[Bug c++/115114] New: aggregate initialization with parens fails when there is a base class

[Bug c++/115114] New: aggregate initialization with parens fails when there is a base class

[eric.niebler at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115114

            Bug ID: 115114
           Summary: aggregate initialization with parens fails when there
                    is a base class
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: eric.niebler at gmail dot com
  Target Milestone: ---

I believe the following is valid C++20:

  struct get_answer {};

  template <class Query, class Value>
  struct with : Query {
    Value value;
  };

  int main() {
    with w1{get_answer(), 42}; // works

    with w2(get_answer(), 42); // fails
  }

clang and msvc accept this code. gcc-trunk rejects it. See
https://godbolt.org/z/KvGjn47f9.

If I change the definition of the `with` class template to the following, the
code compiles:

  template <class Query, class Value>
  struct with {
    Query query;
    Value value;
  };

[Bug c++/115114] aggregate initialization with parens fails when there is a base class

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115114

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-05-17

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
https://gcc.gnu.org/pipermail/gcc-patches/2024-May/651935.html

[Bug c++/115114] aggregate initialization with parens fails when there is a base class

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115114

--- Comment #2 from GCC 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:5aaf47cb1987bbc5508c4b9b7dad5ea7d69af2c2

commit r15-630-g5aaf47cb1987bbc5508c4b9b7dad5ea7d69af2c2
Author: Patrick Palka <ppalka@redhat.com>
Date:   Fri May 17 09:02:52 2024 -0400

    c++: aggregate CTAD w/ paren init and bases [PR115114]

    During aggregate CTAD with paren init, we're accidentally overlooking
    base classes since TYPE_FIELDS of a template type doesn't contain
    corresponding base fields.  So we need to consider them separately.

            PR c++/115114

    gcc/cp/ChangeLog:

            * pt.cc (maybe_aggr_guide): Consider bases in the paren init case.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp2a/class-deduction-aggr15.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>

[Bug c++/115114] aggregate initialization with parens fails when there is a base class

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115114

--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-14 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:a9837934203d41c96b5cf05e34f68c0d3311c973

commit r14-10221-ga9837934203d41c96b5cf05e34f68c0d3311c973
Author: Patrick Palka <ppalka@redhat.com>
Date:   Fri May 17 09:02:52 2024 -0400

    c++: aggregate CTAD w/ paren init and bases [PR115114]

    During aggregate CTAD with paren init, we're accidentally overlooking
    base classes since TYPE_FIELDS of a template type doesn't contain
    corresponding base fields.  So we need to consider them separately.

            PR c++/115114

    gcc/cp/ChangeLog:

            * pt.cc (maybe_aggr_guide): Consider bases in the paren init case.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp2a/class-deduction-aggr15.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>
    (cherry picked from commit 5aaf47cb1987bbc5508c4b9b7dad5ea7d69af2c2)

[Bug c++/115114] aggregate initialization with parens fails when there is a base class

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115114

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot gnu.org
                 CC|                            |ppalka at gcc dot gnu.org
   Target Milestone|---                         |14.2
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 14.2, thanks for the bug report.