| // { dg-do compile { target c++17 } } |
| |
| template <class T> struct A { |
| A(T); // #1 |
| A(const A&); // #2 |
| }; |
| |
| template <class T> A(T) -> A<T>; // #3 |
| |
| A a (42); // uses #3 to deduce A<int> and initializes with #1 |
| A b = a; // uses #2 (not #3) to deduce A<int> and initializes with #2; #2 is more specialized |
| |
| template <class T> A(A<T>) -> A<A<T>>; // #4 |
| |
| A b2 = a; // uses #4 to deduce A<A<int>> and initializes with #1; #4 is as specialized as #2 |
| |
| template <class,class> struct same; |
| template <class T> struct same<T,T> {}; |
| |
| same<decltype(a),A<int>> s1; |
| same<decltype(b),A<int>> s2; |
| same<decltype(b2),A<A<int>>> s3; |
