diff --git a/modules/openapi-generator/src/main/resources/dart2/apilib.mustache b/modules/openapi-generator/src/main/resources/dart2/apilib.mustache
index 876eba03cc6e..1b1898d88dda 100644
--- a/modules/openapi-generator/src/main/resources/dart2/apilib.mustache
+++ b/modules/openapi-generator/src/main/resources/dart2/apilib.mustache
@@ -5,6 +5,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:collection/collection.dart';
 import 'package:http/http.dart';
 import 'package:intl/intl.dart';
 import 'package:meta/meta.dart';
@@ -23,13 +24,16 @@ part 'auth/http_bearer_auth.dart';
 {{#models}}{{#model}}part 'model/{{{classFilename}}}.dart';
 {{/model}}{{/models}}
 
+/// An [ApiClient] instance that uses the default values obtained from
+/// the OpenAPI specification file.
+var defaultApiClient = ApiClient();
+
 const _delimiters = {'csv': ',', 'ssv': ' ', 'tsv': '\t', 'pipes': '|'};
 const _dateEpochMarker = 'epoch';
+const _deepEquality = DeepCollectionEquality();
 final _dateFormatter = DateFormat('yyyy-MM-dd');
 final _regList = RegExp(r'^List<(.*)>$');
 final _regSet = RegExp(r'^Set<(.*)>$');
 final _regMap = RegExp(r'^Map<String,(.*)>$');
 
-ApiClient defaultApiClient = ApiClient();
-
 bool _isEpochMarker(String? pattern) => pattern == _dateEpochMarker || pattern == '/$_dateEpochMarker/';
diff --git a/modules/openapi-generator/src/main/resources/dart2/pubspec.mustache b/modules/openapi-generator/src/main/resources/dart2/pubspec.mustache
index 8a74ffa028e7..db9df9709aca 100644
--- a/modules/openapi-generator/src/main/resources/dart2/pubspec.mustache
+++ b/modules/openapi-generator/src/main/resources/dart2/pubspec.mustache
@@ -15,6 +15,7 @@ publish_to: {{.}}
 environment:
   sdk: '>=2.12.0 <3.0.0'
 dependencies:
+  collection: '^1.17.0'
   http: '>=0.13.0 <0.14.0'
   intl: '^0.18.0'
   meta: '^1.1.8'
@@ -22,4 +23,5 @@ dev_dependencies:
   test: '>=1.16.0 <1.18.0'
 {{#json_serializable}}
   build_runner: '^1.10.9'
-  json_serializable: '^3.5.1'{{/json_serializable}}
+  json_serializable: '^3.5.1'
+{{/json_serializable}}
diff --git a/modules/openapi-generator/src/main/resources/dart2/serialization/native/native_class.mustache b/modules/openapi-generator/src/main/resources/dart2/serialization/native/native_class.mustache
index 6700c86ed1de..1d406ea46318 100644
--- a/modules/openapi-generator/src/main/resources/dart2/serialization/native/native_class.mustache
+++ b/modules/openapi-generator/src/main/resources/dart2/serialization/native/native_class.mustache
@@ -38,7 +38,7 @@ class {{{classname}}} {
   @override
   bool operator ==(Object other) => identical(this, other) || other is {{{classname}}} &&
   {{#vars}}
-     other.{{{name}}} == {{{name}}}{{^-last}} &&{{/-last}}{{#-last}};{{/-last}}
+    {{#isMap}}_deepEquality.equals(other.{{{name}}}, {{{name}}}){{/isMap}}{{^isMap}}{{#isArray}}_deepEquality.equals(other.{{{name}}}, {{{name}}}){{/isArray}}{{^isArray}}other.{{{name}}} == {{{name}}}{{/isArray}}{{/isMap}}{{^-last}} &&{{/-last}}{{#-last}};{{/-last}}
   {{/vars}}
 
   @override
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/api.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/api.dart
index e7da4386a7dd..b1010dd5a231 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/api.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/api.dart
@@ -14,6 +14,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:collection/collection.dart';
 import 'package:http/http.dart';
 import 'package:intl/intl.dart';
 import 'package:meta/meta.dart';
@@ -39,13 +40,16 @@ part 'model/tag.dart';
 part 'model/user.dart';
 
 
+/// An [ApiClient] instance that uses the default values obtained from
+/// the OpenAPI specification file.
