--- a/src/HOL/Proofs/Extraction/Util.thy	Sat Jul 08 17:33:11 2017 +0200
+++ b/src/HOL/Proofs/Extraction/Util.thy	Sat Jul 08 19:34:46 2017 +0200
@@ -5,7 +5,7 @@
 section \<open>Auxiliary lemmas used in program extraction examples\<close>
 
 theory Util
-imports "~~/src/HOL/Library/Old_Datatype"
+imports Main
 begin
 
 text \<open>Decidability of equality on natural numbers.\<close>