From 32e3a5a302a30c8349bd493cfbc6849a49611e83 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gr=C3=A9goire=20Paris?= <postmaster@greg0ire.fr>
Date: Sun, 18 Apr 2021 19:01:57 +0200
Subject: [PATCH] Add type declarations where backwards-compatible

This includes:
- private methods
- return type declarations of final protected methods
- return type declarations of public and protected methods of final classes

Parameter type declarations are a more delicate matter and should
probably be handled separately to make it easier to catch issues during
code review.

Type declarations can be more trusted than simple phpdoc when it
comes to static analysis, having them means we can infer the phpdoc of
calling methods with confidence.

Note that it seems that some of the phpdoc I initially inferred these
declarations from were apparently wrong, in particular some mentioning
Doctrine\Dbal\Statement when was is really passed around is
Doctrine\Dbal\Driver\Statement.
---
 lib/Doctrine/ORM/AbstractQuery.php            |  9 +-
 lib/Doctrine/ORM/Cache/DefaultCache.php       | 15 ++-
 .../ORM/Cache/DefaultCacheFactory.php         |  7 +-
 lib/Doctrine/ORM/Cache/DefaultQueryCache.php  | 10 +-
 .../Entity/AbstractEntityPersister.php        |  4 +-
 ...onStrictReadWriteCachedEntityPersister.php |  7 +-
 .../ORM/Cache/Region/FileLockRegion.php       | 22 ++---
 .../Cache/TimestampQueryCacheValidator.php    |  5 +-
 lib/Doctrine/ORM/EntityManager.php            |  4 +-
 lib/Doctrine/ORM/Event/PreUpdateEventArgs.php |  6 +-
 .../ORM/Internal/CommitOrderCalculator.php    |  6 +-
 .../ORM/Internal/Hydration/ArrayHydrator.php  | 17 ++--
 .../ORM/Internal/Hydration/ObjectHydrator.php | 27 +++---
 .../ORM/Internal/HydrationCompleteHandler.php |  8 +-
 .../ORM/Mapping/ClassMetadataFactory.php      | 67 ++++---------
 .../ORM/Mapping/ClassMetadataInfo.php         |  6 +-
 .../ORM/Mapping/Driver/AnnotationDriver.php   | 15 +--
 .../ORM/Mapping/Driver/DatabaseDriver.php     | 39 +++-----
 lib/Doctrine/ORM/Mapping/Driver/XmlDriver.php | 10 +-
 .../ORM/Mapping/Driver/YamlDriver.php         |  2 +-
 .../Reflection/ReflectionPropertiesGetter.php | 21 +---
 lib/Doctrine/ORM/PersistentCollection.php     | 96 +++++++------------
 .../Collection/ManyToManyPersister.php        | 36 +++----
 .../Collection/OneToManyPersister.php         |  8 +-
 .../Entity/BasicEntityPersister.php           | 59 ++++++------
 .../Entity/JoinedSubclassPersister.php        | 11 +--
 lib/Doctrine/ORM/Proxy/ProxyFactory.php       |  6 +-
 lib/Doctrine/ORM/Query.php                    | 58 ++++-------
 .../ORM/Query/AST/Functions/TrimFunction.php  |  8 +-
 lib/Doctrine/ORM/Query/Expr/Composite.php     |  4 +-
 lib/Doctrine/ORM/Query/Filter/SQLFilter.php   |  4 +-
 lib/Doctrine/ORM/Query/Parser.php             | 18 ++--
 .../ORM/Query/ResultSetMappingBuilder.php     | 23 +++--
 lib/Doctrine/ORM/Query/SqlWalker.php          | 14 +--
 lib/Doctrine/ORM/QueryBuilder.php             | 21 +---
 .../Repository/DefaultRepositoryFactory.php   | 10 +-
 .../Command/MappingDescribeCommand.php        | 33 +++----
 .../ORM/Tools/ConvertDoctrine1Schema.php      | 46 +++++----
 .../ORM/Tools/DebugUnitOfWorkListener.php     |  8 +-
 lib/Doctrine/ORM/Tools/EntityGenerator.php    |  5 +-
 .../ORM/Tools/EntityRepositoryGenerator.php   | 25 ++---
 .../Pagination/LimitSubqueryOutputWalker.php  | 18 +---
 .../Tools/Pagination/LimitSubqueryWalker.php  |  7 +-
 .../ORM/Tools/Pagination/Paginator.php        | 25 +----
 .../ORM/Tools/ResolveTargetEntityListener.php |  8 +-
 lib/Doctrine/ORM/Tools/SchemaTool.php         | 12 +--
 lib/Doctrine/ORM/UnitOfWork.php               | 72 ++++++--------
 .../ORM/Utility/IdentifierFlattener.php       |  2 +-
 phpstan-baseline.neon                         | 75 +++------------
 psalm-baseline.xml                            | 18 +---
 50 files changed, 366 insertions(+), 671 deletions(-)

diff --git a/lib/Doctrine/ORM/AbstractQuery.php b/lib/Doctrine/ORM/AbstractQuery.php
index 232f6534a7a..1a2fc79331d 100644
--- a/lib/Doctrine/ORM/AbstractQuery.php
+++ b/lib/Doctrine/ORM/AbstractQuery.php
@@ -506,10 +506,8 @@ protected function getResultSetMapping()
 
     /**
      * Allows to translate entity namespaces to full qualified names.
-     *
-     * @return void
      */
-    private function translateNamespaces(Query\ResultSetMapping $rsm)
+    private function translateNamespaces(Query\ResultSetMapping $rsm): void
     {
         $translate = function ($alias): string {
             return $this->_em->getClassMetadata($alias)->getName();
@@ -1132,10 +1130,7 @@ private function executeUsingQueryCache($parameters = null, $hydrationMode = nul
         return $result;
     }
 
-    /**
-     * @return TimestampCacheKey|null
-     */
-    private function getTimestampKey()
+    private function getTimestampKey(): ?TimestampCacheKey
     {
         $entityName = reset($this->_resultSetMapping->aliasMap);
 
diff --git a/lib/Doctrine/ORM/Cache/DefaultCache.php b/lib/Doctrine/ORM/Cache/DefaultCache.php
index 54c933799cc..fe8ba92f4df 100644
--- a/lib/Doctrine/ORM/Cache/DefaultCache.php
+++ b/lib/Doctrine/ORM/Cache/DefaultCache.php
@@ -278,10 +278,8 @@ public function getQueryCache($regionName = null)
      /**
       * @param ClassMetadata $metadata   The entity metadata.
       * @param mixed         $identifier The entity identifier.
-      *
-      * @return EntityCacheKey
       */
-    private function buildEntityCacheKey(ClassMetadata $metadata, $identifier)
+    private function buildEntityCacheKey(ClassMetadata $metadata, $identifier): EntityCacheKey
     {
         if (! is_array($identifier)) {
             $identifier = $this->toIdentifierArray($metadata, $identifier);
@@ -294,11 +292,12 @@ private function buildEntityCacheKey(ClassMetadata $metadata, $identifier)
      * @param ClassMetadata $metadata        The entity metadata.
      * @param string        $association     The field name that represents the association.
      * @param mixed         $ownerIdentifier The identifier of the owning entity.
-     *
-     * @return CollectionCacheKey
      */
-    private function buildCollectionCacheKey(ClassMetadata $metadata, $association, $ownerIdentifier)
-    {
+    private function buildCollectionCacheKey(
+        ClassMetadata $metadata,
+        string $association,
+        $ownerIdentifier
+    ): CollectionCacheKey {
         if (! is_array($ownerIdentifier)) {
             $ownerIdentifier = $this->toIdentifierArray($metadata, $ownerIdentifier);
         }
@@ -312,7 +311,7 @@ private function buildCollectionCacheKey(ClassMetadata $metadata, $association,
      *
      * @return array<string, mixed>
      */
-    private function toIdentifierArray(ClassMetadata $metadata, $identifier)
+    private function toIdentifierArray(ClassMetadata $metadata, $identifier): array
     {
         if (is_object($identifier) && $this->em->getMetadataFactory()->hasMetadataFor(ClassUtils::getClass($identifier))) {
             $identifier = $this->uow->getSingleIdentifierValue($identifier);
diff --git a/lib/Doctrine/ORM/Cache/DefaultCacheFactory.php b/lib/Doctrine/ORM/Cache/DefaultCacheFactory.php
index d67690f732d..7b9cf7b9e83 100644
--- a/lib/Doctrine/ORM/Cache/DefaultCacheFactory.php
+++ b/lib/Doctrine/ORM/Cache/DefaultCacheFactory.php
@@ -215,12 +215,7 @@ public function getRegion(array $cache)
         return $this->regions[$cache['region']] = $region;
     }
 
-    /**
-     * @param string $name
-     *
-     * @return CacheAdapter
-     */
-    private function createRegionCache($name)
+    private function createRegionCache(string $name): CacheAdapter
     {
         $cacheAdapter = clone $this->cache;
 
diff --git a/lib/Doctrine/ORM/Cache/DefaultQueryCache.php b/lib/Doctrine/ORM/Cache/DefaultQueryCache.php
index 4c64488bd42..8a3beac4549 100644
--- a/lib/Doctrine/ORM/Cache/DefaultQueryCache.php
+++ b/lib/Doctrine/ORM/Cache/DefaultQueryCache.php
@@ -347,7 +347,7 @@ public function put(QueryCacheKey $key, ResultSetMapping $rsm, $result, array $h
      * @return mixed[]|null
      * @psalm-return array{targetEntity: class-string, type: mixed, list?: array[], identifier?: array}|null
      */
-    private function storeAssociationCache(QueryCacheKey $key, array $assoc, $assocValue)
+    private function storeAssociationCache(QueryCacheKey $key, array $assoc, $assocValue): ?array
     {
         $assocPersister = $this->uow->getEntityPersister($assoc['targetEntity']);
         $assocMetadata  = $assocPersister->getClassMetadata();
@@ -397,13 +397,15 @@ private function storeAssociationCache(QueryCacheKey $key, array $assoc, $assocV
     }
 
     /**
-     * @param string $assocAlias
      * @param object $entity
      *
      * @return array<object>|object
      */
-    private function getAssociationValue(ResultSetMapping $rsm, $assocAlias, $entity)
-    {
+    private function getAssociationValue(
+        ResultSetMapping $rsm,
+        string $assocAlias,
+        $entity
+    ) {
         $path  = [];
         $alias = $assocAlias;
 
diff --git a/lib/Doctrine/ORM/Cache/Persister/Entity/AbstractEntityPersister.php b/lib/Doctrine/ORM/Cache/Persister/Entity/AbstractEntityPersister.php
index 1baa39d9d91..0344c71af84 100644
--- a/lib/Doctrine/ORM/Cache/Persister/Entity/AbstractEntityPersister.php
+++ b/lib/Doctrine/ORM/Cache/Persister/Entity/AbstractEntityPersister.php
@@ -225,10 +225,8 @@ public function storeEntityCache($entity, EntityCacheKey $key)
 
     /**
      * @param object $entity
-     *
-     * @return void
      */
-    private function storeJoinedAssociations($entity)
+    private function storeJoinedAssociations($entity): void
     {
         if ($this->joinedAssociations === null) {
             $associations = [];
diff --git a/lib/Doctrine/ORM/Cache/Persister/Entity/NonStrictReadWriteCachedEntityPersister.php b/lib/Doctrine/ORM/Cache/Persister/Entity/NonStrictReadWriteCachedEntityPersister.php
index c2b36c18d00..3469d9716e4 100644
--- a/lib/Doctrine/ORM/Cache/Persister/Entity/NonStrictReadWriteCachedEntityPersister.php
+++ b/lib/Doctrine/ORM/Cache/Persister/Entity/NonStrictReadWriteCachedEntityPersister.php
@@ -100,17 +100,14 @@ public function update($entity)
 
     /**
      * @param object $entity
-     * @param bool   $isChanged
-     *
-     * @return bool
      */
-    private function updateCache($entity, $isChanged)
+    private function updateCache($entity, bool $isChanged): bool
     {
         $class     = $this->metadataFactory->getMetadataFor(get_class($entity));
         $key       = new EntityCacheKey($class->rootEntityName, $this->uow->getEntityIdentifier($entity));
         $entry     = $this->hydrator->buildCacheEntry($class, $key, $entity);
         $cached    = $this->region->put($key, $entry);
-        $isChanged = $isChanged ?: $cached;
+        $isChanged = $isChanged || $cached;
 
         if ($this->cacheLogger && $cached) {
             $this->cacheLogger->entityCachePut($this->regionName, $key);
diff --git a/lib/Doctrine/ORM/Cache/Region/FileLockRegion.php b/lib/Doctrine/ORM/Cache/Region/FileLockRegion.php
index 5e71d5dc757..f17d0e46adb 100644
--- a/lib/Doctrine/ORM/Cache/Region/FileLockRegion.php
+++ b/lib/Doctrine/ORM/Cache/Region/FileLockRegion.php
@@ -83,10 +83,7 @@ public function __construct(Region $region, $directory, $lockLifetime)
         $this->lockLifetime = $lockLifetime;
     }
 
