[Bug c++/79815] gcc does not implement C++ standard 7.1.7.4.1 p5 correctly.

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79815

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:

https://gcc.gnu.org/g:e7f0873a9c4ebccd078fc5330866efe0cd4c1309

commit r11-2202-ge7f0873a9c4ebccd078fc5330866efe0cd4c1309
Author: Marek Polacek <polacek@redhat.com>
Date:   Wed Jul 8 19:45:34 2020 -0400

    c++: Diagnose cv-qualified decltype(auto) [PR79815]

    "If the placeholder is the decltype(auto) type-specifier, T shall be the
    placeholder alone." but we weren't detecting "const decltype(auto)".

    I've just expanded the existing diagnostic detecting "decltype(auto) &"
    and similar.

    gcc/cp/ChangeLog:

            PR c++/79815
            * decl.c (grokdeclarator): Detect cv-qual decltype(auto).
            * pt.c (do_auto_deduction): Likewise.

    gcc/testsuite/ChangeLog:

            PR c++/79815
            * g++.dg/cpp1y/auto-fn59.C: New test.