+var defaultApiClient = ApiClient();
+
 const _delimiters = {'csv': ',', 'ssv': ' ', 'tsv': '\t', 'pipes': '|'};
 const _dateEpochMarker = 'epoch';
+const _deepEquality = DeepCollectionEquality();
 final _dateFormatter = DateFormat('yyyy-MM-dd');
 final _regList = RegExp(r'^List<(.*)>$');
 final _regSet = RegExp(r'^Set<(.*)>$');
 final _regMap = RegExp(r'^Map<String,(.*)>$');
 
-ApiClient defaultApiClient = ApiClient();
-
 bool _isEpochMarker(String? pattern) => pattern == _dateEpochMarker || pattern == '/$_dateEpochMarker/';
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/api_response.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/api_response.dart
index 556c7ec4a96b..4ed31f5fe0ad 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/api_response.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/api_response.dart
@@ -44,9 +44,9 @@ class ApiResponse {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ApiResponse &&
-     other.code == code &&
-     other.type == type &&
-     other.message == message;
+    other.code == code &&
+    other.type == type &&
+    other.message == message;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/category.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/category.dart
index c5f0f4a8d278..4a64236f8550 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/category.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/category.dart
@@ -35,8 +35,8 @@ class Category {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Category &&
-     other.id == id &&
-     other.name == name;
+    other.id == id &&
+    other.name == name;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/order.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/order.dart
index e052dcc544a9..4871871516fe 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/order.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/order.dart
@@ -60,12 +60,12 @@ class Order {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Order &&
-     other.id == id &&
-     other.petId == petId &&
-     other.quantity == quantity &&
-     other.shipDate == shipDate &&
-     other.status == status &&
-     other.complete == complete;
+    other.id == id &&
+    other.petId == petId &&
+    other.quantity == quantity &&
+    other.shipDate == shipDate &&
+    other.status == status &&
+    other.complete == complete;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/pet.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/pet.dart
index a8e54d9920f0..8c17a4010ddf 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/pet.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/pet.dart
@@ -48,12 +48,12 @@ class Pet {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Pet &&
-     other.id == id &&
-     other.category == category &&
-     other.name == name &&
-     other.photoUrls == photoUrls &&
-     other.tags == tags &&
-     other.status == status;
+    other.id == id &&
+    other.category == category &&
+    other.name == name &&
+    _deepEquality.equals(other.photoUrls, photoUrls) &&
+    _deepEquality.equals(other.tags, tags) &&
+    other.status == status;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/tag.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/tag.dart
index bf557b6522a3..e96eeb3a769c 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/tag.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/tag.dart
@@ -35,8 +35,8 @@ class Tag {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Tag &&
-     other.id == id &&
-     other.name == name;
+    other.id == id &&
+    other.name == name;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/user.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/user.dart
index 57de27fd4052..14c98ee48d16 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/user.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/model/user.dart
@@ -90,14 +90,14 @@ class User {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is User &&
-     other.id == id &&
-     other.username == username &&
-     other.firstName == firstName &&
-     other.lastName == lastName &&
-     other.email == email &&
-     other.password == password &&
-     other.phone == phone &&
-     other.userStatus == userStatus;
+    other.id == id &&
+    other.username == username &&
+    other.firstName == firstName &&
+    other.lastName == lastName &&
+    other.email == email &&
+    other.password == password &&
+    other.phone == phone &&
+    other.userStatus == userStatus;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib/pubspec.yaml b/samples/openapi3/client/petstore/dart2/petstore_client_lib/pubspec.yaml
index 49f21520ec84..41ab08885c85 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib/pubspec.yaml
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib/pubspec.yaml
@@ -9,9 +9,9 @@ homepage: 'homepage'
 environment:
   sdk: '>=2.12.0 <3.0.0'
 dependencies:
+  collection: '^1.17.0'
   http: '>=0.13.0 <0.14.0'
   intl: '^0.18.0'
   meta: '^1.1.8'
 dev_dependencies:
   test: '>=1.16.0 <1.18.0'
-
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api.dart
index 3354e842e543..c48f9bf6a260 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api.dart
@@ -14,6 +14,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:collection/collection.dart';
 import 'package:http/http.dart';
 import 'package:intl/intl.dart';
 import 'package:meta/meta.dart';
@@ -84,13 +85,16 @@ part 'model/tag.dart';
 part 'model/user.dart';
 
 
+/// An [ApiClient] instance that uses the default values obtained from
+/// the OpenAPI specification file.
