[Bug c++/50545] New: [C++0x] SFINAE does not handle an explicit type conversion (functional notation) with a braced-init-list well if target type is not dependent

[gintensubaru at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50545

             Bug #: 50545
           Summary: [C++0x] SFINAE does not handle an explicit type
                    conversion (functional notation) with a
                    braced-init-list well if target type is not dependent
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: gintensub...@gmail.com


// tested on gcc-4.7-20110924 (experimental)

template< class T >
T&& declval();

// #1
template< class T >
auto f( int )
  -> decltype( int{ declval<T>() } );

// #2
template< class >
void f( ... );


#define STATIC_ASSERT( ... ) static_assert( __VA_ARGS__, #__VA_ARGS__ )

template< class T, class U >
struct is_same {
  static constexpr bool value = false;
};

template< class T >
struct is_same<T, T> {
  static constexpr bool value = true;
};


STATIC_ASSERT( is_same< decltype( f<int>(0) ),  int >::value );  // OK;
f<int>(0) calls #1.
STATIC_ASSERT( is_same< decltype( f<int*>(0) ), void >::value ); // static
assertion fails; f<int*>(0) should call #2, because int{ (int*)0 } is
ill-formed, but calls #1.