-    /**
-     * @return bool
-     */
-    private function isLocked(CacheKey $key, ?Lock $lock = null)
+    private function isLocked(CacheKey $key, ?Lock $lock = null): bool
     {
         $filename = $this->getLockFileName($key);
 
@@ -117,30 +114,23 @@ private function isLocked(CacheKey $key, ?Lock $lock = null)
         return true;
     }
 
-    /**
-     * @return string
-     */
-    private function getLockFileName(CacheKey $key)
+    private function getLockFileName(CacheKey $key): string
     {
         return $this->directory . DIRECTORY_SEPARATOR . $key->hash . '.' . self::LOCK_EXTENSION;
     }
 
     /**
-     * @param string $filename
-     *
-     * @return false|string
+     * @return string|false
      */
-    private function getLockContent($filename)
+    private function getLockContent(string $filename)
     {
         return @file_get_contents($filename);
     }
 
     /**
-     * @param string $filename
-     *
-     * @return false|int
+     * @return int|false
      */
-    private function getLockTime($filename)
+    private function getLockTime(string $filename)
     {
         return @fileatime($filename);
     }
diff --git a/lib/Doctrine/ORM/Cache/TimestampQueryCacheValidator.php b/lib/Doctrine/ORM/Cache/TimestampQueryCacheValidator.php
index 196c4e1e0f2..a9cb6f07a7f 100644
--- a/lib/Doctrine/ORM/Cache/TimestampQueryCacheValidator.php
+++ b/lib/Doctrine/ORM/Cache/TimestampQueryCacheValidator.php
@@ -48,10 +48,7 @@ public function isValid(QueryCacheKey $key, QueryCacheEntry $entry)
         return $entry->time + $key->lifetime > microtime(true);
     }
 
-    /**
-     * @return bool
-     */
-    private function regionUpdated(QueryCacheKey $key, QueryCacheEntry $entry)
+    private function regionUpdated(QueryCacheKey $key, QueryCacheEntry $entry): bool
     {
         if ($key->timestampKey === null) {
             return false;
diff --git a/lib/Doctrine/ORM/EntityManager.php b/lib/Doctrine/ORM/EntityManager.php
index 491438280fa..41b877d08da 100644
--- a/lib/Doctrine/ORM/EntityManager.php
+++ b/lib/Doctrine/ORM/EntityManager.php
@@ -799,11 +799,9 @@ public function getConfiguration()
     /**
      * Throws an exception if the EntityManager is closed or currently not active.
      *
-     * @return void
-     *
      * @throws ORMException If the EntityManager is closed.
      */
-    private function errorIfClosed()
+    private function errorIfClosed(): void
     {
         if ($this->closed) {
             throw ORMException::entityManagerClosed();
diff --git a/lib/Doctrine/ORM/Event/PreUpdateEventArgs.php b/lib/Doctrine/ORM/Event/PreUpdateEventArgs.php
index 0f08dec473f..e0ab9155423 100644
--- a/lib/Doctrine/ORM/Event/PreUpdateEventArgs.php
+++ b/lib/Doctrine/ORM/Event/PreUpdateEventArgs.php
@@ -113,13 +113,9 @@ public function setNewValue($field, $value)
     /**
      * Asserts the field exists in changeset.
      *
-     * @param string $field
-     *
-     * @return void
-     *
      * @throws InvalidArgumentException
      */
-    private function assertValidField($field)
+    private function assertValidField(string $field): void
     {
         if (! isset($this->entityChangeSet[$field])) {
             throw new InvalidArgumentException(sprintf(
diff --git a/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php b/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php
index d9bdc1be259..a099d432466 100644
--- a/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php
+++ b/lib/Doctrine/ORM/Internal/CommitOrderCalculator.php
@@ -146,12 +146,8 @@ public function sort()
      * Visit a given node definition for reordering.
      *
      * {@internal Highly performance-sensitive method.}
-     *
-     * @param stdClass $vertex
-     *
-     * @return void
      */
-    private function visit($vertex)
+    private function visit(stdClass $vertex): void
     {
         $vertex->state = self::IN_PROGRESS;
 
diff --git a/lib/Doctrine/ORM/Internal/Hydration/ArrayHydrator.php b/lib/Doctrine/ORM/Internal/Hydration/ArrayHydrator.php
index 80772e8e0d9..28a63b700c0 100644
--- a/lib/Doctrine/ORM/Internal/Hydration/ArrayHydrator.php
+++ b/lib/Doctrine/ORM/Internal/Hydration/ArrayHydrator.php
@@ -259,15 +259,16 @@ protected function hydrateRowData(array $row, array &$result)
      * Updates the result pointer for an Entity. The result pointers point to the
      * last seen instance of each Entity type. This is used for graph construction.
      *
-     * @param mixed[]  $coll     The element.
-     * @param bool|int $index    Index of the element in the collection.
-     * @param string   $dqlAlias
-     * @param bool     $oneToOne Whether it is a single-valued association or not.
-     *
-     * @return void
+     * @param mixed[]|null $coll     The element.
+     * @param bool|int     $index    Index of the element in the collection.
+     * @param bool         $oneToOne Whether it is a single-valued association or not.
      */
-    private function updateResultPointer(array &$coll, $index, $dqlAlias, $oneToOne)
-    {
+    private function updateResultPointer(
+        ?array &$coll,
+        $index,
+        string $dqlAlias,
+        bool $oneToOne
+    ): void {
         if ($coll === null) {
             unset($this->_resultPointers[$dqlAlias]); // Ticket #1228
 
diff --git a/lib/Doctrine/ORM/Internal/Hydration/ObjectHydrator.php b/lib/Doctrine/ORM/Internal/Hydration/ObjectHydrator.php
index b5e917951a1..6a10201d199 100644
--- a/lib/Doctrine/ORM/Internal/Hydration/ObjectHydrator.php
+++ b/lib/Doctrine/ORM/Internal/Hydration/ObjectHydrator.php
@@ -171,15 +171,16 @@ protected function hydrateAllData()
     /**
      * Initializes a related collection.
      *
-     * @param object        $entity         The entity to which the collection belongs.
-     * @param ClassMetadata $class
-     * @param string        $fieldName      The name of the field on the entity that holds the collection.
-     * @param string        $parentDqlAlias Alias of the parent fetch joining this collection.
-     *
-     * @return PersistentCollection
+     * @param object $entity         The entity to which the collection belongs.
+     * @param string $fieldName      The name of the field on the entity that holds the collection.
+     * @param string $parentDqlAlias Alias of the parent fetch joining this collection.
      */
-    private function initRelatedCollection($entity, $class, $fieldName, $parentDqlAlias)
-    {
+    private function initRelatedCollection(
+        $entity,
+        ClassMetadata $class,
+        string $fieldName,
+        string $parentDqlAlias
+    ): PersistentCollection {
         $oid      = spl_object_hash($entity);
         $relation = $class->associationMappings[$fieldName];
         $value    = $class->reflFields[$fieldName]->getValue($entity);
@@ -225,11 +226,11 @@ private function initRelatedCollection($entity, $class, $fieldName, $parentDqlAl
      * @param string $dqlAlias The DQL alias of the entity's class.
      * @psalm-param array<string, mixed> $data     The instance data.
      *
-     * @return object The entity.
-     *
      * @throws HydrationException
+     *
+     * @return object
      */
-    private function getEntity(array $data, $dqlAlias)
+    private function getEntity(array $data, string $dqlAlias)
     {
         $className = $this->_rsm->aliasMap[$dqlAlias];
 
@@ -272,12 +273,12 @@ private function getEntity(array $data, $dqlAlias)
     }
 
     /**
-     * @param string $className
+     * @psalm-param class-string $className
      * @psalm-param array<string, mixed> $data
      *
      * @return mixed
      */
-    private function getEntityFromIdentityMap($className, array $data)
+    private function getEntityFromIdentityMap(string $className, array $data)
     {
         // TODO: Abstract this code and UnitOfWork::createEntity() equivalent?
         $class = $this->_metadataCache[$className];
diff --git a/lib/Doctrine/ORM/Internal/HydrationCompleteHandler.php b/lib/Doctrine/ORM/Internal/HydrationCompleteHandler.php
index b30134d0945..7632ae3d123 100644
--- a/lib/Doctrine/ORM/Internal/HydrationCompleteHandler.php
+++ b/lib/Doctrine/ORM/Internal/HydrationCompleteHandler.php
@@ -54,10 +54,8 @@ public function __construct(ListenersInvoker $listenersInvoker, EntityManagerInt
      * Method schedules invoking of postLoad entity to the very end of current hydration cycle.
      *
      * @param object $entity
-     *
-     * @return void
      */
-    public function deferPostLoadInvoking(ClassMetadata $class, $entity)
+    public function deferPostLoadInvoking(ClassMetadata $class, $entity): void
     {
         $invoke = $this->listenersInvoker->getSubscribedSystems($class, Events::postLoad);
 
@@ -72,10 +70,8 @@ public function deferPostLoadInvoking(ClassMetadata $class, $entity)
      * This method should me called after any hydration cycle completed.
      *
      * Method fires all deferred invocations of postLoad events
-     *
-     * @return void
      */
-    public function hydrationComplete()
+    public function hydrationComplete(): void
     {
         $toInvoke                          = $this->deferredPostLoadInvocations;
         $this->deferredPostLoadInvocations = [];
diff --git a/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php b/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
index 80943b68203..ca3ac800033 100644
--- a/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
+++ b/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
@@ -61,7 +61,7 @@ class ClassMetadataFactory extends AbstractClassMetadataFactory
     /** @var EntityManagerInterface|null */
     private $em;
 
-    /** @var AbstractPlatform */
+    /** @var AbstractPlatform|null */
     private $targetPlatform;
 
     /** @var MappingDriver */
@@ -310,11 +310,9 @@ protected function newClassMetadataInstance($className)
      * Populates the discriminator value of the given metadata (if not set) by iterating over discriminator
      * map classes and looking for a fitting one.
      *
-     * @return void
-     *
      * @throws MappingException
      */
-    private function resolveDiscriminatorValue(ClassMetadata $metadata)
+    private function resolveDiscriminatorValue(ClassMetadata $metadata): void
     {
         if (
             $metadata->discriminatorValue
@@ -357,11 +355,9 @@ private function resolveDiscriminatorValue(ClassMetadata $metadata)
      * The automatically generated discriminator map contains the lowercase short name of
      * each class as key.
      *
-     * @return void
-     *
      * @throws MappingException
      */
-    private function addDefaultDiscriminatorMap(ClassMetadata $class)
+    private function addDefaultDiscriminatorMap(ClassMetadata $class): void
     {
         $allClasses = $this->driver->getAllClassNames();
         $fqcn       = $class->getName();
@@ -390,11 +386,9 @@ private function addDefaultDiscriminatorMap(ClassMetadata $class)
     /**
      * Gets the lower-case short name of a class.
      *
-     * @param string $className
-     *
-     * @return string
+     * @psalm-param class-string $className
      */
-    private function getShortName($className)
+    private function getShortName(string $className): string
     {
         if (strpos($className, '\\') === false) {
             return strtolower($className);
@@ -407,10 +401,8 @@ private function getShortName($className)
 
     /**
      * Adds inherited fields to the subclass mapping.
-     *
-     * @return void
      */
-    private function addInheritedFields(ClassMetadata $subClass, ClassMetadata $parentClass)
+    private function addInheritedFields(ClassMetadata $subClass, ClassMetadata $parentClass): void
     {
         foreach ($parentClass->fieldMappings as $mapping) {
             if (! isset($mapping['inherited']) && ! $parentClass->isMappedSuperclass) {
@@ -432,11 +424,9 @@ private function addInheritedFields(ClassMetadata $subClass, ClassMetadata $pare
     /**
      * Adds inherited association mappings to the subclass mapping.
      *
-     * @return void
-     *
      * @throws MappingException
      */
-    private function addInheritedRelations(ClassMetadata $subClass, ClassMetadata $parentClass)
+    private function addInheritedRelations(ClassMetadata $subClass, ClassMetadata $parentClass): void
     {
         foreach ($parentClass->associationMappings as $field => $mapping) {
             if ($parentClass->isMappedSuperclass) {
@@ -460,10 +450,7 @@ private function addInheritedRelations(ClassMetadata $subClass, ClassMetadata $p
         }
     }
 
