diff --git a/CMakeLists.txt b/CMakeLists.txt
index 97e4c7d..63b2eb6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -38,5 +38,6 @@ target_link_libraries(${PROJECT_NAME} INTERFACE Threads::Threads)
 #
 
 if(PROJECT_IS_TOP_LEVEL)
+    enable_testing()
     add_subdirectory(develop)
 endif()
diff --git a/develop/CMakeLists.txt b/develop/CMakeLists.txt
index 16be87b..83b1241 100644
--- a/develop/CMakeLists.txt
+++ b/develop/CMakeLists.txt
@@ -3,7 +3,6 @@ option(BUILD_WITH_SANITIZERS "Build with sanitizers" OFF)
 option(BUILD_WITH_NO_EXCEPTIONS "Build with no exceptions" ${META_HPP_NO_EXCEPTIONS})
 option(BUILD_WITH_NO_RTTI "Build with no RTTI" ${META_HPP_NO_RTTI})
 
-enable_testing()
 set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 set_property(GLOBAL PROPERTY PREDEFINED_TARGETS_FOLDER "CMake")
 list(INSERT CMAKE_MODULE_PATH 0 "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
diff --git a/develop/singles/headers/meta.hpp/meta_all.hpp b/develop/singles/headers/meta.hpp/meta_all.hpp
index cc9a492..b39dbe8 100644
--- a/develop/singles/headers/meta.hpp/meta_all.hpp
+++ b/develop/singles/headers/meta.hpp/meta_all.hpp
@@ -3677,15 +3677,17 @@ namespace meta_hpp::detail
     private:
         template < array_kind Array >
         [[nodiscard]] array_type_data* resolve_array_type_data() {
-            static array_type_data data{type_list<Array>{}};
-            ensure_type<Array>(data);
+            static array_type_data data = (
+                ensure_type<Array>(data),
+                array_type_data{type_list<Array>{}});
             return &data;
         }
 
         template < class_kind Class >
         [[nodiscard]] class_type_data* resolve_class_type_data() {
-            static class_type_data data{type_list<Class>{}};
-            ensure_type<Class>(data);
+            static class_type_data data = (
+                ensure_type<Class>(data),
+                class_type_data{type_list<Class>{}});
             return &data;
         }
 
@@ -3703,64 +3705,73 @@ namespace meta_hpp::detail
 
         template < enum_kind Enum >
         [[nodiscard]] enum_type_data* resolve_enum_type_data() {
-            static enum_type_data data{type_list<Enum>{}};
-            ensure_type<Enum>(data);
+            static enum_type_data data = (
+                ensure_type<Enum>(data),
+                enum_type_data{type_list<Enum>{}});
             return &data;
         }
 
         template < function_kind Function >
         [[nodiscard]] function_type_data* resolve_function_type_data() {
-            static function_type_data data{type_list<Function>{}};
-            ensure_type<Function>(data);
+            static function_type_data data = (
+                ensure_type<Function>(data),
+                function_type_data{type_list<Function>{}});
             return &data;
         }
 
         template < member_kind Member >
         [[nodiscard]] member_type_data* resolve_member_type_data() {
-            static member_type_data data{type_list<Member>{}};
-            ensure_type<Member>(data);
+            static member_type_data data = (
+                ensure_type<Member>(data),
+                member_type_data{type_list<Member>{}});
             return &data;
         }
 
         template < method_kind Method >
         [[nodiscard]] method_type_data* resolve_method_type_data() {
-            static method_type_data data{type_list<Method>{}};
-            ensure_type<Method>(data);
+            static method_type_data data = (
+                ensure_type<Method>(data),
+                method_type_data{type_list<Method>{}});
             return &data;
         }
 
         template < nullptr_kind Nullptr >
         [[nodiscard]] nullptr_type_data* resolve_nullptr_type_data() {
-            static nullptr_type_data data{type_list<Nullptr>{}};
-            ensure_type<Nullptr>(data);
+            static nullptr_type_data data = (
+                ensure_type<Nullptr>(data),
+                nullptr_type_data{type_list<Nullptr>{}});
             return &data;
         }
 
         template < number_kind Number >
         [[nodiscard]] number_type_data* resolve_number_type_data() {
-            static number_type_data data{type_list<Number>{}};
-            ensure_type<Number>(data);
+            static number_type_data data = (
+                ensure_type<Number>(data),
+                number_type_data{type_list<Number>{}});
             return &data;
         }
 
         template < pointer_kind Pointer >
         [[nodiscard]] pointer_type_data* resolve_pointer_type_data() {
-            static pointer_type_data data{type_list<Pointer>{}};
-            ensure_type<Pointer>(data);
+            static pointer_type_data data = (
+                ensure_type<Pointer>(data),
+                pointer_type_data{type_list<Pointer>{}});
             return &data;
         }
 
         template < reference_kind Reference >
         [[nodiscard]] reference_type_data* resolve_reference_type_data() {
-            static reference_type_data data{type_list<Reference>{}};
-            ensure_type<Reference>(data);
+            static reference_type_data data = (
+                ensure_type<Reference>(data),
+                reference_type_data{type_list<Reference>{}});
             return &data;
         }
 
         template < void_kind Void >
         [[nodiscard]] void_type_data* resolve_void_type_data() {
-            static void_type_data data{type_list<Void>{}};
-            ensure_type<Void>(data);
+            static void_type_data data = (
+                ensure_type<Void>(data),
+                void_type_data{type_list<Void>{}});
             return &data;
         }
     private:
@@ -3768,24 +3779,21 @@ namespace meta_hpp::detail
 
         template < typename Type, typename TypeData >
         void ensure_type(TypeData& type_data) {
-            static std::once_flag init_flag{};
-            std::call_once(init_flag, [this, &type_data](){
-                const locker lock;
+            const locker lock;
 
