https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98355
--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> --- I had stated my intent in the initial submission to complete the C++ support in a followup patch: https://gcc.gnu.org/pipermail/gcc-patches/2018-November/510455.html Jason approved the initial patch with an encouragement to do so: https://gcc.gnu.org/legacy-ml/gcc-patches/2018-10/msg01528.html I might have gotten around to it if you and Jeff hadn't blocked for four months (!) my fixes for a few simple ICEs in the code. Here's the first submission of a patch for the first ICE I found in December 2018: https://gcc.gnu.org/pipermail/gcc-patches/2018-December/512645.html The fixes didn't get approved and committed in r270326 until April 2019, and many rounds of back and forth bickering over whether the built-in should accept expressions or error out on them.