-    /**
-     * @return void
-     */
-    private function addInheritedEmbeddedClasses(ClassMetadata $subClass, ClassMetadata $parentClass)
+    private function addInheritedEmbeddedClasses(ClassMetadata $subClass, ClassMetadata $parentClass): void
     {
         foreach ($parentClass->embeddedClasses as $field => $embeddedClass) {
             if (! isset($embeddedClass['inherited']) && ! $parentClass->isMappedSuperclass) {
@@ -484,11 +471,12 @@ private function addInheritedEmbeddedClasses(ClassMetadata $subClass, ClassMetad
      * @param ClassMetadata $subClass    Sub embedded class metadata to add nested embedded classes metadata from.
      * @param ClassMetadata $parentClass Parent class to add nested embedded classes metadata to.
      * @param string        $prefix      Embedded classes' prefix to use for nested embedded classes field names.
-     *
-     * @return void
      */
-    private function addNestedEmbeddedClasses(ClassMetadata $subClass, ClassMetadata $parentClass, $prefix)
-    {
+    private function addNestedEmbeddedClasses(
+        ClassMetadata $subClass,
+        ClassMetadata $parentClass,
+        string $prefix
+    ): void {
         foreach ($subClass->embeddedClasses as $property => $embeddableClass) {
             if (isset($embeddableClass['inherited'])) {
                 continue;
@@ -512,10 +500,8 @@ private function addNestedEmbeddedClasses(ClassMetadata $subClass, ClassMetadata
 
     /**
      * Copy the table indices from the parent class superclass to the child class
-     *
-     * @return void
      */
-    private function addInheritedIndexes(ClassMetadata $subClass, ClassMetadata $parentClass)
+    private function addInheritedIndexes(ClassMetadata $subClass, ClassMetadata $parentClass): void
     {
         if (! $parentClass->isMappedSuperclass) {
             return;
@@ -536,10 +522,8 @@ private function addInheritedIndexes(ClassMetadata $subClass, ClassMetadata $par
 
     /**
      * Adds inherited named queries to the subclass mapping.
-     *
-     * @return void
      */
-    private function addInheritedNamedQueries(ClassMetadata $subClass, ClassMetadata $parentClass)
+    private function addInheritedNamedQueries(ClassMetadata $subClass, ClassMetadata $parentClass): void
     {
         foreach ($parentClass->namedQueries as $name => $query) {
             if (! isset($subClass->namedQueries[$name])) {
@@ -555,10 +539,8 @@ private function addInheritedNamedQueries(ClassMetadata $subClass, ClassMetadata
 
     /**
      * Adds inherited named native queries to the subclass mapping.
-     *
-     * @return void
      */
-    private function addInheritedNamedNativeQueries(ClassMetadata $subClass, ClassMetadata $parentClass)
+    private function addInheritedNamedNativeQueries(ClassMetadata $subClass, ClassMetadata $parentClass): void
     {
         foreach ($parentClass->namedNativeQueries as $name => $query) {
             if (! isset($subClass->namedNativeQueries[$name])) {
@@ -577,10 +559,8 @@ private function addInheritedNamedNativeQueries(ClassMetadata $subClass, ClassMe
 
     /**
      * Adds inherited sql result set mappings to the subclass mapping.
-     *
-     * @return void
      */
-    private function addInheritedSqlResultSetMappings(ClassMetadata $subClass, ClassMetadata $parentClass)
+    private function addInheritedSqlResultSetMappings(ClassMetadata $subClass, ClassMetadata $parentClass): void
     {
         foreach ($parentClass->sqlResultSetMappings as $name => $mapping) {
             if (! isset($subClass->sqlResultSetMappings[$name])) {
@@ -609,11 +589,9 @@ private function addInheritedSqlResultSetMappings(ClassMetadata $subClass, Class
      * Completes the ID generator mapping. If "auto" is specified we choose the generator
      * most appropriate for the targeted database platform.
      *
-     * @return void
-     *
      * @throws ORMException
      */
-    private function completeIdGeneratorMapping(ClassMetadataInfo $class)
+    private function completeIdGeneratorMapping(ClassMetadataInfo $class): void
     {
         $idGenType = $class->generatorType;
         if ($idGenType === ClassMetadata::GENERATOR_TYPE_AUTO) {
@@ -724,10 +702,8 @@ private function completeIdGeneratorMapping(ClassMetadataInfo $class)
 
     /**
      * Inherits the ID generator mapping from a parent class.
-     *
-     * @return void
      */
-    private function inheritIdGeneratorMapping(ClassMetadataInfo $class, ClassMetadataInfo $parent)
+    private function inheritIdGeneratorMapping(ClassMetadataInfo $class, ClassMetadataInfo $parent): void
     {
         if ($parent->isIdGeneratorSequence()) {
             $class->setSequenceGeneratorDefinition($parent->sequenceGeneratorDefinition);
@@ -786,10 +762,7 @@ protected function isEntity(ClassMetadataInterface $class)
         return isset($class->isMappedSuperclass) && $class->isMappedSuperclass === false;
     }
 
-    /**
-     * @return Platforms\AbstractPlatform
-     */
-    private function getTargetPlatform()
+    private function getTargetPlatform(): Platforms\AbstractPlatform
     {
         if (! $this->targetPlatform) {
             $this->targetPlatform = $this->em->getConnection()->getDatabasePlatform();
diff --git a/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php b/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php
index 8c5b8402d51..9d1e90a303b 100644
--- a/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php
+++ b/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php
@@ -2613,11 +2613,9 @@ public function setPrimaryTable(array $table)
     /**
      * Checks whether the given type identifies an inheritance type.
      *
-     * @param int $type
-     *
-     * @return bool TRUE if the given type identifies an inheritance type, FALSe otherwise.
+     * @return bool TRUE if the given type identifies an inheritance type, FALSE otherwise.
      */
-    private function isInheritanceType($type)
+    private function isInheritanceType(int $type): bool
     {
         return $type === self::INHERITANCE_TYPE_NONE ||
                 $type === self::INHERITANCE_TYPE_SINGLE_TABLE ||
diff --git a/lib/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php b/lib/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php
index e23c17a1aef..6c7fdb862ba 100644
--- a/lib/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php
+++ b/lib/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php
@@ -636,14 +636,11 @@ private function loadRelationShipMapping(
     /**
      * Attempts to resolve the fetch mode.
      *
-     * @param string $className The class name.
-     * @param string $fetchMode The fetch mode.
-     *
-     * @return int The fetch mode as defined in ClassMetadata.
+     * @psalm-return \Doctrine\ORM\Mapping\ClassMetadata::FETCH_* The fetch mode as defined in ClassMetadata.
      *
      * @throws MappingException If the fetch mode is not valid.
      */
-    private function getFetchMode($className, $fetchMode)
+    private function getFetchMode(string $className, string $fetchMode): int
     {
         if (! defined('Doctrine\ORM\Mapping\ClassMetadata::FETCH_' . $fetchMode)) {
             throw MappingException::invalidFetchMode($className, $fetchMode);
@@ -658,7 +655,7 @@ private function getFetchMode($className, $fetchMode)
      * @return callable[]
      * @psalm-return list<callable-array>
      */
-    private function getMethodCallbacks(ReflectionMethod $method)
+    private function getMethodCallbacks(ReflectionMethod $method): array
     {
         $callbacks   = [];
         $annotations = $this->reader->getMethodAnnotations($method);
@@ -713,7 +710,7 @@ private function getMethodCallbacks(ReflectionMethod $method)
      *                   referencedColumnName: string
      *               }
      */
-    private function joinColumnToArray(Mapping\JoinColumn $joinColumn)
+    private function joinColumnToArray(Mapping\JoinColumn $joinColumn): array
     {
         return [
             'name' => $joinColumn->name,
@@ -728,8 +725,6 @@ private function joinColumnToArray(Mapping\JoinColumn $joinColumn)
     /**
      * Parse the given Column as array
      *
-     * @param string $fieldName
-     *
      * @return mixed[]
      * @psalm-return array{
      *                   fieldName: string,
@@ -744,7 +739,7 @@ private function joinColumnToArray(Mapping\JoinColumn $joinColumn)
      *                   columnDefinition?: string
      *               }
      */
-    private function columnToArray($fieldName, Mapping\Column $column)
+    private function columnToArray(string $fieldName, Mapping\Column $column): array
     {
         $mapping = [
             'fieldName' => $fieldName,
diff --git a/lib/Doctrine/ORM/Mapping/Driver/DatabaseDriver.php b/lib/Doctrine/ORM/Mapping/Driver/DatabaseDriver.php
index be71403fa3e..e4e0c1c35eb 100644
--- a/lib/Doctrine/ORM/Mapping/Driver/DatabaseDriver.php
+++ b/lib/Doctrine/ORM/Mapping/Driver/DatabaseDriver.php
@@ -259,11 +259,9 @@ public function loadMetadataForClass($className, ClassMetadata $metadata)
     }
 
     /**
-     * @return void
-     *
      * @throws MappingException
      */
-    private function reverseEngineerMappingFromDatabase()
+    private function reverseEngineerMappingFromDatabase(): void
     {
         if ($this->tables !== null) {
             return;
@@ -315,10 +313,8 @@ private function reverseEngineerMappingFromDatabase()
 
     /**
      * Build indexes from a class metadata.
-     *
-     * @return void
      */
-    private function buildIndexes(ClassMetadataInfo $metadata)
+    private function buildIndexes(ClassMetadataInfo $metadata): void
     {
         $tableName = $metadata->table['name'];
         $indexes   = $this->tables[$tableName]->getIndexes();
@@ -340,10 +336,8 @@ private function buildIndexes(ClassMetadataInfo $metadata)
 
     /**
      * Build field mapping from class metadata.
-     *
-     * @return void
      */
-    private function buildFieldMappings(ClassMetadataInfo $metadata)
+    private function buildFieldMappings(ClassMetadataInfo $metadata): void
     {
         $tableName      = $metadata->table['name'];
         $columns        = $this->tables[$tableName]->getColumns();
@@ -386,8 +380,6 @@ private function buildFieldMappings(ClassMetadataInfo $metadata)
     /**
      * Build field mapping from a schema column definition
      *
-     * @param string $tableName
-     *
      * @psalm-return array{
      *                   fieldName: string,
      *                   columnName: string,
@@ -404,7 +396,7 @@ private function buildFieldMappings(ClassMetadataInfo $metadata)
      *                   length?: int|null
      *               }
      */
-    private function buildFieldMapping($tableName, Column $column)
+    private function buildFieldMapping(string $tableName, Column $column): array
     {
         $fieldMapping = [
             'fieldName'  => $this->getFieldNameForColumn($tableName, $column->getName(), false),
@@ -506,7 +498,7 @@ private function buildToOneAssociationMappings(ClassMetadataInfo $metadata)
      * @return ForeignKeyConstraint[]
      * @psalm-return array<string, ForeignKeyConstraint>
      */
-    private function getTableForeignKeys(Table $table)
+    private function getTableForeignKeys(Table $table): array
     {
         return $this->_sm->getDatabasePlatform()->supportsForeignKeyConstraints()
             ? $table->getForeignKeys()
@@ -518,7 +510,7 @@ private function getTableForeignKeys(Table $table)
      *
      * @return string[]
      */
-    private function getTablePrimaryKeys(Table $table)
+    private function getTablePrimaryKeys(Table $table): array
     {
         try {
             return $table->getPrimaryKey()->getColumns();
@@ -532,11 +524,9 @@ private function getTablePrimaryKeys(Table $table)
     /**
      * Returns the mapped class name for a table if it exists. Otherwise return "classified" version.
      *
-     * @param string $tableName
-     *
-     * @return string
+     * @psalm-return class-string
      */
-    private function getClassNameForTable($tableName)
+    private function getClassNameForTable(string $tableName): string
     {
         if (isset($this->classNamesForTables[$tableName])) {
             return $this->namespace . $this->classNamesForTables[$tableName];
@@ -548,14 +538,13 @@ private function getClassNameForTable($tableName)
     /**
      * Return the mapped field name for a column, if it exists. Otherwise return camelized version.
      *
-     * @param string $tableName
-     * @param string $columnName
-     * @param bool   $fk         Whether the column is a foreignkey or not.
-     *
-     * @return string
+     * @param bool $fk Whether the column is a foreignkey or not.
      */
-    private function getFieldNameForColumn($tableName, $columnName, $fk = false)
-    {
+    private function getFieldNameForColumn(
+        string $tableName,
+        string $columnName,
+        bool $fk = false
+    ): string {
         if (isset($this->fieldNamesForColumns[$tableName]) && isset($this->fieldNamesForColumns[$tableName][$columnName])) {
             return $this->fieldNamesForColumns[$tableName][$columnName];
         }
diff --git a/lib/Doctrine/ORM/Mapping/Driver/XmlDriver.php b/lib/Doctrine/ORM/Mapping/Driver/XmlDriver.php
index 8fd8d35f046..99c34abb37f 100644
--- a/lib/Doctrine/ORM/Mapping/Driver/XmlDriver.php
+++ b/lib/Doctrine/ORM/Mapping/Driver/XmlDriver.php
@@ -737,7 +737,7 @@ public function loadMetadataForClass($className, ClassMetadata $metadata)
      * @return mixed[] The options array.
      * @psalm-return array<int|string, array<int|string, mixed|string>|bool|string>
      */
-    private function parseOptions(SimpleXMLElement $options)
+    private function parseOptions(SimpleXMLElement $options): array
     {
         $array = [];
 