-                auto&& [position, emplaced] = types_.emplace(any_type{&type_data});
-                if ( !emplaced ) {
-                    return;
-                }
+            auto&& [position, emplaced] = types_.emplace(any_type{&type_data});
+            if ( !emplaced ) {
+                return;
+            }
 
-            #if !defined(META_HPP_NO_RTTI)
-                META_HPP_TRY {
-                    rtti_types_.emplace(typeid(Type), any_type{&type_data});
-                } META_HPP_CATCH(...) {
-                    types_.erase(position);
-                    META_HPP_RETHROW();
-                }
-            #endif
-            });
+        #if !defined(META_HPP_NO_RTTI)
+            META_HPP_TRY {
+                rtti_types_.emplace(typeid(Type), any_type{&type_data});
+            } META_HPP_CATCH(...) {
+                types_.erase(position);
+                META_HPP_RETHROW();
+            }
+        #endif
         }
     private:
         std::recursive_mutex mutex_;
diff --git a/develop/untests/meta_utilities/value2_tests.cpp b/develop/untests/meta_utilities/value2_tests.cpp
index 86fa095..4760712 100644
--- a/develop/untests/meta_utilities/value2_tests.cpp
+++ b/develop/untests/meta_utilities/value2_tests.cpp
@@ -187,12 +187,12 @@ TEST_CASE("meta/meta_utilities/value2/counters/small") {
             CHECK(v1.get_as<ivec2>().x == 3);
             CHECK(v2.get_as<ivec2>().x == 1);
 
-            CHECK(ivec2::destructor_counter == 5);
-            CHECK(ivec2::move_constructor_counter == 5);
+            CHECK((ivec2::destructor_counter == 5 || ivec2::destructor_counter == 6));
+            CHECK((ivec2::move_constructor_counter == 5 || ivec2::move_constructor_counter == 6));
             CHECK(ivec2::copy_constructor_counter == 0);
         }
-        CHECK(ivec2::destructor_counter == 7);
-        CHECK(ivec2::move_constructor_counter == 5);
+        CHECK((ivec2::destructor_counter == 7 || ivec2::destructor_counter == 8));
+        CHECK((ivec2::move_constructor_counter == 5 || ivec2::move_constructor_counter == 6));
         CHECK(ivec2::copy_constructor_counter == 0);
     }
 }
diff --git a/develop/untests/meta_utilities/value_tests.cpp b/develop/untests/meta_utilities/value_tests.cpp
index 60bd0ca..16dc13f 100644
--- a/develop/untests/meta_utilities/value_tests.cpp
+++ b/develop/untests/meta_utilities/value_tests.cpp
@@ -618,15 +618,15 @@ TEST_CASE("meta/meta_utilities/value") {
             CHECK(ivec2::copy_constructor_counter == 0);
 
             meta::uvalue vv1{*vp};
-            CHECK((ivec2::move_constructor_counter == 0 || ivec2::move_constructor_counter == 1 || ivec2::move_constructor_counter == 2));
+            CHECK(ivec2::move_constructor_counter <= 3);
             CHECK(ivec2::copy_constructor_counter == 1);
 
             meta::uvalue vv2{*std::move(vp)};
-            CHECK((ivec2::move_constructor_counter == 0 || ivec2::move_constructor_counter == 2 || ivec2::move_constructor_counter == 4));
+            CHECK(ivec2::move_constructor_counter <= 6);
             CHECK(ivec2::copy_constructor_counter == 2);
 
             meta::uvalue vv3{*std::as_const(vp)};
-            CHECK((ivec2::move_constructor_counter == 0 || ivec2::move_constructor_counter == 3 || ivec2::move_constructor_counter == 6));
+            CHECK(ivec2::move_constructor_counter <= 9);
             CHECK(ivec2::copy_constructor_counter == 3);
         }
         {
diff --git a/headers/meta.hpp/meta_detail/type_registry.hpp b/headers/meta.hpp/meta_detail/type_registry.hpp
index 942f877..bb84f99 100644
--- a/headers/meta.hpp/meta_detail/type_registry.hpp
+++ b/headers/meta.hpp/meta_detail/type_registry.hpp
@@ -136,15 +136,17 @@ namespace meta_hpp::detail
     private:
         template < array_kind Array >
         [[nodiscard]] array_type_data* resolve_array_type_data() {
-            static array_type_data data{type_list<Array>{}};
-            ensure_type<Array>(data);
+            static array_type_data data = (
+                ensure_type<Array>(data),
+                array_type_data{type_list<Array>{}});
             return &data;
         }
 
         template < class_kind Class >
         [[nodiscard]] class_type_data* resolve_class_type_data() {
-            static class_type_data data{type_list<Class>{}};
-            ensure_type<Class>(data);
+            static class_type_data data = (
+                ensure_type<Class>(data),
+                class_type_data{type_list<Class>{}});
             return &data;
         }
 
