[Bug c++/100975] [C++23] Allow pointer to array of auto

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100975

--- Comment #3 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:e66d0b7b87d105d24da8c4784a0b907fb6b2c095

commit r12-1933-ge66d0b7b87d105d24da8c4784a0b907fb6b2c095
Author: Marek Polacek <polacek@redhat.com>
Date:   Tue Jun 29 14:30:51 2021 -0400

    c++: DR2397 - auto specifier for * and & to arrays [PR100975]

    This patch implements DR2397, which removes the restriction in
    [dcl.array]p4 that the array element type may not be a placeholder
    type.  We don't need to worry about decltype(auto) here, so this
    allows code like

      int a[3];
      auto (*p)[3] = &a;
      auto (&r)[3] = a;

    However, note that

      auto (&&r)[2] = { 1, 2 };
      auto arr[2] = { 1, 2 };

    still doesn't work (although one day it might) and neither does

      int arr[5];
      auto x[5] = arr;

    given that auto deduction is performed in terms of function template
    argument deduction, so the array decays to *.

            PR c++/100975
            DR 2397

    gcc/cp/ChangeLog:

            * decl.c (create_array_type_for_decl): Allow array of auto.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/auto24.C: Remove dg-error.
            * g++.dg/cpp0x/auto3.C: Adjust dg-error.
            * g++.dg/cpp0x/auto42.C: Likewise.
            * g++.dg/cpp0x/initlist75.C: Likewise.
            * g++.dg/cpp0x/initlist80.C: Likewise.
            * g++.dg/diagnostic/auto1.C: Remove dg-error.
            * g++.dg/cpp23/auto-array.C: New test.