--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/concepts/variadic4.C	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,20 @@
+// PR c++/73456
+// { dg-options "-std=c++17 -fconcepts" }
+
+template<typename...> struct list {};
+
+template<typename Seq>
+concept bool Sequence = true;
+
+template<Sequence... Seqs>
+struct zip;
+
+template<Sequence... Seqs>
+    requires requires { typename list<Seqs...>; }
+// main.cpp:12:8: internal compiler error: in non_atomic_constraint_p, at cp/logic.cc:315
+struct zip<Seqs...> {};
+
+int main()
+{
+    zip<list<>, list<int>> {};
+}