| // PR c++/73456 |
| // { dg-do compile { target c++17_only } } |
| // { dg-options "-fconcepts" } |
| |
| template<typename...> struct list {}; |
| |
| template<typename Seq> |
| concept bool Sequence = true; |
| |
| template<Sequence... Seqs> // requires (Sequence<Seqs> && ...) |
| struct zip; |
| |
| template<Sequence... Seqs> |
| requires requires { typename list<Seqs...>; } // && (Sequence<Seqs> && ...) |
| struct zip<Seqs...> {}; // { dg-error "does not specialize" } |
| // The constraints of the specialization and the sequence are not |
| // comparable; the specializations are unordered. |
| |
| int main() |
| { |
| zip<list<>, list<int>> {}; |
| } |
