[Bug c++/99103] Initializer-list constructors in CTAD for vector is still wrong

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99103

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

https://gcc.gnu.org/g:676f6f3277181662cf3ed07769edfa2d4fb7df28

commit r11-7405-g676f6f3277181662cf3ed07769edfa2d4fb7df28
Author: Patrick Palka <ppalka@redhat.com>
Date:   Thu Feb 25 16:38:08 2021 -0500

    c++: Fix CTAD of single-element initializer list [PR99103]

    When determining whether to rule out initializer-list constructors
    during CTAD with a single-element initializer list (as per P0702), the
    element type's cv-qualifiers should be irrelevant.  This patch fixes
    this by making is_spec_or_derived strip cv-qualifiers from the supplied
    expression type.

    In passing, I noticed in maybe_aggr_guide we were calling
    is_spec_or_derived with swapped arguments.  This led us to prefer the
    aggregate deduction candidate over copying deduction in the second
    testcase below with -std=c++20.

    gcc/cp/ChangeLog:

            PR c++/99103
            * pt.c (is_spec_or_derived): Drop cv-qualifiers from 'etype'.
            (maybe_aggr_guide): Fix order of arguments to is_spec_or_derived.

    gcc/testsuite/ChangeLog:

            PR c++/99103
            * g++.dg/cpp1z/class-deduction79.C: New test.
            * g++.dg/cpp1z/class-deduction80.C: New test.