https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110340
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:fca089e8a47314a40ad93527ba9f9d0d374b3afb commit r14-2626-gfca089e8a47314a40ad93527ba9f9d0d374b3afb Author: Marek Polacek <pola...@redhat.com> Date: Tue Jul 18 13:26:39 2023 -0400 c++: Add tests for P2621, no UB in lexer [PR110340] C++26 P2621 removes UB in the lexer and either makes the construct valid or ill-formed. We're already handling this correctly so this patch only adds tests. PR c++/110340 gcc/testsuite/ChangeLog: * g++.dg/cpp/string-4.C: New test. * g++.dg/cpp/ucn-2.C: New test.