diff --git a/.github/workflows/coding-standard.yml b/.github/workflows/coding-standard.yml
index 5ca4f70d055..05cf50375f5 100644
--- a/.github/workflows/coding-standard.yml
+++ b/.github/workflows/coding-standard.yml
@@ -29,14 +29,14 @@ jobs:
       - name: "Install dependencies with Composer"
         uses: "ramsey/composer-install@v1"
 
-      - name: "Install git-phpcs"
-        run: "wget https://github.com/diff-sniffer/git/releases/download/0.3.2/git-phpcs.phar"
+      - name: "Install diff-sniffer"
+        run: "wget https://github.com/diff-sniffer/diff-sniffer/releases/download/0.5.1/diff-sniffer.phar"
 
       - name: "Fetch head branch"
         run: "git remote set-branches --add origin $GITHUB_BASE_REF && git fetch origin $GITHUB_BASE_REF"
 
-      - name: "Run git-phpcs"
-        run: "php git-phpcs.phar origin/$GITHUB_BASE_REF...$GITHUB_SHA --report=checkstyle | cs2pr"
+      - name: "Run diff-sniffer"
+        run: "php diff-sniffer.phar origin/$GITHUB_BASE_REF...$GITHUB_SHA --report=checkstyle | cs2pr"
 
       - name: "Run phpcbf"
         run: "vendor/bin/phpcbf"
diff --git a/lib/Doctrine/ORM/AbstractQuery.php b/lib/Doctrine/ORM/AbstractQuery.php
index 2ba30bc4fa8..7e54820d01a 100644
--- a/lib/Doctrine/ORM/AbstractQuery.php
+++ b/lib/Doctrine/ORM/AbstractQuery.php
@@ -795,7 +795,7 @@ public function getResult($hydrationMode = self::HYDRATE_OBJECT)
      *
      * Alias for execute(null, HYDRATE_ARRAY).
      *
-     * @return array
+     * @return array<int,mixed>
      */
     public function getArrayResult()
     {
@@ -807,7 +807,7 @@ public function getArrayResult()
      *
      * Alias for execute(null, HYDRATE_SCALAR).
      *
-     * @return array
+     * @return array<int,mixed>
      */
     public function getScalarResult()
     {
@@ -937,7 +937,7 @@ public function hasHint($name)
     /**
      * Return the key value map of query hints that are currently set.
      *
-     * @return array
+     * @return array<string,mixed>
      */
     public function getHints()
     {
@@ -950,8 +950,8 @@ public function getHints()
      *
      * @deprecated
      *
-     * @param ArrayCollection|array|null $parameters    The query parameters.
-     * @param string|int|null            $hydrationMode The hydration mode to use.
+     * @param ArrayCollection|mixed[]|null $parameters    The query parameters.
+     * @param string|int|null              $hydrationMode The hydration mode to use.
      *
      * @return IterableResult
      */
@@ -1024,8 +1024,8 @@ public function execute($parameters = null, $hydrationMode = null)
     /**
      * Execute query ignoring second level cache.
      *
-     * @param ArrayCollection|array|null $parameters
-     * @param string|int|null            $hydrationMode
+     * @param ArrayCollection|mixed[]|null $parameters
+     * @param string|int|null              $hydrationMode
      *
      * @return mixed
      */
@@ -1083,8 +1083,8 @@ private function executeIgnoreQueryCache($parameters = null, $hydrationMode = nu
     /**
      * Load from second level cache or executes the query and put into cache.
      *
-     * @param ArrayCollection|array|null $parameters
-     * @param string|int|null            $hydrationMode
+     * @param ArrayCollection|mixed[]|null $parameters
+     * @param string|int|null              $hydrationMode
      *
      * @return mixed
      */
@@ -1224,9 +1224,11 @@ protected function getHash()
         $query  = $this->getSQL();
         $hints  = $this->getHints();
         $params = array_map(function (Parameter $parameter) {
+            $value = $parameter->getValue();
+
             // Small optimization
-            // Does not invoke processParameterValue for scalar values
-            if (is_scalar($value = $parameter->getValue())) {
+            // Does not invoke processParameterValue for scalar value
+            if (is_scalar($value)) {
                 return $value;
             }
 
diff --git a/lib/Doctrine/ORM/Cache/AssociationCacheEntry.php b/lib/Doctrine/ORM/Cache/AssociationCacheEntry.php
index e3db6e0af48..1703eee4c16 100644
--- a/lib/Doctrine/ORM/Cache/AssociationCacheEntry.php
+++ b/lib/Doctrine/ORM/Cache/AssociationCacheEntry.php
@@ -28,7 +28,7 @@ class AssociationCacheEntry implements CacheEntry
     /**
      * READ-ONLY: Public only for performance reasons, it should be considered immutable.
      *
-     * @var array The entity identifier
+     * @var array<string, mixed> The entity identifier
      */
     public $identifier;
 
@@ -40,8 +40,8 @@ class AssociationCacheEntry implements CacheEntry
     public $class;
 
     /**
-     * @param string $class      The entity class.
-     * @param array  $identifier The entity identifier.
+     * @param string               $class      The entity class.
+     * @param array<string, mixed> $identifier The entity identifier.
      */
     public function __construct($class, array $identifier)
     {
@@ -54,7 +54,7 @@ public function __construct($class, array $identifier)
      *
      * This method allow Doctrine\Common\Cache\PhpFileCache compatibility
      *
-     * @param array $values array containing property values
+     * @param array<string, mixed> $values array containing property values
      *
      * @return AssociationCacheEntry
      */
diff --git a/lib/Doctrine/ORM/Cache/CacheFactory.php b/lib/Doctrine/ORM/Cache/CacheFactory.php
index 6839b043d81..c880fca81d8 100644
--- a/lib/Doctrine/ORM/Cache/CacheFactory.php
+++ b/lib/Doctrine/ORM/Cache/CacheFactory.php
@@ -88,7 +88,7 @@ public function buildCollectionHydrator(EntityManagerInterface $em, array $mappi
     /**
      * Build a cache region
      *
-     * @param array $cache The cache configuration.
+     * @param array<string,mixed> $cache The cache configuration.
      *
      * @return Region The cache region.
      */
diff --git a/lib/Doctrine/ORM/Cache/CollectionCacheEntry.php b/lib/Doctrine/ORM/Cache/CollectionCacheEntry.php
index 38b49b897ec..9bcf5b5567c 100644
--- a/lib/Doctrine/ORM/Cache/CollectionCacheEntry.php
+++ b/lib/Doctrine/ORM/Cache/CollectionCacheEntry.php
@@ -45,7 +45,7 @@ public function __construct(array $identifiers)
      *
      * This method allows for Doctrine\Common\Cache\PhpFileCache compatibility
      *
-     * @param array $values array containing property values
+     * @param array<string, mixed> $values array containing property values
      *
      * @return CollectionCacheEntry
      */
diff --git a/lib/Doctrine/ORM/Cache/CollectionCacheKey.php b/lib/Doctrine/ORM/Cache/CollectionCacheKey.php
index bfeee8c31c1..91a2ae9e59f 100644
--- a/lib/Doctrine/ORM/Cache/CollectionCacheKey.php
+++ b/lib/Doctrine/ORM/Cache/CollectionCacheKey.php
@@ -33,7 +33,7 @@ class CollectionCacheKey extends CacheKey
     /**
      * READ-ONLY: Public only for performance reasons, it should be considered immutable.
      *
-     * @var array The owner entity identifier
+     * @var array<string, mixed> The owner entity identifier
      */
     public $ownerIdentifier;
 
