diff -r 5eb932e604a2 -r eab6ce8368fa src/HOL/Corec_Examples/Tests/GPV_Bare_Bones.thy
--- a/src/HOL/Corec_Examples/Tests/GPV_Bare_Bones.thy	Wed Jan 10 15:21:49 2018 +0100
+++ b/src/HOL/Corec_Examples/Tests/GPV_Bare_Bones.thy	Wed Jan 10 15:25:09 2018 +0100
@@ -39,9 +39,9 @@
 
 friend_of_corec bind_gpv'
 where "bind_gpv' r f =
-GPV' (map_spmf (map_generat id id (op \<circ> (case_sum id (\<lambda>r. bind_gpv' r f))))
+GPV' (map_spmf (map_generat id id ((\<circ>) (case_sum id (\<lambda>r. bind_gpv' r f))))
       (bind_spmf (the_gpv r)
-        (case_generat (\<lambda>x. map_spmf (map_generat id id (op \<circ> Inl)) (the_gpv' (f x)))
+        (case_generat (\<lambda>x. map_spmf (map_generat id id ((\<circ>) Inl)) (the_gpv' (f x)))
           (\<lambda>out c. return_spmf (IO out (\<lambda>input. Inr (c input)))))))"
   sorry