anchor.diff:  final _newIssue = Uri.parse('$_rootUri/issues/new');
   final _assignedIssues = Uri.parse('$_rootUri/issues/assigned/');
   final _openedIssues = Uri.parse('$_rootUri/issues/created_by/');
  +
  +final _matchers = <RegExp, Uri Function(String)>{
  +  RegExp(r'^/([0-9]+)$'): _showIssue.resolve,
  +  RegExp(r'^/new$', caseSensitive: false): (_) => _newIssue,
  +  RegExp(r'^/assigned/([A-Za-z0-9\-]+)$'): _assignedIssues.resolve,
  +  RegExp(r'^/opened/([A-Za-z0-9\-]+)$'): _openedIssues.resolve,
  +  RegExp(r'^/area/([A-Za-z0-9\-]+)$'): (match) => _listIssues.replace(
  +        queryParameters: {
  +          'label': 'area-$match',
  +        },
  +      ),
  +  RegExp(r'^/triage$', caseSensitive: false): (_) => _listIssues.replace(
  +        queryParameters: {
  +          'q': [
  +            'is:issue',
  +            'is:open',
  +            ..._areaLabels.map((label) => '-label:$label'),
  +          ].join(' '),
  +        },
  +      )
  +};
   
   String _checkMatch(RegExp re, String path) {
     var match = re.firstMatch(path);
  
positive.code: ///
  /// Returns the [Uri] to redirect to or `null` if no redirect is defined.
  Uri findRedirect(Uri requestUri) {
    var path = requestUri.path;
    String match;
  
    if (requestUri.pathSegments.isEmpty) {
      return _listIssues;
    }
  
    match = _checkMatch(issueRegExp, path);
    if (match != null) {
      return _showIssue.resolve(match);
    }
  
    match = _checkMatch(newRegExp, path);
    if (match != null) {
      return _newIssue;
    }
  
    match = _checkMatch(assignedRegExp, path);
    if (match != null) {
      return _assignedIssues.resolve(match);
    }
  
    match = _checkMatch(openedRegExp, path);
    if (match != null) {
      return _openedIssues.resolve(match);
    }
  
    match = _checkMatch(areaRegExp, path);
    if (match != null) {
      return _listIssues.replace(
        queryParameters: {
          'label': 'area-$match',
        },
      );
    }
  
    match = _checkMatch(triageRegExp, path);
    if (match != null) {
      return _listIssues.replace(
        queryParameters: {
          'q': [
            'is:issue',
            'is:open',
            ..._areaLabels.map((label) => '-label:$label'),
          ].join(' '),
        },
      );
    }
  
    // No redirect found.
  
negative.code: const organization = 'dart-lang';
  const repository = 'sdk';
  
  // Redirect URIs
  final _rootUri = '$gitHub/$organization/$repository';
  final _listIssues = Uri.parse('$_rootUri/issues');
  