gistfile1.txt

diff --git a/lib/dm-core/collection.rb b/lib/dm-core/collection.rb
index c62dd9e..73a83fa 100644
--- a/lib/dm-core/collection.rb
+++ b/lib/dm-core/collection.rb
@@ -80,7 +80,7 @@ module DataMapper
       end
 
       properties = model.properties(repository.name)
-      fields     = properties.key | [ properties.discriminator ].compact | self.query.fields | query.fields
+      fields     = properties.key | [ properties.discriminator ].compact | query.fields
 
       # replace the list of resources
       replace(all(query.update(:fields => fields, :reload => true)))