https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111642
--- Comment #14 from Sergei Trofimovich <slyfox at gcc dot gnu.org> --- (In reply to Richard Sandiford from comment #13) > Created attachment 56023 [details] > Tentative fix Re " That now triggers a warning in some configurations, since the NUM_POLY_INT_COEFFS>1 tests used the global poly_int64, whose definition does not depend on the template parameter." Minor note: it's a type error for clang++ and g++ -fchecking=2, not just a warning. I think both gcc and clang do reject the code as they see a type mismatch in `poly_int64<1, T>(1,1)` call. Otherwise the fix works for me and passes `make bootstrap4`. Thank you!