@@ -52,9 +52,9 @@ class CollectionCacheKey extends CacheKey
     public $association;
 
     /**
-     * @param string $entityClass     The entity class.
-     * @param string $association     The field name that represents the association.
-     * @param array  $ownerIdentifier The identifier of the owning entity.
+     * @param string               $entityClass     The entity class.
+     * @param string               $association     The field name that represents the association.
+     * @param array<string, mixed> $ownerIdentifier The identifier of the owning entity.
      */
     public function __construct($entityClass, $association, array $ownerIdentifier)
     {
diff --git a/lib/Doctrine/ORM/Cache/CollectionHydrator.php b/lib/Doctrine/ORM/Cache/CollectionHydrator.php
index 87a042eff9b..0eb47e65d51 100644
--- a/lib/Doctrine/ORM/Cache/CollectionHydrator.php
+++ b/lib/Doctrine/ORM/Cache/CollectionHydrator.php
@@ -44,7 +44,7 @@ public function buildCacheEntry(ClassMetadata $metadata, CollectionCacheKey $key
      * @param CollectionCacheEntry $entry      The cached collection entry.
      * @param PersistentCollection $collection The collection to load the cache into.
      *
-     * @return array
+     * @return mixed[]
      */
     public function loadCacheEntry(ClassMetadata $metadata, CollectionCacheKey $key, CollectionCacheEntry $entry, PersistentCollection $collection);
 }
diff --git a/lib/Doctrine/ORM/Cache/DefaultCache.php b/lib/Doctrine/ORM/Cache/DefaultCache.php
index f8b7b46a001..54c933799cc 100644
--- a/lib/Doctrine/ORM/Cache/DefaultCache.php
+++ b/lib/Doctrine/ORM/Cache/DefaultCache.php
@@ -310,7 +310,7 @@ private function buildCollectionCacheKey(ClassMetadata $metadata, $association,
      * @param ClassMetadata $metadata   The entity metadata.
      * @param mixed         $identifier The entity identifier.
      *
-     * @return array
+     * @return array<string, mixed>
      */
     private function toIdentifierArray(ClassMetadata $metadata, $identifier)
     {
diff --git a/lib/Doctrine/ORM/Cache/DefaultCollectionHydrator.php b/lib/Doctrine/ORM/Cache/DefaultCollectionHydrator.php
index a4b16451ba6..99a2bd4e618 100644
--- a/lib/Doctrine/ORM/Cache/DefaultCollectionHydrator.php
+++ b/lib/Doctrine/ORM/Cache/DefaultCollectionHydrator.php
@@ -78,13 +78,13 @@ public function loadCacheEntry(ClassMetadata $metadata, CollectionCacheKey $key,
         $targetRegion = $targetPersister->getCacheRegion();
         $list         = [];
 
+        /** @var EntityCacheEntry[]|null $entityEntries */
         $entityEntries = $targetRegion->getMultiple($entry);
 
         if ($entityEntries === null) {
             return null;
         }
 
-        /** @var EntityCacheEntry[] $entityEntries */
         foreach ($entityEntries as $index => $entityEntry) {
             $list[$index] = $this->uow->createEntity($entityEntry->class, $entityEntry->resolveAssociationEntries($this->em), self::$hints);
         }
diff --git a/lib/Doctrine/ORM/Cache/DefaultQueryCache.php b/lib/Doctrine/ORM/Cache/DefaultQueryCache.php
index f2884b2f29a..8d31931dbac 100644
--- a/lib/Doctrine/ORM/Cache/DefaultQueryCache.php
+++ b/lib/Doctrine/ORM/Cache/DefaultQueryCache.php
@@ -151,7 +151,10 @@ public function get(QueryCacheKey $key, ResultSetMapping $rsm, array $hints = []
                 $assocMetadata = $this->em->getClassMetadata($assoc['targetEntity']);
 
                 if ($assoc['type'] & ClassMetadata::TO_ONE) {
-                    if (($assocEntry = $assocRegion->get($assocKey = new EntityCacheKey($assocMetadata->rootEntityName, $assoc['identifier']))) === null) {
+                    $assocKey   = new EntityCacheKey($assocMetadata->rootEntityName, $assoc['identifier']);
+                    $assocEntry = $assocRegion->get($assocKey);
+
+                    if ($assocEntry === null) {
                         if ($this->cacheLogger !== null) {
                             $this->cacheLogger->entityCacheMiss($assocRegion->getName(), $assocKey);
                         }
@@ -398,7 +401,7 @@ private function storeAssociationCache(QueryCacheKey $key, array $assoc, $assocV
      * @param string $assocAlias
      * @param object $entity
      *
-     * @return array|object
+     * @return array<object>|object
      */
     private function getAssociationValue(ResultSetMapping $rsm, $assocAlias, $entity)
     {
@@ -422,10 +425,10 @@ private function getAssociationValue(ResultSetMapping $rsm, $assocAlias, $entity
     }
 
     /**
-     * @param mixed $value
-     * @param array $path
+     * @param mixed        $value
+     * @param array<mixed> $path
      *
-     * @return array|object|null
+     * @return array<object>|object|null
      */
     private function getAssociationPathValue($value, array $path)
     {
diff --git a/lib/Doctrine/ORM/Cache/EntityCacheEntry.php b/lib/Doctrine/ORM/Cache/EntityCacheEntry.php
index 81b00ff72c2..ac95cb8df7b 100644
--- a/lib/Doctrine/ORM/Cache/EntityCacheEntry.php
+++ b/lib/Doctrine/ORM/Cache/EntityCacheEntry.php
@@ -32,7 +32,7 @@ class EntityCacheEntry implements CacheEntry
     /**
      * READ-ONLY: Public only for performance reasons, it should be considered immutable.
      *
-     * @var array The entity map data
+     * @var array<string,mixed> The entity map data
      */
     public $data;
 
@@ -44,8 +44,8 @@ class EntityCacheEntry implements CacheEntry
     public $class;
 
     /**
-     * @param string $class The entity class.
-     * @param array  $data  The entity data.
+     * @param string              $class The entity class.
+     * @param array<string,mixed> $data  The entity data.
      */
     public function __construct($class, array $data)
     {
@@ -58,7 +58,7 @@ public function __construct($class, array $data)
      *
      * This method allow Doctrine\Common\Cache\PhpFileCache compatibility
      *
-     * @param array $values array containing property values
+     * @param array<string,mixed> $values array containing property values
      *
      * @return EntityCacheEntry
      */
@@ -70,7 +70,7 @@ public static function __set_state(array $values)
     /**
      * Retrieves the entity data resolving cache entries
      *
-     * @return array
+     * @return array<string, mixed>
      */
     public function resolveAssociationEntries(EntityManagerInterface $em)
     {
diff --git a/lib/Doctrine/ORM/Cache/EntityCacheKey.php b/lib/Doctrine/ORM/Cache/EntityCacheKey.php
index ee2d1471f67..e9aef0bfb09 100644
--- a/lib/Doctrine/ORM/Cache/EntityCacheKey.php
+++ b/lib/Doctrine/ORM/Cache/EntityCacheKey.php
@@ -33,7 +33,7 @@ class EntityCacheKey extends CacheKey
     /**
      * READ-ONLY: Public only for performance reasons, it should be considered immutable.
      *
-     * @var array The entity identifier
+     * @var array<string, mixed> The entity identifier
      */
     public $identifier;
 
