https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103919
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:6aa0859afaf28f4fb13121352225bc5877e02a44 commit r12-6267-g6aa0859afaf28f4fb13121352225bc5877e02a44 Author: Jonathan Wakely <jwak...@redhat.com> Date: Wed Jan 5 15:16:33 2022 +0000 libstdc++: Fix overconstrained std::string constructor [PR103919] The C++17 basic_string(const T&, size_t, size_t) constructor is overconstrained, so it can't be used for a NTBS and a temporary string gets constructed (potentially allocating memory). There is no corresponding constructor taking an NTBS, so no need to disambiguate from it. Accepting an NTBS avoids the temporary (and potential allocation) and is what the standard requires. libstdc++-v3/ChangeLog: PR libstdc++/103919 * include/bits/basic_string.h (basic_string(const T&, size_t, size_t)): Relax constraints on string_view parameter. * include/bits/cow_string.h (basic_string(const T&, size_t, size_t)): Likewise. * testsuite/21_strings/basic_string/cons/char/103919.cc: New test.