[Bug c++/58709] New: [c++11] Bogus? int vs. scoped enum printf warning when -fabi-version >= 6

[ppluzhnikov at google dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58709

            Bug ID: 58709
           Summary: [c++11] Bogus? int vs. scoped enum printf warning when
                    -fabi-version >= 6
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ppluzhnikov at google dot com

Test:

#include <stdio.h>

enum class Foo {
  FOO
};

int main()
{
  printf("%d\n", Foo::FOO);
}

Using "g++ (GCC) 4.9.0 20131005 (experimental)":

$ g++ -c -std=c++11 -Wformat t.cc
$

$ g++ -c -std=c++11 -Wformat t.cc -fabi-version=6

t.cc:9:26: warning: format ‘%d’ expects argument of type ‘int’, but argument 2
has type ‘Foo’ [-Wformat=]
   printf("%d\n", Foo::FOO);
                          ^

From gcc/common.opt:

; 6: The version of the ABI that doesn't promote scoped enums to int and ...

This seems like a bug -- even though the scoped enum is not promoted to an int,
printf warning doesn't seem appropriate here either.