@@ -779,7 +779,7 @@ private function parseOptions(SimpleXMLElement $options)
      *                   columnDefinition?: string
      *               }
      */
-    private function joinColumnToArray(SimpleXMLElement $joinColumnElement)
+    private function joinColumnToArray(SimpleXMLElement $joinColumnElement): array
     {
         $joinColumn = [
             'name' => (string) $joinColumnElement['name'],
@@ -823,7 +823,7 @@ private function joinColumnToArray(SimpleXMLElement $joinColumnElement)
       *                   options?: array
       *               }
       */
-    private function columnToArray(SimpleXMLElement $fieldMapping)
+    private function columnToArray(SimpleXMLElement $fieldMapping): array
     {
         $mapping = [
             'fieldName' => (string) $fieldMapping['name'],
@@ -878,7 +878,7 @@ private function columnToArray(SimpleXMLElement $fieldMapping)
      * @return mixed[]
      * @psalm-return array{usage: int|null, region?: string}
      */
-    private function cacheToArray(SimpleXMLElement $cacheMapping)
+    private function cacheToArray(SimpleXMLElement $cacheMapping): array
     {
         $region = isset($cacheMapping['region']) ? (string) $cacheMapping['region'] : null;
         $usage  = isset($cacheMapping['usage']) ? strtoupper($cacheMapping['usage']) : null;
@@ -905,7 +905,7 @@ private function cacheToArray(SimpleXMLElement $cacheMapping)
      * @return string[] The list of cascade options.
      * @psalm-return list<string>
      */
-    private function getCascadeMappings(SimpleXMLElement $cascadeElement)
+    private function getCascadeMappings(SimpleXMLElement $cascadeElement): array
     {
         $cascades = [];
         foreach ($cascadeElement->children() as $action) {
diff --git a/lib/Doctrine/ORM/Mapping/Driver/YamlDriver.php b/lib/Doctrine/ORM/Mapping/Driver/YamlDriver.php
index 15aef6f497f..668bfe57802 100644
--- a/lib/Doctrine/ORM/Mapping/Driver/YamlDriver.php
+++ b/lib/Doctrine/ORM/Mapping/Driver/YamlDriver.php
@@ -887,7 +887,7 @@ private function columnToArray(string $fieldName, ?array $column): array
      * @return mixed[]
      * @psalm-return array{usage: int, region: string|null}
      */
-    private function cacheToArray($cacheMapping)
+    private function cacheToArray(array $cacheMapping): array
     {
         $region = isset($cacheMapping['region']) ? (string) $cacheMapping['region'] : null;
         $usage  = isset($cacheMapping['usage']) ? strtoupper($cacheMapping['usage']) : null;
diff --git a/lib/Doctrine/ORM/Mapping/Reflection/ReflectionPropertiesGetter.php b/lib/Doctrine/ORM/Mapping/Reflection/ReflectionPropertiesGetter.php
index 6030db40f58..c2c6afad451 100644
--- a/lib/Doctrine/ORM/Mapping/Reflection/ReflectionPropertiesGetter.php
+++ b/lib/Doctrine/ORM/Mapping/Reflection/ReflectionPropertiesGetter.php
@@ -55,7 +55,7 @@ public function __construct(ReflectionService $reflectionService)
      *
      * @return ReflectionProperty[] indexed by property internal name
      */
-    public function getProperties($className)
+    public function getProperties($className): array
     {
         if (isset($this->properties[$className])) {
             return $this->properties[$className];
@@ -75,12 +75,10 @@ public function getProperties($className)
     }
 
     /**
-     * @param string $className
-     *
      * @return ReflectionClass[]
      * @psalm-return list<ReflectionClass<object>>
      */
-    private function getHierarchyClasses($className): array
+    private function getHierarchyClasses(string $className): array
     {
         $classes         = [];
         $parentClassName = $className;
@@ -121,18 +119,12 @@ private function getClassProperties(ReflectionClass $reflectionClass): array
         );
     }
 
-    /**
-     * @return bool
-     */
-    private function isInstanceProperty(ReflectionProperty $reflectionProperty)
+    private function isInstanceProperty(ReflectionProperty $reflectionProperty): bool
     {
         return ! $reflectionProperty->isStatic();
     }
 
-    /**
-     * @return ReflectionProperty|null
-     */
-    private function getAccessibleProperty(ReflectionProperty $property)
+    private function getAccessibleProperty(ReflectionProperty $property): ?ReflectionProperty
     {
         return $this->reflectionService->getAccessibleProperty(
             $property->getDeclaringClass()->getName(),
@@ -140,10 +132,7 @@ private function getAccessibleProperty(ReflectionProperty $property)
         );
     }
 
-    /**
-     * @return string
-     */
-    private function getLogicalName(ReflectionProperty $property)
+    private function getLogicalName(ReflectionProperty $property): string
     {
         $propertyName = $property->getName();
 
diff --git a/lib/Doctrine/ORM/PersistentCollection.php b/lib/Doctrine/ORM/PersistentCollection.php
index 0f7b47cc17b..e060db6e268 100644
--- a/lib/Doctrine/ORM/PersistentCollection.php
+++ b/lib/Doctrine/ORM/PersistentCollection.php
@@ -64,7 +64,7 @@ final class PersistentCollection extends AbstractLazyCollection implements Selec
     /**
      * The entity that owns this collection.
      *
-     * @var object
+     * @var object|null
      */
     private $owner;
 
@@ -72,7 +72,7 @@ final class PersistentCollection extends AbstractLazyCollection implements Selec
      * The association mapping the collection belongs to.
      * This is currently either a OneToManyMapping or a ManyToManyMapping.
      *
-     * @psalm-var array<string, mixed>
+     * @psalm-var array<string, mixed>|null
      */
     private $association;
 
@@ -128,10 +128,8 @@ public function __construct(EntityManagerInterface $em, $class, Collection $coll
      *
      * @param object $entity
      * @psalm-param array<string, mixed> $assoc
-     *
-     * @return void
      */
-    public function setOwner($entity, array $assoc)
+    public function setOwner($entity, array $assoc): void
     {
         $this->owner            = $entity;
         $this->association      = $assoc;
@@ -142,7 +140,7 @@ public function setOwner($entity, array $assoc)
      * INTERNAL:
      * Gets the collection owner.
      *
-     * @return object
+     * @return object|null
      */
     public function getOwner()
     {
@@ -152,7 +150,7 @@ public function getOwner()
     /**
      * @return Mapping\ClassMetadata
      */
-    public function getTypeClass()
+    public function getTypeClass(): Mapping\ClassMetadataInfo
     {
         return $this->typeClass;
     }
@@ -163,10 +161,8 @@ public function getTypeClass()
      * complete bidirectional associations in the case of a one-to-many association.
      *
      * @param mixed $element The element to add.
-     *
-     * @return void
      */
-    public function hydrateAdd($element)
+    public function hydrateAdd($element): void
     {
         $this->collection->add($element);
 
@@ -193,10 +189,8 @@ public function hydrateAdd($element)
      *
      * @param mixed $key     The key to set.
      * @param mixed $element The element to set.
-     *
-     * @return void
      */
-    public function hydrateSet($key, $element)
+    public function hydrateSet($key, $element): void
     {
         $this->collection->set($key, $element);
 
@@ -214,10 +208,8 @@ public function hydrateSet($key, $element)
     /**
      * Initializes the collection by loading its contents from the database
      * if the collection is not yet initialized.
-     *
-     * @return void
      */
-    public function initialize()
+    public function initialize(): void
     {
         if ($this->initialized || ! $this->association) {
             return;
@@ -231,10 +223,8 @@ public function initialize()
     /**
      * INTERNAL:
      * Tells this collection to take a snapshot of its current state.
-     *
-     * @return void
      */
-    public function takeSnapshot()
+    public function takeSnapshot(): void
     {
         $this->snapshot = $this->collection->toArray();
         $this->isDirty  = false;
@@ -246,7 +236,7 @@ public function takeSnapshot()
      *
      * @psalm-return array<string|int, mixed> The last snapshot of the elements.
      */
-    public function getSnapshot()
+    public function getSnapshot(): array
     {
         return $this->snapshot;
     }
@@ -257,7 +247,7 @@ public function getSnapshot()
      *
      * @return mixed[]
      */
-    public function getDeleteDiff()
+    public function getDeleteDiff(): array
     {
         return array_udiff_assoc(
             $this->snapshot,
@@ -274,7 +264,7 @@ static function ($a, $b): int {
      *
      * @return mixed[]
      */
-    public function getInsertDiff()
+    public function getInsertDiff(): array
     {
         return array_udiff_assoc(
             $this->collection->toArray(),
@@ -288,19 +278,17 @@ static function ($a, $b): int {
     /**
      * INTERNAL: Gets the association mapping of the collection.
      *
-     * @psalm-return array<string, mixed>
+     * @psalm-return array<string, mixed>|null
      */
-    public function getMapping()
+    public function getMapping(): ?array
     {
         return $this->association;
     }
 
     /**
      * Marks this collection as changed/dirty.
-     *
-     * @return void
      */
-    private function changed()
+    private function changed(): void
     {
         if ($this->isDirty) {
             return;
@@ -325,7 +313,7 @@ private function changed()
      *
      * @return bool TRUE if the collection is dirty, FALSE otherwise.
      */
-    public function isDirty()
+    public function isDirty(): bool
     {
         return $this->isDirty;
     }
@@ -334,10 +322,8 @@ public function isDirty()
      * Sets a boolean flag, indicating whether this collection is dirty.
      *
      * @param bool $dirty Whether the collection should be marked dirty or not.
-     *
-     * @return void
      */
-    public function setDirty($dirty)
+    public function setDirty($dirty): void
     {
         $this->isDirty = $dirty;
     }
@@ -346,10 +332,8 @@ public function setDirty($dirty)
      * Sets the initialized flag of the collection, forcing it into that state.
      *
      * @param bool $bool
-     *
-     * @return void
      */
-    public function setInitialized($bool)
+    public function setInitialized($bool): void
     {
         $this->initialized = $bool;
     }
@@ -388,7 +372,7 @@ public function remove($key)
     /**
      * {@inheritdoc}
      */
-    public function removeElement($element)
+    public function removeElement($element): bool
     {
         $removed = parent::removeElement($element);
 
@@ -413,7 +397,7 @@ public function removeElement($element)
     /**
      * {@inheritdoc}
      */
-    public function containsKey($key)
+    public function containsKey($key): bool
     {
         if (
             ! $this->initialized && $this->association['fetch'] === ClassMetadata::FETCH_EXTRA_LAZY
@@ -430,7 +414,7 @@ public function containsKey($key)
     /**
      * {@inheritdoc}
      */
-    public function contains($element)
+    public function contains($element): bool
     {
         if (! $this->initialized && $this->association['fetch'] === ClassMetadata::FETCH_EXTRA_LAZY) {
             $persister = $this->em->getUnitOfWork()->getCollectionPersister($this->association);
@@ -461,10 +445,7 @@ public function get($key)
         return parent::get($key);
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    public function count()
+    public function count(): int
     {
         if (! $this->initialized && $this->association !== null && $this->association['fetch'] === ClassMetadata::FETCH_EXTRA_LAZY) {
             $persister = $this->em->getUnitOfWork()->getCollectionPersister($this->association);
@@ -478,7 +459,7 @@ public function count()
     /**
      * {@inheritdoc}
      */
-    public function set($key, $value)
+    public function set($key, $value): void
     {
         parent::set($key, $value);
 
@@ -492,7 +473,7 @@ public function set($key, $value)
     /**
      * {@inheritdoc}
      */
-    public function add($value)
+    public function add($value): bool
     {
         $this->collection->add($value);
 