@@ -45,8 +45,8 @@ class EntityCacheKey extends CacheKey
     public $entityClass;
 
     /**
-     * @param string $entityClass The entity class name. In a inheritance hierarchy it should always be the root entity class.
-     * @param array  $identifier  The entity identifier
+     * @param string               $entityClass The entity class name. In a inheritance hierarchy it should always be the root entity class.
+     * @param array<string, mixed> $identifier  The entity identifier
      */
     public function __construct($entityClass, array $identifier)
     {
diff --git a/lib/Doctrine/ORM/Cache/Logging/StatisticsCacheLogger.php b/lib/Doctrine/ORM/Cache/Logging/StatisticsCacheLogger.php
index 879c3eeb27f..6234063f164 100644
--- a/lib/Doctrine/ORM/Cache/Logging/StatisticsCacheLogger.php
+++ b/lib/Doctrine/ORM/Cache/Logging/StatisticsCacheLogger.php
@@ -167,7 +167,7 @@ public function getRegionPutCount($regionName)
     }
 
     /**
-     * @return array
+     * @return array<string, int>
      */
     public function getRegionsMiss()
     {
@@ -175,7 +175,7 @@ public function getRegionsMiss()
     }
 
     /**
-     * @return array
+     * @return array<string, int>
      */
     public function getRegionsHit()
     {
@@ -183,7 +183,7 @@ public function getRegionsHit()
     }
 
     /**
-     * @return array
+     * @return array<string, int>
      */
     public function getRegionsPut()
     {
diff --git a/lib/Doctrine/ORM/Cache/Persister/Collection/AbstractCollectionPersister.php b/lib/Doctrine/ORM/Cache/Persister/Collection/AbstractCollectionPersister.php
index 941a9b8a2e2..7c43a965470 100644
--- a/lib/Doctrine/ORM/Cache/Persister/Collection/AbstractCollectionPersister.php
+++ b/lib/Doctrine/ORM/Cache/Persister/Collection/AbstractCollectionPersister.php
@@ -128,15 +128,13 @@ public function getTargetEntityMetadata()
      */
     public function loadCollectionCache(PersistentCollection $collection, CollectionCacheKey $key)
     {
-        if (($cache = $this->region->get($key)) === null) {
-            return null;
-        }
+        $cache = $this->region->get($key);
 
-        if (($cache = $this->hydrator->loadCacheEntry($this->sourceEntity, $key, $cache, $collection)) === null) {
+        if ($cache === null) {
             return null;
         }
 
-        return $cache;
+        return $this->hydrator->loadCacheEntry($this->sourceEntity, $key, $cache, $collection);
     }
 
     /**
@@ -144,11 +142,11 @@ public function loadCollectionCache(PersistentCollection $collection, Collection
      */
     public function storeCollectionCache(CollectionCacheKey $key, $elements)
     {
-        /** @var CachedEntityPersister $targetPersister */
         $associationMapping = $this->sourceEntity->associationMappings[$key->association];
         $targetPersister    = $this->uow->getEntityPersister($this->targetEntity->rootEntityName);
-        $targetRegion       = $targetPersister->getCacheRegion();
-        $targetHydrator     = $targetPersister->getEntityHydrator();
+        assert($targetPersister instanceof CachedEntityPersister);
+        $targetRegion   = $targetPersister->getCacheRegion();
+        $targetHydrator = $targetPersister->getEntityHydrator();
 
         // Only preserve ordering if association configured it
         if (! (isset($associationMapping['indexBy']) && $associationMapping['indexBy'])) {
diff --git a/lib/Doctrine/ORM/Cache/Persister/Entity/AbstractEntityPersister.php b/lib/Doctrine/ORM/Cache/Persister/Entity/AbstractEntityPersister.php
index 53d8c7614e9..5e96c309c63 100644
--- a/lib/Doctrine/ORM/Cache/Persister/Entity/AbstractEntityPersister.php
+++ b/lib/Doctrine/ORM/Cache/Persister/Entity/AbstractEntityPersister.php
@@ -84,7 +84,7 @@ abstract class AbstractEntityPersister implements CachedEntityPersister
     /**
      * Associations configured as FETCH_EAGER, as well as all inverse one-to-one associations.
      *
-     * @var array|null
+     * @var array<string>|null
      */
     protected $joinedAssociations;
 
@@ -364,7 +364,9 @@ public function load(array $criteria, $entity = null, $assoc = null, array $hint
             return $result[0];
         }
 
-        if (($result = $this->persister->load($criteria, $entity, $assoc, $hints, $lockMode, $limit, $orderBy)) === null) {
+        $result = $this->persister->load($criteria, $entity, $assoc, $hints, $lockMode, $limit, $orderBy);
+
+        if ($result === null) {
             return null;
         }
 
@@ -617,8 +619,8 @@ public function refresh(array $id, $entity, $lockMode = null)
     }
 
     /**
-     * @param array $association
-     * @param array $ownerId
+     * @param array<string, mixed> $association
+     * @param array<string, mixed> $ownerId
      *
      * @return CollectionCacheKey
      */
diff --git a/lib/Doctrine/ORM/Cache/QueryCache.php b/lib/Doctrine/ORM/Cache/QueryCache.php
index 9a3c6e82701..24dba30f74e 100644
--- a/lib/Doctrine/ORM/Cache/QueryCache.php
+++ b/lib/Doctrine/ORM/Cache/QueryCache.php
@@ -44,7 +44,7 @@ public function put(QueryCacheKey $key, ResultSetMapping $rsm, $result, array $h
     /**
      * @param mixed[] $hints
      *
-     * @return array|null
+     * @return mixed[]|null
      */
     public function get(QueryCacheKey $key, ResultSetMapping $rsm, array $hints = []);
 
diff --git a/lib/Doctrine/ORM/Cache/QueryCacheEntry.php b/lib/Doctrine/ORM/Cache/QueryCacheEntry.php
index cc4c964d6f0..6361cf1a929 100644
--- a/lib/Doctrine/ORM/Cache/QueryCacheEntry.php
+++ b/lib/Doctrine/ORM/Cache/QueryCacheEntry.php
@@ -30,7 +30,7 @@ class QueryCacheEntry implements CacheEntry
     /**
      * READ-ONLY: Public only for performance reasons, it should be considered immutable.
      *
-     * @var array List of entity identifiers
+     * @var array<string, mixed> List of entity identifiers
      */
     public $result;
 
@@ -42,8 +42,8 @@ class QueryCacheEntry implements CacheEntry
     public $time;
 
     /**
-     * @param array $result
-     * @param float $time
+     * @param array<string, mixed> $result
+     * @param float                $time
      */
     public function __construct($result, $time = null)
     {
@@ -52,7 +52,7 @@ public function __construct($result, $time = null)
     }
 
