[Bug c++/110345] New: [C++26] P2552R3 - On the ignorability of standard attributes

[Bug c++/110345] New: [C++26] P2552R3 - On the ignorability of standard attributes

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110345

            Bug ID: 110345
           Summary: [C++26] P2552R3 - On the ignorability of standard
                    attributes
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mpolacek at gcc dot gnu.org
  Target Milestone: ---

See <https://wg21.link/P2552R3>.

[Bug c++/110345] [C++26] P2552R3 - On the ignorability of standard attributes

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110345

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 55791
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55791&action=edit
gcc14-pr110345-wip.patch

So, parts of this paper has been already fixed in r13-3848-g05119c345797bc04c .
The fallthrough stuff is still outstanding I think and I'll have a look.
The largest nightmare is diagnostics on standard attributes which appertain to
something that shouldn't allow them, I'm lost there.
I went through the grammar (except for modules) and tried to find all spots
where standard allows attribute-specifier-seq and tried to write that into a
testcase in the attached patch, for now for deprecated attribute and marked all
-pedantic-errors diagnostics.  I've added lots of FIXMEs in there where I don't
really know.  There are
even 4 spots where we don't parse the attributes at all (and clang++ does), on
the other side there are 4 spots where we do parse them and clang++ doesn't.
I think to mark this paper fully resolved we'd need to resolve the FIXMEs and
copy/adjust the test for all other standard attributes and verify we emit at
least some diagnostics with -pedantic-errors where the standard attributes
aren't allowed to appertain to.

[Bug c++/110345] [C++26] P2552R3 - On the ignorability of standard attributes

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110345

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The fallthrough stuff is still outstanding I think and I'll have a look.
part is done in r14-5561-g52eedfa00960f2d255ec542626e3531a65aa8bb8
The rest unresolved.