1 // PR c++/73456
2 // { dg-options "-std=c++17 -fconcepts" }
3 
4 template<typename...> struct list {};
5 
6 template<typename Seq>
7 concept bool Sequence = true;
8 
9 template<Sequence... Seqs>
10 struct zip;
11 
12 template<Sequence... Seqs>
13     requires requires { typename list<Seqs...>; }
14 // main.cpp:12:8: internal compiler error: in non_atomic_constraint_p, at cp/logic.cc:315
15 struct zip<Seqs...> {};
16 
17 int main()
18 {
19     zip<list<>, list<int>> {};
20 }
21