     /**
-     * @param array $values
+     * @param array<string, mixed> $values
      *
      * @return QueryCacheEntry
      */
diff --git a/lib/Doctrine/ORM/Cache/Region/DefaultMultiGetRegion.php b/lib/Doctrine/ORM/Cache/Region/DefaultMultiGetRegion.php
index 61ae0de8733..1ce47f138fd 100644
--- a/lib/Doctrine/ORM/Cache/Region/DefaultMultiGetRegion.php
+++ b/lib/Doctrine/ORM/Cache/Region/DefaultMultiGetRegion.php
@@ -25,6 +25,7 @@
 use Doctrine\ORM\Cache\CacheEntry;
 use Doctrine\ORM\Cache\CollectionCacheEntry;
 
+use function assert;
 use function count;
 
 /**
@@ -47,7 +48,7 @@ class DefaultMultiGetRegion extends DefaultRegion
      */
     public function __construct($name, MultiGetCache $cache, $lifetime = 0)
     {
-        /** @var Cache $cache */
+        assert($cache instanceof Cache);
         parent::__construct($name, $cache, $lifetime);
     }
 
diff --git a/lib/Doctrine/ORM/Cache/TimestampCacheEntry.php b/lib/Doctrine/ORM/Cache/TimestampCacheEntry.php
index f803429fe17..a399f248865 100644
--- a/lib/Doctrine/ORM/Cache/TimestampCacheEntry.php
+++ b/lib/Doctrine/ORM/Cache/TimestampCacheEntry.php
@@ -47,7 +47,7 @@ public function __construct($time = null)
      *
      * This method allow Doctrine\Common\Cache\PhpFileCache compatibility
      *
-     * @param array $values array containing property values
+     * @param array<string,float> $values array containing property values
      *
      * @return TimestampCacheEntry
      */
diff --git a/lib/Doctrine/ORM/EntityManager.php b/lib/Doctrine/ORM/EntityManager.php
index 81da7f6957b..70bbab82994 100644
--- a/lib/Doctrine/ORM/EntityManager.php
+++ b/lib/Doctrine/ORM/EntityManager.php
@@ -441,8 +441,10 @@ public function find($className, $id, $lockMode = null, $lockVersion = null)
 
         $unitOfWork = $this->getUnitOfWork();
 
+        $entity = $unitOfWork->tryGetById($sortedId, $class->rootEntityName);
+
         // Check identity map first
-        if (($entity = $unitOfWork->tryGetById($sortedId, $class->rootEntityName)) !== false) {
+        if ($entity !== false) {
             if (! ($entity instanceof $class->name)) {
                 return null;
             }
@@ -508,8 +510,10 @@ public function getReference($entityName, $id)
             throw ORMException::unrecognizedIdentifierFields($class->name, array_keys($id));
         }
 
+        $entity = $this->unitOfWork->tryGetById($sortedId, $class->rootEntityName);
+
         // Check identity map first, if its already in there just return it.
-        if (($entity = $this->unitOfWork->tryGetById($sortedId, $class->rootEntityName)) !== false) {
+        if ($entity !== false) {
             return $entity instanceof $class->name ? $entity : null;
         }
 
@@ -531,8 +535,10 @@ public function getPartialReference($entityName, $identifier)
     {
         $class = $this->metadataFactory->getMetadataFor(ltrim($entityName, '\\'));
 
+        $entity = $this->unitOfWork->tryGetById($identifier, $class->rootEntityName);
+
         // Check identity map first, if its already in there just return it.
-        if (($entity = $this->unitOfWork->tryGetById($identifier, $class->rootEntityName)) !== false) {
+        if ($entity !== false) {
             return $entity instanceof $class->name ? $entity : null;
         }
 
@@ -842,7 +848,9 @@ public function newHydrator($hydrationMode)
                 return new Internal\Hydration\SimpleObjectHydrator($this);
 
             default:
-                if (($class = $this->config->getCustomHydrationMode($hydrationMode)) !== null) {
+                $class = $this->config->getCustomHydrationMode($hydrationMode);
+
+                if ($class !== null) {
                     return new $class($this);
                 }
         }
@@ -869,9 +877,9 @@ public function initializeObject($obj)
     /**
      * Factory method to create EntityManager instances.
      *
-     * @param array|Connection $connection   An array with the connection parameters or an existing Connection instance.
-     * @param Configuration    $config       The Configuration instance to use.
-     * @param EventManager     $eventManager The EventManager instance to use.
+     * @param array<string, mixed>|Connection $connection   An array with the connection parameters or an existing Connection instance.
+     * @param Configuration                   $config       The Configuration instance to use.
+     * @param EventManager                    $eventManager The EventManager instance to use.
      *
      * @return EntityManager The created EntityManager.
      *
@@ -892,9 +900,9 @@ public static function create($connection, Configuration $config, ?EventManager
     /**
      * Factory method to create Connection instances.
      *
-     * @param array|Connection $connection   An array with the connection parameters or an existing Connection instance.
-     * @param Configuration    $config       The Configuration instance to use.
-     * @param EventManager     $eventManager The EventManager instance to use.
+     * @param array<string, mixed>|Connection $connection   An array with the connection parameters or an existing Connection instance.
+     * @param Configuration                   $config       The Configuration instance to use.
+     * @param EventManager                    $eventManager The EventManager instance to use.
      *
      * @return Connection
      *
diff --git a/lib/Doctrine/ORM/Event/PreUpdateEventArgs.php b/lib/Doctrine/ORM/Event/PreUpdateEventArgs.php
index ca0a116e0f8..0f08dec473f 100644
--- a/lib/Doctrine/ORM/Event/PreUpdateEventArgs.php
+++ b/lib/Doctrine/ORM/Event/PreUpdateEventArgs.php
@@ -48,7 +48,7 @@ public function __construct($entity, EntityManagerInterface $em, array &$changeS
     /**
      * Retrieves entity changeset.
      *
-     * @return array
+     * @return array<string,array<int,mixed>>
      */
     public function getEntityChangeSet()
     {
diff --git a/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php b/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php
index db769f3a09f..589a3a08776 100644
--- a/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php
+++ b/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php
@@ -59,7 +59,7 @@ class CommitOrderCalculator
     /**
      * Volatile variable holding calculated nodes during sorting process.
      *
-     * @var array
+     * @psalm-var list<object>
      */
     private $sortedNodeList = [];
 
@@ -122,7 +122,7 @@ public function addDependency($fromHash, $toHash, $weight)
      *
      * {@internal Highly performance-sensitive method.}
      *
-     * @return array
+     * @psalm-return list<object>
      */
     public function sort()
     {
diff --git a/lib/Doctrine/ORM/NativeQuery.php b/lib/Doctrine/ORM/NativeQuery.php
index 7ee571a57c7..d39f4a6890a 100644
--- a/lib/Doctrine/ORM/NativeQuery.php
+++ b/lib/Doctrine/ORM/NativeQuery.php
@@ -31,7 +31,7 @@
 final class NativeQuery extends AbstractQuery
 {
     /** @var string */
-    private $_sql;
+    private $sql;
 
     /**
      * Sets the SQL of the query.
@@ -42,7 +42,7 @@ final class NativeQuery extends AbstractQuery
      */
     public function setSQL($sql): self
     {
-        $this->_sql = $sql;
+        $this->sql = $sql;
 
         return $this;
     }
@@ -56,7 +56,7 @@ public function setSQL($sql): self
      */
     public function getSQL()
     {
-        return $this->_sql;
+        return $this->sql;
     }
 
