diff -r 450cefec7c11 -r cc19f7ca2ed6 src/HOL/Library/Preorder.thy
--- a/src/HOL/Library/Preorder.thy	Fri Aug 18 13:55:05 2017 +0200
+++ b/src/HOL/Library/Preorder.thy	Fri Aug 18 20:47:47 2017 +0200
@@ -3,7 +3,7 @@
 section \<open>Preorders with explicit equivalence relation\<close>
 
 theory Preorder
-imports Orderings
+imports HOL.Orderings
 begin
 
 class preorder_equiv = preorder