anchor.diff:    }
   
     if (comment != null) {
  -    for (var commentLine in comment.split('\n')) {
  -      output.write('#');
  +    var lines = comment.split('\n');
  +    if (lines.last.isEmpty) lines.removeLast();
  +    for (var commentLine in lines) {
  +      output.write('# ');
         output.writeln(commentLine);
       }
     } else {
  
positive.code: /// Writes the mapping to a [StringSink].
  ///
  /// If [comment] is provided, the output will contain this comment
  /// with `#` in front of each line.
  ///
  /// If [baseUri] is provided, package locations will be made relative
  /// to the base URI, if possible, before writing.
  
negative.code: }
  
  // TODO: inline to uri.normalizePath() when we move to 1.11
  Uri _normalizePath(Uri uri) => new Uri().resolveUri(uri);
  