https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100288
--- Comment #4 from Frank B. Brokken <f.b.brokken at rug dot nl> --- Dear ppalka at gcc dot gnu.org, you wrote: > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100288 > > Patrick Palka <ppalka at gcc dot gnu.org> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > Keywords| |ice-on-invalid-code > See Also| |https://gcc.gnu.org/bugzill > | |a/show_bug.cgi?id=99599 > > --- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> --- > Agreed, the testcase looks invalid much like PR99599. One workaround for > avoiding the constraint recursion here would be to change the signature of > > template <OstreamInsertable Type> > inline void operator<<(CSVTabIns &&tab, Type const &value) > > to something like > > template <std::same_as<std::remove_cvref_t<CSVTabIns>> U, OstreamInsertable > Type> > inline void operator<<(U &&tab, Type const &value) > > so that the constraint OstreamInsertable<Type> is checked on this overload > only > if the first argument to << has the expected type. > > -- > You are receiving this mail because: > You reported the bug. Hi Patrick, Thanks for your e-mail. Since (AFAICS) you directly and only sent your e-mail to me I'm wondering whether you want me to comment on your e-mail. It's getting kind of late here, but I could send a more extensive reply tomorrow. Let me know if that's what you want. I tried your suggestion, and it seems to solve the issue. But at the same time it puzzles me why template <OstreamInsertable Type> inline void operator<<(CSVTabIns &&tab, Type const &value) {} won't be instantiated for FMT in inline void operator<<(CSVTabIns &tab, FMT::FMTHline hline) { tab << (*hline)(1); // insert hline in the next column } when FMT defines FMTHline as 'typedef FMT (*FMTHline)(unsigned)' and std::ostream &operator<<(std::ostream &out, FMT const &fmt) is declared. I would have expected that tab << (*hline)(1); // insert hline in the next column would cause the compiler to instantiate template <OstreamInsertable Type> inline void operator<<(CSVTabIns &&tab, Type const &value) {} for Type = FMT. Maybe I'm missing something here? And it's also not something that caused the compiler's internal error.
