diff --git a/Upsilon/BaseTypes/UserData/ListUserData.cs b/Upsilon/BaseTypes/UserData/ListUserData.cs
index b6da440..cc7c5a3 100644
--- a/Upsilon/BaseTypes/UserData/ListUserData.cs
+++ b/Upsilon/BaseTypes/UserData/ListUserData.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using Upsilon.BaseTypes.Number;
 using Upsilon.BaseTypes.ScriptTypeInterfaces;
 using Upsilon.BoundTypes;
@@ -18,7 +19,16 @@ namespace Upsilon.BaseTypes.UserData
         public ListUserData(IList list)
         {
             List = list;
-            TypeName = BoundTypeHandler.GetTypeName(list.GetType());
+            var type = list.GetType();
+            if (type.IsArray)
+            {
+                TypeName = BoundTypeHandler.GetTypeName(type.GetElementType());
+            }
+            else
+            {
+                var generic = type.GetGenericArguments()[0];
+                TypeName = BoundTypeHandler.GetTypeName(generic);
+            }
         }
 
         public ScriptType Get(Diagnostics diagnostics, TextSpan span, ScriptType index, EvaluationScope scope)
@@ -78,7 +88,10 @@ namespace Upsilon.BaseTypes.UserData
             }
         }
 
-        public override TypeContainer Type => new TypeContainer(TypeName);
+        public override TypeContainer Type => new CompositeTypeContainer()
+        {
+            Types = new TypeContainer[]{BaseTypes.Type.Number, new TypeContainer(TypeName)}.ToImmutableArray()
+        };
         public override object ToCSharpObject()
         {
             return List;