+var defaultApiClient = ApiClient();
+
 const _delimiters = {'csv': ',', 'ssv': ' ', 'tsv': '\t', 'pipes': '|'};
 const _dateEpochMarker = 'epoch';
+const _deepEquality = DeepCollectionEquality();
 final _dateFormatter = DateFormat('yyyy-MM-dd');
 final _regList = RegExp(r'^List<(.*)>$');
 final _regSet = RegExp(r'^Set<(.*)>$');
 final _regMap = RegExp(r'^Map<String,(.*)>$');
 
-ApiClient defaultApiClient = ApiClient();
-
 bool _isEpochMarker(String? pattern) => pattern == _dateEpochMarker || pattern == '/$_dateEpochMarker/';
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/additional_properties_class.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/additional_properties_class.dart
index 42a70fc7fba4..ac0b660489b5 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/additional_properties_class.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/additional_properties_class.dart
@@ -23,8 +23,8 @@ class AdditionalPropertiesClass {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is AdditionalPropertiesClass &&
-     other.mapProperty == mapProperty &&
-     other.mapOfMapProperty == mapOfMapProperty;
+    _deepEquality.equals(other.mapProperty, mapProperty) &&
+    _deepEquality.equals(other.mapOfMapProperty, mapOfMapProperty);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/all_of_with_single_ref.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/all_of_with_single_ref.dart
index 9f43c826b408..7e4757242724 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/all_of_with_single_ref.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/all_of_with_single_ref.dart
@@ -35,8 +35,8 @@ class AllOfWithSingleRef {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is AllOfWithSingleRef &&
-     other.username == username &&
-     other.singleRefType == singleRefType;
+    other.username == username &&
+    other.singleRefType == singleRefType;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/animal.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/animal.dart
index 0a2cd1bc4498..1ee9a56021ec 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/animal.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/animal.dart
@@ -23,8 +23,8 @@ class Animal {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Animal &&
-     other.className == className &&
-     other.color == color;
+    other.className == className &&
+    other.color == color;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/api_response.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/api_response.dart
index 556c7ec4a96b..4ed31f5fe0ad 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/api_response.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/api_response.dart
@@ -44,9 +44,9 @@ class ApiResponse {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ApiResponse &&
-     other.code == code &&
-     other.type == type &&
-     other.message == message;
+    other.code == code &&
+    other.type == type &&
+    other.message == message;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_of_array_of_number_only.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_of_array_of_number_only.dart
index 6066b348dbb5..ebc92fa35baa 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_of_array_of_number_only.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_of_array_of_number_only.dart
@@ -20,7 +20,7 @@ class ArrayOfArrayOfNumberOnly {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ArrayOfArrayOfNumberOnly &&
-     other.arrayArrayNumber == arrayArrayNumber;
+    _deepEquality.equals(other.arrayArrayNumber, arrayArrayNumber);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_of_number_only.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_of_number_only.dart
index 9275a619a5a1..c3d5b1c7928c 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_of_number_only.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_of_number_only.dart
@@ -20,7 +20,7 @@ class ArrayOfNumberOnly {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ArrayOfNumberOnly &&
-     other.arrayNumber == arrayNumber;
+    _deepEquality.equals(other.arrayNumber, arrayNumber);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_test.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_test.dart
index 282d225cfa6d..7d07c4f23545 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_test.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/array_test.dart
@@ -26,9 +26,9 @@ class ArrayTest {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ArrayTest &&
-     other.arrayOfString == arrayOfString &&
-     other.arrayArrayOfInteger == arrayArrayOfInteger &&
-     other.arrayArrayOfModel == arrayArrayOfModel;
+    _deepEquality.equals(other.arrayOfString, arrayOfString) &&
+    _deepEquality.equals(other.arrayArrayOfInteger, arrayArrayOfInteger) &&
+    _deepEquality.equals(other.arrayArrayOfModel, arrayArrayOfModel);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/capitalization.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/capitalization.dart
index 28c2e9d9c64c..84866a375ad3 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/capitalization.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/capitalization.dart
@@ -72,12 +72,12 @@ class Capitalization {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Capitalization &&
-     other.smallCamel == smallCamel &&
-     other.capitalCamel == capitalCamel &&
-     other.smallSnake == smallSnake &&
-     other.capitalSnake == capitalSnake &&
-     other.sCAETHFlowPoints == sCAETHFlowPoints &&
-     other.ATT_NAME == ATT_NAME;
+    other.smallCamel == smallCamel &&
+    other.capitalCamel == capitalCamel &&
+    other.smallSnake == smallSnake &&
+    other.capitalSnake == capitalSnake &&
