anchor.diff:       Include warnings about behaviour callbacks which drift from the published
        recommended interfaces.
     -Wunderspecs ***
  -     Warn about underspecified functions 
  +     Warn about underspecified functions
        (those whose -spec is strictly more allowing than the success typing).
   
   The following options are also available but their use is not recommended:
   (they are mostly for Dialyzer developers and internal debugging)
     -Woverspecs ***
  -     Warn about overspecified functions 
  +     Warn about overspecified functions
        (those whose -spec is strictly less allowing than the success typing).
     -Wspecdiffs ***
        Warn when the -spec is different than the success typing.
  
positive.code: cl(["--help"|_]) ->
    help_message();
  cl(["-I"]) ->
    error("no include directory specified after -I");
  cl(["-I", Dir|T]) ->
    append_include(Dir),
    cl(T);
  
negative.code: -type dial_cl_parse_ret() :: {'check_init', #options{}}
                             | {'plt_info', #options{}}
                             | {'cl', #options{}}
                             | {{'gui', 'gs' | 'wx'}, #options{}}
                             | {'error', string()}.
  
  -type deep_string() :: string() | [deep_string()].
  
  %%-----------------------------------------------------------------------
  
  