--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/cpp1z/decomp46.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,25 @@
+// PR c++/86836
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+struct A {
+  int operator*();
+  void operator++();
+  bool operator!=(A);
+};
+template <typename> class map {
+public:
+  A begin();
+  A end();
+};
+
+template <typename T> void mergemap(map<T> orig, map<T> toadd) {
+  for (auto p : toadd)
+    auto [orig] = orig;		// { dg-error "use of 'orig' before deduction of 'auto'" }
+}				// { dg-warning "structured bindings only available with" "" { target c++14_down } .-1 }
+
+int
+main() {
+  map<double> x, y;
+  mergemap(x, y);
+}