@@ -510,7 +491,7 @@ public function add($value)
     /**
      * {@inheritdoc}
      */
-    public function offsetExists($offset)
+    public function offsetExists($offset): bool
     {
         return $this->containsKey($offset);
     }
@@ -526,7 +507,7 @@ public function offsetGet($offset)
     /**
      * {@inheritdoc}
      */
-    public function offsetSet($offset, $value)
+    public function offsetSet($offset, $value): void
     {
         if (! isset($offset)) {
             $this->add($value);
@@ -540,25 +521,19 @@ public function offsetSet($offset, $value)
     /**
      * {@inheritdoc}
      *
-     * @return object
+     * @return object|null
      */
     public function offsetUnset($offset)
     {
         return $this->remove($offset);
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    public function isEmpty()
+    public function isEmpty(): bool
     {
         return $this->collection->isEmpty() && $this->count() === 0;
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    public function clear()
+    public function clear(): void
     {
         if ($this->initialized && $this->isEmpty()) {
             $this->collection->clear();
@@ -622,7 +597,7 @@ public function __sleep(): array
      *
      * @psalm-return array<TKey,T>
      */
-    public function slice($offset, $length = null)
+    public function slice($offset, $length = null): array
     {
         if (! $this->initialized && ! $this->isDirty && $this->association['fetch'] === ClassMetadata::FETCH_EXTRA_LAZY) {
             $persister = $this->em->getUnitOfWork()->getCollectionPersister($this->association);
@@ -643,8 +618,6 @@ public function slice($offset, $length = null)
      * 3. Snapshot leads to invalid diffs being generated.
      * 4. Lazy loading grabs entities from old owner object.
      * 5. New collection is connected to old owner and leads to duplicate keys.
-     *
-     * @return void
      */
     public function __clone()
     {
@@ -668,7 +641,7 @@ public function __clone()
      *
      * @throws RuntimeException
      */
-    public function matching(Criteria $criteria)
+    public function matching(Criteria $criteria): Collection
     {
         if ($this->isDirty) {
             $this->initialize();
@@ -705,15 +678,12 @@ public function matching(Criteria $criteria)
      *
      * @return Collection<TKey, T>
      */
-    public function unwrap()
+    public function unwrap(): Collection
     {
         return $this->collection;
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    protected function doInitialize()
+    protected function doInitialize(): void
     {
         // Has NEW objects added through add(). Remember them.
         $newlyAddedDirtyObjects = [];
diff --git a/lib/Doctrine/ORM/Persisters/Collection/ManyToManyPersister.php b/lib/Doctrine/ORM/Persisters/Collection/ManyToManyPersister.php
index ac35f3491cd..c8277b9e7ac 100644
--- a/lib/Doctrine/ORM/Persisters/Collection/ManyToManyPersister.php
+++ b/lib/Doctrine/ORM/Persisters/Collection/ManyToManyPersister.php
@@ -529,8 +529,10 @@ protected function getInsertRowSQLParameters(PersistentCollection $collection, $
      * @return mixed[]
      * @psalm-return list<mixed>
      */
-    private function collectJoinTableColumnParameters(PersistentCollection $collection, $element)
-    {
+    private function collectJoinTableColumnParameters(
+        PersistentCollection $collection,
+        $element
+    ): array {
         $params      = [];
         $mapping     = $collection->getMapping();
         $isComposite = count($mapping['joinTableColumns']) > 2;
@@ -566,8 +568,7 @@ private function collectJoinTableColumnParameters(PersistentCollection $collecti
     }
 
     /**
-     * @param string $key
-     * @param bool   $addFilters Whether the filter SQL should be included or not.
+     * @param bool $addFilters Whether the filter SQL should be included or not.
      *
      * @return mixed[] ordered vector:
      *                - quoted join table name
@@ -576,8 +577,11 @@ private function collectJoinTableColumnParameters(PersistentCollection $collecti
      *                - types of the parameters to be bound for filtering
      * @psalm-return array{0: string, 1: list<string>, 2: list<mixed>, 3: list<string>}
      */
-    private function getJoinTableRestrictionsWithKey(PersistentCollection $collection, $key, $addFilters)
-    {
+    private function getJoinTableRestrictionsWithKey(
+        PersistentCollection $collection,
+        string $key,
+        bool $addFilters
+    ): array {
         $filterMapping = $collection->getMapping();
         $mapping       = $filterMapping;
         $indexBy       = $mapping['indexBy'];
@@ -651,8 +655,8 @@ private function getJoinTableRestrictionsWithKey(PersistentCollection $collectio
     }
 
     /**
-     * @param object $element
      * @param bool   $addFilters Whether the filter SQL should be included or not.
+     * @param object $element
      *
      * @return mixed[] ordered vector:
      *                - quoted join table name
@@ -661,8 +665,11 @@ private function getJoinTableRestrictionsWithKey(PersistentCollection $collectio
      *                - types of the parameters to be bound for filtering
      * @psalm-return array{0: string, 1: list<string>, 2: list<mixed>, 3: list<string>}
      */
-    private function getJoinTableRestrictions(PersistentCollection $collection, $element, $addFilters)
-    {
+    private function getJoinTableRestrictions(
+        PersistentCollection $collection,
+        $element,
+        bool $addFilters
+    ): array {
         $filterMapping = $collection->getMapping();
         $mapping       = $filterMapping;
 
@@ -722,7 +729,7 @@ private function getJoinTableRestrictions(PersistentCollection $collection, $ele
      *
      * @return mixed[][]
      */
-    private function expandCriteriaParameters(Criteria $criteria)
+    private function expandCriteriaParameters(Criteria $criteria): array
     {
         $expression = $criteria->getWhereExpression();
 
@@ -739,10 +746,7 @@ private function expandCriteriaParameters(Criteria $criteria)
         return $types;
     }
 
-    /**
-     * @return string
-     */
-    private function getOrderingSql(Criteria $criteria, ClassMetadata $targetClass)
+    private function getOrderingSql(Criteria $criteria, ClassMetadata $targetClass): string
     {
         $orderings = $criteria->getOrderings();
         if ($orderings) {
@@ -763,11 +767,9 @@ private function getOrderingSql(Criteria $criteria, ClassMetadata $targetClass)
     }
 
     /**
-     * @return string
-     *
      * @throws DBALException
      */
-    private function getLimitSql(Criteria $criteria)
+    private function getLimitSql(Criteria $criteria): string
     {
         $limit  = $criteria->getMaxResults();
         $offset = $criteria->getFirstResult();
diff --git a/lib/Doctrine/ORM/Persisters/Collection/OneToManyPersister.php b/lib/Doctrine/ORM/Persisters/Collection/OneToManyPersister.php
index f872cc1c6d4..36efcc6999a 100644
--- a/lib/Doctrine/ORM/Persisters/Collection/OneToManyPersister.php
+++ b/lib/Doctrine/ORM/Persisters/Collection/OneToManyPersister.php
@@ -180,11 +180,9 @@ public function loadCriteria(PersistentCollection $collection, Criteria $criteri
     }
 
     /**
-     * @return int
-     *
      * @throws DBALException
      */
-    private function deleteEntityCollection(PersistentCollection $collection)
+    private function deleteEntityCollection(PersistentCollection $collection): int
     {
         $mapping     = $collection->getMapping();
         $identifier  = $this->uow->getEntityIdentifier($collection->getOwner());
@@ -210,11 +208,9 @@ private function deleteEntityCollection(PersistentCollection $collection)
      *
      * Thanks Steve Ebersole (Hibernate) for idea on how to tackle reliably this scenario, we owe him a beer! =)
      *
-     * @return int
-     *
      * @throws DBALException
      */
-    private function deleteJoinedEntityCollection(PersistentCollection $collection)
+    private function deleteJoinedEntityCollection(PersistentCollection $collection): int
     {
         $mapping     = $collection->getMapping();
         $sourceClass = $this->em->getClassMetadata($mapping['sourceEntity']);
diff --git a/lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php b/lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php
index c81c3d67713..5d2362f8f8c 100644
--- a/lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php
+++ b/lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php
@@ -24,9 +24,9 @@
 use Doctrine\Common\Collections\Expr\Comparison;
 use Doctrine\Common\Util\ClassUtils;
 use Doctrine\DBAL\Connection;
+use Doctrine\DBAL\Driver\ResultStatement as DriverStatement;
 use Doctrine\DBAL\LockMode;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
-use Doctrine\DBAL\Statement;
 use Doctrine\DBAL\Types\Type;
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\Mapping\ClassMetadata;
@@ -414,13 +414,15 @@ public function update($entity)
      * @param mixed[] $updateData      The map of columns to update (column => value).
      * @param bool    $versioned       Whether the UPDATE should be versioned.
      *
-     * @return void
-     *
      * @throws ORMException
      * @throws OptimisticLockException
      */
-    final protected function updateTable($entity, $quotedTableName, array $updateData, $versioned = false)
-    {
+    final protected function updateTable(
+        $entity,
+        $quotedTableName,
+        array $updateData,
+        $versioned = false
+    ): void {
         $set    = [];
         $types  = [];
         $params = [];
@@ -913,12 +915,11 @@ public function getManyToManyCollection(array $assoc, $sourceEntity, $offset = n
     /**
      * Loads an array of entities from a given DBAL statement.
      *
-     * @param mixed[]   $assoc
-     * @param Statement $stmt
+     * @param mixed[] $assoc
      *
      * @return mixed[]
      */
-    private function loadArrayFromStatement($assoc, $stmt)
+    private function loadArrayFromStatement(array $assoc, DriverStatement $stmt): array
     {
         $rsm   = $this->currentPersisterContext->rsm;
         $hints = [UnitOfWork::HINT_DEFEREAGERLOAD => true];
@@ -934,14 +935,15 @@ private function loadArrayFromStatement($assoc, $stmt)
     /**
      * Hydrates a collection from a given DBAL statement.
      *
-     * @param mixed[]              $assoc
-     * @param Statement            $stmt
-     * @param PersistentCollection $coll
+     * @param mixed[] $assoc
      *
      * @return mixed[]
      */
-    private function loadCollectionFromStatement($assoc, $stmt, $coll)
-    {
+    private function loadCollectionFromStatement(
+        array $assoc,
+        DriverStatement $stmt,
+        PersistentCollection $coll
+    ): array {
         $rsm   = $this->currentPersisterContext->rsm;
         $hints = [
             UnitOfWork::HINT_DEFEREAGERLOAD => true,
@@ -970,7 +972,7 @@ public function loadManyToManyCollection(array $assoc, $sourceEntity, Persistent
      * @param object $sourceEntity
      * @psalm-param array<string, mixed> $assoc
      *
-     * @return \Doctrine\DBAL\Driver\Statement
+     * @return DriverStatement
      *
      * @throws MappingException
      */
@@ -1651,7 +1653,6 @@ public function getSelectConditionStatementSQL($field, $value, $assoc = null, $c
     /**
      * Builds the left-hand-side of a where condition statement.
      *
-     * @param string $field
      * @psalm-param array<string, mixed>|null $assoc
      *
      * @return string[]
@@ -1659,8 +1660,10 @@ public function getSelectConditionStatementSQL($field, $value, $assoc = null, $c
      *
      * @throws ORMException
      */
-    private function getSelectConditionStatementColumnSQL($field, $assoc = null)
-    {
+    private function getSelectConditionStatementColumnSQL(
+        string $field,
+        ?array $assoc = null
+    ): array {
         if (isset($this->class->fieldMappings[$field])) {
             $className = $this->class->fieldMappings[$field]['inherited'] ?? $this->class->name;
 
@@ -1760,15 +1763,14 @@ public function loadOneToManyCollection(array $assoc, $sourceEntity, PersistentC
     /**
      * Builds criteria and execute SQL statement to fetch the one to many entities from.
      *
-     * @param object   $sourceEntity
-     * @param int|null $offset
-     * @param int|null $limit
      * @psalm-param array<string, mixed> $assoc
-     *
-     * @return Statement
      */
-    private function getOneToManyStatement(array $assoc, $sourceEntity, $offset = null, $limit = null)
-    {
+    private function getOneToManyStatement(
+        array $assoc,
+        object $sourceEntity,
+        ?int $offset = null,
+        ?int $limit = null
+    ): DriverStatement {
         $this->switchPersisterContext($offset, $limit);
 
         $criteria    = [];
@@ -1846,7 +1848,7 @@ public function expandParameters($criteria)
      * @return mixed[][]
      * @psalm-return array{0: array, 1: list<int|string|null>}
      */
-    private function expandToManyParameters($criteria)
+    private function expandToManyParameters(array $criteria): array
     {
         $params = [];
         $types  = [];
@@ -1866,15 +1868,14 @@ private function expandToManyParameters($criteria)
     /**
      * Infers field types to be used by parameter type casting.
      *
-     * @param string $field
-     * @param mixed  $value
+     * @param mixed $value
      *
      * @return int[]|null[]|string[]
      * @psalm-return list<int|string|null>
      *
      * @throws QueryException
      */
-    private function getTypes($field, $value, ClassMetadata $class)
+    private function getTypes(string $field, $value, ClassMetadata $class): array
     {
         $types = [];
 