+    other.sCAETHFlowPoints == sCAETHFlowPoints &&
+    other.ATT_NAME == ATT_NAME;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/cat.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/cat.dart
index 98d12dd09359..9e8ce7936156 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/cat.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/cat.dart
@@ -32,9 +32,9 @@ class Cat {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Cat &&
-     other.className == className &&
-     other.color == color &&
-     other.declawed == declawed;
+    other.className == className &&
+    other.color == color &&
+    other.declawed == declawed;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/category.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/category.dart
index 3d46deb157a1..78b2efe39735 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/category.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/category.dart
@@ -29,8 +29,8 @@ class Category {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Category &&
-     other.id == id &&
-     other.name == name;
+    other.id == id &&
+    other.name == name;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/class_model.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/class_model.dart
index 0308856e250a..a07e652c804e 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/class_model.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/class_model.dart
@@ -26,7 +26,7 @@ class ClassModel {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ClassModel &&
-     other.class_ == class_;
+    other.class_ == class_;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/deprecated_object.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/deprecated_object.dart
index facf8aa49110..d9e2be395cde 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/deprecated_object.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/deprecated_object.dart
@@ -26,7 +26,7 @@ class DeprecatedObject {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is DeprecatedObject &&
-     other.name == name;
+    other.name == name;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/dog.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/dog.dart
index 512f5e4344e2..e68451440911 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/dog.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/dog.dart
@@ -32,9 +32,9 @@ class Dog {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Dog &&
-     other.className == className &&
-     other.color == color &&
-     other.breed == breed;
+    other.className == className &&
+    other.color == color &&
+    other.breed == breed;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/enum_arrays.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/enum_arrays.dart
index 9f48dc8afec9..467ff1aaaf78 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/enum_arrays.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/enum_arrays.dart
@@ -23,8 +23,8 @@ class EnumArrays {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is EnumArrays &&
-     other.justSymbol == justSymbol &&
-     other.arrayEnum == arrayEnum;
+    other.justSymbol == justSymbol &&
+    _deepEquality.equals(other.arrayEnum, arrayEnum);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/enum_test.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/enum_test.dart
index a5afdc9ea1ec..d3e405221f9b 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/enum_test.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/enum_test.dart
@@ -59,14 +59,14 @@ class EnumTest {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is EnumTest &&
-     other.enumString == enumString &&
-     other.enumStringRequired == enumStringRequired &&
-     other.enumInteger == enumInteger &&
-     other.enumNumber == enumNumber &&
-     other.outerEnum == outerEnum &&
-     other.outerEnumInteger == outerEnumInteger &&
-     other.outerEnumDefaultValue == outerEnumDefaultValue &&
-     other.outerEnumIntegerDefaultValue == outerEnumIntegerDefaultValue;
+    other.enumString == enumString &&
+    other.enumStringRequired == enumStringRequired &&
+    other.enumInteger == enumInteger &&
+    other.enumNumber == enumNumber &&
+    other.outerEnum == outerEnum &&
+    other.outerEnumInteger == outerEnumInteger &&
+    other.outerEnumDefaultValue == outerEnumDefaultValue &&
+    other.outerEnumIntegerDefaultValue == outerEnumIntegerDefaultValue;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/fake_big_decimal_map200_response.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/fake_big_decimal_map200_response.dart
index eae75fa0fa26..07c35ffbeb5b 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/fake_big_decimal_map200_response.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/fake_big_decimal_map200_response.dart
@@ -29,8 +29,8 @@ class FakeBigDecimalMap200Response {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is FakeBigDecimalMap200Response &&
-     other.someId == someId &&
-     other.someMap == someMap;
+    other.someId == someId &&
+    _deepEquality.equals(other.someMap, someMap);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/file_schema_test_class.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/file_schema_test_class.dart
index 73b23874dc13..7243bbe4d687 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/file_schema_test_class.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/file_schema_test_class.dart
@@ -29,8 +29,8 @@ class FileSchemaTestClass {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is FileSchemaTestClass &&
-     other.file == file &&
-     other.files == files;
+    other.file == file &&
+    _deepEquality.equals(other.files, files);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/foo.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/foo.dart
