diff --git a/cmake/Modules/FindLuaBuild/LuaVanilla.cmake b/cmake/Modules/FindLuaBuild/LuaVanilla.cmake
index a6dcc5d7..0ab67a5f 100644
--- a/cmake/Modules/FindLuaBuild/LuaVanilla.cmake
+++ b/cmake/Modules/FindLuaBuild/LuaVanilla.cmake
@@ -35,10 +35,12 @@ include(Common/Core)
 set(LUA_VANILLA_5.1_LATEST_VERSION 5.1.5)
 set(LUA_VANILLA_5.2_LATEST_VERSION 5.2.4)
 set(LUA_VANILLA_5.3_LATEST_VERSION 5.3.5)
-set(LUA_VANILLA_5.4_LATEST_VERSION 5.4.0-work1)
+set(LUA_VANILLA_5.4_LATEST_VERSION 5.4.0-alpha)
 
 # exact version, coming from CI: pull directly from Lua and use external project to build
 # list of known md5 / sha1: must update when there are changes
+set(LUA_VANILLA_MD5_5.4.0-alpha d49d30b394794b96ffad53513ac647a5)
+set(LUA_VANILLA_SHA1_5.4.0-alpha cf3559dc43cad35463740c6fbedeb1ea501e5e23)
 set(LUA_VANILLA_MD5_5.4.0-work2 3cdf2a4eb84dde6b6aaf5d2d1de07be9)
 set(LUA_VANILLA_SHA1_5.4.0-work2 e8484e61c5c338e3ec2f75dbe0f6703d079fecf9)
 set(LUA_VANILLA_MD5_5.4.0-work1 0ff232b8658884155a43cf72212edbd9)
@@ -212,7 +214,7 @@ if (LUA_BUILD_LUA_COMPILER)
 endif()
 	set(LUA_VANILLA_GENERATE_LUA_HPP false)
 elseif (LUA_VANILLA_VERSION MATCHES "^5\\.4")
-	if (LUA_VANILLA_VERSION MATCHES "work")
+	if (LUA_VANILLA_VERSION MATCHES "work" OR LUA_VANILLA_VERSION MATCHES "alpha")
 		set(LUA_VANILLA_DOWNLOAD_URL https://www.lua.org/work/lua-${LUA_VANILLA_VERSION}.tar.gz)
 	endif()
 	set(LUA_VANILLA_LIB_SOURCES lapi.c lauxlib.c lbaselib.c lcode.c lcorolib.c 
diff --git a/include/sol/usertype_container.hpp b/include/sol/usertype_container.hpp
index f48232d0..6e7cbfc8 100644
--- a/include/sol/usertype_container.hpp
+++ b/include/sol/usertype_container.hpp
@@ -709,14 +709,30 @@ namespace sol {
 
 			template <typename Iter>
 			static detail::error_result set_associative_insert(std::true_type, lua_State*, T& self, Iter& it, K& key, stack_object value) {
-				self.insert(it, value_type(key, value.as<V>()));
-				return {};
+				if constexpr(meta::has_insert<T>::value) {
+					self.insert(it, value_type(key, value.as<V>()));
+					return {};
+				}
+				else {
+					(void)self;
+					(void)it;
+					(void)key;
+					return detail::error_result("cannot call 'set' on '%s': there is no 'insert' function on this associative type", detail::demangle<T>().c_str());
+				}
 			}
 
 			template <typename Iter>
 			static detail::error_result set_associative_insert(std::false_type, lua_State*, T& self, Iter& it, K& key, stack_object) {
-				self.insert(it, key);
-				return {};
+				if constexpr(has_insert<T>::value) {
+					self.insert(it, key);
+					return {};
+				}
+				else {
+					(void)self;
+					(void)it;
+					(void)key;
+					return detail::error_result("cannot call 'set' on '%s': there is no 'insert' function on this non-associative type", detail::demangle<T>().c_str());
+				}
 			}
 
 			static detail::error_result set_associative_find(std::true_type, lua_State* L, T& self, stack_object okey, stack_object value) {
@@ -898,8 +914,17 @@ namespace sol {
 
 			template <typename Iter>
 			static detail::error_result add_associative(std::true_type, lua_State* L, T& self, stack_object key, Iter& pos) {
-				self.insert(pos, value_type(key.as<K>(), stack::unqualified_get<V>(L, 3)));
-				return {};
+				if constexpr(meta::has_insert<T>::value) {
+					self.insert(pos, value_type(key.as<K>(), stack::unqualified_get<V>(L, 3)));
+					return {};
+				}
+				else {
+					(void)L;
+					(void)self;
+					(void)key;
+					(void)pos;
+					return detail::error_result("cannot call 'insert' on '%s': there is no 'insert' function on this associative type", detail::demangle<T>().c_str());
+				}
 			}
 
 			static detail::error_result add_associative(std::true_type, lua_State* L, T& self, stack_object key) {
@@ -1067,10 +1092,23 @@ namespace sol {
 				return deferred_uc::begin(L, self) == deferred_uc::end(L, self);
 			}
 
-			static detail::error_result get_start(lua_State* L, T& self, K& key) {
+			static detail::error_result get_associative_find(std::true_type, lua_State* L, T& self, K& key) {
+				auto it = self.find(key);
+				if (it == deferred_uc::end(L, self)) {
+					stack::push(L, lua_nil);
+					return {};
+				}
+				return get_associative(std::true_type(), L, it);
+			}
+
+			static detail::error_result get_associative_find(std::false_type, lua_State* L, T& self, K& key) {
 				return get_it(is_linear_integral(), L, self, key);
 			}
 
