anchor.diff:          bool fieldInConstructor(constructor) =>
               constructor.initializers.any((initializer) =>
                   _containedInInitializer(element, initializer)) ||
  -                constructor.parameters.parameters
  -                    .any((formal) => _containedInFormal(element, formal));
  +            constructor.parameters.parameters
  +                .any((formal) => _containedInFormal(element, formal));
   
           final classDeclaration = node.parent;
           final constructors = (classDeclaration is ClassDeclaration
               ? classDeclaration.members
  -            .whereType<ConstructorDeclaration>()
  -            .toSet()
  +                .whereType<ConstructorDeclaration>()
  +                .toSet()
               : <ConstructorDeclaration>{});
           final isFieldInConstructors = constructors.any(fieldInConstructor);
           final isFieldInAllConstructors = constructors.every(fieldInConstructor);
  
positive.code: 
    void _addMutatedFieldElement(Expression expression) {
      final element =
      DartTypeUtilities.getCanonicalElementFromIdentifier(expression);
      if (element is FieldElement) {
        _mutatedFields.add(element);
      }
  
negative.code: class PreferFinalFields extends LintRule implements NodeLintRule {
    PreferFinalFields()
        : super(
              name: 'prefer_final_fields',
              description: _desc,
              details: _details,
              group: Group.style);
  
    @override
    void registerNodeProcessors(NodeLintRegistry registry,
  