anchor.diff:            'test/test_files/json_test_example.non_nullable.dart'
           ],
         )),
  -  applyToRoot(jsonPartBuilder(header: copyrightHeader, anyMap: true),
  +  applyToRoot(_jsonPartBuilder(anyMap: true),
         generateFor: const InputSet(
           include: const [
             'test/kitchen_sink_test_files/kitchen_sink.dart',
  
positive.code: 
  import 'dart:io' show exitCode;
  
  import 'package:build_config/build_config.dart';
  import 'package:build_runner/build_runner.dart';
  import 'package:build_test/builder.dart';
  import 'package:json_serializable/src/json_part_builder.dart';
  
  import 'builder.dart';
  
  final List<BuilderApplication> builders = [
    applyToRoot(nonNull(),
  
negative.code:         'test/test_files/json_test_example.dart',
          'test/test_files/json_test_example.non_nullable.dart',
        ])),
    applyToRoot(_jsonPartBuilder(),
        generateFor: const InputSet(
          include: const [
            'example/example.dart',
  