+			static detail::error_result get_start(lua_State* L, T& self, K& key) {
+				return get_associative_find(std::integral_constant<bool, is_associative::value && has_find<T>::value>(), L, self, key);
+			}
+
 			static detail::error_result set_start(lua_State* L, T& self, stack_object key, stack_object value) {
 				return set_it(is_linear_integral(), L, self, std::move(key), std::move(value));
 			}
diff --git a/single/include/sol/forward.hpp b/single/include/sol/forward.hpp
index 56e35f50..c96fdf09 100644
--- a/single/include/sol/forward.hpp
+++ b/single/include/sol/forward.hpp
@@ -20,8 +20,8 @@
 // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 // This file was generated with a script.
-// Generated 2019-08-15 05:26:10.792424 UTC
-// This header was generated with sol v3.0.3 (revision 09f5e86)
+// Generated 2019-08-15 06:28:23.273623 UTC
+// This header was generated with sol v3.0.3 (revision cb3acaa)
 // https://github.com/ThePhD/sol2
 
 #ifndef SOL_SINGLE_INCLUDE_FORWARD_HPP
diff --git a/single/include/sol/sol.hpp b/single/include/sol/sol.hpp
index fb6ba5d1..b8a92c20 100644
--- a/single/include/sol/sol.hpp
+++ b/single/include/sol/sol.hpp
@@ -20,8 +20,8 @@
 // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 // This file was generated with a script.
-// Generated 2019-08-15 05:26:10.095950 UTC
-// This header was generated with sol v3.0.3 (revision 09f5e86)
+// Generated 2019-08-15 06:28:22.668458 UTC
+// This header was generated with sol v3.0.3 (revision cb3acaa)
 // https://github.com/ThePhD/sol2
 
 #ifndef SOL_SINGLE_INCLUDE_HPP
@@ -19672,14 +19672,30 @@ namespace sol {
 
 			template <typename Iter>
 			static detail::error_result set_associative_insert(std::true_type, lua_State*, T& self, Iter& it, K& key, stack_object value) {
-				self.insert(it, value_type(key, value.as<V>()));
-				return {};
+				if constexpr(meta::has_insert<T>::value) {
+					self.insert(it, value_type(key, value.as<V>()));
+					return {};
+				}
+				else {
+					(void)self;
+					(void)it;
+					(void)key;
+					return detail::error_result("cannot call 'set' on '%s': there is no 'insert' function on this associative type", detail::demangle<T>().c_str());
+				}
 			}
 
 			template <typename Iter>
 			static detail::error_result set_associative_insert(std::false_type, lua_State*, T& self, Iter& it, K& key, stack_object) {
-				self.insert(it, key);
-				return {};
+				if constexpr(has_insert<T>::value) {
+					self.insert(it, key);
+					return {};
+				}
+				else {
+					(void)self;
+					(void)it;
+					(void)key;
+					return detail::error_result("cannot call 'set' on '%s': there is no 'insert' function on this non-associative type", detail::demangle<T>().c_str());
+				}
 			}
 
 			static detail::error_result set_associative_find(std::true_type, lua_State* L, T& self, stack_object okey, stack_object value) {
@@ -19861,8 +19877,17 @@ namespace sol {
 
 			template <typename Iter>
 			static detail::error_result add_associative(std::true_type, lua_State* L, T& self, stack_object key, Iter& pos) {
-				self.insert(pos, value_type(key.as<K>(), stack::unqualified_get<V>(L, 3)));
-				return {};
+				if constexpr(meta::has_insert<T>::value) {
+					self.insert(pos, value_type(key.as<K>(), stack::unqualified_get<V>(L, 3)));
+					return {};
+				}
+				else {
+					(void)L;
+					(void)self;
+					(void)key;
+					(void)pos;
+					return detail::error_result("cannot call 'insert' on '%s': there is no 'insert' function on this associative type", detail::demangle<T>().c_str());
+				}
 			}
 
 			static detail::error_result add_associative(std::true_type, lua_State* L, T& self, stack_object key) {
@@ -20030,10 +20055,23 @@ namespace sol {
 				return deferred_uc::begin(L, self) == deferred_uc::end(L, self);
 			}
 
-			static detail::error_result get_start(lua_State* L, T& self, K& key) {
+			static detail::error_result get_associative_find(std::true_type, lua_State* L, T& self, K& key) {
+				auto it = self.find(key);
+				if (it == deferred_uc::end(L, self)) {
+					stack::push(L, lua_nil);
+					return {};
+				}
+				return get_associative(std::true_type(), L, it);
+			}
+
+			static detail::error_result get_associative_find(std::false_type, lua_State* L, T& self, K& key) {
 				return get_it(is_linear_integral(), L, self, key);
 			}
 
+			static detail::error_result get_start(lua_State* L, T& self, K& key) {
+				return get_associative_find(std::integral_constant<bool, is_associative::value && has_find<T>::value>(), L, self, key);
+			}
+
 			static detail::error_result set_start(lua_State* L, T& self, stack_object key, stack_object value) {
 				return set_it(is_linear_integral(), L, self, std::move(key), std::move(value));
 			}