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diff --git a/deps/sol2/include/sol/metatable.hpp b/deps/sol2/include/sol/metatable.hpp
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+++ b/deps/sol2/include/sol/metatable.hpp
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+// sol3
+
+// The MIT License (MIT)
+
+// Copyright (c) 2013-2019 Rapptz, ThePhD and contributors
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy of
+// this software and associated documentation files (the "Software"), to deal in
+// the Software without restriction, including without limitation the rights to
+// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+// the Software, and to permit persons to whom the Software is furnished to do so,
+// subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+#ifndef SOL_METATABLE_HPP
+#define SOL_METATABLE_HPP
+
+#include "table_core.hpp"
+#include "usertype.hpp"
+
+namespace sol {
+
+	template <typename base_type>
+	class basic_metatable : public basic_table<base_type> {
+		typedef basic_table<base_type> base_t;
+		friend class state;
+		friend class state_view;
+
+	protected:
+		basic_metatable(detail::no_safety_tag, lua_nil_t n) : base_t(n) {
+		}
+		basic_metatable(detail::no_safety_tag, lua_State* L, int index) : base_t(L, index) {
+		}
+		basic_metatable(detail::no_safety_tag, lua_State* L, ref_index index) : base_t(L, index) {
+		}
+		template <typename T,
+		     meta::enable<meta::neg<meta::any_same<meta::unqualified_t<T>, basic_metatable>>, meta::neg<std::is_same<base_type, stack_reference>>,
+		          meta::neg<std::is_same<lua_nil_t, meta::unqualified_t<T>>>, is_lua_reference<meta::unqualified_t<T>>> = meta::enabler>
+		basic_metatable(detail::no_safety_tag, T&& r) noexcept : base_t(std::forward<T>(r)) {
+		}
+		template <typename T, meta::enable<is_lua_reference<meta::unqualified_t<T>>> = meta::enabler>
+		basic_metatable(detail::no_safety_tag, lua_State* L, T&& r) noexcept : base_t(L, std::forward<T>(r)) {
+		}
+
+	public:
+		using base_t::lua_state;
+
+		basic_metatable() noexcept = default;
+		basic_metatable(const basic_metatable&) = default;
+		basic_metatable(basic_metatable&&) = default;
+		basic_metatable& operator=(const basic_metatable&) = default;
+		basic_metatable& operator=(basic_metatable&&) = default;
+		basic_metatable(const stack_reference& r) : basic_metatable(r.lua_state(), r.stack_index()) {
+		}
+		basic_metatable(stack_reference&& r) : basic_metatable(r.lua_state(), r.stack_index()) {
+		}
+		template <typename T, meta::enable_any<is_lua_reference<meta::unqualified_t<T>>> = meta::enabler>
+		basic_metatable(lua_State* L, T&& r) : base_t(L, std::forward<T>(r)) {
+#if defined(SOL_SAFE_REFERENCES) && SOL_SAFE_REFERENCES
+			auto pp = stack::push_pop(*this);
+			constructor_handler handler{};
+			stack::check<basic_metatable>(lua_state(), -1, handler);
+#endif // Safety
+		}
+		basic_metatable(lua_State* L, int index = -1) : basic_metatable(detail::no_safety, L, index) {
+#if defined(SOL_SAFE_REFERENCES) && SOL_SAFE_REFERENCES
+			constructor_handler handler{};
+			stack::check<basic_metatable>(L, index, handler);
+#endif // Safety
+		}
+		basic_metatable(lua_State* L, ref_index index) : basic_metatable(detail::no_safety, L, index) {
+#if defined(SOL_SAFE_REFERENCES) && SOL_SAFE_REFERENCES
+			auto pp = stack::push_pop(*this);
+			constructor_handler handler{};
+			stack::check<basic_metatable>(lua_state(), -1, handler);
+#endif // Safety
+		}
+		template <typename T,
+		     meta::enable<meta::neg<meta::any_same<meta::unqualified_t<T>, basic_metatable>>, meta::neg<std::is_same<base_type, stack_reference>>,
+		          meta::neg<std::is_same<lua_nil_t, meta::unqualified_t<T>>>, is_lua_reference<meta::unqualified_t<T>>> = meta::enabler>
+		basic_metatable(T&& r) noexcept : basic_metatable(detail::no_safety, std::forward<T>(r)) {
+#if defined(SOL_SAFE_REFERENCES) && SOL_SAFE_REFERENCES
+			if (!is_table<meta::unqualified_t<T>>::value) {
+				auto pp = stack::push_pop(*this);
+				constructor_handler handler{};
+				stack::check<basic_metatable>(base_t::lua_state(), -1, handler);
+			}
+#endif // Safety
+		}
+		basic_metatable(lua_nil_t r) noexcept : basic_metatable(detail::no_safety, r) {
+		}
+
+		template <typename Key, typename Value>
+		void set(Key&& key, Value&& value);
+
+		void unregister() {
+			using ustorage_base = u_detail::usertype_storage_base;
+
+			lua_State* L = this->lua_state();
+
+			auto pp = stack::push_pop(*this);
+			int top = lua_gettop(L);
+
+			stack_reference mt(L, -1);
+			stack::get_field(L, meta_function::gc_names, mt.stack_index());
+			if (type_of(L, -1) != type::table) {
+				return;
+			}
+			stack_reference gc_names_table(L, -1);
+			stack::get_field(L, meta_function::storage, mt.stack_index());
+			if (type_of(L, -1) != type::lightuserdata) {
+				return;
+			}
+			ustorage_base& base_storage = *static_cast<ustorage_base*>(stack::get<void*>(L, -1));
+			std::array<string_view, 6> registry_traits;
+			for (std::size_t i = 0; i < registry_traits.size(); ++i) {
+				u_detail::submetatable_type smt = static_cast<u_detail::submetatable_type>(i);
+				stack::get_field<false, true>(L, smt, gc_names_table.stack_index());
+				registry_traits[i] = stack::get<string_view>(L, -1);
+			}
+
+			// get the registry
+			stack_reference registry(L, raw_index(LUA_REGISTRYINDEX));
+			registry.push();
+			// eliminate all named entries for this usertype
+			// in the registry (luaL_newmetatable does
+			// [name] = new table
+			// in registry upon creation)
+			for (std::size_t i = 0; i < registry_traits.size(); ++i) {
+				u_detail::submetatable_type smt = static_cast<u_detail::submetatable_type>(i);
+				const string_view& gcmetakey = registry_traits[i];
+				if (smt == u_detail::submetatable_type::named) {
+					// use .data() to make it treat it like a c string,
+					// which it is...
+					stack::set_field<true>(L, gcmetakey.data(), lua_nil);
+				}
+				else {
+					// do not change the values in the registry: they need to be present
+					// no matter what, for safety's sake
+					//stack::set_field(L, gcmetakey, lua_nil, registry.stack_index());
+				}
+			}
+
+			// destroy all storage and tables
+			base_storage.clear();
+
+			// 6 strings from gc_names table,
+			// + 1 registry,
+			// + 1 gc_names table
+			// + 1 light userdata of storage
+			// + 1 registry
+			// 10 total, 4 left since popping off 6 gc_names tables
+			lua_settop(L, top);
+		}
+	};
+
+} // namespace sol
+
+#endif // SOL_METATABLE_HPP