[Bug c++/91618] [9/10/11/12 Regression] template-id required to friend a function template, even for a qualified-id

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91618

--- Comment #12 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>:

https://gcc.gnu.org/g:58586721c79f77224b8571a5dba732620d5546ab

commit r12-8065-g58586721c79f77224b8571a5dba732620d5546ab
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Apr 6 23:46:53 2022 -0400

    c++: friend implicit template instantiation [PR91618]

    This rule that for a friend with a qualified name we try to find a
    matching template was already in C++98, but it seems we never implemented
    it, and nobody reported it until 2019.

    This patch sets DECL_IMPLICIT_INSTANTIATION to signal to
    check_explicit_specialization that we want to find a template, like
    grokfndecl already did for explicit template args.  check_classfn also
needs
    to call it, as check_classfn is called after the call to
    check_explicit_specialization in grokfndecl, whereas the call to
    set_decl_namespace comes sooner.  This inconsistency is inelegant, but
safer
    at this point in the release cycle; I'll unify them in stage 1.

            PR c++/91618
            PR c++/96604

    gcc/cp/ChangeLog:

            * name-lookup.cc (set_decl_namespace): Set
            DECL_IMPLICIT_INSTANTIATION if no non-template match.
            * pt.cc (check_explicit_specialization): Check it.
            * decl2.cc (check_classfn): Call it.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/friend7.C: Remove xfail.
            * g++.dg/template/friend72.C: New test.
            * g++.dg/template/friend72a.C: New test.
            * g++.dg/template/friend73.C: New test.