--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/cpp0x/noexcept42.C	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,21 @@
+// PR c++/84698
+// { dg-do compile { target c++11 } }
+
+template<typename A, typename B>
+struct X {
+  void swap(X& o) noexcept { }
+
+  template<typename... Args>
+  friend void swap(X<Args...>& a, X<Args...>& b) noexcept(noexcept(a.swap(b)));
+};
+
+template<typename... Args>
+inline void swap(X<Args...>& a, X<Args...>& b) noexcept(noexcept(a.swap(b)))
+{
+}
+
+int
+main ()
+{
+  X<int, int> x;
+}