[Bug c++/106395] New: [10/11 regression] [mingw] "redeclared without dllimport attribute: previous dllimport ignored" on C++ friend

[Bug c++/106395] New: [10/11 regression] [mingw] "redeclared without dllimport attribute: previous dllimport ignored" on C++ friend

[thiago at kde dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106395

            Bug ID: 106395
           Summary: [10/11 regression] [mingw] "redeclared without
                    dllimport attribute: previous dllimport ignored" on
                    C++ friend
           Product: gcc
           Version: 12.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: thiago at kde dot org
  Target Milestone: ---

__attribute__((dllimport)) void f();
class S
{
private:
    int i;
    friend __attribute__((dllimport)) void f();
};

With GCC 10.3.0 (OpenSUSE Tumbleweed):
$ x86_64-w64-mingw32-gcc -c -Werror /tmp/test.cpp        

With GCC 11.2.1 (Fedora 35 & 36):
$ x86_64-w64-mingw32-gcc -Wall -Wextra -Werror -c /tmp/test.cpp

With GCC 12.1.0 (Arch Linux, self built):
$ x86_64-w64-mingw32-g++ -Werror -c /tmp/test.cpp
/tmp/test.cpp:6:44: error: ‘void f()’ redeclared without dllimport attribute:
previous dllimport ignored [-Werror=attributes]
    6 |     friend __attribute__((dllimport)) void f();
      |                                            ^
cc1plus: all warnings being treated as errors

GCC 12 is obviously wrong because it is complaining that the attribute is
missing and then shows that the attribute is right there.

[Bug c++/106395] [12/13 regression] [mingw] "redeclared without dllimport attribute: previous dllimport ignored" on C++ friend

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106395

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |12.2
           Keywords|                            |rejects-valid
            Summary|[10/11 regression] [mingw]  |[12/13 regression] [mingw]
                   |"redeclared without         |"redeclared without
                   |dllimport attribute:        |dllimport attribute:
                   |previous dllimport ignored" |previous dllimport ignored"
                   |on C++ friend               |on C++ friend
      Known to fail|                            |12.1.0
             Target|                            |mingw
      Known to work|                            |10.3.0, 11.2.1

[Bug c++/106395] [12/13 regression] [mingw] "redeclared without dllimport attribute: previous dllimport ignored" on C++ friend

[m101010a at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106395

m101010a at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |m101010a at gmail dot com

--- Comment #1 from m101010a at gmail dot com ---
Git bisect indicates this was caused by commit
a0fdff3cf33f72848d3f894272431a5d49fe6a16 "c++: Fix friend attributes
[PR51344]".
Also, you don't need a member variable to trigger this; I was able to reproduce
it with just

__attribute__((dllimport)) void f();
struct s
{
        friend __attribute__((dllimport)) void f();
};

[Bug c++/106395] [12/13 regression] [mingw] "redeclared without dllimport attribute: previous dllimport ignored" on C++ friend since r12-299-ga0fdff3cf33f72

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106395

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-08-10
                 CC|                            |jason at gcc dot gnu.org
           Priority|P3                          |P2
            Summary|[12/13 regression] [mingw]  |[12/13 regression] [mingw]
                   |"redeclared without         |"redeclared without
                   |dllimport attribute:        |dllimport attribute:
                   |previous dllimport ignored" |previous dllimport ignored"
                   |on C++ friend               |on C++ friend since
                   |                            |r12-299-ga0fdff3cf33f72
           Keywords|needs-bisection             |
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Thanks for the bisect.

[Bug c++/106395] [12/13 regression] [mingw] "redeclared without dllimport attribute: previous dllimport ignored" on C++ friend since r12-299-ga0fdff3cf33f72

[nightstrike at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106395

nightstrike <nightstrike at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nightstrike at gmail dot com

--- Comment #4 from nightstrike <nightstrike at gmail dot com> ---
This appears to be fixed in GCC 13

[Bug c++/106395] [12/13 regression] [mingw] "redeclared without dllimport attribute: previous dllimport ignored" on C++ friend since r12-299-ga0fdff3cf33f72

[i.nixman at autistici dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106395

niXman <i.nixman at autistici dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |i.nixman at autistici dot org

--- Comment #5 from niXman <i.nixman at autistici dot org> ---
(In reply to nightstrike from comment #4)
> This appears to be fixed in GCC 13

yeah, looks like it got fixed for the master/main.

[Bug c++/106395] [12 regression] [mingw] "redeclared without dllimport attribute: previous dllimport ignored" on C++ friend since r12-299-ga0fdff3cf33f72

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106395

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|12.3                        |12.4

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 12.3 is being released, retargeting bugs to GCC 12.4.