Added some extra properties/functions to DynamicNull to provide a way to check to see if a child doc type actually exists.

.HasProperty will check for a property existence but because the child types are returned as DynamicNull, you couldn't check for null equality.
Use DynamicNull's .IsNull (true) or .HasValue (false) or .Count() (0) or a typeof check

umbraco.MacroEngines.Juno/RazorDynamicNode/DynamicNull.cs

@@ -26,6 +26,10 @@ namespace umbraco.MacroEngines
         {
             return this;
         }
+        public int Count()
+        {
+            return 0;
+        }
         public override string ToString()
         {
             return string.Empty;
@@ -35,5 +39,19 @@ namespace umbraco.MacroEngines
             result = this;
             return true;
         }
+        public bool IsNull
+        {
+            get
+            {
+                return true;
+            }
+        }
+        public bool HasValue
+        {
+            get
+            {
+                return false;
+            }
+        }
     }
 }