diff --git a/README.md b/README.md
index 3451e5bc..a1b565ce 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,8 @@ Sol makes use of C++11 features. The features used are as follows:
 - auto
 - uniform initialisation
 - noexcept
+- in class initialisation
+- default functions
 
 GCC 4.7 and Clang 3.3 or higher should be able to compile without problems. Visual Studio 2013 with the November CTP should
 be able to support this as well.
diff --git a/sol/reference.hpp b/sol/reference.hpp
index bcab8a05..90a2d2e1 100644
--- a/sol/reference.hpp
+++ b/sol/reference.hpp
@@ -35,7 +35,7 @@ private:
         return luaL_ref(L, LUA_REGISTRYINDEX);
     }
 public:
-    constexpr reference() noexcept = default;
+    reference() noexcept = default;
 
     reference(lua_State* L, int index): L(L) {
         lua_pushvalue(L, index);
diff --git a/sol/types.hpp b/sol/types.hpp
index 31956544..3efd749d 100644
--- a/sol/types.hpp
+++ b/sol/types.hpp
@@ -28,7 +28,7 @@
 
 namespace sol {
 struct nil_t {};
-constexpr nil_t nil{};
+const nil_t nil{};
 
 enum class type : int {
     none = LUA_TNONE,