src/Pure/pure_syn.ML

     (Resources.parse_files "ML_file" >> (fn files => Toplevel.generic_theory (fn gthy =>
         let
           val [{src_path, lines, digest, pos}] = files (Context.theory_of gthy);
           val provide = Resources.provide (src_path, digest);
           val source = {delimited = true, text = cat_lines lines, pos = pos};
-          val flags = {SML = false, redirect = true, verbose = true};
+          val flags = {SML = false, exchange = false, redirect = true, verbose = true};
         in
           gthy
           |> ML_Context.exec (fn () => ML_Context.eval_source flags source)
           |> Local_Theory.propagate_ml_env
           |> Context.mapping provide (Local_Theory.background_theory provide)