     /**
@@ -87,7 +87,7 @@ protected function _doExecute()
         }
 
         return $this->_em->getConnection()->executeQuery(
-            $this->_sql,
+            $this->sql,
             $parameters,
             $types,
             $this->_queryCacheProfile
diff --git a/lib/Doctrine/ORM/Query.php b/lib/Doctrine/ORM/Query.php
index 7f5ad59bc07..a26861da8b8 100644
--- a/lib/Doctrine/ORM/Query.php
+++ b/lib/Doctrine/ORM/Query.php
@@ -23,6 +23,7 @@
 use Doctrine\Common\Cache\Cache;
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\DBAL\LockMode;
+use Doctrine\DBAL\Types\Type;
 use Doctrine\ORM\Internal\Hydration\IterableResult;
 use Doctrine\ORM\Mapping\ClassMetadata;
 use Doctrine\ORM\Query\AST\DeleteStatement;
@@ -126,65 +127,65 @@ final class Query extends AbstractQuery
     /**
      * A snapshot of the parameter types the query was parsed with.
      *
-     * @var array
+     * @var array<string,Type>
      */
-    private $_parsedTypes = [];
+    private $parsedTypes = [];
 
     /**
      * Cached DQL query.
      *
      * @var string|null
      */
-    private $_dql = null;
+    private $dql = null;
 
     /**
      * The parser result that holds DQL => SQL information.
      *
      * @var ParserResult
      */
-    private $_parserResult;
+    private $parserResult;
 
     /**
      * The first result to return (the "offset").
      *
      * @var int|null
      */
-    private $_firstResult = null;
+    private $firstResult = null;
 
     /**
      * The maximum number of results to return (the "limit").
      *
      * @var int|null
      */
-    private $_maxResults = null;
+    private $maxResults = null;
 
     /**
      * The cache driver used for caching queries.
      *
      * @var Cache|null
      */
-    private $_queryCache;
+    private $queryCache;
 
     /**
      * Whether or not expire the query cache.
      *
      * @var bool
      */
-    private $_expireQueryCache = false;
+    private $expireQueryCache = false;
 
     /**
      * The query cache lifetime.
      *
      * @var int
      */
-    private $_queryCacheTTL;
+    private $queryCacheTTL;
 
     /**
      * Whether to use a query cache, if available. Defaults to TRUE.
      *
      * @var bool
      */
-    private $_useQueryCache = true;
+    private $useQueryCache = true;
 
     /**
      * Gets the SQL query/queries that correspond to this DQL query.
@@ -195,7 +196,7 @@ final class Query extends AbstractQuery
      */
     public function getSQL()
     {
-        return $this->_parse()->getSqlExecutor()->getSqlStatements();
+        return $this->parse()->getSqlExecutor()->getSqlStatements();
     }
 
     /**
@@ -217,7 +218,7 @@ protected function getResultSetMapping()
     {
         // parse query or load from cache
         if ($this->_resultSetMapping === null) {
-            $this->_resultSetMapping = $this->_parse()->getResultSetMapping();
+            $this->_resultSetMapping = $this->parse()->getResultSetMapping();
         }
 
         return $this->_resultSetMapping;
@@ -230,7 +231,7 @@ protected function getResultSetMapping()
      *
      * @return ParserResult
      */
-    private function _parse()
+    private function parse()
     {
         $types = [];
 
@@ -240,41 +241,41 @@ private function _parse()
         }
 
         // Return previous parser result if the query and the filter collection are both clean
-        if ($this->_state === self::STATE_CLEAN && $this->_parsedTypes === $types && $this->_em->isFiltersStateClean()) {
-            return $this->_parserResult;
+        if ($this->_state === self::STATE_CLEAN && $this->parsedTypes === $types && $this->_em->isFiltersStateClean()) {
+            return $this->parserResult;
         }
 
-        $this->_state       = self::STATE_CLEAN;
-        $this->_parsedTypes = $types;
+        $this->_state      = self::STATE_CLEAN;
+        $this->parsedTypes = $types;
 
         $queryCache = $this->getQueryCacheDriver();
         // Check query cache.
-        if (! ($this->_useQueryCache && $queryCache)) {
+        if (! ($this->useQueryCache && $queryCache)) {
             $parser = new Parser($this);
 
-            $this->_parserResult = $parser->parse();
+            $this->parserResult = $parser->parse();
 
-            return $this->_parserResult;
+            return $this->parserResult;
         }
 
         $hash   = $this->_getQueryCacheId();
-        $cached = $this->_expireQueryCache ? false : $queryCache->fetch($hash);
+        $cached = $this->expireQueryCache ? false : $queryCache->fetch($hash);
 
         if ($cached instanceof ParserResult) {
             // Cache hit.
-            $this->_parserResult = $cached;
+            $this->parserResult = $cached;
 
-            return $this->_parserResult;
+            return $this->parserResult;
         }
 
         // Cache miss.
         $parser = new Parser($this);
 
-        $this->_parserResult = $parser->parse();
+        $this->parserResult = $parser->parse();
 
-        $queryCache->save($hash, $this->_parserResult, $this->_queryCacheTTL);
+        $queryCache->save($hash, $this->parserResult, $this->queryCacheTTL);
 
-        return $this->_parserResult;
+        return $this->parserResult;
     }
 
     /**
@@ -282,7 +283,7 @@ private function _parse()
      */
     protected function _doExecute()
     {
-        $executor = $this->_parse()->getSqlExecutor();
+        $executor = $this->parse()->getSqlExecutor();
 
         if ($this->_queryCacheProfile) {
             $executor->setQueryCacheProfile($this->_queryCacheProfile);
@@ -291,11 +292,11 @@ protected function _doExecute()
         }
 
         if ($this->_resultSetMapping === null) {
-            $this->_resultSetMapping = $this->_parserResult->getResultSetMapping();
+            $this->_resultSetMapping = $this->parserResult->getResultSetMapping();
         }
 
         // Prepare parameters
-        $paramMappings = $this->_parserResult->getParameterMappings();
+        $paramMappings = $this->parserResult->getParameterMappings();
         $paramCount    = count($this->parameters);
         $mappingCount  = count($paramMappings);
 
@@ -324,6 +325,11 @@ protected function _doExecute()
         return $executor->execute($this->_em->getConnection(), $sqlParams, $types);
     }
 
+    /**
+     * @param array<string,mixed> $sqlParams
+     * @param array<string,Type>  $types
+     * @param array<string,mixed> $connectionParams
+     */
     private function evictResultSetCache(
         AbstractSqlExecutor $executor,
         array $sqlParams,
@@ -365,7 +371,7 @@ private function evictEntityCacheRegion()
     /**
      * Processes query parameter mappings.
      *
-     * @param array $paramMappings
+     * @param Parameter[] $paramMappings
      *
      * @return mixed[][]
      *
@@ -373,7 +379,7 @@ private function evictEntityCacheRegion()
      *
      * @psalm-return array{0: list<mixed>, 1: array}
      */
-    private function processParameterMappings($paramMappings): array
+    private function processParameterMappings(array $paramMappings): array
     {
         $sqlParams = [];
         $types     = [];
@@ -463,7 +469,7 @@ private function resolveParameterValue(Parameter $parameter): array
      */
     public function setQueryCacheDriver($queryCache): self
     {
-        $this->_queryCache = $queryCache;
+        $this->queryCache = $queryCache;
 
         return $this;
     }
@@ -477,7 +483,7 @@ public function setQueryCacheDriver($queryCache): self
      */
     public function useQueryCache($bool): self
     {
-        $this->_useQueryCache = $bool;
+        $this->useQueryCache = $bool;
 
         return $this;
     }
@@ -490,8 +496,8 @@ public function useQueryCache($bool): self
      */
     public function getQueryCacheDriver()
     {
-        if ($this->_queryCache) {
-            return $this->_queryCache;
+        if ($this->queryCache) {
+            return $this->queryCache;
         }
 
         return $this->_em->getConfiguration()->getQueryCacheImpl();
@@ -510,7 +516,7 @@ public function setQueryCacheLifetime($timeToLive): self
             $timeToLive = (int) $timeToLive;
         }
 
