Lint to detect dangling identifiers in docs (#240).

test/rule_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library linter.test.rule;
 
 import 'dart:io';
 
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
@@ skipping 291 matching lines @@
     if (entry is! File || !isDartFile(entry)) continue;
     var ruleName = p.basenameWithoutExtension(entry.path);
     if (ruleName == ruleToTest) {
       testRule(ruleName, entry);
     }
   }
 }
 
 Annotation extractAnnotation(String line) {
   int index = line.indexOf(new RegExp(r'(//|#)[ ]?LINT'));
-  //Grab the first comment to see if there's one preceding the annotation.
-  int comment = line.indexOf(new RegExp(r'(//|#)'));
+
+  // Grab the first comment to see if there's one preceding the annotation.
+  // Check for '#' first to allow for lints on dartdocs.
+  int comment = line.indexOf('#');
+  if (comment == -1) {
+    comment = line.indexOf('//');
+  }
+
   if (index > -1 && comment == index) {
     int column;
     int length;
     var annotation = line.substring(index);
     var leftBrace = annotation.indexOf('[');
     if (leftBrace != -1) {
       var sep = annotation.indexOf(':');
       column = int.parse(annotation.substring(leftBrace + 1, sep));
       var rightBrace = annotation.indexOf(']');
       length = int.parse(annotation.substring(sep + 1, rightBrace));
     }
 
     int msgIndex = annotation.indexOf(']') + 1;
     if (msgIndex < 1) {
       msgIndex = annotation.indexOf('T') + 1;
     }
     String msg = null;
     if (msgIndex < line.length) {
       msg = line.substring(index + msgIndex).trim();
-      if (msg.length == 0) {
+      if (msg.isEmpty) {
         msg = null;
       }
     }
     return new Annotation.forLint(msg, column, length);
   }
   return null;
 }
 
 AnnotationMatcher matchesAnnotation(
         String message, ErrorType type, int lineNumber) =>
@@ skipping 130 matching lines @@
 
 class NoFilter implements LintFilter {
   @override
   bool filter(AnalysisError lint) => false;
 }
 
 class ResultReporter extends DetailedReporter {
   ResultReporter(Iterable<AnalysisErrorInfo> errors)
       : super(errors, new NoFilter(), stdout);
 }