Fix crash when spawning C# object that inherits from abstract C++ class

Source/Engine/Level/SceneObject.h

@@ -46,6 +46,7 @@ typedef Dictionary<Guid, Actor*, HeapAllocation> ActorsLookup;
 
 #define DECLARE_SCENE_OBJECT_ABSTRACT(type) \
     DECLARE_SCRIPTING_TYPE_NO_SPAWN(type); \
+    static type* Spawn(const SpawnParams& params) { return nullptr; } \
     explicit type(const SpawnParams& params)
 
 #define DECLARE_SCENE_OBJECT_NO_SPAWN(type) \

Source/Engine/Scripting/BinaryModule.cpp

@@ -492,6 +492,7 @@ ScriptingObject* ManagedBinaryModule::ManagedObjectSpawn(const ScriptingObjectSp
     ScriptingObject* object = nativeTypePtr->Script.Spawn(params);
     if (!object)
     {
+        LOG(Error, "Failed to spawn object of type {0} with native base type {1}.", managedTypePtr->ToString(), nativeTypePtr->ToString());
         return nullptr;
     }