src/HOL/Tools/function_package/size.ML

--- a/src/HOL/Tools/function_package/size.ML	Thu Sep 25 19:15:50 2008 +0200
+++ b/src/HOL/Tools/function_package/size.ML	Thu Sep 25 20:34:15 2008 +0200
@@ -231,6 +231,7 @@
       thy
       |> Sign.root_path
       |> Sign.add_path prefix
+      |> Theory.checkpoint
       |> prove_size_thms info new_type_names
       |> Sign.restore_naming thy
   end;