@@ -1925,7 +1926,7 @@ private function getTypes($field, $value, ClassMetadata $class)
      *
      * @return mixed[]
      */
-    private function getValues($value)
+    private function getValues($value): array
     {
         if (is_array($value)) {
             $newValue = [];
diff --git a/lib/Doctrine/ORM/Persisters/Entity/JoinedSubclassPersister.php b/lib/Doctrine/ORM/Persisters/Entity/JoinedSubclassPersister.php
index 0ad5bab07b3..1f5026bb669 100644
--- a/lib/Doctrine/ORM/Persisters/Entity/JoinedSubclassPersister.php
+++ b/lib/Doctrine/ORM/Persisters/Entity/JoinedSubclassPersister.php
@@ -68,10 +68,8 @@ protected function getDiscriminatorColumnTableName()
     /**
      * This function finds the ClassMetadata instance in an inheritance hierarchy
      * that is responsible for enabling versioning.
-     *
-     * @return ClassMetadata
      */
-    private function getVersionedClassMetadata()
+    private function getVersionedClassMetadata(): ClassMetadata
     {
         if (isset($this->class->fieldMappings[$this->class->versionField]['inherited'])) {
             $definingClassName = $this->class->fieldMappings[$this->class->versionField]['inherited'];
@@ -576,12 +574,7 @@ protected function assignDefaultVersionValue($entity, array $id)
         $this->class->setFieldValue($entity, $this->class->versionField, $value);
     }
 
-    /**
-     * @param string $baseTableAlias
-     *
-     * @return string
-     */
-    private function getJoinSql($baseTableAlias)
+    private function getJoinSql(string $baseTableAlias): string
     {
         $joinSql          = '';
         $identifierColumn = $this->class->getIdentifierColumnNames();
diff --git a/lib/Doctrine/ORM/Proxy/ProxyFactory.php b/lib/Doctrine/ORM/Proxy/ProxyFactory.php
index d7c8c156581..f853b2ebb07 100644
--- a/lib/Doctrine/ORM/Proxy/ProxyFactory.php
+++ b/lib/Doctrine/ORM/Proxy/ProxyFactory.php
@@ -109,12 +109,11 @@ protected function createProxyDefinition($className)
     /**
      * Creates a closure capable of initializing a proxy
      *
-     * @return Closure
      * @psalm-return Closure(BaseProxy):void
      *
      * @throws EntityNotFoundException
      */
-    private function createInitializer(ClassMetadata $classMetadata, EntityPersister $entityPersister)
+    private function createInitializer(ClassMetadata $classMetadata, EntityPersister $entityPersister): Closure
     {
         $wakeupProxy = $classMetadata->getReflectionClass()->hasMethod('__wakeup');
 
@@ -161,12 +160,11 @@ private function createInitializer(ClassMetadata $classMetadata, EntityPersister
     /**
      * Creates a closure capable of finalizing state a cloned proxy
      *
-     * @return Closure
      * @psalm-return Closure(BaseProxy):void
      *
      * @throws EntityNotFoundException
      */
-    private function createCloner(ClassMetadata $classMetadata, EntityPersister $entityPersister)
+    private function createCloner(ClassMetadata $classMetadata, EntityPersister $entityPersister): Closure
     {
         return function (BaseProxy $proxy) use ($entityPersister, $classMetadata): void {
             if ($proxy->__isInitialized()) {
diff --git a/lib/Doctrine/ORM/Query.php b/lib/Doctrine/ORM/Query.php
index d08ebdc7877..88cd5aaf027 100644
--- a/lib/Doctrine/ORM/Query.php
+++ b/lib/Doctrine/ORM/Query.php
@@ -22,6 +22,7 @@
 
 use Doctrine\Common\Cache\Cache;
 use Doctrine\Common\Collections\ArrayCollection;
+use Doctrine\DBAL\Driver\Statement;
 use Doctrine\DBAL\LockMode;
 use Doctrine\DBAL\Types\Type;
 use Doctrine\ORM\Internal\Hydration\IterableResult;
@@ -234,10 +235,8 @@ protected function getResultSetMapping()
      * Parses the DQL query, if necessary, and stores the parser result.
      *
      * Note: Populates $this->_parserResult as a side-effect.
-     *
-     * @return ParserResult
      */
-    private function parse()
+    private function parse(): ParserResult
     {
         $types = [];
 
@@ -335,15 +334,13 @@ protected function _doExecute()
      * @param array<string,mixed> $sqlParams
      * @param array<string,Type>  $types
      * @param array<string,mixed> $connectionParams
-     *
-     * @return void
      */
     private function evictResultSetCache(
         AbstractSqlExecutor $executor,
         array $sqlParams,
         array $types,
         array $connectionParams
-    ) {
+    ): void {
         if ($this->_queryCacheProfile === null || ! $this->getExpireResultCache()) {
             return;
         }
@@ -360,10 +357,8 @@ private function evictResultSetCache(
 
     /**
      * Evict entity cache region
-     *
-     * @return void
      */
-    private function evictEntityCacheRegion()
+    private function evictEntityCacheRegion(): void
     {
         $AST = $this->getAST();
 
@@ -502,7 +497,7 @@ public function useQueryCache($bool): self
      * @return Cache|null The cache driver used for query caching or NULL, if
      * this Query does not use query caching.
      */
-    public function getQueryCacheDriver()
+    public function getQueryCacheDriver(): ?Cache
     {
         if ($this->queryCache) {
             return $this->queryCache;
@@ -531,10 +526,8 @@ public function setQueryCacheLifetime($timeToLive): self
 
     /**
      * Retrieves the lifetime of resultset cache.
-     *
-     * @return int
      */
-    public function getQueryCacheLifetime()
+    public function getQueryCacheLifetime(): ?int
     {
         return $this->queryCacheTTL;
     }
@@ -555,20 +548,16 @@ public function expireQueryCache($expire = true): self
 
     /**
      * Retrieves if the query cache is active or not.
-     *
-     * @return bool
      */
-    public function getExpireQueryCache()
+    public function getExpireQueryCache(): bool
     {
         return $this->expireQueryCache;
     }
 
     /**
-     * @return void
-     *
      * @override
      */
-    public function free()
+    public function free(): void
     {
         parent::free();
 
@@ -593,10 +582,8 @@ public function setDQL($dqlQuery): self
 
     /**
      * Returns the DQL query that is represented by this query object.
-     *
-     * @return string|null
      */
-    public function getDQL()
+    public function getDQL(): ?string
     {
         return $this->dql;
     }
@@ -611,7 +598,7 @@ public function getDQL()
      *
      * @return int The query state.
      */
-    public function getState()
+    public function getState(): int
     {
         return $this->_state;
     }
@@ -620,10 +607,8 @@ public function getState()
      * Method to check if an arbitrary piece of DQL exists
      *
      * @param string $dql Arbitrary piece of DQL to check for.
-     *
-     * @return bool
      */
-    public function contains($dql)
+    public function contains($dql): bool
     {
         return stripos($this->getDQL(), $dql) !== false;
     }
@@ -649,7 +634,7 @@ public function setFirstResult($firstResult): self
      *
      * @return int|null The position of the first result.
      */
-    public function getFirstResult()
+    public function getFirstResult(): ?int
     {
         return $this->firstResult;
     }
@@ -675,7 +660,7 @@ public function setMaxResults($maxResults): self
      *
      * @return int|null Maximum number of results.
      */
-    public function getMaxResults()
+    public function getMaxResults(): ?int
     {
         return $this->maxResults;
     }
@@ -689,10 +674,8 @@ public function getMaxResults()
      * @param ArrayCollection|mixed[]|null $parameters    The query parameters.
      * @param string|int                   $hydrationMode The hydration mode to use.
      * @psalm-param ArrayCollection<int, Parameter>|array<string, mixed>|null $parameters
-     *
-     * @return IterableResult
      */
-    public function iterate($parameters = null, $hydrationMode = self::HYDRATE_OBJECT)
+    public function iterate($parameters = null, $hydrationMode = self::HYDRATE_OBJECT): IterableResult
     {
         $this->setHint(self::HINT_INTERNAL_ITERATION, true);
 
@@ -710,7 +693,7 @@ public function toIterable(iterable $parameters = [], $hydrationMode = self::HYD
     /**
      * {@inheritdoc}
      */
-    public function setHint($name, $value)
+    public function setHint($name, $value): self
     {
         $this->_state = self::STATE_DIRTY;
 
@@ -720,7 +703,7 @@ public function setHint($name, $value)
     /**
      * {@inheritdoc}
      */
-    public function setHydrationMode($hydrationMode)
+    public function setHydrationMode($hydrationMode): self
     {
         $this->_state = self::STATE_DIRTY;
 
@@ -754,7 +737,7 @@ public function setLockMode($lockMode): self
      *
      * @return int|null The current lock mode of this query or NULL if no specific lock mode is set.
      */
-    public function getLockMode()
+    public function getLockMode(): ?int
     {
         $lockMode = $this->getHint(self::HINT_LOCK_MODE);
 
@@ -786,18 +769,13 @@ protected function getQueryCacheId(): string
         );
     }
 
-     /**
-      * {@inheritdoc}
-      */
-    protected function getHash()
+    protected function getHash(): string
     {
         return sha1(parent::getHash() . '-' . $this->firstResult . '-' . $this->maxResults);
     }
 
     /**
      * Cleanup Query resource when clone is called.
-     *
-     * @return void
      */
     public function __clone()
     {
diff --git a/lib/Doctrine/ORM/Query/AST/Functions/TrimFunction.php b/lib/Doctrine/ORM/Query/AST/Functions/TrimFunction.php
index 9a6642decf9..e41122b37c7 100644
--- a/lib/Doctrine/ORM/Query/AST/Functions/TrimFunction.php
+++ b/lib/Doctrine/ORM/Query/AST/Functions/TrimFunction.php
@@ -93,10 +93,9 @@ public function parse(Parser $parser)
     }
 
     /**
-     * @return int
      * @psalm-return AbstractPlatform::TRIM_*
      */
-    private function getTrimMode()
+    private function getTrimMode(): int
     {
         if ($this->leading) {
             return AbstractPlatform::TRIM_LEADING;
@@ -113,10 +112,7 @@ private function getTrimMode()
         return AbstractPlatform::TRIM_UNSPECIFIED;
     }
 
-    /**
-     * @return void
-     */
-    private function parseTrimMode(Parser $parser)
+    private function parseTrimMode(Parser $parser): void
     {
         $lexer = $parser->getLexer();
         $value = $lexer->lookahead['value'];
diff --git a/lib/Doctrine/ORM/Query/Expr/Composite.php b/lib/Doctrine/ORM/Query/Expr/Composite.php
index 425e352d01a..b84902eeb4d 100644
--- a/lib/Doctrine/ORM/Query/Expr/Composite.php
+++ b/lib/Doctrine/ORM/Query/Expr/Composite.php
@@ -51,10 +51,8 @@ public function __toString()
 
     /**
      * @param string|object $part
-     *
-     * @return string
      */
-    private function processQueryPart($part)
+    private function processQueryPart($part): string
     {
         $queryPart = (string) $part;
 
diff --git a/lib/Doctrine/ORM/Query/Filter/SQLFilter.php b/lib/Doctrine/ORM/Query/Filter/SQLFilter.php
index f9cb0a59a40..9cd80d05482 100644
--- a/lib/Doctrine/ORM/Query/Filter/SQLFilter.php
+++ b/lib/Doctrine/ORM/Query/Filter/SQLFilter.php
@@ -135,10 +135,8 @@ final public function __toString()
 
     /**
      * Returns the database connection used by the entity manager
-     *
-     * @return Connection
      */
-    final protected function getConnection()
+    final protected function getConnection(): Connection
     {
         return $this->em->getConnection();
     }
diff --git a/lib/Doctrine/ORM/Query/Parser.php b/lib/Doctrine/ORM/Query/Parser.php
index 60244a8e63e..d8199649d89 100644
--- a/lib/Doctrine/ORM/Query/Parser.php
+++ b/lib/Doctrine/ORM/Query/Parser.php
@@ -463,10 +463,8 @@ public function parse()
      * as the hydration process relies on that order for proper operation.
      *
      * @param AST\SelectStatement|AST\DeleteStatement|AST\UpdateStatement $AST
-     *
-     * @return void
      */
-    private function fixIdentificationVariableOrder($AST)
+    private function fixIdentificationVariableOrder(Node $AST): void
     {
         if (count($this->identVariableExpressions) <= 1) {
             return;
@@ -557,7 +555,7 @@ public function semanticalError($message = '', $token = null)
      * @return mixed[]
      * @psalm-return array{value: string, type: int|null|string, position: int}|null
      */
-    private function peekBeyondClosingParenthesis(bool $resetPeek = true)
+    private function peekBeyondClosingParenthesis(bool $resetPeek = true): ?array
     {
         $token        = $this->lexer->peek();
         $numUnmatched = 1;
@@ -589,9 +587,9 @@ private function peekBeyondClosingParenthesis(bool $resetPeek = true)
     /**
      * Checks if the given token indicates a mathematical operator.
      *
-     * @psalm-param array<string, mixed> $token
+     * @psalm-param array<string, mixed>|null $token
      */
-    private function isMathOperator($token): bool
+    private function isMathOperator(?array $token): bool
     {
         return $token !== null && in_array($token['type'], [Lexer::T_PLUS, Lexer::T_MINUS, Lexer::T_DIVIDE, Lexer::T_MULTIPLY]);
     }
@@ -1039,11 +1037,9 @@ public function AbstractSchemaName()
      *
      * @param string $schemaName The name to validate.
      *
-     * @return void
-     *
      * @throws QueryException if the name does not exist.
      */
-    private function validateAbstractSchemaName($schemaName)
+    private function validateAbstractSchemaName(string $schemaName): void
     {
         if (! (class_exists($schemaName, true) || interface_exists($schemaName, true))) {
             $this->semanticalError(
@@ -3488,10 +3484,8 @@ public function FunctionDeclaration()
 
