[Bug c++/98515] [11 Regression] Possible regression causing "is protected within this context" error

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98515

--- Comment #5 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:98a1fb705ead9258642f2dec0431f11508a9b13c

commit r11-6553-g98a1fb705ead9258642f2dec0431f11508a9b13c
Author: Patrick Palka <ppalka@redhat.com>
Date:   Fri Jan 8 10:02:04 2021 -0500

    c++: Fix access checking of scoped non-static member [PR98515]

    In the first testcase below, we incorrectly reject the use of the
    protected non-static member A::var0 from C<int>::g() because
    check_accessibility_of_qualified_id, at template parse time, determines
    that the access doesn't go through 'this'.  (This happens because the
    dependent base B<T> of C<T> doesn't have a binfo object, so it appears
    to DERIVED_FROM_P that A is not an indirect base of C<T>.)  From there
    we create the corresponding deferred access check, which we then
    perform at instantiation time and which (expectedly) fails.

    The problem ultimately seems to be that we can't in general determine
    whether a use of a scoped non-static member goes through 'this' until
    instantiation time, as the second testcase below illustrates.  So this
    patch makes check_accessibility_of_qualified_id punt in such situations
    to avoid creating a bogus deferred access check.

    gcc/cp/ChangeLog:

            PR c++/98515
            * semantics.c (check_accessibility_of_qualified_id): Punt if
            we're checking access of a scoped non-static member inside a
            class template.

    gcc/testsuite/ChangeLog:

            PR c++/98515
            * g++.dg/template/access32.C: New test.
            * g++.dg/template/access33.C: New test.