anchor.diff:          (node is IndexExpression &&
               _containsNullAwareInvocationInChain(node.target)));
   
  -Iterable<Element?> _extractElementsOfSimpleIdentifiers(AstNode node) => node
  -    .traverseNodesInDFS()
  -    .whereType<SimpleIdentifier>()
  -    .map((e) => e.staticElement);
  +Iterable<Element?> _extractElementsOfSimpleIdentifiers(AstNode node) =>
  +    _IdentifierVisitor().extractElements(node);
   
   class UnnecessaryLambdas extends LintRule {
     UnnecessaryLambdas()
  
positive.code:     }
  
      return false;
    }
  }
  
  
negative.code: import 'package:analyzer/dart/element/type.dart';
  
  import '../analyzer.dart';
  import '../util/dart_type_utilities.dart';
  
  const _desc = r"Don't create a lambda when a tear-off will do.";
  