GCC. Since those were accepted even prior to r230365, and in fact are accepted by 5.1.0, I raised a separate bug for those: bug 68727.
