diff --git a/_test_yaml/pubspec.yaml b/_test_yaml/pubspec.yaml
index 715a0d11..3fbd2c01 100644
--- a/_test_yaml/pubspec.yaml
+++ b/_test_yaml/pubspec.yaml
@@ -12,7 +12,7 @@ dev_dependencies:
   build_runner: ^2.10.5
   build_verify: ^3.0.0
   checked_yaml: ^2.0.4
-  json_annotation: ^4.9.0
+  json_annotation: '>=4.13.0-0 <4.14.0'
   json_serializable: ^6.8.0
   path: ^1.9.0
   test: ^1.29.0
diff --git a/_test_yaml/test/src/build_config.g.dart b/_test_yaml/test/src/build_config.g.dart
index e453d996..ebec2c16 100644
--- a/_test_yaml/test/src/build_config.g.dart
+++ b/_test_yaml/test/src/build_config.g.dart
@@ -31,7 +31,7 @@ Config _$ConfigFromJson(Map json) => $checkedCreate('Config', json, (
 Map<String, dynamic> _$ConfigToJson(Config instance) => <String, dynamic>{
   'builders': instance.builders,
   'weights': instance.weights?.map(
-    (k, e) => MapEntry(_$AutoApplyEnumMap[k]!, e),
+    (k, e) => MapEntry($enumEncode(_$AutoApplyEnumMap, k), e),
   ),
 };
 
diff --git a/json_annotation/CHANGELOG.md b/json_annotation/CHANGELOG.md
index 5c34039b..00c2873e 100644
--- a/json_annotation/CHANGELOG.md
+++ b/json_annotation/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.13.0-wip
+
+- Add `$enumEncode` helper for generated enum `toJson` code.
+
 ## 4.12.0
 
 - Add `JsonKey.explicitJsonNullWhenNonNullField` for PATCH-style tri-state JSON
diff --git a/json_annotation/lib/src/enum_helpers.dart b/json_annotation/lib/src/enum_helpers.dart
index c0c5cb3e..ed2c04ee 100644
--- a/json_annotation/lib/src/enum_helpers.dart
+++ b/json_annotation/lib/src/enum_helpers.dart
@@ -88,3 +88,15 @@ K $enumDecode<K extends Enum, V>(
 
   return unknownValue;
 }
+
+/// Returns the encoded JSON value associated with [value] in [enumValues].
+///
+/// [enumValues] is assumed to contain an entry for every possible value of
+/// type [K], so the returned value is never `null`.
+///
+/// Exposed only for code generated by `package:json_serializable`.
+/// Not meant to be used directly by user code.
+V $enumEncode<K extends Enum, V extends Object>(
+  Map<K, V> enumValues,
+  K value,
+) => enumValues[value]!;
diff --git a/json_annotation/pubspec.yaml b/json_annotation/pubspec.yaml
index 5707db45..d0990a5e 100644
--- a/json_annotation/pubspec.yaml
+++ b/json_annotation/pubspec.yaml
@@ -1,5 +1,5 @@
 name: json_annotation
-version: 4.12.0
+version: 4.13.0-wip
 description: >-
   Classes and helper functions that support JSON code generation via the
   `json_serializable` package.
diff --git a/json_serializable/CHANGELOG.md b/json_serializable/CHANGELOG.md
index 5ca9ab2b..2f9dd655 100644
--- a/json_serializable/CHANGELOG.md
+++ b/json_serializable/CHANGELOG.md
@@ -1,5 +1,10 @@
 ## 6.15.0-wip
 
+- Use `$enumEncode` for non-nullable enum `toJson` map lookups so generated
+  code no longer triggers `unnecessary_null_checks` on `_$EnumMap[value]!`.
+  ([#1515](https://github.com/google/json_serializable.dart/issues/1515))
+- Require `json_annotation: '>=4.13.0-0 <4.14.0'`
+
 - Fix `createJsonSchema` to emit an `enum` constraint (and `default`) for
   enum-typed fields, respecting `@JsonValue` and `JsonEnum.valueField`.
   ([#1577](https://github.com/google/json_serializable.dart/issues/1577))
diff --git a/json_serializable/README.md b/json_serializable/README.md
index 01ddbe09..29db530a 100644
--- a/json_serializable/README.md
+++ b/json_serializable/README.md
@@ -351,15 +351,15 @@ targets:
 [`Enum`]: https://api.dart.dev/dart-core/Enum-class.html
 [`int`]: https://api.dart.dev/dart-core/int-class.html
 [`Iterable`]: https://api.dart.dev/dart-core/Iterable-class.html
-[`JsonConverter`]: https://pub.dev/documentation/json_annotation/4.12.0/json_annotation/JsonConverter-class.html
-[`JsonEnum.valueField`]: https://pub.dev/documentation/json_annotation/4.12.0/json_annotation/JsonEnum/valueField.html
-[`JsonEnum`]: https://pub.dev/documentation/json_annotation/4.12.0/json_annotation/JsonEnum-class.html
-[`JsonKey.fromJson`]: https://pub.dev/documentation/json_annotation/4.12.0/json_annotation/JsonKey/fromJson.html
-[`JsonKey.toJson`]: https://pub.dev/documentation/json_annotation/4.12.0/json_annotation/JsonKey/toJson.html
-[`JsonKey`]: https://pub.dev/documentation/json_annotation/4.12.0/json_annotation/JsonKey-class.html
-[`JsonLiteral`]: https://pub.dev/documentation/json_annotation/4.12.0/json_annotation/JsonLiteral-class.html
-[`JsonSerializable`]: https://pub.dev/documentation/json_annotation/4.12.0/json_annotation/JsonSerializable-class.html
-[`JsonValue`]: https://pub.dev/documentation/json_annotation/4.12.0/json_annotation/JsonValue-class.html
+[`JsonConverter`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonConverter-class.html
+[`JsonEnum.valueField`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonEnum/valueField.html
+[`JsonEnum`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonEnum-class.html
+[`JsonKey.fromJson`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonKey/fromJson.html
+[`JsonKey.toJson`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonKey/toJson.html
+[`JsonKey`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonKey-class.html
+[`JsonLiteral`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonLiteral-class.html
+[`JsonSerializable`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonSerializable-class.html
+[`JsonValue`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonValue-class.html
 [`List`]: https://api.dart.dev/dart-core/List-class.html
 [`Map`]: https://api.dart.dev/dart-core/Map-class.html
 [`num`]: https://api.dart.dev/dart-core/num-class.html
diff --git a/json_serializable/lib/src/check_dependencies.dart b/json_serializable/lib/src/check_dependencies.dart
index ecdda809..9fefde19 100644
--- a/json_serializable/lib/src/check_dependencies.dart
+++ b/json_serializable/lib/src/check_dependencies.dart
@@ -15,7 +15,7 @@ const _annotationPkgName = 'json_annotation';
 final _supportLanguageRange = VersionConstraint.parse(
   supportedLanguageConstraint,
 );
-final requiredJsonAnnotationMinVersion = Version.parse('4.12.0');
+final requiredJsonAnnotationMinVersion = Version.parse('4.13.0-0');
 