index 637f700923e4..60850737dbbf 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/foo.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/foo.dart
@@ -20,7 +20,7 @@ class Foo {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Foo &&
-     other.bar == bar;
+    other.bar == bar;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/foo_get_default_response.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/foo_get_default_response.dart
index a50b62d7be9c..6b0734ba2baf 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/foo_get_default_response.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/foo_get_default_response.dart
@@ -26,7 +26,7 @@ class FooGetDefaultResponse {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is FooGetDefaultResponse &&
-     other.string == string;
+    other.string == string;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/format_test.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/format_test.dart
index 67d169c4d8a2..582bcab5a07b 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/format_test.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/format_test.dart
@@ -149,22 +149,22 @@ class FormatTest {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is FormatTest &&
-     other.integer == integer &&
-     other.int32 == int32 &&
-     other.int64 == int64 &&
-     other.number == number &&
-     other.float == float &&
-     other.double_ == double_ &&
-     other.decimal == decimal &&
-     other.string == string &&
-     other.byte == byte &&
-     other.binary == binary &&
-     other.date == date &&
-     other.dateTime == dateTime &&
-     other.uuid == uuid &&
-     other.password == password &&
-     other.patternWithDigits == patternWithDigits &&
-     other.patternWithDigitsAndDelimiter == patternWithDigitsAndDelimiter;
+    other.integer == integer &&
+    other.int32 == int32 &&
+    other.int64 == int64 &&
+    other.number == number &&
+    other.float == float &&
+    other.double_ == double_ &&
+    other.decimal == decimal &&
+    other.string == string &&
+    other.byte == byte &&
+    other.binary == binary &&
+    other.date == date &&
+    other.dateTime == dateTime &&
+    other.uuid == uuid &&
+    other.password == password &&
+    other.patternWithDigits == patternWithDigits &&
+    other.patternWithDigitsAndDelimiter == patternWithDigitsAndDelimiter;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/has_only_read_only.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/has_only_read_only.dart
index 4211499352c7..d98b94526180 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/has_only_read_only.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/has_only_read_only.dart
@@ -35,8 +35,8 @@ class HasOnlyReadOnly {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is HasOnlyReadOnly &&
-     other.bar == bar &&
-     other.foo == foo;
+    other.bar == bar &&
+    other.foo == foo;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/health_check_result.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/health_check_result.dart
index c8ce4c0c359b..0da0d7975cfc 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/health_check_result.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/health_check_result.dart
@@ -20,7 +20,7 @@ class HealthCheckResult {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is HealthCheckResult &&
-     other.nullableMessage == nullableMessage;
+    other.nullableMessage == nullableMessage;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/map_test.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/map_test.dart
index 0a66b0722783..487af40478b1 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/map_test.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/map_test.dart
@@ -29,10 +29,10 @@ class MapTest {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is MapTest &&
-     other.mapMapOfString == mapMapOfString &&
-     other.mapOfEnumString == mapOfEnumString &&
-     other.directMap == directMap &&
-     other.indirectMap == indirectMap;
+    _deepEquality.equals(other.mapMapOfString, mapMapOfString) &&
+    _deepEquality.equals(other.mapOfEnumString, mapOfEnumString) &&
+    _deepEquality.equals(other.directMap, directMap) &&
+    _deepEquality.equals(other.indirectMap, indirectMap);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/mixed_properties_and_additional_properties_class.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/mixed_properties_and_additional_properties_class.dart
index 976cbee2afea..654c6f441bb9 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/mixed_properties_and_additional_properties_class.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/mixed_properties_and_additional_properties_class.dart
@@ -38,9 +38,9 @@ class MixedPropertiesAndAdditionalPropertiesClass {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is MixedPropertiesAndAdditionalPropertiesClass &&
-     other.uuid == uuid &&
-     other.dateTime == dateTime &&
-     other.map == map;
+    other.uuid == uuid &&
+    other.dateTime == dateTime &&
+    _deepEquality.equals(other.map, map);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model200_response.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model200_response.dart
index acaa8220f3eb..88516302d808 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model200_response.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model200_response.dart
@@ -35,8 +35,8 @@ class Model200Response {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Model200Response &&
-     other.name == name &&
-     other.class_ == class_;
+    other.name == name &&
