no ord instance for String.literal in Haskell when list is also ordered lexicographically

--- a/src/HOL/Library/List_lexord.thy	Wed Nov 20 11:59:33 2013 +0100
+++ b/src/HOL/Library/List_lexord.thy	Wed Nov 20 12:11:12 2013 +0100
@@ -118,4 +118,6 @@
   "(x\<Colon>'a\<Colon>{equal, order}) # xs \<le> y # ys \<longleftrightarrow> x < y \<or> x = y \<and> xs \<le> ys"
   by simp_all
 
+code_printing class_instance String.literal :: ord \<rightharpoonup> (Haskell) -
+
 end