[Bug c++/94771] New: g++.dg/concepts/diagnostic10.C fails on mingw

[Bug c++/94771] New: g++.dg/concepts/diagnostic10.C fails on mingw

[sbence92 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94771

            Bug ID: 94771
           Summary: g++.dg/concepts/diagnostic10.C fails on mingw
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sbence92 at gmail dot com
  Target Milestone: ---

g++.dg/concepts/diagnostic10.C fails with gcc 10 (ead1c27a530) on mingw target
and host.

Instead of 
diagnostic10.C:6:31: error: invalid use of non-static member function 'int
S::f()'
we get
diagnostic10.C:6:31: error: statement cannot resolve address of overloaded
function.

Seems like the fix for Bug 52597 (typeck.c invalid_nonstatic_memfn_p) went with
a special case for -fms-extensions which is a default for mingw.

Compiling with -fno-ms-extensions provides the correct diagnostic.

[Bug c++/94771] g++.dg/concepts/diagnostic10.C fails on mingw

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94771

Iain Sandoe <iains at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2020-04-27

--- Comment #1 from Iain Sandoe <iains at gcc dot gnu.org> ---
the commit you mention appears to be unrelated to the test fail, please could
you identify commit the failure started?

[Bug c++/94771] g++.dg/concepts/diagnostic10.C fails on mingw

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94771

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The fix for Bug 52597 does seem related, see the change to
invalid_nonstatic_memfn_p in r197131.

I don't know what the MS extension is that requires the t.f syntax to be
allowed. Maybe the extension should be disabled in a requires-expression?

[Bug c++/94771] g++.dg/concepts/diagnostic10.C fails on mingw

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94771

Jonathan Wakely <redi at gcc dot gnu.org> changed:

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

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
CC Jason to ask why the change does:

+  /* Don't enforce this in MS mode.  */
+  if (flag_ms_extensions)
+    return false;

[Bug c++/94771] g++.dg/concepts/diagnostic10.C fails on mingw

[sbence92 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94771

--- Comment #4 from Bence Szabó <sbence92 at gmail dot com> ---
Interesting, the t.f syntax is not allowed anymore even with MSVC:
https://godbolt.org/z/YCK-mv

msvc also doesn't list under extensions_
https://docs.microsoft.com/en-us/cpp/build/reference/microsoft-extensions-to-c-and-cpp?view=vs-2015

and some recent overview on ms extensions:
https://stackoverflow.com/questions/56554567/what-does-the-ms-extensions-flag-do-exactly-with-gcc

Is this a dinosaur that forgot to die?