diff --git a/src/Action/ExceptionAction.php b/src/Action/ExceptionAction.php
index cb02961801e..492768bb027 100644
--- a/src/Action/ExceptionAction.php
+++ b/src/Action/ExceptionAction.php
@@ -40,7 +40,7 @@ public function __construct(SerializerInterface $serializer, array $errorFormats
     {
         $this->serializer = $serializer;
         $this->errorFormats = $errorFormats;
-        $this->exceptionToStatus = array_merge(self::DEFAULT_EXCEPTION_TO_STATUS, $exceptionToStatus);
+        $this->exceptionToStatus = self::DEFAULT_EXCEPTION_TO_STATUS + $exceptionToStatus;
     }
 
     /**
diff --git a/src/Bridge/NelmioApiDoc/Parser/ApiPlatformParser.php b/src/Bridge/NelmioApiDoc/Parser/ApiPlatformParser.php
index 4d07f8ed537..9d2d73656e1 100644
--- a/src/Bridge/NelmioApiDoc/Parser/ApiPlatformParser.php
+++ b/src/Bridge/NelmioApiDoc/Parser/ApiPlatformParser.php
@@ -112,7 +112,11 @@ private function parseResource(ResourceMetadata $resourceMetadata, string $resou
         }
 
         if (isset($attributes['denormalization_context']['groups'])) {
-            $options['serializer_groups'] = isset($options['serializer_groups']) ? array_merge($options['serializer_groups'], $attributes['denormalization_context']['groups']) : $options['serializer_groups'];
+            if (isset($context['serializer_groups'])) {
+                $options['serializer_groups'] += $attributes['denormalization_context']['groups'];
+            } else {
+                $options['serializer_groups'] = $attributes['denormalization_context']['groups'];
+            }
         }
 
         return $this->getPropertyMetadata($resourceMetadata, $resourceClass, $io, $visited, $options);
@@ -129,8 +133,8 @@ private function parseResource(ResourceMetadata $resourceMetadata, string $resou
     private function getGroupsForItemAndCollectionOperation(ResourceMetadata $resourceMetadata, string $operationName) : array
     {
         $operation = [
-            'denormalization_context' => array_merge($resourceMetadata->getItemOperationAttribute($operationName, 'denormalization_context', []), $resourceMetadata->getCollectionOperationAttribute($operationName, 'denormalization_context', [])),
-            'normalization_context' => array_merge($resourceMetadata->getItemOperationAttribute($operationName, 'normalization_context', []), $resourceMetadata->getCollectionOperationAttribute($operationName, 'normalization_context', [])),
+            'denormalization_context' => $resourceMetadata->getItemOperationAttribute($operationName, 'denormalization_context', []) + $resourceMetadata->getCollectionOperationAttribute($operationName, 'denormalization_context', []),
+            'normalization_context' => $resourceMetadata->getItemOperationAttribute($operationName, 'normalization_context', []) + $resourceMetadata->getCollectionOperationAttribute($operationName, 'normalization_context', []),
         ];
 
         $options = [
diff --git a/src/Swagger/Serializer/DocumentationNormalizer.php b/src/Swagger/Serializer/DocumentationNormalizer.php
index 03d5b70cb50..ebf2eb827b1 100644
--- a/src/Swagger/Serializer/DocumentationNormalizer.php
+++ b/src/Swagger/Serializer/DocumentationNormalizer.php
@@ -335,8 +335,7 @@ private function getPropertySchema(PropertyMetadata $propertyMetadata) : \ArrayO
                 break;
 
             case Type::BUILTIN_TYPE_OBJECT:
-                $className = $valueType->getClassName();
-                if (null === $className) {
+                if (null === $className = $valueType->getClassName()) {
                     break;
                 }
 
@@ -350,7 +349,7 @@ private function getPropertySchema(PropertyMetadata $propertyMetadata) : \ArrayO
                     break;
                 }
 
-                if ($propertyMetadata->isReadableLink()) {
+                if (true === $propertyMetadata->isReadableLink()) {
                     $valueSchema['$ref'] = sprintf('#/definitions/%s', $this->resourceMetadataFactory->create($className)->getShortName());
                     break;
                 }
@@ -358,16 +357,13 @@ private function getPropertySchema(PropertyMetadata $propertyMetadata) : \ArrayO
                 $valueSchema['type'] = 'string';
                 $valueSchema['format'] = 'uri';
                 break;
-
-            default:
-                break;
         }
 
         if ($type->isCollection()) {
             $propertySchema['type'] = 'array';
             $propertySchema['items'] = $valueSchema;
         } else {
-            $propertySchema = new \ArrayObject(array_merge((array) $propertySchema, (array) $valueSchema));
+            $propertySchema = new \ArrayObject((array) $propertySchema + (array) $valueSchema);
         }
 
         return $propertySchema;