anchor.diff:  let tc_one_fragment curmod dsenv env frag =
       try
           match Parser.Driver.parse_fragment curmod dsenv frag with
  -            | Parser.Driver.Empty -> 
  +            | Parser.Driver.Empty ->
                 Some (curmod, dsenv, env)
   
               | Parser.Driver.Modul (dsenv, modul) ->
  
positive.code:     prims_mod, dsenv, env
  
  
  let test_universes filenames = 
      try
          let prims_mod, dsenv, env = u_tc_prims() in
          let dsenv, mods, env = List.fold_left (fun (dsenv, fmods, env) fn ->
             Util.print1 "Parsing file %s\n" fn; 
             let dsenv, mods = u_parse dsenv fn in
             let _, env = TypeChecker.Tc.check_module env (List.hd mods) in
             dsenv, mods@fmods, env) (dsenv, [], env) filenames in
          env.solver.finish();
          dsenv, mods, env
      with 
          | Syntax.Syntax.Error(msg, r) when not (!Options.trace_error) -> 
            Util.print_string (Util.format2 "Error : %s\n%s\n" (Range.string_of_range r) msg);
            exit 1
         
  open FStar.Tc.Env 
  let tc_prims () =
      let solver = if !Options.verify then ToSMT.Encode.solver else ToSMT.Encode.dummy in
      let env = Tc.Env.initial_env solver Const.prims_lid in
  
negative.code: let has_prims_cache (l: list<string>) :bool = List.mem "Prims.cache" l
  
  open FStar.TypeChecker.Env
  let u_parse env fn =
      try
          match Parser.ParseIt.parse (Inl fn) with
              | Inl (Inl ast) ->
                  Parser.ToSyntax.desugar_file env ast
  