src/HOL/ex/Seq.thy

--- a/src/HOL/ex/Seq.thy	Tue Sep 09 17:51:07 2014 +0200
+++ b/src/HOL/ex/Seq.thy	Tue Sep 09 20:51:36 2014 +0200
@@ -8,7 +8,7 @@
 imports Main
 begin
 
-datatype 'a seq = Empty | Seq 'a "'a seq"
+datatype_new 'a seq = Empty | Seq 'a "'a seq"
 
 fun conc :: "'a seq \<Rightarrow> 'a seq \<Rightarrow> 'a seq"
 where