diff -r c8a2755bf220 -r ff784d5a5bfb src/HOL/Auth/OtwayReesBella.thy
--- a/src/HOL/Auth/OtwayReesBella.thy	Sat Jan 05 17:00:43 2019 +0100
+++ b/src/HOL/Auth/OtwayReesBella.thy	Sat Jan 05 17:24:33 2019 +0100
@@ -239,7 +239,7 @@
 
 val analz_image_freshK_ss =
   simpset_of
-   (@{context} delsimps [image_insert, image_Un]
+   (\<^context> delsimps [image_insert, image_Un]
       delsimps [@{thm imp_disjL}]    (*reduces blow-up*)
       addsimps @{thms analz_image_freshK_simps})