===================================================================
@@ -5398,6 +5398,7 @@ finish_decltype_type (tree expr, bool id_expressio
break;
case COMPONENT_REF:
+ case COMPOUND_EXPR:
mark_type_use (expr);
type = is_bitfield_expr_with_lowered_type (expr);
if (!type)
===================================================================
@@ -0,0 +1,18 @@
+// PR c++/56450
+// { dg-do compile { target c++11 } }
+
+template<typename T>
+T&& declval();
+
+template<typename, typename>
+struct is_same
+{ static constexpr bool value = false; };
+
+template<typename T>
+struct is_same<T, T>
+{ static constexpr bool value = true; };
+
+struct A { static const int dummy = 0; };
+
+static_assert(is_same<decltype(declval<A>().dummy), const int>::value, "");
+static_assert(!is_same<decltype(declval<A>().dummy), const int&>::value, "");