anchor.diff:                    end, Warnings).
   
   %% @doc If the plt option is present in rebar.config return its value,
  -%% otherwise return $HOME/.dialyzer_plt.
  +%% otherwise return $HOME/.dialyzer_plt or $REBAR_PLT_DIR/.dialyzer_plt.
   -spec new_plt_path(Config::rebar_config:config(),
                      File::file:filename()) -> file:filename().
   new_plt_path(Config, File) ->
  
positive.code:     DialyzerOpts = rebar_config:get(Config, dialyzer_opts, []),
      case proplists:get_value(plt, DialyzerOpts) of
          undefined ->
              filename:join(os:getenv("HOME"),
                            "." ++ atom_to_list(AppName) ++ "_dialyzer_plt");
          Plt ->
              Plt
      end.
  
  %% @doc If the plt option is present in rebar.config and the file exists
  %% return its value or if ~/.AppName_dialyzer_plt exists return that.
  %% Otherwise return ~/.dialyzer_plt if it exists or abort.
  -spec existing_plt_path(Config::rebar_config:config(),
                          File::file:filename()) -> file:filename().
  existing_plt_path(Config, File) ->
      AppName = rebar_app_utils:app_name(File),
      DialyzerOpts = rebar_config:get(Config, dialyzer_opts, []),
      Home = os:getenv("HOME"),
      case proplists:get_value(plt, DialyzerOpts) of
          undefined ->
              AppPlt = filename:join(Home, "." ++ atom_to_list(AppName)
                                     ++ "_dialyzer_plt"),
              case filelib:is_regular(AppPlt) of
                  true ->
                      AppPlt;
                  false ->
                      HomePlt = filename:join(Home, ".dialyzer_plt"),
                      case filelib:is_regular(HomePlt) of
                          true ->
                              HomePlt;
                          false ->
                              ?ABORT("No PLT found~n", [])
                      end
              end;
          "~/" ++ Plt ->
              filename:join(Home,Plt);
          Plt ->
              Plt
      end.
  
negative.code: %% A single option <code>plt</code> can be presented in the
  %% <code>dialyzer_opts</code> options in <code>rebar.config</code>. If it
  %% is present, it is used as the PLT for the supported commands. Should it
  %% not be present, then the default is <code>$HOME/.dialyzer_plt</code> or
  %% <code>$REBAR_PLT_DIR/.dialyzer_plt</code> if $REBAR_PLT_DIR is defined.
  %%
  %% @reference <a href="http://user.it.uu.se/~kostis/Papers/bugs05.pdf">
  %% Experience from developing the Dialyzer: A static analysis tool detecting
  