src/Pure/Isar/theory_target.ML

   else if not is_class then Locale.init target
   else Class_Target.init target;
 
 fun init_lthy (ta as Target {target, instantiation, overloading, ...}) =
   Data.put ta #>
-  LocalTheory.init (NameSpace.base_name target)
+  LocalTheory.init (Long_Name.base_name target)
    {pretty = pretty ta,
     abbrev = abbrev ta,
     define = define ta,
     notes = notes ta,
     type_syntax = type_syntax ta,