     /**
      * Helper function for FunctionDeclaration grammar rule.
-     *
-     * @return FunctionNode
      */
-    private function CustomFunctionDeclaration()
+    private function CustomFunctionDeclaration(): ?FunctionNode
     {
         $token    = $this->lexer->lookahead;
         $funcName = strtolower($token['value']);
diff --git a/lib/Doctrine/ORM/Query/ResultSetMappingBuilder.php b/lib/Doctrine/ORM/Query/ResultSetMappingBuilder.php
index 9a2af839d1f..23c7714c445 100644
--- a/lib/Doctrine/ORM/Query/ResultSetMappingBuilder.php
+++ b/lib/Doctrine/ORM/Query/ResultSetMappingBuilder.php
@@ -194,13 +194,9 @@ private function isInheritanceSupported(ClassMetadataInfo $classMetadata): bool
     /**
      * Gets column alias for a given column.
      *
-     * @param string $columnName
-     * @param int    $mode
      * @psalm-param array<string, string>  $customRenameColumns
-     *
-     * @return string
      */
-    private function getColumnAlias($columnName, $mode, array $customRenameColumns)
+    private function getColumnAlias(string $columnName, int $mode, array $customRenameColumns): string
     {
         switch ($mode) {
             case self::COLUMN_RENAMING_INCREMENT:
@@ -211,6 +207,12 @@ private function getColumnAlias($columnName, $mode, array $customRenameColumns)
 
             case self::COLUMN_RENAMING_NONE:
                 return $columnName;
+
+            default:
+                throw new InvalidArgumentException(sprintf(
+                    '%d is not a valid value for $mode',
+                    $mode
+                ));
         }
     }
 
@@ -219,15 +221,18 @@ private function getColumnAlias($columnName, $mode, array $customRenameColumns)
      *
      * This depends on the renaming mode selected by the user.
      *
-     * @param string $className
-     * @param int    $mode
+     * @psalm-param class-string $className
+     * @psalm-param self::COLUMN_RENAMING_* $mode
      * @psalm-param array<string, string> $customRenameColumns
      *
      * @return string[]
      * @psalm-return array<array-key, string>
      */
-    private function getColumnAliasMap($className, $mode, array $customRenameColumns)
-    {
+    private function getColumnAliasMap(
+        string $className,
+        int $mode,
+        array $customRenameColumns
+    ): array {
         if ($customRenameColumns) { // for BC with 2.2-2.3 API
             $mode = self::COLUMN_RENAMING_CUSTOM;
         }
diff --git a/lib/Doctrine/ORM/Query/SqlWalker.php b/lib/Doctrine/ORM/Query/SqlWalker.php
index fc36b82edd1..e93d463d2fc 100644
--- a/lib/Doctrine/ORM/Query/SqlWalker.php
+++ b/lib/Doctrine/ORM/Query/SqlWalker.php
@@ -934,11 +934,11 @@ public function walkRangeVariableDeclaration($rangeVariableDeclaration)
 
     /**
      * Generate appropriate SQL for RangeVariableDeclaration AST node
-     *
-     * @param AST\RangeVariableDeclaration $rangeVariableDeclaration
      */
-    private function generateRangeVariableDeclarationSQL($rangeVariableDeclaration, bool $buildNestedJoins): string
-    {
+    private function generateRangeVariableDeclarationSQL(
+        AST\RangeVariableDeclaration $rangeVariableDeclaration,
+        bool $buildNestedJoins
+    ): string {
         $class    = $this->em->getClassMetadata($rangeVariableDeclaration->abstractSchemaName);
         $dqlAlias = $rangeVariableDeclaration->aliasIdentificationVariable;
 
@@ -2352,8 +2352,10 @@ public function walkResultVariable($resultVariable)
      *
      * @throws QueryException
      */
-    private function getChildDiscriminatorsFromClassMetadata(ClassMetadataInfo $rootClass, AST\InstanceOfExpression $instanceOfExpr): string
-    {
+    private function getChildDiscriminatorsFromClassMetadata(
+        ClassMetadataInfo $rootClass,
+        AST\InstanceOfExpression $instanceOfExpr
+    ): string {
         $sqlParameterList = [];
         $discriminators   = [];
         foreach ($instanceOfExpr->value as $parameter) {
diff --git a/lib/Doctrine/ORM/QueryBuilder.php b/lib/Doctrine/ORM/QueryBuilder.php
index 365ac4a570c..6541f8c2420 100644
--- a/lib/Doctrine/ORM/QueryBuilder.php
+++ b/lib/Doctrine/ORM/QueryBuilder.php
@@ -292,7 +292,7 @@ public function getType()
     /**
      * Gets the associated EntityManager for this query builder.
      *
-     * @return EntityManager
+     * @return EntityManagerInterface
      */
     public function getEntityManager()
     {
@@ -393,10 +393,8 @@ public function getQuery()
      *
      * @param string $alias       The alias of the new join entity
      * @param string $parentAlias The parent entity alias of the join relationship
-     *
-     * @return string
      */
-    private function findRootAlias($alias, $parentAlias)
+    private function findRootAlias(string $alias, string $parentAlias): string
     {
         $rootAlias = null;
 
@@ -1388,10 +1386,7 @@ public function getDQLParts()
         return $this->_dqlParts;
     }
 
-    /**
-     * @return string
-     */
-    private function getDQLForDelete()
+    private function getDQLForDelete(): string
     {
          return 'DELETE'
               . $this->getReducedDQLQueryPart('from', ['pre' => ' ', 'separator' => ', '])
@@ -1399,10 +1394,7 @@ private function getDQLForDelete()
               . $this->getReducedDQLQueryPart('orderBy', ['pre' => ' ORDER BY ', 'separator' => ', ']);
     }
 
-    /**
-     * @return string
-     */
-    private function getDQLForUpdate()
+    private function getDQLForUpdate(): string
     {
          return 'UPDATE'
               . $this->getReducedDQLQueryPart('from', ['pre' => ' ', 'separator' => ', '])
@@ -1411,10 +1403,7 @@ private function getDQLForUpdate()
               . $this->getReducedDQLQueryPart('orderBy', ['pre' => ' ORDER BY ', 'separator' => ', ']);
     }
 
-    /**
-     * @return string
-     */
-    private function getDQLForSelect()
+    private function getDQLForSelect(): string
     {
         $dql = 'SELECT'
              . ($this->_dqlParts['distinct'] === true ? ' DISTINCT' : '')
diff --git a/lib/Doctrine/ORM/Repository/DefaultRepositoryFactory.php b/lib/Doctrine/ORM/Repository/DefaultRepositoryFactory.php
index 53a1b017cb1..f7fe2476a42 100644
--- a/lib/Doctrine/ORM/Repository/DefaultRepositoryFactory.php
+++ b/lib/Doctrine/ORM/Repository/DefaultRepositoryFactory.php
@@ -40,7 +40,7 @@ final class DefaultRepositoryFactory implements RepositoryFactory
     /**
      * {@inheritdoc}
      */
-    public function getRepository(EntityManagerInterface $entityManager, $entityName)
+    public function getRepository(EntityManagerInterface $entityManager, $entityName): ObjectRepository
     {
         $repositoryHash = $entityManager->getClassMetadata($entityName)->getName() . spl_object_hash($entityManager);
 
@@ -56,11 +56,11 @@ public function getRepository(EntityManagerInterface $entityManager, $entityName
      *
      * @param EntityManagerInterface $entityManager The EntityManager instance.
      * @param string                 $entityName    The name of the entity.
-     *
-     * @return ObjectRepository
      */
-    private function createRepository(EntityManagerInterface $entityManager, $entityName)
-    {
+    private function createRepository(
+        EntityManagerInterface $entityManager,
+        string $entityName
+    ): ObjectRepository {
         $metadata            = $entityManager->getClassMetadata($entityName);
         $repositoryClassName = $metadata->customRepositoryClassName
             ?: $entityManager->getConfiguration()->getDefaultRepositoryClassName();
diff --git a/lib/Doctrine/ORM/Tools/Console/Command/MappingDescribeCommand.php b/lib/Doctrine/ORM/Tools/Console/Command/MappingDescribeCommand.php
index 02b95ea16f2..87fffe0f4d7 100644
--- a/lib/Doctrine/ORM/Tools/Console/Command/MappingDescribeCommand.php
+++ b/lib/Doctrine/ORM/Tools/Console/Command/MappingDescribeCommand.php
@@ -58,10 +58,7 @@
  */
 final class MappingDescribeCommand extends AbstractEntityManagerCommand
 {
-    /**
-     * {@inheritdoc}
-     */
-    protected function configure()
+    protected function configure(): void
     {
         $this->setName('orm:mapping:describe')
              ->addArgument('entityName', InputArgument::REQUIRED, 'Full or partial name of entity')
@@ -79,10 +76,7 @@ protected function configure()
              );
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $ui = new SymfonyStyle($input, $output);
 
@@ -97,11 +91,12 @@ protected function execute(InputInterface $input, OutputInterface $output)
      * Display all the mapping information for a single Entity.
      *
      * @param string $entityName Full or partial entity class name
-     *
-     * @return void
      */
-    private function displayEntity($entityName, EntityManagerInterface $entityManager, SymfonyStyle $ui)
-    {
+    private function displayEntity(
+        string $entityName,
+        EntityManagerInterface $entityManager,
+        SymfonyStyle $ui
+    ): void {
         $metadata = $this->getClassMetadata($entityName, $entityManager);
 
         $ui->table(
@@ -172,11 +167,11 @@ private function getMappedEntities(EntityManagerInterface $entityManager): array
      * name
      *
      * @param string $entityName Full or partial entity name
-     *
-     * @return ClassMetadata
      */
-    private function getClassMetadata($entityName, EntityManagerInterface $entityManager)
-    {
+    private function getClassMetadata(
+        string $entityName,
+        EntityManagerInterface $entityManager
+    ): ClassMetadata {
         try {
             return $entityManager->getClassMetadata($entityName);
         } catch (MappingException $e) {
@@ -211,10 +206,8 @@ static function ($mappedEntity) use ($entityName) {
      * Format the given value for console output
      *
      * @param mixed $value
-     *
-     * @return string
      */
-    private function formatValue($value)
+    private function formatValue($value): string
     {
         if ($value === '') {
             return '';
@@ -256,7 +249,7 @@ private function formatValue($value)
      * @return string[]
      * @psalm-return array{0: string, 1: string}
      */
-    private function formatField($label, $value): array
+    private function formatField(string $label, $value): array
     {
         if ($value === null) {
             $value = '<comment>None</comment>';
diff --git a/lib/Doctrine/ORM/Tools/ConvertDoctrine1Schema.php b/lib/Doctrine/ORM/Tools/ConvertDoctrine1Schema.php
index d1a1f162dd5..7c1a0cf8274 100644
--- a/lib/Doctrine/ORM/Tools/ConvertDoctrine1Schema.php
+++ b/lib/Doctrine/ORM/Tools/ConvertDoctrine1Schema.php
@@ -106,8 +106,10 @@ public function getMetadata()
     /**
      * @param mixed[] $mappingInformation
      */
-    private function convertToClassMetadataInfo(string $className, $mappingInformation): ClassMetadataInfo
-    {
+    private function convertToClassMetadataInfo(
+        string $className,
+        array $mappingInformation
+    ): ClassMetadataInfo {
         $metadata = new ClassMetadataInfo($className);
 
         $this->convertTableName($className, $mappingInformation, $metadata);
@@ -136,13 +138,13 @@ private function convertTableName(string $className, array $model, ClassMetadata
     }
 
     /**
-     * @param string  $className
      * @param mixed[] $model
-     *
-     * @return void
      */
-    private function convertColumns($className, array $model, ClassMetadataInfo $metadata)
-    {
+    private function convertColumns(
+        string $className,
+        array $model,
+        ClassMetadataInfo $metadata
+    ): void {
         $id = false;
 
         if (isset($model['columns']) && $model['columns']) {
@@ -168,16 +170,18 @@ private function convertColumns($className, array $model, ClassMetadataInfo $met
     }
 
