[Bug c++/61216] New: wrong name lookup for operator functions with using-declaration

["palpatin91 at mail dot ru" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61216

            Bug ID: 61216
           Summary: wrong name lookup for operator functions with
                    using-declaration
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: trivial
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: palpatin91 at mail dot ru

In GCC 4.8.1 for Windows XP:
---------------------------------------------
gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=f:/dev-cpp/mingw32/bin/../libexec/gcc/mingw32/4.8.1/lto-wrap
per.exe
Target: mingw32
Configured with: ../gcc-4.8.1/configure --prefix=/mingw --host=mingw32
--build=m
ingw32 --without-pic --enable-shared --enable-static --with-gnu-ld --enable-lto
--enable-libssp --disable-multilib
--enable-languages=c,c++,fortran,objc,obj-c++
,ada --disable-sjlj-exceptions --with-dwarf2 --disable-win32-registry
--enable-l
ibstdcxx-debug --enable-version-specific-runtime-libs
--with-gmp=/usr/src/pkg/gm
p-5.1.2-1-mingw32-src/bld --with-mpc=/usr/src/pkg/mpc-1.0.1-1-mingw32-src/bld
--
with-mpfr= --with-system-zlib --with-gnu-as --enable-decimal-float=yes
--enable-
libgomp --enable-threads --with-libiconv-prefix=/mingw32
--with-libintl-prefix=/
mingw --disable-bootstrap LDFLAGS=-s CFLAGS=-D_USE_32BIT_TIME_T
Thread model: win32
gcc version 4.8.1 (GCC)
---------------------------------------------

following code fragment gives compilation error:
---------------------------------------------
class C {

};

namespace N {
C& operator ++(C& obj) { return obj; }
}

C& operator ++(C& obj) { return obj; }

int main()
{
    using N::operator ++;
    C c;
    ++c;
}
---------------------------------------------
main.cpp: In function 'int main()':
main.cpp:69:2: error: ambiguous overload for 'operator++' (operand type is 'C')
  ++c;
  ^
main.cpp:69:2: note: candidates are:
main.cpp:60:4: note: C& N::operator++(C&)
 C& operator ++(C& obj) { return obj; }
    ^
main.cpp:63:4: note: C& operator++(C&)
 C& operator ++(C& obj) { return obj; }
    ^
---------------------------------------------
But according to 13.3.1.2p3:
"The set of non-member candidates is the result of the unqualified lookup of
operator@ in the context
of the expression according to the usual rules for name lookup in unqualified
function calls (3.4.2)
except that all member functions are ignored."

And the following code compiles just fine:
---------------------------------------------
namespace N {
void f() {}
}

void f() {}

int main()
{
    using N::f;
    f();
}
---------------------------------------------
So I assume in case of operator functions it should compile also and choose
N::operator ++ version