diff --git a/src/Base/BaseClass.h b/src/Base/BaseClass.h
index 66be845d6a..f5b5a20f4f 100644
--- a/src/Base/BaseClass.h
+++ b/src/Base/BaseClass.h
@@ -63,7 +63,6 @@ void * _class_::create(void){\
 
 /// define to implement a  subclass of Base::BaseClass
 #define TYPESYSTEM_SOURCE_TEMPLATE_P(_class_) \
-template<> Base::Type _class_::classTypeId = Base::Type::badType();  \
 template<> Base::Type _class_::getClassTypeId(void) { return _class_::classTypeId; } \
 template<> Base::Type _class_::getTypeId(void) const { return _class_::classTypeId; } \
 template<> void * _class_::create(void){\
diff --git a/src/Mod/Part/App/GeometryDefaultExtension.h b/src/Mod/Part/App/GeometryDefaultExtension.h
index 246f55d185..4eaf1de579 100644
--- a/src/Mod/Part/App/GeometryDefaultExtension.h
+++ b/src/Mod/Part/App/GeometryDefaultExtension.h
@@ -86,6 +86,15 @@ namespace Part {
     // 5. Provide specialisations if your type does not meet the assumptions above (e.g. for serialisation) (cpp file)
     // 6. Register your type and corresponding python type in AppPart.cpp
 
+    template <typename T>
+    Base::Type GeometryDefaultExtension<T>::classTypeId{Base::Type::badType()};
+
+    // Must be explicitly declared here
+    template<> void * GeometryDefaultExtension<long>::create();
+    template<> void * GeometryDefaultExtension<std::string>::create();
+    template<> void * GeometryDefaultExtension<bool>::create();
+    template<> void * GeometryDefaultExtension<double>::create();
+
     template <typename T>
     inline GeometryDefaultExtension<T>::GeometryDefaultExtension():value{}{}