diff -r 56cf1249ee20 -r bf5fcc65586b src/HOL/Tools/typedef.ML
--- a/src/HOL/Tools/typedef.ML	Sun Apr 17 16:36:47 2016 +0200
+++ b/src/HOL/Tools/typedef.ML	Sun Apr 17 20:11:02 2016 +0200
@@ -177,7 +177,7 @@
 type bindings = {Rep_name: binding, Abs_name: binding, type_definition_name: binding};
 
 fun prefix_binding prfx name =
-  Binding.reset_pos (Binding.qualified false (prfx ^ Binding.name_of name) name);
+  Binding.reset_pos (Binding.qualify_name false name (prfx ^ Binding.name_of name));
 
 fun qualify_binding name = Binding.qualify false (Binding.name_of name);