[Bug libstdc++/109993] std::regex("\\a", std::regex::basic) does not diagnose invalid BRE

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109993

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |INVALID
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
We do diagnose this, but only for strict -std=c++NN modes.  I keep forgetting
that for -std=gnu++NN modes we treat escaped ordinary characters as the
characters themselves.

So this is working as intended.