https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83601
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2017-12-27 CC| |timshen at gcc dot gnu.org Ever confirmed|0 |1 --- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- Reduced: #include <regex> int main() { auto format = std::regex_constants::format_sed; auto out = regex_replace("ab", std::regex("(a)(b)"), R"(\\1\&\\2)", format); if (out != R"(\1&\2)") throw 1; } Tim, is there an easy fix for this that I can try, or should I leave it to you?