-        $this->_queryCacheTTL = $timeToLive;
+        $this->queryCacheTTL = $timeToLive;
 
         return $this;
     }
@@ -522,7 +528,7 @@ public function setQueryCacheLifetime($timeToLive): self
      */
     public function getQueryCacheLifetime()
     {
-        return $this->_queryCacheTTL;
+        return $this->queryCacheTTL;
     }
 
     /**
@@ -534,7 +540,7 @@ public function getQueryCacheLifetime()
      */
     public function expireQueryCache($expire = true): self
     {
-        $this->_expireQueryCache = $expire;
+        $this->expireQueryCache = $expire;
 
         return $this;
     }
@@ -546,7 +552,7 @@ public function expireQueryCache($expire = true): self
      */
     public function getExpireQueryCache()
     {
-        return $this->_expireQueryCache;
+        return $this->expireQueryCache;
     }
 
     /**
@@ -556,7 +562,7 @@ public function free()
     {
         parent::free();
 
-        $this->_dql   = null;
+        $this->dql    = null;
         $this->_state = self::STATE_CLEAN;
     }
 
@@ -568,7 +574,7 @@ public function free()
     public function setDQL($dqlQuery): self
     {
         if ($dqlQuery !== null) {
-            $this->_dql   = $dqlQuery;
+            $this->dql    = $dqlQuery;
             $this->_state = self::STATE_DIRTY;
         }
 
@@ -582,7 +588,7 @@ public function setDQL($dqlQuery): self
      */
     public function getDQL()
     {
-        return $this->_dql;
+        return $this->dql;
     }
 
     /**
@@ -621,8 +627,8 @@ public function contains($dql)
      */
     public function setFirstResult($firstResult): self
     {
-        $this->_firstResult = $firstResult;
-        $this->_state       = self::STATE_DIRTY;
+        $this->firstResult = $firstResult;
+        $this->_state      = self::STATE_DIRTY;
 
         return $this;
     }
@@ -635,7 +641,7 @@ public function setFirstResult($firstResult): self
      */
     public function getFirstResult()
     {
-        return $this->_firstResult;
+        return $this->firstResult;
     }
 
     /**
@@ -647,8 +653,8 @@ public function getFirstResult()
      */
     public function setMaxResults($maxResults): self
     {
-        $this->_maxResults = $maxResults;
-        $this->_state      = self::STATE_DIRTY;
+        $this->maxResults = $maxResults;
+        $this->_state     = self::STATE_DIRTY;
 
         return $this;
     }
@@ -661,15 +667,15 @@ public function setMaxResults($maxResults): self
      */
     public function getMaxResults()
     {
-        return $this->_maxResults;
+        return $this->maxResults;
     }
 
     /**
      * Executes the query and returns an IterableResult that can be used to incrementally
      * iterated over the result.
      *
-     * @param ArrayCollection|array|null $parameters    The query parameters.
-     * @param string|int                 $hydrationMode The hydration mode to use.
+     * @param ArrayCollection|mixed[]|null $parameters    The query parameters.
+     * @param string|int                   $hydrationMode The hydration mode to use.
      *
      * @return IterableResult
      */
@@ -764,8 +770,8 @@ protected function _getQueryCacheId()
             $this->getDQL() . serialize($this->_hints) .
             '&platform=' . $platform .
             ($this->_em->hasFilters() ? $this->_em->getFilters()->getHash() : '') .
-            '&firstResult=' . $this->_firstResult . '&maxResult=' . $this->_maxResults .
-            '&hydrationMode=' . $this->_hydrationMode . '&types=' . serialize($this->_parsedTypes) . 'DOCTRINE_QUERY_CACHE_SALT'
+            '&firstResult=' . $this->firstResult . '&maxResult=' . $this->maxResults .
+            '&hydrationMode=' . $this->_hydrationMode . '&types=' . serialize($this->parsedTypes) . 'DOCTRINE_QUERY_CACHE_SALT'
         );
     }
 
@@ -774,7 +780,7 @@ protected function _getQueryCacheId()
       */
     protected function getHash()
     {
-        return sha1(parent::getHash() . '-' . $this->_firstResult . '-' . $this->_maxResults);
+        return sha1(parent::getHash() . '-' . $this->firstResult . '-' . $this->maxResults);
     }
 
     /**
diff --git a/lib/Doctrine/ORM/Query/TreeWalker.php b/lib/Doctrine/ORM/Query/TreeWalker.php
index a8ab903912f..8cc8521fdf0 100644
--- a/lib/Doctrine/ORM/Query/TreeWalker.php
+++ b/lib/Doctrine/ORM/Query/TreeWalker.php
@@ -39,15 +39,17 @@ public function __construct($query, $parserResult, array $queryComponents);
     /**
      * Returns internal queryComponents array.
      *
-     * @return array
+     * @return array<string, array<string, mixed>>
+     *
+     * @psalm-var array<string, array{metadata: ClassMetadata, token: array, relation: mixed[], parent: string}>
      */
     public function getQueryComponents();
 
     /**
      * Sets or overrides a query component for a given dql alias.
      *
-     * @param string $dqlAlias       The DQL alias.
-     * @param array  $queryComponent
+     * @param string               $dqlAlias       The DQL alias.
+     * @param array<string, mixed> $queryComponent
      *
      * @return void
      */
@@ -58,7 +60,7 @@ public function setQueryComponent($dqlAlias, array $queryComponent);
      *
      * @return string The SQL.
      */
-    function walkSelectStatement(AST\SelectStatement $AST);
+    public function walkSelectStatement(AST\SelectStatement $AST);
 
     /**
      * Walks down a SelectClause AST node, thereby generating the appropriate SQL.
@@ -67,7 +69,7 @@ function walkSelectStatement(AST\SelectStatement $AST);
      *
      * @return string The SQL.
      */
-    function walkSelectClause($selectClause);
+    public function walkSelectClause($selectClause);
 
     /**
      * Walks down a FromClause AST node, thereby generating the appropriate SQL.
@@ -76,7 +78,7 @@ function walkSelectClause($selectClause);
      *
      * @return string The SQL.
      */
-    function walkFromClause($fromClause);
+    public function walkFromClause($fromClause);
 
     /**
      * Walks down a FunctionNode AST node, thereby generating the appropriate SQL.
@@ -85,7 +87,7 @@ function walkFromClause($fromClause);
      *
      * @return string The SQL.
      */
-    function walkFunction($function);
+    public function walkFunction($function);
 
     /**
      * Walks down an OrderByClause AST node, thereby generating the appropriate SQL.
@@ -94,7 +96,7 @@ function walkFunction($function);
      *
      * @return string The SQL.
      */
-    function walkOrderByClause($orderByClause);
+    public function walkOrderByClause($orderByClause);
 