+    other.class_ == class_;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_client.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_client.dart
index 9010847ca744..67a443b2af4a 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_client.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_client.dart
@@ -26,7 +26,7 @@ class ModelClient {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ModelClient &&
-     other.client == client;
+    other.client == client;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_file.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_file.dart
index 9b98486ecea7..978ce1d02f43 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_file.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_file.dart
@@ -27,7 +27,7 @@ class ModelFile {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ModelFile &&
-     other.sourceURI == sourceURI;
+    other.sourceURI == sourceURI;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_list.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_list.dart
index ca6abae44c9b..18e1cbb643bd 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_list.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_list.dart
@@ -26,7 +26,7 @@ class ModelList {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ModelList &&
-     other.n123list == n123list;
+    other.n123list == n123list;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_return.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_return.dart
index 087ca4cbfa9d..663223684c79 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_return.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/model_return.dart
@@ -26,7 +26,7 @@ class ModelReturn {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ModelReturn &&
-     other.return_ == return_;
+    other.return_ == return_;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/name.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/name.dart
index 92e8093a807a..c3675f19581e 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/name.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/name.dart
@@ -47,10 +47,10 @@ class Name {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Name &&
-     other.name == name &&
-     other.snakeCase == snakeCase &&
-     other.property == property &&
-     other.n123number == n123number;
+    other.name == name &&
+    other.snakeCase == snakeCase &&
+    other.property == property &&
+    other.n123number == n123number;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/nullable_class.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/nullable_class.dart
index ed9b75289ff2..ed6c53cd1062 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/nullable_class.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/nullable_class.dart
@@ -53,18 +53,18 @@ class NullableClass {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is NullableClass &&
-     other.integerProp == integerProp &&
-     other.numberProp == numberProp &&
-     other.booleanProp == booleanProp &&
-     other.stringProp == stringProp &&
-     other.dateProp == dateProp &&
-     other.datetimeProp == datetimeProp &&
-     other.arrayNullableProp == arrayNullableProp &&
-     other.arrayAndItemsNullableProp == arrayAndItemsNullableProp &&
-     other.arrayItemsNullable == arrayItemsNullable &&
-     other.objectNullableProp == objectNullableProp &&
-     other.objectAndItemsNullableProp == objectAndItemsNullableProp &&
-     other.objectItemsNullable == objectItemsNullable;
+    other.integerProp == integerProp &&
+    other.numberProp == numberProp &&
+    other.booleanProp == booleanProp &&
+    other.stringProp == stringProp &&
+    other.dateProp == dateProp &&
+    other.datetimeProp == datetimeProp &&
+    _deepEquality.equals(other.arrayNullableProp, arrayNullableProp) &&
+    _deepEquality.equals(other.arrayAndItemsNullableProp, arrayAndItemsNullableProp) &&
+    _deepEquality.equals(other.arrayItemsNullable, arrayItemsNullable) &&
+    _deepEquality.equals(other.objectNullableProp, objectNullableProp) &&
+    _deepEquality.equals(other.objectAndItemsNullableProp, objectAndItemsNullableProp) &&
+    _deepEquality.equals(other.objectItemsNullable, objectItemsNullable);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/number_only.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/number_only.dart
index 74366c354254..14c9cde0d4d5 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/number_only.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/number_only.dart
@@ -26,7 +26,7 @@ class NumberOnly {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is NumberOnly &&
-     other.justNumber == justNumber;
+    other.justNumber == justNumber;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/object_with_deprecated_fields.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/object_with_deprecated_fields.dart
index 2afb378ba25b..020c0fe55818 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/object_with_deprecated_fields.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/object_with_deprecated_fields.dart
@@ -47,10 +47,10 @@ class ObjectWithDeprecatedFields {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ObjectWithDeprecatedFields &&
-     other.uuid == uuid &&
-     other.id == id &&
-     other.deprecatedRef == deprecatedRef &&
-     other.bars == bars;
+    other.uuid == uuid &&
+    other.id == id &&
+    other.deprecatedRef == deprecatedRef &&
+    _deepEquality.equals(other.bars, bars);
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/order.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/order.dart
index e052dcc544a9..4871871516fe 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/order.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/order.dart
