[Bug libstdc++/103919] The basic_string(const T&, size_type, size_type) constructor is overconstrained

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103919

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:

https://gcc.gnu.org/g:4c64143f32642d22590959704e2ec6c686d745ff

commit r11-9435-g4c64143f32642d22590959704e2ec6c686d745ff
Author: Jonathan Wakely <jwakely@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.
            [!_GLIBCXX_USE_CXX11_ABI] (basic_string(const T&, size_t, size_t)):
            Likewise.
            * testsuite/21_strings/basic_string/cons/char/103919.cc: New test.

    (cherry picked from commit 6aa0859afaf28f4fb13121352225bc5877e02a44)