 Future<void> pubspecHasRightVersion(BuildStep buildStep) async {
   final segments = buildStep.inputId.pathSegments;
diff --git a/json_serializable/lib/src/type_helpers/enum_helper.dart b/json_serializable/lib/src/type_helpers/enum_helper.dart
index ce7641fd..15b2ecd7 100644
--- a/json_serializable/lib/src/type_helpers/enum_helper.dart
+++ b/json_serializable/lib/src/type_helpers/enum_helper.dart
@@ -33,7 +33,10 @@ class EnumHelper extends TypeHelper<TypeHelperContextWithConfig> {
         enumFieldWithNullInEncodeMap(targetType) == true) {
       return '${constMapName(targetType)}[$expression]';
     } else {
-      return '${constMapName(targetType)}[$expression]!';
+      // Avoid `_$EnumMap[value]!` which triggers `unnecessary_null_checks` when
+      // the result is stored in a `Map<String, dynamic>` (#1515), while still
+      // producing a non-nullable value for Map keys (#1145).
+      return '\$enumEncode(${constMapName(targetType)}, $expression)';
     }
   }
 
diff --git a/json_serializable/pubspec.yaml b/json_serializable/pubspec.yaml
index ff663171..18eb55c3 100644
--- a/json_serializable/pubspec.yaml
+++ b/json_serializable/pubspec.yaml
@@ -23,7 +23,7 @@ dependencies:
 
   # Use a tight version constraint to ensure that a constraint on
   # `json_annotation` properly constrains all features it provides.
-  json_annotation: '>=4.12.0 <4.13.0'
+  json_annotation: '>=4.13.0-0 <4.14.0'
   meta: ^1.16.0
   path: ^1.9.0
   pub_semver: ^2.1.4
diff --git a/json_serializable/test/default_value/default_value.g.dart b/json_serializable/test/default_value/default_value.g.dart
index af639517..61335b04 100644
--- a/json_serializable/test/default_value/default_value.g.dart
+++ b/json_serializable/test/default_value/default_value.g.dart
@@ -80,7 +80,7 @@ Map<String, dynamic> _$DefaultValueToJson(DefaultValue instance) =>
       'fieldMapSimple': instance.fieldMapSimple,
       'fieldMapListString': instance.fieldMapListString,
       'durationField': instance.durationField.inMicroseconds,
-      'fieldEnum': _$GreekEnumMap[instance.fieldEnum]!,
+      'fieldEnum': $enumEncode(_$GreekEnumMap, instance.fieldEnum),
       'constClass': instance.constClass,
       'valueFromConverter': const ConstClassConverter().toJson(
         instance.valueFromConverter,
diff --git a/json_serializable/test/default_value/default_value.g_any_map__checked.g.dart b/json_serializable/test/default_value/default_value.g_any_map__checked.g.dart
index 0462bd16..e514e5a2 100644
--- a/json_serializable/test/default_value/default_value.g_any_map__checked.g.dart
+++ b/json_serializable/test/default_value/default_value.g_any_map__checked.g.dart
@@ -116,7 +116,7 @@ Map<String, dynamic> _$DefaultValueToJson(DefaultValue instance) =>
       'fieldMapSimple': instance.fieldMapSimple,
       'fieldMapListString': instance.fieldMapListString,
       'durationField': instance.durationField.inMicroseconds,
-      'fieldEnum': _$GreekEnumMap[instance.fieldEnum]!,
+      'fieldEnum': $enumEncode(_$GreekEnumMap, instance.fieldEnum),
       'constClass': instance.constClass,
       'valueFromConverter': const ConstClassConverter().toJson(
         instance.valueFromConverter,
diff --git a/json_serializable/test/default_value/implicit_default_value.g.dart b/json_serializable/test/default_value/implicit_default_value.g.dart
index 06cb4a46..76953494 100644
--- a/json_serializable/test/default_value/implicit_default_value.g.dart
+++ b/json_serializable/test/default_value/implicit_default_value.g.dart
@@ -89,7 +89,7 @@ Map<String, dynamic> _$DefaultValueImplicitToJson(
   'fieldMapSimple': instance.fieldMapSimple,
   'fieldMapListString': instance.fieldMapListString,
   'durationField': instance.durationField.inMicroseconds,
-  'fieldEnum': _$GreekEnumMap[instance.fieldEnum]!,
+  'fieldEnum': $enumEncode(_$GreekEnumMap, instance.fieldEnum),
   'constClass': instance.constClass,
   'valueFromConverter': const ConstClassConverter().toJson(
     instance.valueFromConverter,
diff --git a/json_serializable/test/integration/integration_test.dart b/json_serializable/test/integration/integration_test.dart
index f2e8e4c8..0f212fe5 100644
--- a/json_serializable/test/integration/integration_test.dart
+++ b/json_serializable/test/integration/integration_test.dart
@@ -333,6 +333,14 @@ void main() {
     expect(dayTypeEnumValues, ['no-good', 'rotten', 'very-bad']);
   });
 
