https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96592
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> --- As further evidence the compile is confused, the preprocessed source from GCC 10 can be compiled by GCC 8, but not GCC 9, 10 or trunk. It started to be rejected with r262172 (fixing PR c++/80290), but the problem was latent until r10-908 made std::tuple vulnerable to it. I'll start reducing the preprocessed source ...
