1 files changed, 5 insertions, 0 deletions
diff --git a/lib/arel/tree_manager.rb b/lib/arel/tree_manager.rb
index d2027bedfa..24df5e0c09 100644
--- a/lib/arel/tree_manager.rb
+++ b/lib/arel/tree_manager.rb
@@ -15,5 +15,10 @@ module Arel
       viz = Visitors::ToSql.new @engine
       viz.accept @head
     end
+
+    def initialize_copy other
+      super
+      @head = @head.clone
+    end
   end
 end