anchor.diff:  
     @override
     void visitIsExpression(IsExpression node) {
  -    // After the `is`.
  -    _recordElementKind('IsExpression', node.type);
  +    _recordElementKind('IsExpression (type)', node.type);
       super.visitIsExpression(node);
     }
   
  
positive.code: 
    @override
    void visitPostfixExpression(PostfixExpression node) {
      // The invocation.
      _recordTypeMatch(node.operand);
      super.visitPostfixExpression(node);
    }
  
negative.code: 
    @override
    void visitLabeledStatement(LabeledStatement node) {
      _recordElementKindAndTokenType(
          'LabeledStatement (statement)', node.statement);
      super.visitLabeledStatement(node);
    }
  
  