anchor.diff:  // BSD-style license that can be found in the LICENSE file.
   
   import 'package:analyzer/analyzer.dart';
  -import 'package:analyzer/dart/analysis/declared_variables.dart';
   import 'package:analyzer/dart/ast/ast.dart';
   import 'package:analyzer/dart/ast/token.dart';
   import 'package:analyzer/dart/element/element.dart';
   import 'package:analyzer/dart/element/type.dart';
  -import 'package:analyzer/error/listener.dart';
   import 'package:linter/src/analyzer.dart';
   
   const alwaysFalse = 'Always false because length is always greater or equal 0.';
  
positive.code:     BinaryExpression binaryExpression = search;
  
      Token operator = binaryExpression.operator;
      DeclaredVariables declaredVariables = context.declaredVariables;
  
      // Comparing constants with length.
      int value = _getIntValue(binaryExpression.rightOperand);
  
negative.code:         return -operand.value;
        }
      }
      // ignore: avoid_returning_null
      return null;
    }
  }
  