anchor.diff:        List<String> tokens = new Tokenizer(expression_string).tokenize();
         SetExpression expression =
             new ExpressionParser(new Scanner(tokens)).parseSetExpression();
  -      current.testRules.add(new TestRule(name, expression));
  +
  +      // Look for issue number in comment.
  +      String issueString = null;
  +      match = IssueNumberPattern.firstMatch(comment);
  +      if (match != null) {
  +        issueString = match[1];
  +        if (issueString == null) issueString = match[2];
  +      }
  +      int issue = issueString != null ? int.parse(issueString) : null;
  +      current.testRules.add(new TestRule(name, expression, issue));
         return;
       }
   
  
positive.code: class TestRule {
    String name;
    SetExpression expression;
  
    TestRule(this.name, this.expression);
  
    String toString() => 'TestRule($name, $expression)';
  }
  
  
  
negative.code:  */
  const SLOW = "slow";
  
  final RegExp SplitComment = new RegExp("^([^#]*)(#.*)?\$");
  final RegExp HeaderPattern = new RegExp(r"^\[([^\]]+)\]");
  final RegExp RulePattern = new RegExp(r"\s*([^: ]*)\s*:(.*)");
  final RegExp IssueNumberPattern =
      new RegExp("Issue ([0-9]+)|dartbug.com/([0-9]+)", caseSensitive: false);
  
  // TODO(whesse): Implement configuration_info library that contains data
  // structures for test configuration, including Section.
  