anchor.diff:          summary = await analyzer.inspectPackage(package,
               version: version, options: options);
         } else if (source == 'path') {
  -        final path = firstArg('No path was provided.');
  +        final path = firstArg() ?? '.';
           final absolutePath = await Directory(path).resolveSymbolicLinks();
           if (showWarning) {
             log.Logger.root
  
positive.code:       help:
            'The source where the package is located (hosted on $defaultHostedUrl, or local directory path).',
        allowed: ['hosted', 'path'],
        defaultsTo: 'hosted')
    ..addOption('hosted-url',
        help: 'The server that hosts <package>.', defaultsTo: defaultHostedUrl)
    ..addOption('line-length',
  
negative.code:     try {
        Summary summary;
        if (source == 'hosted') {
          final package = firstArg();
          if (package == null) {
            _printHelp(errorMessage: 'No package was provided.');
          }
          String version;
          if (result.rest.length > 1) {
            version = result.rest[1];
  