src/Pure/theory.ML

       thy
       |> init_markup (name, pos)
       |> Sign.init_naming
       |> Sign.local_path
       |> apply_wrappers wrappers
-      |> tap (Syntax.cache_syntax o Sign.syn_of)
+      |> tap (Syntax.cache_syntax o Sign.syntax_of)
     end;
 
 fun end_theory thy =
   thy
   |> apply_wrappers (end_wrappers thy)