diff -r e81d0f04ffdf -r c04f8c51d0ab src/HOL/Library/List_Set.thy
--- a/src/HOL/Library/List_Set.thy	Mon Jun 29 12:18:56 2009 +0200
+++ b/src/HOL/Library/List_Set.thy	Mon Jun 29 12:18:57 2009 +0200
@@ -160,4 +160,7 @@
   "A \<inter> B = project (\<lambda>x. x \<in> A) B"
   by (auto simp add: project_def)
 
+
+hide (open) const insert
+
 end
\ No newline at end of file