src/Pure/Isar/locale.ML

     val mixin =
       (case export' of
         NONE => Morphism.identity
       | SOME export => collect_mixins context (name, morph $> export) $> export);
     val morph' = transfer input $> morph $> mixin;
-    val notes' = map (Element.transform_ctxt morph' o Notes o #1) (#notes (the_locale thy name));
+    val notes' =
+      Par_List.map (Element.transform_ctxt morph' o Notes o #1) (#notes (the_locale thy name));
   in
     fold_rev (fn elem => fn res => activ_elem (Element.transform_ctxt (transfer res) elem) res)
       notes' input
   end;