anchor.diff:  
     @override
     void registerNodeProcessors(NodeLintRegistry registry) {
  -    final visitor = new _Visitor(this);
  +    final visitor = _Visitor(this);
       registry.addInstanceCreationExpression(this, visitor);
       registry.addMethodInvocation(this, visitor);
     }
  
positive.code:     var constructorName = node.constructorName;
      var type = node.staticType;
      for (var constructor in _constructorsWithNonNullableArguments) {
        if (DartTypeUtilities.extendsClass(
            type, constructor.type, constructor.library)) {
          if (constructorName?.name?.name == constructor.name) {
            _checkNullArgForClosure(
                node.argumentList, constructor.positional, constructor.named);
          }
  
negative.code: import 'package:analyzer/dart/ast/visitor.dart';
  import 'package:analyzer/dart/element/type.dart';
  import 'package:analyzer/dart/element/element.dart';
  import 'package:analyzer/src/generated/utilities_general.dart';
  import 'package:linter/src/analyzer.dart';
  import 'package:linter/src/util/dart_type_utilities.dart';
  
  