| // Testcase from P0512R0 for C++17 NB comment US 20 |
| // { dg-do compile { target c++17 } } |
| |
| template <class,class> struct same; |
| template <class T> struct same<T,T> {}; |
| |
| template<class T> struct A { |
| template<class U> |
| A(T&&, U&&, int*); // #1: T&& is not a forwarding reference |
| // U&& is a forwarding reference |
| A(T&&, int*); // #2 |
| }; |
| template<class T> |
| A(T&&, int*) -> A<T>; // #3: T&& is a forwarding reference |
| |
| int i; |
| int *ip; |
| A a0{0, 0, ip}; // uses #1 to deduce A<int> and #1 to initialize |
| same<decltype(a0),A<int>> s1; |
| A a2{i, ip}; // uses #3 to deduce A<int&> and #2 to initialize |
| same<decltype(a2),A<int&>> s2; |
| |
| A a{i, 0, ip}; // { dg-error "" } cannot deduce from #1 |
