| // PR c++/79501 | |
| // { dg-do compile { target c++17 } } | |
| template<auto V> | |
| struct X { | |
| template<class T, auto> | |
| struct B { T t; }; | |
| template<class T> B(T, decltype(V)=V) -> B<const T, V>; | |
| auto foo() { return B{V}; } | |
| }; | |
| X<42> x; | |
| using type = decltype(x.foo()); | |
| using type = decltype(decltype(x)::B{42}); | |
| using type = X<42>::B<const int, 42>; |