src/HOL/Tools/BNF/bnf_def.ML

           List.map (pretty_set sets) (0 upto length sets - 1) @
           [Pretty.block [Pretty.str (bdN ^ ":"), Pretty.brk 1,
             Pretty.quote (Syntax.pretty_term ctxt bd)]]);
   in
     Pretty.big_list "Registered bounded natural functors:"
-      (map pretty_bnf (sort_wrt fst (Symtab.dest (Data.get (Context.Proof ctxt)))))
+      (map pretty_bnf (sort_by fst (Symtab.dest (Data.get (Context.Proof ctxt)))))
     |> Pretty.writeln
   end;
 
 val _ =
   Outer_Syntax.command @{command_keyword print_bnfs}