+  test('non-nullable enum toJson uses enumEncode without a bang', () {
+    final json = Issue1515Regression(
+      state: Issue1145RegressionEnum.alpha,
+    ).toJson();
+    expect(json, {'state': 'alpha'});
+    expect(json['state'], const TypeMatcher<String>());
+  });
+
   test('serializing a non-nullable enum as a key in a map should produce a '
       'non-nullable string key', () {
     final cls = Issue1145RegressionA(
diff --git a/json_serializable/test/integration/json_enum_example.dart b/json_serializable/test/integration/json_enum_example.dart
index f36159cc..2f3b8059 100644
--- a/json_serializable/test/integration/json_enum_example.dart
+++ b/json_serializable/test/integration/json_enum_example.dart
@@ -99,3 +99,12 @@ class Issue1226Regression {
 
   Map<String, dynamic> toJson() => _$Issue1226RegressionToJson(this);
 }
+
+@JsonSerializable(createFactory: false)
+class Issue1515Regression {
+  Issue1515Regression({required this.state});
+
+  Map<String, dynamic> toJson() => _$Issue1515RegressionToJson(this);
+
+  final Issue1145RegressionEnum state;
+}
diff --git a/json_serializable/test/integration/json_enum_example.g.dart b/json_serializable/test/integration/json_enum_example.g.dart
index 0cbe2616..c0395be0 100644
--- a/json_serializable/test/integration/json_enum_example.g.dart
+++ b/json_serializable/test/integration/json_enum_example.g.dart
@@ -33,7 +33,7 @@ Map<String, dynamic> _$Issue1145RegressionAToJson(
   Issue1145RegressionA instance,
 ) => <String, dynamic>{
   'status': instance.status.map(
-    (k, e) => MapEntry(_$Issue1145RegressionEnumEnumMap[k]!, e),
+    (k, e) => MapEntry($enumEncode(_$Issue1145RegressionEnumEnumMap, k), e),
   ),
 };
 
@@ -65,6 +65,12 @@ Map<String, dynamic> _$Issue1226RegressionToJson(
   'durationType': ?_$Issue1145RegressionEnumEnumMap[instance.durationType],
 };
 
+Map<String, dynamic> _$Issue1515RegressionToJson(
+  Issue1515Regression instance,
+) => <String, dynamic>{
+  'state': $enumEncode(_$Issue1145RegressionEnumEnumMap, instance.state),
+};
+
 const _$StandAloneEnumEnumMap = {
   StandAloneEnum.alpha: 'a',
   StandAloneEnum.beta: 'b',
diff --git a/json_serializable/test/integration/json_test_example.g.dart b/json_serializable/test/integration/json_test_example.g.dart
index 66b12fa7..c158e26c 100644
--- a/json_serializable/test/integration/json_test_example.g.dart
+++ b/json_serializable/test/integration/json_test_example.g.dart
@@ -41,14 +41,14 @@ Map<String, dynamic> _$PersonToJson(Person instance) => <String, dynamic>{
   'lastName': instance.lastName,
   'middleName': instance.middleName,
   'dateOfBirth': instance.dateOfBirth?.toIso8601String(),
-  r'$house': _$CategoryEnumMap[instance.house]!,
+  r'$house': $enumEncode(_$CategoryEnumMap, instance.house),
   'order': instance.order,
   'customOrders': instance.customOrders,
   'houseMap': instance.houseMap?.map(
-    (k, e) => MapEntry(k, _$CategoryEnumMap[e]!),
+    (k, e) => MapEntry(k, $enumEncode(_$CategoryEnumMap, e)),
   ),
   'categoryCounts': instance.categoryCounts?.map(
-    (k, e) => MapEntry(_$CategoryEnumMap[k]!, e),
+    (k, e) => MapEntry($enumEncode(_$CategoryEnumMap, k), e),
   ),
 };
 
diff --git a/json_serializable/test/integration/json_test_example.g_any_map.g.dart b/json_serializable/test/integration/json_test_example.g_any_map.g.dart
index fdcd10b2..a0facbdb 100644
--- a/json_serializable/test/integration/json_test_example.g_any_map.g.dart
+++ b/json_serializable/test/integration/json_test_example.g_any_map.g.dart
@@ -43,14 +43,14 @@ Map<String, dynamic> _$PersonToJson(Person instance) => <String, dynamic>{
   'lastName': instance.lastName,
   'middleName': instance.middleName,
   'dateOfBirth': instance.dateOfBirth?.toIso8601String(),
-  r'$house': _$CategoryEnumMap[instance.house]!,
+  r'$house': $enumEncode(_$CategoryEnumMap, instance.house),
   'order': instance.order,
   'customOrders': instance.customOrders,
   'houseMap': instance.houseMap?.map(
-    (k, e) => MapEntry(k, _$CategoryEnumMap[e]!),
+    (k, e) => MapEntry(k, $enumEncode(_$CategoryEnumMap, e)),
   ),
   'categoryCounts': instance.categoryCounts?.map(
-    (k, e) => MapEntry(_$CategoryEnumMap[k]!, e),
+    (k, e) => MapEntry($enumEncode(_$CategoryEnumMap, k), e),
   ),
 };
 
diff --git a/json_serializable/test/integration/schema_example.g.dart b/json_serializable/test/integration/schema_example.g.dart
index be42c84a..8e8a411f 100644
--- a/json_serializable/test/integration/schema_example.g.dart
+++ b/json_serializable/test/integration/schema_example.g.dart
@@ -183,8 +183,10 @@ SchemaEnumExample _$SchemaEnumExampleFromJson(Map<String, dynamic> json) =>
 
