anchor.diff:    ) filenames;
     map
   
  -(** For all items [i] in the map that start with [prefix], add an additional
  -    entry where [i] stripped from [prefix] points to the same value. Returns a
  -    boolean telling whether the map was modified. *)
  -let enter_namespace (original_map: files_for_module_name) (working_map: files_for_module_name) (prefix: string): bool =
  -  let found = BU.mk_ref false in
  -  let prefix = prefix ^ "." in
  -  smap_iter original_map (fun k _ ->
  -    if Util.starts_with k prefix then
  -      let suffix =
  -        String.substring k (String.length prefix) (String.length k - String.length prefix)
  -      in
  -      let filename = must (smap_try_find original_map k) in
  -      smap_add working_map suffix filename;
  -      found := true
  -  );
  -  !found
  -
  -
   let string_of_lid (l: lident) (last: bool) =
     let suffix = if last then [ (string_of_id (ident_of_lid l)) ] else [ ] in
     let names = List.map (fun x -> (string_of_id x)) (ns_of_lid l) @ suffix in
  
positive.code:          end
         in
  
         let record_open_namespace lid =
           let key = lowercase_join_longident lid true in
           let r = enter_namespace original_map working_map key in
           if not r then
             FStar.Errors.log_issue (range_of_lid lid)
               (Errors.Warning_ModuleOrFileNotFoundWarning, (Util.format1 "No modules in namespace %s and no file with \
  
negative.code:   | VerifyFigureItOut
  
  type files_for_module_name = smap<(option<string> * option<string>)>
  
  let files_for_module_name_to_string (m:files_for_module_name) =
    BU.print_string "Printing the file system map {\n";
    let str_opt_to_string sopt =
      match sopt with
      | None -> "<None>"
      | Some s -> s in
    smap_iter m (fun k (intf, impl) -> BU.print3 "%s:(%s, %s)\n" k (str_opt_to_string intf) (str_opt_to_string impl));
    BU.print_string "}\n"
  
  type color = | White | Gray | Black
  
  