[Bug c++/95486] ICE for alias CTAD with non-dependent argument and constrained constructor

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95486

--- Comment #6 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:1a19d334ce493ec2ce2daeac74beef63fd67e2bc

commit r11-8104-g1a19d334ce493ec2ce2daeac74beef63fd67e2bc
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Apr 9 18:02:38 2021 -0400

    c++: deduction guide using alias [PR99180]

    alias_ctad_tweaks was expecting that all deduction guides for the class
    would be suitable for deduction from the alias definition; in this case,
the
    deduction guide uses 'true' and the alias B uses 'false', so deduction
    fails.  But that's OK, we just don't use that deduction guide.  I also
    noticed that we were giving up on deduction entirely if substitution failed
    for some guide; we should only give up on that particular deduction guide.

    We ought to give a better diagnostic about this case when deduction fails,
    but that can wait.

    gcc/cp/ChangeLog:

            PR c++/99180
            PR c++/93295
            PR c++/93867
            PR c++/99118
            PR c++/96873
            * pt.c (alias_ctad_tweaks): Handle failure better.

    gcc/testsuite/ChangeLog:

            PR c++/99180
            PR c++/93295
            PR c++/93867
            PR c++/95486
            * g++.dg/cpp2a/class-deduction-alias5.C: New test.
            * g++.dg/cpp2a/class-deduction-alias6.C: New test.
            * g++.dg/cpp2a/class-deduction-alias7.C: New test.
            * g++.dg/cpp2a/class-deduction-alias8.C: New test.