 Map<String, dynamic> _$SchemaEnumExampleToJson(SchemaEnumExample instance) =>
     <String, dynamic>{
-      'season': _$SeasonEnumMap[instance.season]!,
-      'seasons': instance.seasons.map((e) => _$SeasonEnumMap[e]!).toList(),
+      'season': $enumEncode(_$SeasonEnumMap, instance.season),
+      'seasons': instance.seasons
+          .map((e) => $enumEncode(_$SeasonEnumMap, e))
+          .toList(),
     };
 
 const _$SchemaEnumExampleJsonSchema = {
diff --git a/json_serializable/test/supported_types/input.type_enumtype.g.dart b/json_serializable/test/supported_types/input.type_enumtype.g.dart
index 3e25a019..b3d04684 100644
--- a/json_serializable/test/supported_types/input.type_enumtype.g.dart
+++ b/json_serializable/test/supported_types/input.type_enumtype.g.dart
@@ -15,8 +15,8 @@ SimpleClass _$SimpleClassFromJson(Map<String, dynamic> json) => SimpleClass(
 
 Map<String, dynamic> _$SimpleClassToJson(SimpleClass instance) =>
     <String, dynamic>{
-      'value': _$EnumTypeEnumMap[instance.value]!,
-      'withDefault': _$EnumTypeEnumMap[instance.withDefault]!,
+      'value': $enumEncode(_$EnumTypeEnumMap, instance.value),
+      'withDefault': $enumEncode(_$EnumTypeEnumMap, instance.withDefault),
     };
 
 const _$EnumTypeEnumMap = {
diff --git a/json_serializable/test/supported_types/input.type_iterable.g.dart b/json_serializable/test/supported_types/input.type_iterable.g.dart
index 6f2df94a..f9777a66 100644
--- a/json_serializable/test/supported_types/input.type_iterable.g.dart
+++ b/json_serializable/test/supported_types/input.type_iterable.g.dart
@@ -293,7 +293,9 @@ SimpleClassOfEnumType _$SimpleClassOfEnumTypeFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToJson(
   SimpleClassOfEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((e) => _$EnumTypeEnumMap[e]!).toList(),
+  'value': instance.value
+      .map((e) => $enumEncode(_$EnumTypeEnumMap, e))
+      .toList(),
 };
 
 const _$EnumTypeEnumMap = {
@@ -314,7 +316,9 @@ SimpleClassNullableOfEnumType _$SimpleClassNullableOfEnumTypeFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToJson(
   SimpleClassNullableOfEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((e) => _$EnumTypeEnumMap[e]!).toList(),
+  'value': instance.value
+      ?.map((e) => $enumEncode(_$EnumTypeEnumMap, e))
+      .toList(),
 };
 
 SimpleClassOfEnumTypeNullable _$SimpleClassOfEnumTypeNullableFromJson(
diff --git a/json_serializable/test/supported_types/input.type_list.g.dart b/json_serializable/test/supported_types/input.type_list.g.dart
index c89d184e..0cb1ac55 100644
--- a/json_serializable/test/supported_types/input.type_list.g.dart
+++ b/json_serializable/test/supported_types/input.type_list.g.dart
@@ -310,7 +310,9 @@ SimpleClassOfEnumType _$SimpleClassOfEnumTypeFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToJson(
   SimpleClassOfEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((e) => _$EnumTypeEnumMap[e]!).toList(),
+  'value': instance.value
+      .map((e) => $enumEncode(_$EnumTypeEnumMap, e))
+      .toList(),
 };
 
 const _$EnumTypeEnumMap = {
@@ -331,7 +333,9 @@ SimpleClassNullableOfEnumType _$SimpleClassNullableOfEnumTypeFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToJson(
   SimpleClassNullableOfEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((e) => _$EnumTypeEnumMap[e]!).toList(),
+  'value': instance.value
+      ?.map((e) => $enumEncode(_$EnumTypeEnumMap, e))
+      .toList(),
 };
 
 SimpleClassOfEnumTypeNullable _$SimpleClassOfEnumTypeNullableFromJson(
diff --git a/json_serializable/test/supported_types/input.type_map.g.dart b/json_serializable/test/supported_types/input.type_map.g.dart
index 7077797f..6de01ed1 100644
--- a/json_serializable/test/supported_types/input.type_map.g.dart
+++ b/json_serializable/test/supported_types/input.type_map.g.dart
@@ -133,7 +133,7 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToBigIntToJson(
   SimpleClassOfEnumTypeToBigInt instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e.toString()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e.toString()),
   ),
 };
 
@@ -159,7 +159,7 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToBigIntToJson(
   SimpleClassNullableOfEnumTypeToBigInt instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e.toString()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e.toString()),
   ),
 };
 
@@ -391,7 +391,7 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToBigIntNullableToJson(
   SimpleClassOfEnumTypeToBigIntNullable instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e?.toString()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e?.toString()),
   ),
 };
 
