| // PR c++/50545 |
| // { dg-do compile { target c++11 } } |
| |
| 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. |
