https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84798
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Outside of lambdas the patch essentially changed an error diagnostic to else if (cxx_dialect < cxx1y) pedwarn (location_of (type), 0, "use of %<auto%> in parameter declaration " "only available with " "-std=c++1y or -std=gnu++1y"); else pedwarn (location_of (type), OPT_Wpedantic, "ISO C++ forbids use of %<auto%> in parameter " "declaration"); Do we really want that extension and what uses it?