@@ -411,7 +411,7 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToBigIntNullableToJson(
   SimpleClassNullableOfEnumTypeToBigIntNullable instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e?.toString()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e?.toString()),
   ),
 };
 
@@ -624,7 +624,9 @@ SimpleClassOfEnumTypeToBool _$SimpleClassOfEnumTypeToBoolFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToBoolToJson(
   SimpleClassOfEnumTypeToBool instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToBool
@@ -638,7 +640,9 @@ _$SimpleClassNullableOfEnumTypeToBoolFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToBoolToJson(
   SimpleClassNullableOfEnumTypeToBool instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToBool _$SimpleClassOfIntToBoolFromJson(
@@ -829,7 +833,9 @@ _$SimpleClassOfEnumTypeToBoolNullableFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassOfEnumTypeToBoolNullableToJson(
   SimpleClassOfEnumTypeToBoolNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToBoolNullable
@@ -844,7 +850,9 @@ _$SimpleClassNullableOfEnumTypeToBoolNullableFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToBoolNullableToJson(
   SimpleClassNullableOfEnumTypeToBoolNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToBoolNullable _$SimpleClassOfIntToBoolNullableFromJson(
@@ -1056,7 +1064,7 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToDateTimeToJson(
   SimpleClassOfEnumTypeToDateTime instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e.toIso8601String()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e.toIso8601String()),
   ),
 };
 
@@ -1075,7 +1083,7 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToDateTimeToJson(
   SimpleClassNullableOfEnumTypeToDateTime instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e.toIso8601String()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e.toIso8601String()),
   ),
 };
 
@@ -1321,7 +1329,7 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToDateTimeNullableToJson(
   SimpleClassOfEnumTypeToDateTimeNullable instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e?.toIso8601String()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e?.toIso8601String()),
   ),
 };
 
@@ -1341,7 +1349,7 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToDateTimeNullableToJson(
   SimpleClassNullableOfEnumTypeToDateTimeNullable instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e?.toIso8601String()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e?.toIso8601String()),
   ),
 };
 
@@ -1565,7 +1573,9 @@ SimpleClassOfEnumTypeToDouble _$SimpleClassOfEnumTypeToDoubleFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToDoubleToJson(
   SimpleClassOfEnumTypeToDouble instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToDouble
@@ -1580,7 +1590,9 @@ _$SimpleClassNullableOfEnumTypeToDoubleFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToDoubleToJson(
   SimpleClassNullableOfEnumTypeToDouble instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToDouble _$SimpleClassOfIntToDoubleFromJson(
@@ -1784,7 +1796,9 @@ _$SimpleClassOfEnumTypeToDoubleNullableFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassOfEnumTypeToDoubleNullableToJson(
   SimpleClassOfEnumTypeToDoubleNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToDoubleNullable
@@ -1800,7 +1814,9 @@ _$SimpleClassNullableOfEnumTypeToDoubleNullableFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToDoubleNullableToJson(
   SimpleClassNullableOfEnumTypeToDoubleNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToDoubleNullable _$SimpleClassOfIntToDoubleNullableFromJson(
@@ -2024,7 +2040,7 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToDurationToJson(
   SimpleClassOfEnumTypeToDuration instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e.inMicroseconds),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e.inMicroseconds),
   ),
 };
 
@@ -2043,7 +2059,7 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToDurationToJson(
   SimpleClassNullableOfEnumTypeToDuration instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e.inMicroseconds),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e.inMicroseconds),
   ),
 };
 
@@ -2299,7 +2315,7 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToDurationNullableToJson(
   SimpleClassOfEnumTypeToDurationNullable instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e?.inMicroseconds),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e?.inMicroseconds),
   ),
 };
 
@@ -2319,7 +2335,7 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToDurationNullableToJson(
   SimpleClassNullableOfEnumTypeToDurationNullable instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e?.inMicroseconds),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e?.inMicroseconds),
   ),
 };
 
@@ -2556,7 +2572,9 @@ SimpleClassOfEnumTypeToDynamic _$SimpleClassOfEnumTypeToDynamicFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToDynamicToJson(
   SimpleClassOfEnumTypeToDynamic instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToDynamic
@@ -2570,7 +2588,9 @@ _$SimpleClassNullableOfEnumTypeToDynamicFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToDynamicToJson(
   SimpleClassNullableOfEnumTypeToDynamic instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToDynamic _$SimpleClassOfIntToDynamicFromJson(
@@ -2677,7 +2697,7 @@ Map<String, dynamic> _$SimpleClassOfBigIntToEnumTypeToJson(
   SimpleClassOfBigIntToEnumType instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(k.toString(), _$EnumTypeEnumMap[e]!),
+    (k, e) => MapEntry(k.toString(), $enumEncode(_$EnumTypeEnumMap, e)),
   ),
 };
 
@@ -2693,7 +2713,7 @@ Map<String, dynamic> _$SimpleClassNullableOfBigIntToEnumTypeToJson(
   SimpleClassNullableOfBigIntToEnumType instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(k.toString(), _$EnumTypeEnumMap[e]!),
+    (k, e) => MapEntry(k.toString(), $enumEncode(_$EnumTypeEnumMap, e)),
   ),
 };
 
@@ -2709,7 +2729,7 @@ Map<String, dynamic> _$SimpleClassOfDateTimeToEnumTypeToJson(
   SimpleClassOfDateTimeToEnumType instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(k.toIso8601String(), _$EnumTypeEnumMap[e]!),
+    (k, e) => MapEntry(k.toIso8601String(), $enumEncode(_$EnumTypeEnumMap, e)),
   ),
 };
 
