diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index f401c75b9e507a8c2f4a13049d9257fbdd2222f2..c033a286407d30a60e4e195944a0cfd17436e503 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -29278,6 +29278,8 @@ do_auto_deduction (tree type, tree init, tree auto_node,
   else if (AUTO_IS_DECLTYPE (auto_node))
     {
       tree stripped_init = tree_strip_any_location_wrapper (init);
+      if (REFERENCE_REF_P (stripped_init))
+	stripped_init = TREE_OPERAND (stripped_init, 0);
       bool id = (DECL_P (stripped_init)
 		 || ((TREE_CODE (init) == COMPONENT_REF
 		      || TREE_CODE (init) == SCOPE_REF)
diff --git a/gcc/testsuite/g++.dg/cpp1y/decltype-auto1.C b/gcc/testsuite/g++.dg/cpp1y/decltype-auto1.C
new file mode 100644
index 0000000000000000000000000000000000000000..13baf8eba06c48894f14670f95759e2ce9c8b1e5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/decltype-auto1.C
@@ -0,0 +1,8 @@
+// PR c++/78209
+// { dg-do compile { target c++14 } }
+
+int main()
+{
+  int &&i = 0;
+  decltype(auto) j = i; // { dg-error "cannot bind rvalue reference" }
+}