diff -r d80b2df54d31 -r a96320074298 src/HOL/Fun.thy
--- a/src/HOL/Fun.thy	Sun Jan 06 13:44:33 2019 +0100
+++ b/src/HOL/Fun.thy	Sun Jan 06 15:04:34 2019 +0100
@@ -886,7 +886,7 @@
 
 subsubsection \<open>Functorial structure of types\<close>
 
-ML_file "Tools/functor.ML"
+ML_file \<open>Tools/functor.ML\<close>
 
 functor map_fun: map_fun
   by (simp_all add: fun_eq_iff)