diff --git a/src/FluentNHibernate/Automapping/AutoPersistenceModel.cs b/src/FluentNHibernate/Automapping/AutoPersistenceModel.cs
index 4b27ce2af..ed4870cf1 100644
--- a/src/FluentNHibernate/Automapping/AutoPersistenceModel.cs
+++ b/src/FluentNHibernate/Automapping/AutoPersistenceModel.cs
@@ -121,7 +121,7 @@ private void CompileMappings()
 
             var types = sources
                 .SelectMany(x => x.GetTypes())
-                .OrderBy(InheritanceHierarchyDepth);
+                .OrderBy(x => InheritanceHierarchyDepth(x));
 
             foreach (var type in types)
             {