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[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
- From: "gintensubaru at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 27 Sep 2011 20:44:52 +0000
- Subject: [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
- Auto-submitted: auto-generated
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: unassigned@gcc.gnu.org
ReportedBy: gintensubaru@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.