     /**
      * Walks down an OrderByItem AST node, thereby generating the appropriate SQL.
@@ -103,7 +105,7 @@ function walkOrderByClause($orderByClause);
      *
      * @return string The SQL.
      */
-    function walkOrderByItem($orderByItem);
+    public function walkOrderByItem($orderByItem);
 
     /**
      * Walks down a HavingClause AST node, thereby generating the appropriate SQL.
@@ -112,7 +114,7 @@ function walkOrderByItem($orderByItem);
      *
      * @return string The SQL.
      */
-    function walkHavingClause($havingClause);
+    public function walkHavingClause($havingClause);
 
     /**
      * Walks down a Join AST node and creates the corresponding SQL.
@@ -121,7 +123,7 @@ function walkHavingClause($havingClause);
      *
      * @return string The SQL.
      */
-    function walkJoin($join);
+    public function walkJoin($join);
 
     /**
      * Walks down a SelectExpression AST node and generates the corresponding SQL.
@@ -130,7 +132,7 @@ function walkJoin($join);
      *
      * @return string The SQL.
      */
-    function walkSelectExpression($selectExpression);
+    public function walkSelectExpression($selectExpression);
 
     /**
      * Walks down a QuantifiedExpression AST node, thereby generating the appropriate SQL.
@@ -139,7 +141,7 @@ function walkSelectExpression($selectExpression);
      *
      * @return string The SQL.
      */
-    function walkQuantifiedExpression($qExpr);
+    public function walkQuantifiedExpression($qExpr);
 
     /**
      * Walks down a Subselect AST node, thereby generating the appropriate SQL.
@@ -148,7 +150,7 @@ function walkQuantifiedExpression($qExpr);
      *
      * @return string The SQL.
      */
-    function walkSubselect($subselect);
+    public function walkSubselect($subselect);
 
     /**
      * Walks down a SubselectFromClause AST node, thereby generating the appropriate SQL.
@@ -157,7 +159,7 @@ function walkSubselect($subselect);
      *
      * @return string The SQL.
      */
-    function walkSubselectFromClause($subselectFromClause);
+    public function walkSubselectFromClause($subselectFromClause);
 
     /**
      * Walks down a SimpleSelectClause AST node, thereby generating the appropriate SQL.
@@ -166,7 +168,7 @@ function walkSubselectFromClause($subselectFromClause);
      *
      * @return string The SQL.
      */
-    function walkSimpleSelectClause($simpleSelectClause);
+    public function walkSimpleSelectClause($simpleSelectClause);
 
     /**
      * Walks down a SimpleSelectExpression AST node, thereby generating the appropriate SQL.
@@ -175,7 +177,7 @@ function walkSimpleSelectClause($simpleSelectClause);
      *
      * @return string The SQL.
      */
-    function walkSimpleSelectExpression($simpleSelectExpression);
+    public function walkSimpleSelectExpression($simpleSelectExpression);
 
     /**
      * Walks down an AggregateExpression AST node, thereby generating the appropriate SQL.
@@ -184,7 +186,7 @@ function walkSimpleSelectExpression($simpleSelectExpression);
      *
      * @return string The SQL.
      */
-    function walkAggregateExpression($aggExpression);
+    public function walkAggregateExpression($aggExpression);
 
     /**
      * Walks down a GroupByClause AST node, thereby generating the appropriate SQL.
@@ -193,7 +195,7 @@ function walkAggregateExpression($aggExpression);
      *
      * @return string The SQL.
      */
-    function walkGroupByClause($groupByClause);
+    public function walkGroupByClause($groupByClause);
 
     /**
      * Walks down a GroupByItem AST node, thereby generating the appropriate SQL.
@@ -202,28 +204,28 @@ function walkGroupByClause($groupByClause);
      *
      * @return string The SQL.
      */
-    function walkGroupByItem($groupByItem);
+    public function walkGroupByItem($groupByItem);
 
     /**
      * Walks down an UpdateStatement AST node, thereby generating the appropriate SQL.
      *
      * @return string The SQL.
      */
-    function walkUpdateStatement(AST\UpdateStatement $AST);
+    public function walkUpdateStatement(AST\UpdateStatement $AST);
 
     /**
      * Walks down a DeleteStatement AST node, thereby generating the appropriate SQL.
      *
      * @return string The SQL.
      */
-    function walkDeleteStatement(AST\DeleteStatement $AST);
+    public function walkDeleteStatement(AST\DeleteStatement $AST);
 
     /**
      * Walks down a DeleteClause AST node, thereby generating the appropriate SQL.
      *
      * @return string The SQL.
      */
-    function walkDeleteClause(AST\DeleteClause $deleteClause);
+    public function walkDeleteClause(AST\DeleteClause $deleteClause);
 
     /**
      * Walks down an UpdateClause AST node, thereby generating the appropriate SQL.
@@ -232,7 +234,7 @@ function walkDeleteClause(AST\DeleteClause $deleteClause);
      *
      * @return string The SQL.
      */
-    function walkUpdateClause($updateClause);
+    public function walkUpdateClause($updateClause);
 
     /**
      * Walks down an UpdateItem AST node, thereby generating the appropriate SQL.
@@ -241,7 +243,7 @@ function walkUpdateClause($updateClause);
      *
      * @return string The SQL.
      */
-    function walkUpdateItem($updateItem);
+    public function walkUpdateItem($updateItem);
 
     /**
      * Walks down a WhereClause AST node, thereby generating the appropriate SQL.
@@ -251,7 +253,7 @@ function walkUpdateItem($updateItem);
      *
      * @return string The SQL.
      */
-    function walkWhereClause($whereClause);
+    public function walkWhereClause($whereClause);
 
     /**
      * Walk down a ConditionalExpression AST node, thereby generating the appropriate SQL.
@@ -260,7 +262,7 @@ function walkWhereClause($whereClause);
      *
      * @return string The SQL.
      */
-    function walkConditionalExpression($condExpr);
+    public function walkConditionalExpression($condExpr);
 
     /**
      * Walks down a ConditionalTerm AST node, thereby generating the appropriate SQL.
@@ -269,7 +271,7 @@ function walkConditionalExpression($condExpr);
      *
      * @return string The SQL.
      */
-    function walkConditionalTerm($condTerm);
+    public function walkConditionalTerm($condTerm);
 
     /**
      * Walks down a ConditionalFactor AST node, thereby generating the appropriate SQL.
@@ -278,7 +280,7 @@ function walkConditionalTerm($condTerm);
      *
      * @return string The SQL.
      */
-    function walkConditionalFactor($factor);
+    public function walkConditionalFactor($factor);
 
     /**
      * Walks down a ConditionalPrimary AST node, thereby generating the appropriate SQL.
@@ -287,7 +289,7 @@ function walkConditionalFactor($factor);
      *
      * @return string The SQL.
      */
-    function walkConditionalPrimary($primary);
+    public function walkConditionalPrimary($primary);
 
     /**
      * Walks down an ExistsExpression AST node, thereby generating the appropriate SQL.
@@ -296,7 +298,7 @@ function walkConditionalPrimary($primary);
      *
      * @return string The SQL.
      */
-    function walkExistsExpression($existsExpr);
+    public function walkExistsExpression($existsExpr);
 
