[Bug c++/109177] New: Call to C++ function marked unavailable gets diagnosed twice

[Bug c++/109177] New: Call to C++ function marked unavailable gets diagnosed twice

[acoplan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109177

            Bug ID: 109177
           Summary: Call to C++ function marked unavailable gets diagnosed
                    twice
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: acoplan at gcc dot gnu.org
  Target Milestone: ---

Reproducer:

$ cat t.cc
void f() __attribute__((unavailable));
void g() { f(); }
$ gcc/xgcc -B gcc -c t.cc
t.cc: In function ‘void g()’:
t.cc:2:13: error: ‘void f()’ is unavailable
    2 | void g() { f(); }
      |            ~^~
t.cc:1:6: note: declared here
    1 | void f() __attribute__((unavailable));
      |      ^
t.cc:2:13: error: ‘void f()’ is unavailable
    2 | void g() { f(); }
      |            ~^~
t.cc:1:6: note: declared here
    1 | void f() __attribute__((unavailable));
      |      ^

This only seems to happen in C++ mode, C diagnoses this once as expected.

[Bug c++/109177] Call to C++ function marked unavailable gets diagnosed twice

[acoplan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109177

Alex Coplan <acoplan at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2023-03-18
           Assignee|unassigned at gcc dot gnu.org      |acoplan at gcc dot gnu.org

--- Comment #1 from Alex Coplan <acoplan at gcc dot gnu.org> ---
Testing a patch.

[Bug c++/109177] Call to C++ function marked unavailable gets diagnosed twice

[acoplan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109177

--- Comment #2 from Alex Coplan <acoplan at gcc dot gnu.org> ---
Part of the problem here seems to be that dg-error doesn't care how many times
the same diagnostic is emitted, so it doesn't seem able to detect this failure
mode. Otherwise, I expect this would have shown up in failures of the existing
g++.dg/ext/attr-unavailable*.C tests.

[Bug c++/109177] Call to C++ function marked unavailable gets diagnosed twice

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109177

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

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

--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
FWIW one way to test against duplicate errors currently is something like:

void f() __attribute__((unavailable)); // { dg-bogus "is unavailable.*is
unavailable" }
// { dg-error "is unavailable" "" { target *-*-* } .-1 }

[Bug c++/109177] Call to C++ function marked unavailable gets diagnosed twice

[acoplan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109177

--- Comment #4 from Alex Coplan <acoplan at gcc dot gnu.org> ---
(In reply to Patrick Palka from comment #3)
> FWIW one way to test against duplicate errors currently is something like:
> 
> void f() __attribute__((unavailable)); // { dg-bogus "is unavailable.*is
> unavailable" }
> // { dg-error "is unavailable" "" { target *-*-* } .-1 }

Thanks, that's helpful. I suppose it would be nice if DejaGnu could be modified
(or perhaps configured) so that errors are only matched at most once, but that
seems unlikely to happen and it would be awkward to coordinate across projects.

[Bug c++/109177] Call to C++ function marked unavailable gets diagnosed twice

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109177

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Alex Coplan <acoplan@gcc.gnu.org>:

https://gcc.gnu.org/g:d3a6f174543816600b1f472997d492088e4e396a

commit r13-6801-gd3a6f174543816600b1f472997d492088e4e396a
Author: Alex Coplan <alex.coplan@arm.com>
Date:   Wed Mar 22 15:20:49 2023 +0000

    c++: Avoid duplicate diagnostic calling unavailable function [PR109177]

    As the PR shows, we currently emit duplicate diagnostics for calls to
    functions marked with __attribute__((unavailable)). This patch fixes
    that.

    gcc/cp/ChangeLog:

            PR c++/109177
            * call.cc (build_over_call): Use make_temp_override to suppress
            both unavailable and deprecated warnings when calling
            build_addr_func.

    gcc/testsuite/ChangeLog:

            PR c++/109177
            * g++.dg/ext/pr109177.C: New test.

[Bug c++/109177] Call to C++ function marked unavailable gets diagnosed twice

[acoplan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109177

Alex Coplan <acoplan at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #6 from Alex Coplan <acoplan at gcc dot gnu.org> ---
Fixed for GCC 13. Since this doesn't seem to be a regression (and it's quite a
minor issue) I guess it's not worth backporting.