@@ -2726,7 +2746,7 @@ Map<String, dynamic> _$SimpleClassNullableOfDateTimeToEnumTypeToJson(
   SimpleClassNullableOfDateTimeToEnumType instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(k.toIso8601String(), _$EnumTypeEnumMap[e]!),
+    (k, e) => MapEntry(k.toIso8601String(), $enumEncode(_$EnumTypeEnumMap, e)),
   ),
 };
 
@@ -2741,7 +2761,9 @@ SimpleClassOfDynamicToEnumType _$SimpleClassOfDynamicToEnumTypeFromJson(
 Map<String, dynamic> _$SimpleClassOfDynamicToEnumTypeToJson(
   SimpleClassOfDynamicToEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(k, _$EnumTypeEnumMap[e]!)),
+  'value': instance.value.map(
+    (k, e) => MapEntry(k, $enumEncode(_$EnumTypeEnumMap, e)),
+  ),
 };
 
 SimpleClassNullableOfDynamicToEnumType
@@ -2755,7 +2777,9 @@ _$SimpleClassNullableOfDynamicToEnumTypeFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassNullableOfDynamicToEnumTypeToJson(
   SimpleClassNullableOfDynamicToEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(k, _$EnumTypeEnumMap[e]!)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry(k, $enumEncode(_$EnumTypeEnumMap, e)),
+  ),
 };
 
 SimpleClassOfEnumTypeToEnumType _$SimpleClassOfEnumTypeToEnumTypeFromJson(
@@ -2773,7 +2797,10 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToEnumTypeToJson(
   SimpleClassOfEnumTypeToEnumType instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, _$EnumTypeEnumMap[e]!),
+    (k, e) => MapEntry(
+      $enumEncode(_$EnumTypeEnumMap, k),
+      $enumEncode(_$EnumTypeEnumMap, e),
+    ),
   ),
 };
 
@@ -2792,7 +2819,10 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToEnumTypeToJson(
   SimpleClassNullableOfEnumTypeToEnumType instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, _$EnumTypeEnumMap[e]!),
+    (k, e) => MapEntry(
+      $enumEncode(_$EnumTypeEnumMap, k),
+      $enumEncode(_$EnumTypeEnumMap, e),
+    ),
   ),
 };
 
@@ -2808,7 +2838,7 @@ Map<String, dynamic> _$SimpleClassOfIntToEnumTypeToJson(
   SimpleClassOfIntToEnumType instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(k.toString(), _$EnumTypeEnumMap[e]!),
+    (k, e) => MapEntry(k.toString(), $enumEncode(_$EnumTypeEnumMap, e)),
   ),
 };
 
@@ -2824,7 +2854,7 @@ Map<String, dynamic> _$SimpleClassNullableOfIntToEnumTypeToJson(
   SimpleClassNullableOfIntToEnumType instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(k.toString(), _$EnumTypeEnumMap[e]!),
+    (k, e) => MapEntry(k.toString(), $enumEncode(_$EnumTypeEnumMap, e)),
   ),
 };
 
@@ -2839,7 +2869,9 @@ SimpleClassOfObjectToEnumType _$SimpleClassOfObjectToEnumTypeFromJson(
 Map<String, dynamic> _$SimpleClassOfObjectToEnumTypeToJson(
   SimpleClassOfObjectToEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(k, _$EnumTypeEnumMap[e]!)),
+  'value': instance.value.map(
+    (k, e) => MapEntry(k, $enumEncode(_$EnumTypeEnumMap, e)),
+  ),
 };
 
 SimpleClassNullableOfObjectToEnumType
@@ -2853,7 +2885,9 @@ _$SimpleClassNullableOfObjectToEnumTypeFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassNullableOfObjectToEnumTypeToJson(
   SimpleClassNullableOfObjectToEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(k, _$EnumTypeEnumMap[e]!)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry(k, $enumEncode(_$EnumTypeEnumMap, e)),
+  ),
 };
 
 SimpleClassOfStringToEnumType _$SimpleClassOfStringToEnumTypeFromJson(
@@ -2867,7 +2901,9 @@ SimpleClassOfStringToEnumType _$SimpleClassOfStringToEnumTypeFromJson(
 Map<String, dynamic> _$SimpleClassOfStringToEnumTypeToJson(
   SimpleClassOfStringToEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(k, _$EnumTypeEnumMap[e]!)),
+  'value': instance.value.map(
+    (k, e) => MapEntry(k, $enumEncode(_$EnumTypeEnumMap, e)),
+  ),
 };
 
 SimpleClassNullableOfStringToEnumType
@@ -2881,7 +2917,9 @@ _$SimpleClassNullableOfStringToEnumTypeFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassNullableOfStringToEnumTypeToJson(
   SimpleClassNullableOfStringToEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(k, _$EnumTypeEnumMap[e]!)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry(k, $enumEncode(_$EnumTypeEnumMap, e)),
+  ),
 };
 
 SimpleClassOfUriToEnumType _$SimpleClassOfUriToEnumTypeFromJson(
@@ -2896,7 +2934,7 @@ Map<String, dynamic> _$SimpleClassOfUriToEnumTypeToJson(
   SimpleClassOfUriToEnumType instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(k.toString(), _$EnumTypeEnumMap[e]!),
+    (k, e) => MapEntry(k.toString(), $enumEncode(_$EnumTypeEnumMap, e)),
   ),
 };
 
@@ -2912,7 +2950,7 @@ Map<String, dynamic> _$SimpleClassNullableOfUriToEnumTypeToJson(
   SimpleClassNullableOfUriToEnumType instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(k.toString(), _$EnumTypeEnumMap[e]!),
+    (k, e) => MapEntry(k.toString(), $enumEncode(_$EnumTypeEnumMap, e)),
   ),
 };
 