     /**
      * Walks down a CollectionMemberExpression AST node, thereby generating the appropriate SQL.
@@ -305,7 +307,7 @@ function walkExistsExpression($existsExpr);
      *
      * @return string The SQL.
      */
-    function walkCollectionMemberExpression($collMemberExpr);
+    public function walkCollectionMemberExpression($collMemberExpr);
 
     /**
      * Walks down an EmptyCollectionComparisonExpression AST node, thereby generating the appropriate SQL.
@@ -314,7 +316,7 @@ function walkCollectionMemberExpression($collMemberExpr);
      *
      * @return string The SQL.
      */
-    function walkEmptyCollectionComparisonExpression($emptyCollCompExpr);
+    public function walkEmptyCollectionComparisonExpression($emptyCollCompExpr);
 
     /**
      * Walks down a NullComparisonExpression AST node, thereby generating the appropriate SQL.
@@ -323,7 +325,7 @@ function walkEmptyCollectionComparisonExpression($emptyCollCompExpr);
      *
      * @return string The SQL.
      */
-    function walkNullComparisonExpression($nullCompExpr);
+    public function walkNullComparisonExpression($nullCompExpr);
 
     /**
      * Walks down an InExpression AST node, thereby generating the appropriate SQL.
@@ -332,7 +334,7 @@ function walkNullComparisonExpression($nullCompExpr);
      *
      * @return string The SQL.
      */
-    function walkInExpression($inExpr);
+    public function walkInExpression($inExpr);
 
     /**
      * Walks down an InstanceOfExpression AST node, thereby generating the appropriate SQL.
@@ -341,7 +343,7 @@ function walkInExpression($inExpr);
      *
      * @return string The SQL.
      */
-    function walkInstanceOfExpression($instanceOfExpr);
+    public function walkInstanceOfExpression($instanceOfExpr);
 
     /**
      * Walks down a literal that represents an AST node, thereby generating the appropriate SQL.
@@ -350,7 +352,7 @@ function walkInstanceOfExpression($instanceOfExpr);
      *
      * @return string The SQL.
      */
-    function walkLiteral($literal);
+    public function walkLiteral($literal);
 
     /**
      * Walks down a BetweenExpression AST node, thereby generating the appropriate SQL.
@@ -359,7 +361,7 @@ function walkLiteral($literal);
      *
      * @return string The SQL.
      */
-    function walkBetweenExpression($betweenExpr);
+    public function walkBetweenExpression($betweenExpr);
 
     /**
      * Walks down a LikeExpression AST node, thereby generating the appropriate SQL.
@@ -368,7 +370,7 @@ function walkBetweenExpression($betweenExpr);
      *
      * @return string The SQL.
      */
-    function walkLikeExpression($likeExpr);
+    public function walkLikeExpression($likeExpr);
 
     /**
      * Walks down a StateFieldPathExpression AST node, thereby generating the appropriate SQL.
@@ -377,7 +379,7 @@ function walkLikeExpression($likeExpr);
      *
      * @return string The SQL.
      */
-    function walkStateFieldPathExpression($stateFieldPathExpression);
+    public function walkStateFieldPathExpression($stateFieldPathExpression);
 
     /**
      * Walks down a ComparisonExpression AST node, thereby generating the appropriate SQL.
@@ -386,7 +388,7 @@ function walkStateFieldPathExpression($stateFieldPathExpression);
      *
      * @return string The SQL.
      */
-    function walkComparisonExpression($compExpr);
+    public function walkComparisonExpression($compExpr);
 
     /**
      * Walks down an InputParameter AST node, thereby generating the appropriate SQL.
@@ -395,7 +397,7 @@ function walkComparisonExpression($compExpr);
      *
      * @return string The SQL.
      */
-    function walkInputParameter($inputParam);
+    public function walkInputParameter($inputParam);
 
     /**
      * Walks down an ArithmeticExpression AST node, thereby generating the appropriate SQL.
@@ -404,7 +406,7 @@ function walkInputParameter($inputParam);
      *
      * @return string The SQL.
      */
-    function walkArithmeticExpression($arithmeticExpr);
+    public function walkArithmeticExpression($arithmeticExpr);
 
     /**
      * Walks down an ArithmeticTerm AST node, thereby generating the appropriate SQL.
@@ -413,7 +415,7 @@ function walkArithmeticExpression($arithmeticExpr);
      *
      * @return string The SQL.
      */
-    function walkArithmeticTerm($term);
+    public function walkArithmeticTerm($term);
 
     /**
      * Walks down a StringPrimary that represents an AST node, thereby generating the appropriate SQL.
@@ -422,7 +424,7 @@ function walkArithmeticTerm($term);
      *
      * @return string The SQL.
      */
-    function walkStringPrimary($stringPrimary);
+    public function walkStringPrimary($stringPrimary);
 
     /**
      * Walks down an ArithmeticFactor that represents an AST node, thereby generating the appropriate SQL.
@@ -431,7 +433,7 @@ function walkStringPrimary($stringPrimary);
      *
      * @return string The SQL.
      */
-    function walkArithmeticFactor($factor);
+    public function walkArithmeticFactor($factor);
 
     /**
      * Walks down an SimpleArithmeticExpression AST node, thereby generating the appropriate SQL.
@@ -440,7 +442,7 @@ function walkArithmeticFactor($factor);
      *
      * @return string The SQL.
      */
-    function walkSimpleArithmeticExpression($simpleArithmeticExpr);
+    public function walkSimpleArithmeticExpression($simpleArithmeticExpr);
 
     /**
      * Walks down a PathExpression AST node, thereby generating the appropriate SQL.
@@ -449,7 +451,7 @@ function walkSimpleArithmeticExpression($simpleArithmeticExpr);
      *
      * @return string The SQL.
      */
-    function walkPathExpression($pathExpr);
+    public function walkPathExpression($pathExpr);
 
     /**
      * Walks down a ResultVariable that represents an AST node, thereby generating the appropriate SQL.
@@ -458,7 +460,7 @@ function walkPathExpression($pathExpr);
      *
      * @return string The SQL.
      */
-    function walkResultVariable($resultVariable);
+    public function walkResultVariable($resultVariable);
 
     /**
      * Gets an executor that can be used to execute the result of this walker.
@@ -467,5 +469,5 @@ function walkResultVariable($resultVariable);
      *
      * @return Exec\AbstractSqlExecutor
      */
-    function getExecutor($AST);
+    public function getExecutor($AST);
 }
diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index 4fbe3636f71..7d9486e1ed5 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -1255,17 +1255,12 @@ private function executeDeletions($class)
     /**
      * Gets the commit order.
      *
-     * @param array|null $entityChangeSet
-     *
-     * @return array
+     * @return list<object>
      */
-    private function getCommitOrder(?array $entityChangeSet = null)
+    private function getCommitOrder(): array
     {
-        if ($entityChangeSet === null) {
-            $entityChangeSet = array_merge($this->entityInsertions, $this->entityUpdates, $this->entityDeletions);
-        }
-
-        $calc = $this->getCommitOrderCalculator();
+        $entityChangeSet = array_merge($this->entityInsertions, $this->entityUpdates, $this->entityDeletions);
+        $calc            = $this->getCommitOrderCalculator();
 
         // See if there are any new classes in the changeset, that are not in the
         // commit order graph yet (don't have a node).