src/Pure/sorts.ML

           SOME sorts =>
             SOME (c, Ss |> map2 (curry (inter_sort algebra)) sorts |> map restrict_sort)
         | NONE => NONE)
       else NONE;
     val classes' = classes |> Graph.subgraph P;
-    val arities' = arities |> Symtab.map' (map_filter o restrict_arity);
+    val arities' = arities |> Symtab.map (map_filter o restrict_arity);
   in (restrict_sort, rebuild_arities pp (make_algebra (classes', arities'))) end;
 
 
 
 (** sorts of types **)