gistfile1.diff

diff --git a/lib/dm-core/collection.rb b/lib/dm-core/collection.rb
index 0ef2942..6d8658a 100644
--- a/lib/dm-core/collection.rb
+++ b/lib/dm-core/collection.rb
@@ -1197,7 +1197,7 @@ module DataMapper
       conditions = query.conditions
 
       if conditions.slug == :and
-        properties = self.properties.dup
+        properties = self.send(:properties).dup
 
         if query.condition_properties.to_set.superset?(model_key.to_set)
           properties -= model_key