From cfa2be5d71345dc244d901172ee4be3b6c56e06e Mon Sep 17 00:00:00 2001
From: sebas77 <ssense@tiscali.it>
Date: Sat, 21 Oct 2017 22:00:15 +0100
Subject: [PATCH] fix bugs introduce with the latest update

---
 ECS/EnginesRoot.cs      | 3 +--
 ECS/EntityDescriptor.cs | 5 +++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/ECS/EnginesRoot.cs b/ECS/EnginesRoot.cs
index 4aa482a..ad0769c 100644
--- a/ECS/EnginesRoot.cs
+++ b/ECS/EnginesRoot.cs
@@ -176,8 +176,7 @@ namespace Svelto.ECS
 
                 var genericTypeDefinition = interfaceType.GetGenericTypeDefinition();
 
-                _implementedInterfaceTypes.Add(genericTypeDefinition,
-                    interfaceType.GetGenericArguments());
+                _implementedInterfaceTypes[genericTypeDefinition] = interfaceType.GetGenericArguments();
             }
         }
 
diff --git a/ECS/EntityDescriptor.cs b/ECS/EntityDescriptor.cs
index 946e1a8..4f09db1 100644
--- a/ECS/EntityDescriptor.cs
+++ b/ECS/EntityDescriptor.cs
@@ -10,6 +10,9 @@ namespace Svelto.ECS
 {
     public class EntityDescriptor
     {
+        protected EntityDescriptor()
+        {
+        }
         protected EntityDescriptor(INodeBuilder[] nodesToBuild)
         {
             _nodesToBuild = new FasterList<INodeBuilder>(nodesToBuild);
@@ -29,6 +32,8 @@ namespace Svelto.ECS
             for (int index = 0; index < implementors.Length; index++)
             {
                 var implementor = implementors[index];
+                if (implementor == null) continue;
+
                 if (implementor is IRemoveEntityComponent)
                     _removingImplementors.Add(implementor as IRemoveEntityComponent);
                 if (implementor is IDisableEntityComponent)