diff --git a/lib/src/code_generators/swagger_models_generator.dart b/lib/src/code_generators/swagger_models_generator.dart
index d39901ac..b9dc9e78 100644
--- a/lib/src/code_generators/swagger_models_generator.dart
+++ b/lib/src/code_generators/swagger_models_generator.dart
@@ -1679,7 +1679,8 @@ $allHashComponents;
 
     final newModelMap = allOf.firstWhereOrNull((m) => m.properties.isNotEmpty);
 
-    final currentProperties = schema.properties;
+    final currentProperties =
+        Map<String, SwaggerSchema>.from(schema.properties);
 
     currentProperties.addAll(newModelMap?.properties ?? {});
 
diff --git a/pubspec.yaml b/pubspec.yaml
index 0bb866ca..3ece755a 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: swagger_dart_code_generator
 
-version: 2.14.2
+version: 2.15.0
 
 homepage: https://github.com/epam-cross-platform-lab/swagger-dart-code-generator
 repository: https://github.com/epam-cross-platform-lab/swagger-dart-code-generator