@@ -60,12 +60,12 @@ class Order {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Order &&
-     other.id == id &&
-     other.petId == petId &&
-     other.quantity == quantity &&
-     other.shipDate == shipDate &&
-     other.status == status &&
-     other.complete == complete;
+    other.id == id &&
+    other.petId == petId &&
+    other.quantity == quantity &&
+    other.shipDate == shipDate &&
+    other.status == status &&
+    other.complete == complete;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/outer_composite.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/outer_composite.dart
index 2acc8f718dbb..a45764652ecb 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/outer_composite.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/outer_composite.dart
@@ -44,9 +44,9 @@ class OuterComposite {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is OuterComposite &&
-     other.myNumber == myNumber &&
-     other.myString == myString &&
-     other.myBoolean == myBoolean;
+    other.myNumber == myNumber &&
+    other.myString == myString &&
+    other.myBoolean == myBoolean;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/outer_object_with_enum_property.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/outer_object_with_enum_property.dart
index 44aecf1a2955..db8febdb6558 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/outer_object_with_enum_property.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/outer_object_with_enum_property.dart
@@ -20,7 +20,7 @@ class OuterObjectWithEnumProperty {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is OuterObjectWithEnumProperty &&
-     other.value == value;
+    other.value == value;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/pet.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/pet.dart
index 9e0c77e120b4..5c1cf7243841 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/pet.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/pet.dart
@@ -48,12 +48,12 @@ class Pet {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Pet &&
-     other.id == id &&
-     other.category == category &&
-     other.name == name &&
-     other.photoUrls == photoUrls &&
-     other.tags == tags &&
-     other.status == status;
+    other.id == id &&
+    other.category == category &&
+    other.name == name &&
+    _deepEquality.equals(other.photoUrls, photoUrls) &&
+    _deepEquality.equals(other.tags, tags) &&
+    other.status == status;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/read_only_first.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/read_only_first.dart
index e266da487457..17b1e2379164 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/read_only_first.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/read_only_first.dart
@@ -35,8 +35,8 @@ class ReadOnlyFirst {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is ReadOnlyFirst &&
-     other.bar == bar &&
-     other.baz == baz;
+    other.bar == bar &&
+    other.baz == baz;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/special_model_name.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/special_model_name.dart
index 5d745143dcc1..e80724f18dda 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/special_model_name.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/special_model_name.dart
@@ -26,7 +26,7 @@ class SpecialModelName {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is SpecialModelName &&
-     other.dollarSpecialLeftSquareBracketPropertyPeriodNameRightSquareBracket == dollarSpecialLeftSquareBracketPropertyPeriodNameRightSquareBracket;
+    other.dollarSpecialLeftSquareBracketPropertyPeriodNameRightSquareBracket == dollarSpecialLeftSquareBracketPropertyPeriodNameRightSquareBracket;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/tag.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/tag.dart
index bf557b6522a3..e96eeb3a769c 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/tag.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/tag.dart
@@ -35,8 +35,8 @@ class Tag {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is Tag &&
-     other.id == id &&
-     other.name == name;
+    other.id == id &&
+    other.name == name;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/user.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/user.dart
index 57de27fd4052..14c98ee48d16 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/user.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/user.dart
@@ -90,14 +90,14 @@ class User {
 
   @override
   bool operator ==(Object other) => identical(this, other) || other is User &&
-     other.id == id &&
-     other.username == username &&
-     other.firstName == firstName &&
-     other.lastName == lastName &&
-     other.email == email &&
-     other.password == password &&
-     other.phone == phone &&
-     other.userStatus == userStatus;
+    other.id == id &&
+    other.username == username &&
+    other.firstName == firstName &&
+    other.lastName == lastName &&
+    other.email == email &&
+    other.password == password &&
+    other.phone == phone &&
+    other.userStatus == userStatus;
 
   @override
   int get hashCode =>
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/pubspec.yaml b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/pubspec.yaml
index 49f21520ec84..41ab08885c85 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/pubspec.yaml
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/pubspec.yaml
@@ -9,9 +9,9 @@ homepage: 'homepage'
 environment:
   sdk: '>=2.12.0 <3.0.0'
 dependencies:
+  collection: '^1.17.0'
   http: '>=0.13.0 <0.14.0'
   intl: '^0.18.0'
   meta: '^1.1.8'
 dev_dependencies:
   test: '>=1.16.0 <1.18.0'
-