@@ -3034,7 +3072,7 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToEnumTypeNullableToJson(
   SimpleClassOfEnumTypeToEnumTypeNullable instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, _$EnumTypeEnumMap[e]),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), _$EnumTypeEnumMap[e]),
   ),
 };
 
@@ -3054,7 +3092,7 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToEnumTypeNullableToJson(
   SimpleClassNullableOfEnumTypeToEnumTypeNullable instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, _$EnumTypeEnumMap[e]),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), _$EnumTypeEnumMap[e]),
   ),
 };
 
@@ -3284,7 +3322,9 @@ _$SimpleClassOfEnumTypeToFromJsonDynamicParamFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToFromJsonDynamicParamToJson(
   SimpleClassOfEnumTypeToFromJsonDynamicParam instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToFromJsonDynamicParam
@@ -3303,7 +3343,9 @@ Map<String, dynamic>
 _$SimpleClassNullableOfEnumTypeToFromJsonDynamicParamToJson(
   SimpleClassNullableOfEnumTypeToFromJsonDynamicParam instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToFromJsonDynamicParam
@@ -3524,7 +3566,9 @@ _$SimpleClassOfEnumTypeToFromJsonNullableObjectParamFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToFromJsonNullableObjectParamToJson(
   SimpleClassOfEnumTypeToFromJsonNullableObjectParam instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToFromJsonNullableObjectParam
@@ -3543,7 +3587,9 @@ Map<String, dynamic>
 _$SimpleClassNullableOfEnumTypeToFromJsonNullableObjectParamToJson(
   SimpleClassNullableOfEnumTypeToFromJsonNullableObjectParam instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToFromJsonNullableObjectParam
@@ -3768,7 +3814,9 @@ _$SimpleClassOfEnumTypeToFromJsonObjectParamFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToFromJsonObjectParamToJson(
   SimpleClassOfEnumTypeToFromJsonObjectParam instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToFromJsonObjectParam
@@ -3786,7 +3834,9 @@ _$SimpleClassNullableOfEnumTypeToFromJsonObjectParamFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToFromJsonObjectParamToJson(
   SimpleClassNullableOfEnumTypeToFromJsonObjectParam instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToFromJsonObjectParam
@@ -3986,7 +4036,9 @@ SimpleClassOfEnumTypeToInt _$SimpleClassOfEnumTypeToIntFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToIntToJson(
   SimpleClassOfEnumTypeToInt instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToInt _$SimpleClassNullableOfEnumTypeToIntFromJson(
@@ -4000,7 +4052,9 @@ SimpleClassNullableOfEnumTypeToInt _$SimpleClassNullableOfEnumTypeToIntFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToIntToJson(
   SimpleClassNullableOfEnumTypeToInt instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToInt _$SimpleClassOfIntToIntFromJson(
@@ -4190,7 +4244,9 @@ SimpleClassOfEnumTypeToIntNullable _$SimpleClassOfEnumTypeToIntNullableFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToIntNullableToJson(
   SimpleClassOfEnumTypeToIntNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToIntNullable
@@ -4205,7 +4261,9 @@ _$SimpleClassNullableOfEnumTypeToIntNullableFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToIntNullableToJson(
   SimpleClassNullableOfEnumTypeToIntNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToIntNullable _$SimpleClassOfIntToIntNullableFromJson(
@@ -4395,7 +4453,9 @@ SimpleClassOfEnumTypeToNum _$SimpleClassOfEnumTypeToNumFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToNumToJson(
   SimpleClassOfEnumTypeToNum instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToNum _$SimpleClassNullableOfEnumTypeToNumFromJson(
@@ -4409,7 +4469,9 @@ SimpleClassNullableOfEnumTypeToNum _$SimpleClassNullableOfEnumTypeToNumFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToNumToJson(
   SimpleClassNullableOfEnumTypeToNum instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToNum _$SimpleClassOfIntToNumFromJson(
@@ -4599,7 +4661,9 @@ SimpleClassOfEnumTypeToNumNullable _$SimpleClassOfEnumTypeToNumNullableFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToNumNullableToJson(
   SimpleClassOfEnumTypeToNumNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToNumNullable
@@ -4614,7 +4678,9 @@ _$SimpleClassNullableOfEnumTypeToNumNullableFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToNumNullableToJson(
   SimpleClassNullableOfEnumTypeToNumNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToNumNullable _$SimpleClassOfIntToNumNullableFromJson(
@@ -4808,7 +4874,9 @@ SimpleClassOfEnumTypeToObject _$SimpleClassOfEnumTypeToObjectFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToObjectToJson(
   SimpleClassOfEnumTypeToObject instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToObject
@@ -4822,7 +4890,9 @@ _$SimpleClassNullableOfEnumTypeToObjectFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToObjectToJson(
   SimpleClassNullableOfEnumTypeToObject instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToObject _$SimpleClassOfIntToObjectFromJson(
@@ -5017,7 +5087,9 @@ _$SimpleClassOfEnumTypeToObjectNullableFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassOfEnumTypeToObjectNullableToJson(
   SimpleClassOfEnumTypeToObjectNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToObjectNullable
@@ -5032,7 +5104,9 @@ _$SimpleClassNullableOfEnumTypeToObjectNullableFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToObjectNullableToJson(
   SimpleClassNullableOfEnumTypeToObjectNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToObjectNullable _$SimpleClassOfIntToObjectNullableFromJson(
@@ -5334,7 +5408,7 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToRecordToJson(
   SimpleClassOfEnumTypeToRecord instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, <String, dynamic>{
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), <String, dynamic>{
       r'$1': e.$1,
       r'$2': e.$2,
       'truth': e.truth,
@@ -5364,7 +5438,7 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToRecordToJson(
   SimpleClassNullableOfEnumTypeToRecord instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, <String, dynamic>{
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), <String, dynamic>{
       r'$1': e.$1,
       r'$2': e.$2,
       'truth': e.truth,
@@ -5701,7 +5775,9 @@ SimpleClassOfEnumTypeToString _$SimpleClassOfEnumTypeToStringFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToStringToJson(
   SimpleClassOfEnumTypeToString instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToString
@@ -5715,7 +5791,9 @@ _$SimpleClassNullableOfEnumTypeToStringFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToStringToJson(
   SimpleClassNullableOfEnumTypeToString instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToString _$SimpleClassOfIntToStringFromJson(
@@ -5908,7 +5986,9 @@ _$SimpleClassOfEnumTypeToStringNullableFromJson(Map<String, dynamic> json) =>
 Map<String, dynamic> _$SimpleClassOfEnumTypeToStringNullableToJson(
   SimpleClassOfEnumTypeToStringNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassNullableOfEnumTypeToStringNullable
@@ -5923,7 +6003,9 @@ _$SimpleClassNullableOfEnumTypeToStringNullableFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToStringNullableToJson(
   SimpleClassNullableOfEnumTypeToStringNullable instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e)),
+  'value': instance.value?.map(
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e),
+  ),
 };
 