@@ -162,64 +164,73 @@ namespace meta_hpp::detail
 
         template < enum_kind Enum >
         [[nodiscard]] enum_type_data* resolve_enum_type_data() {
-            static enum_type_data data{type_list<Enum>{}};
-            ensure_type<Enum>(data);
+            static enum_type_data data = (
+                ensure_type<Enum>(data),
+                enum_type_data{type_list<Enum>{}});
             return &data;
         }
 
         template < function_kind Function >
         [[nodiscard]] function_type_data* resolve_function_type_data() {
-            static function_type_data data{type_list<Function>{}};
-            ensure_type<Function>(data);
+            static function_type_data data = (
+                ensure_type<Function>(data),
+                function_type_data{type_list<Function>{}});
             return &data;
         }
 
         template < member_kind Member >
         [[nodiscard]] member_type_data* resolve_member_type_data() {
-            static member_type_data data{type_list<Member>{}};
-            ensure_type<Member>(data);
+            static member_type_data data = (
+                ensure_type<Member>(data),
+                member_type_data{type_list<Member>{}});
             return &data;
         }
 
         template < method_kind Method >
         [[nodiscard]] method_type_data* resolve_method_type_data() {
-            static method_type_data data{type_list<Method>{}};
-            ensure_type<Method>(data);
+            static method_type_data data = (
+                ensure_type<Method>(data),
+                method_type_data{type_list<Method>{}});
             return &data;
         }
 
         template < nullptr_kind Nullptr >
         [[nodiscard]] nullptr_type_data* resolve_nullptr_type_data() {
-            static nullptr_type_data data{type_list<Nullptr>{}};
-            ensure_type<Nullptr>(data);
+            static nullptr_type_data data = (
+                ensure_type<Nullptr>(data),
+                nullptr_type_data{type_list<Nullptr>{}});
             return &data;
         }
 
         template < number_kind Number >
         [[nodiscard]] number_type_data* resolve_number_type_data() {
-            static number_type_data data{type_list<Number>{}};
-            ensure_type<Number>(data);
+            static number_type_data data = (
+                ensure_type<Number>(data),
+                number_type_data{type_list<Number>{}});
             return &data;
         }
 
         template < pointer_kind Pointer >
         [[nodiscard]] pointer_type_data* resolve_pointer_type_data() {
-            static pointer_type_data data{type_list<Pointer>{}};
-            ensure_type<Pointer>(data);
+            static pointer_type_data data = (
+                ensure_type<Pointer>(data),
+                pointer_type_data{type_list<Pointer>{}});
             return &data;
         }
 
         template < reference_kind Reference >
         [[nodiscard]] reference_type_data* resolve_reference_type_data() {
-            static reference_type_data data{type_list<Reference>{}};
-            ensure_type<Reference>(data);
+            static reference_type_data data = (
+                ensure_type<Reference>(data),
+                reference_type_data{type_list<Reference>{}});
             return &data;
         }
 
         template < void_kind Void >
         [[nodiscard]] void_type_data* resolve_void_type_data() {
-            static void_type_data data{type_list<Void>{}};
-            ensure_type<Void>(data);
+            static void_type_data data = (
+                ensure_type<Void>(data),
+                void_type_data{type_list<Void>{}});
             return &data;
         }
     private:
@@ -227,24 +238,21 @@ namespace meta_hpp::detail
 
         template < typename Type, typename TypeData >
         void ensure_type(TypeData& type_data) {
-            static std::once_flag init_flag{};
-            std::call_once(init_flag, [this, &type_data](){
-                const locker lock;
+            const locker lock;
 
-                auto&& [position, emplaced] = types_.emplace(any_type{&type_data});
-                if ( !emplaced ) {
-                    return;
-                }
+            auto&& [position, emplaced] = types_.emplace(any_type{&type_data});
+            if ( !emplaced ) {
+                return;
+            }
 
-            #if !defined(META_HPP_NO_RTTI)
-                META_HPP_TRY {
-                    rtti_types_.emplace(typeid(Type), any_type{&type_data});
-                } META_HPP_CATCH(...) {
-                    types_.erase(position);
-                    META_HPP_RETHROW();
-                }
-            #endif
-            });
+        #if !defined(META_HPP_NO_RTTI)
+            META_HPP_TRY {
+                rtti_types_.emplace(typeid(Type), any_type{&type_data});
+            } META_HPP_CATCH(...) {
+                types_.erase(position);
+                META_HPP_RETHROW();
+            }
+        #endif
         }
     private:
         std::recursive_mutex mutex_;