anchor.diff:  
   -spec text(Text, Context, Env, Opts) -> Tags when
         Text :: string(),
  -      Context :: overview,
  +      Context :: context(),
         Env :: edoc:env(),
         Opts :: proplist(),
         Tags :: [term()].
  
positive.code: 
  -spec file(File, Context, Env, Opts) -> {ok, Tags} | {error, Reason} when
        File :: filename(),
        Context :: edoc_tags:tag_flag(),
        Env :: edoc:env(),
        Opts :: proplist(),
        Tags :: [term()],
  
negative.code: 
  -type filename() :: file:filename().
  -type proplist() :: proplists:proplist().
  -type context() :: module | footer | function | overview | single.
  
  %% @doc Like {@link source/5}, but reads the syntax tree and the
  %% comments from the specified file.
  