 SimpleClassOfIntToStringNullable _$SimpleClassOfIntToStringNullableFromJson(
@@ -6129,7 +6211,7 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToUriToJson(
   SimpleClassOfEnumTypeToUri instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e.toString()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e.toString()),
   ),
 };
 
@@ -6146,7 +6228,7 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToUriToJson(
   SimpleClassNullableOfEnumTypeToUri instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e.toString()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e.toString()),
   ),
 };
 
@@ -6373,7 +6455,7 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToUriNullableToJson(
   SimpleClassOfEnumTypeToUriNullable instance,
 ) => <String, dynamic>{
   'value': instance.value.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e?.toString()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e?.toString()),
   ),
 };
 
@@ -6393,7 +6475,7 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToUriNullableToJson(
   SimpleClassNullableOfEnumTypeToUriNullable instance,
 ) => <String, dynamic>{
   'value': instance.value?.map(
-    (k, e) => MapEntry(_$EnumTypeEnumMap[k]!, e?.toString()),
+    (k, e) => MapEntry($enumEncode(_$EnumTypeEnumMap, k), e?.toString()),
   ),
 };
 
diff --git a/json_serializable/test/supported_types/input.type_record.g.dart b/json_serializable/test/supported_types/input.type_record.g.dart
index 98e18304..86680224 100644
--- a/json_serializable/test/supported_types/input.type_record.g.dart
+++ b/json_serializable/test/supported_types/input.type_record.g.dart
@@ -536,8 +536,8 @@ Map<String, dynamic> _$SimpleClassOfEnumTypeToJson(
   SimpleClassOfEnumType instance,
 ) => <String, dynamic>{
   'value': <String, dynamic>{
-    r'$1': _$EnumTypeEnumMap[instance.value.$1]!,
-    'named': _$EnumTypeEnumMap[instance.value.named]!,
+    r'$1': $enumEncode(_$EnumTypeEnumMap, instance.value.$1),
+    'named': $enumEncode(_$EnumTypeEnumMap, instance.value.named),
   },
 };
 
@@ -566,8 +566,8 @@ Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToJson(
   'value': instance.value == null
       ? null
       : <String, dynamic>{
-          r'$1': _$EnumTypeEnumMap[instance.value!.$1]!,
-          'named': _$EnumTypeEnumMap[instance.value!.named]!,
+          r'$1': $enumEncode(_$EnumTypeEnumMap, instance.value!.$1),
+          'named': $enumEncode(_$EnumTypeEnumMap, instance.value!.named),
         },
 };
 
diff --git a/json_serializable/test/supported_types/input.type_set.g.dart b/json_serializable/test/supported_types/input.type_set.g.dart
index f7100e17..f05d094e 100644
--- a/json_serializable/test/supported_types/input.type_set.g.dart
+++ b/json_serializable/test/supported_types/input.type_set.g.dart
@@ -311,7 +311,9 @@ SimpleClassOfEnumType _$SimpleClassOfEnumTypeFromJson(
 Map<String, dynamic> _$SimpleClassOfEnumTypeToJson(
   SimpleClassOfEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value.map((e) => _$EnumTypeEnumMap[e]!).toList(),
+  'value': instance.value
+      .map((e) => $enumEncode(_$EnumTypeEnumMap, e))
+      .toList(),
 };
 
 const _$EnumTypeEnumMap = {
@@ -332,7 +334,9 @@ SimpleClassNullableOfEnumType _$SimpleClassNullableOfEnumTypeFromJson(
 Map<String, dynamic> _$SimpleClassNullableOfEnumTypeToJson(
   SimpleClassNullableOfEnumType instance,
 ) => <String, dynamic>{
-  'value': instance.value?.map((e) => _$EnumTypeEnumMap[e]!).toList(),
+  'value': instance.value
+      ?.map((e) => $enumEncode(_$EnumTypeEnumMap, e))
+      .toList(),
 };
 
 SimpleClassOfEnumTypeNullable _$SimpleClassOfEnumTypeNullableFromJson(