https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89883
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Last reconfirmed| |2022-03-26 Status|UNCONFIRMED |NEW --- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- Clang just says: am.C:13:6: error: use of overloaded operator '<<' is ambiguous (with operand types 'std::ostream' (aka 'basic_ostream<char>') and 'Foo') os << Bar; ~~ ^ ~~~ am.C:8:14: note: candidate function std::ostream operator<<( std::ostream& os, Foo ); ^ am.C:9:14: note: candidate function std::ostream operator<<( std::ostream& os, Foo const& ); ^ 1 error generated.