     /**
-     * @param string         $className
-     * @param string         $name
      * @param string|mixed[] $column
      *
      * @return mixed[]
      *
      * @throws ToolsException
      */
-    private function convertColumn($className, $name, $column, ClassMetadataInfo $metadata)
-    {
+    private function convertColumn(
+        string $className,
+        string $name,
+        $column,
+        ClassMetadataInfo $metadata
+    ): array {
         if (is_string($column)) {
             $string         = $column;
             $column         = [];
@@ -258,13 +262,13 @@ private function convertColumn($className, $name, $column, ClassMetadataInfo $me
     }
 
     /**
-     * @param string  $className
      * @param mixed[] $model
-     *
-     * @return void
      */
-    private function convertIndexes($className, array $model, ClassMetadataInfo $metadata)
-    {
+    private function convertIndexes(
+        string $className,
+        array $model,
+        ClassMetadataInfo $metadata
+    ): void {
         if (empty($model['indexes'])) {
             return;
         }
@@ -280,13 +284,13 @@ private function convertIndexes($className, array $model, ClassMetadataInfo $met
     }
 
     /**
-     * @param string  $className
      * @param mixed[] $model
-     *
-     * @return void
      */
-    private function convertRelations($className, array $model, ClassMetadataInfo $metadata)
-    {
+    private function convertRelations(
+        string $className,
+        array $model,
+        ClassMetadataInfo $metadata
+    ): void {
         if (empty($model['relations'])) {
             return;
         }
diff --git a/lib/Doctrine/ORM/Tools/DebugUnitOfWorkListener.php b/lib/Doctrine/ORM/Tools/DebugUnitOfWorkListener.php
index f9a9b046aba..e4ee09ae2b0 100644
--- a/lib/Doctrine/ORM/Tools/DebugUnitOfWorkListener.php
+++ b/lib/Doctrine/ORM/Tools/DebugUnitOfWorkListener.php
@@ -137,10 +137,8 @@ public function dumpIdentityMap(EntityManagerInterface $em)
 
     /**
      * @param mixed $var
-     *
-     * @return string
      */
-    private function getType($var)
+    private function getType($var): string
     {
         if (is_object($var)) {
             $refl = new ReflectionObject($var);
@@ -153,10 +151,8 @@ private function getType($var)
 
     /**
      * @param object $entity
-     *
-     * @return string
      */
-    private function getIdString($entity, UnitOfWork $uow)
+    private function getIdString($entity, UnitOfWork $uow): string
     {
         if ($uow->isInIdentityMap($entity)) {
             $ids      = $uow->getEntityIdentifier($entity);
diff --git a/lib/Doctrine/ORM/Tools/EntityGenerator.php b/lib/Doctrine/ORM/Tools/EntityGenerator.php
index 959d02d23fb..a10e165dba0 100644
--- a/lib/Doctrine/ORM/Tools/EntityGenerator.php
+++ b/lib/Doctrine/ORM/Tools/EntityGenerator.php
@@ -747,10 +747,7 @@ protected function generateEntityConstructor(ClassMetadataInfo $metadata)
         return '';
     }
 
-    /**
-     * @return string
-     */
-    private function generateEmbeddableConstructor(ClassMetadataInfo $metadata)
+    private function generateEmbeddableConstructor(ClassMetadataInfo $metadata): string
     {
         $paramTypes     = [];
         $paramVariables = [];
diff --git a/lib/Doctrine/ORM/Tools/EntityRepositoryGenerator.php b/lib/Doctrine/ORM/Tools/EntityRepositoryGenerator.php
index 6bf9baf7fcd..cc8852f7ec3 100644
--- a/lib/Doctrine/ORM/Tools/EntityRepositoryGenerator.php
+++ b/lib/Doctrine/ORM/Tools/EntityRepositoryGenerator.php
@@ -96,11 +96,9 @@ public function generateEntityRepositoryClass($fullClassName)
     /**
      * Generates the namespace, if class do not have namespace, return empty string instead.
      *
-     * @param string $fullClassName
-     *
-     * @return string $namespace
+     * @psalm-param class-string $fullClassName
      */
-    private function getClassNamespace($fullClassName)
+    private function getClassNamespace(string $fullClassName): string
     {
         return substr($fullClassName, 0, strrpos($fullClassName, '\\'));
     }
@@ -108,11 +106,9 @@ private function getClassNamespace($fullClassName)
     /**
      * Generates the class name
      *
-     * @param string $fullClassName
-     *
-     * @return string
+     * @psalm-param class-string $fullClassName
      */
-    private function generateClassName($fullClassName)
+    private function generateClassName(string $fullClassName): string
     {
         $namespace = $this->getClassNamespace($fullClassName);
 
@@ -128,23 +124,16 @@ private function generateClassName($fullClassName)
     /**
      * Generates the namespace statement, if class do not have namespace, return empty string instead.
      *
-     * @param string $fullClassName The full repository class name.
-     *
-     * @return string
+     * @psalm-param class-string $fullClassName The full repository class name.
      */
-    private function generateEntityRepositoryNamespace($fullClassName)
+    private function generateEntityRepositoryNamespace(string $fullClassName): string
     {
         $namespace = $this->getClassNamespace($fullClassName);
 
         return $namespace ? 'namespace ' . $namespace . ';' : '';
     }
 
-    /**
-     * @param string $fullClassName
-     *
-     * @return string $repositoryName
-     */
-    private function generateEntityRepositoryName($fullClassName)
+    private function generateEntityRepositoryName(string $fullClassName): string
     {
         $namespace = $this->getClassNamespace($fullClassName);
 
diff --git a/lib/Doctrine/ORM/Tools/Pagination/LimitSubqueryOutputWalker.php b/lib/Doctrine/ORM/Tools/Pagination/LimitSubqueryOutputWalker.php
index 6a80ddfc40f..a47a018dd0a 100644
--- a/lib/Doctrine/ORM/Tools/Pagination/LimitSubqueryOutputWalker.php
+++ b/lib/Doctrine/ORM/Tools/Pagination/LimitSubqueryOutputWalker.php
@@ -128,10 +128,8 @@ public function __construct($query, $parserResult, array $queryComponents)
 
     /**
      * Check if the platform supports the ROW_NUMBER window function.
-     *
-     * @return bool
      */
-    private function platformSupportsRowNumber()
+    private function platformSupportsRowNumber(): bool
     {
         return $this->platform instanceof PostgreSqlPlatform
             || $this->platform instanceof SQLServerPlatform
@@ -145,10 +143,8 @@ private function platformSupportsRowNumber()
     /**
      * Rebuilds a select statement's order by clause for use in a
      * ROW_NUMBER() OVER() expression.
-     *
-     * @return void
      */
-    private function rebuildOrderByForRowNumber(SelectStatement $AST)
+    private function rebuildOrderByForRowNumber(SelectStatement $AST): void
     {
         $orderByClause              = $AST->orderByClause;
         $selectAliasToExpressionMap = [];
@@ -307,10 +303,8 @@ public function walkSelectStatementWithoutRowNumber(SelectStatement $AST, $addMi
     /**
      * Finds all PathExpressions in an AST's OrderByClause, and ensures that
      * the referenced fields are present in the SelectClause of the passed AST.
-     *
-     * @return void
      */
-    private function addMissingItemsFromOrderByToSelect(SelectStatement $AST)
+    private function addMissingItemsFromOrderByToSelect(SelectStatement $AST): void
     {
         $this->orderByPathExpressions = [];
 
@@ -490,12 +484,10 @@ public function getOrderByPathExpressions()
     }
 
     /**
-     * @return string
-     *
      * @throws OptimisticLockException
      * @throws QueryException
      */
-    private function getInnerSQL(SelectStatement $AST)
+    private function getInnerSQL(SelectStatement $AST): string
     {
         // Set every select expression as visible(hidden = false) to
         // make $AST have scalar mappings properly - this is relevant for referencing selected
@@ -520,7 +512,7 @@ private function getInnerSQL(SelectStatement $AST)
     /**
      * @return string[]
      */
-    private function getSQLIdentifier(SelectStatement $AST)
+    private function getSQLIdentifier(SelectStatement $AST): array
     {
         // Find out the SQL alias of the identifier column of the root entity.
         // It may be possible to make this work with multiple root entities but that
diff --git a/lib/Doctrine/ORM/Tools/Pagination/LimitSubqueryWalker.php b/lib/Doctrine/ORM/Tools/Pagination/LimitSubqueryWalker.php
index 129f3dcc140..694d06b4d3b 100644
--- a/lib/Doctrine/ORM/Tools/Pagination/LimitSubqueryWalker.php
+++ b/lib/Doctrine/ORM/Tools/Pagination/LimitSubqueryWalker.php
@@ -24,6 +24,7 @@
 use Doctrine\ORM\Mapping\ClassMetadataInfo;
 use Doctrine\ORM\Query;
 use Doctrine\ORM\Query\AST\Functions\IdentityFunction;
+use Doctrine\ORM\Query\AST\Node;
 use Doctrine\ORM\Query\AST\PathExpression;
 use Doctrine\ORM\Query\AST\SelectExpression;
 use Doctrine\ORM\Query\AST\SelectStatement;
@@ -121,10 +122,8 @@ public function walkSelectStatement(SelectStatement $AST)
 
     /**
      * Validate the AST to ensure that this walker is able to properly manipulate it.
-     *
-     * @return void
      */
-    private function validate(SelectStatement $AST)
+    private function validate(SelectStatement $AST): void
     {
         // Prevent LimitSubqueryWalker from being used with queries that include
         // a limit, a fetched to-many join, and an order by condition that
@@ -165,7 +164,7 @@ private function validate(SelectStatement $AST)
      *
      * @return IdentityFunction|PathExpression
      */
-    private function createSelectExpressionItem(PathExpression $pathExpression)
+    private function createSelectExpressionItem(PathExpression $pathExpression): Node
     {
         if ($pathExpression->type === PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION) {
             $identity = new IdentityFunction('identity');
diff --git a/lib/Doctrine/ORM/Tools/Pagination/Paginator.php b/lib/Doctrine/ORM/Tools/Pagination/Paginator.php
index d7387faa4fa..318e0ef4c69 100644
--- a/lib/Doctrine/ORM/Tools/Pagination/Paginator.php
+++ b/lib/Doctrine/ORM/Tools/Pagination/Paginator.php
@@ -181,14 +181,7 @@ public function getIterator()
         return new ArrayIterator($result);
     }
 
-    /**
-     * Clones a query.
-     *
-     * @param Query $query The query.
-     *
-     * @return Query The cloned query.
-     */
-    private function cloneQuery(Query $query)
+    private function cloneQuery(Query $query): Query
     {
         $cloneQuery = clone $query;
 
@@ -204,12 +197,8 @@ private function cloneQuery(Query $query)
 
     /**
      * Determines whether to use an output walker for the query.
-     *
-     * @param Query $query The query.
-     *
-     * @return bool
      */
-    private function useOutputWalker(Query $query)
+    private function useOutputWalker(Query $query): bool
     {
         if ($this->useOutputWalkers === null) {
             return (bool) $query->getHint(Query::HINT_CUSTOM_OUTPUT_WALKER) === false;
@@ -221,11 +210,9 @@ private function useOutputWalker(Query $query)
     /**
      * Appends a custom tree walker to the tree walkers hint.
      *
-     * @param string $walkerClass
-     *
-     * @return void
+     * @psalm-param class-string $walkerClass
      */
-    private function appendTreeWalker(Query $query, $walkerClass)
+    private function appendTreeWalker(Query $query, string $walkerClass): void
     {
         $hints = $query->getHint(Query::HINT_CUSTOM_TREE_WALKERS);
 
@@ -239,10 +226,8 @@ private function appendTreeWalker(Query $query, $walkerClass)
 
     /**
      * Returns Query prepared to count.
-     *
-     * @return Query
      */
-    private function getCountQuery()
+    private function getCountQuery(): Query
     {
         $countQuery = $this->cloneQuery($this->query);
 
diff --git a/lib/Doctrine/ORM/Tools/ResolveTargetEntityListener.php b/lib/Doctrine/ORM/Tools/ResolveTargetEntityListener.php
index 4218020b906..63b75fc1f07 100644
--- a/lib/Doctrine/ORM/Tools/ResolveTargetEntityListener.php
+++ b/lib/Doctrine/ORM/Tools/ResolveTargetEntityListener.php
@@ -25,7 +25,6 @@
 use Doctrine\ORM\Event\OnClassMetadataNotFoundEventArgs;
 use Doctrine\ORM\Events;
 use Doctrine\ORM\Mapping\ClassMetadata;
-use Doctrine\ORM\Mapping\ClassMetadataInfo;
 
 use function array_key_exists;
 use function array_replace_recursive;
@@ -109,12 +108,9 @@ public function loadClassMetadata(LoadClassMetadataEventArgs $args)
     }
 
     /**
-     * @param ClassMetadataInfo $classMetadata
-     * @param mixed[]           $mapping
-     *
-     * @return void
+     * @param mixed[] $mapping
      */
-    private function remapAssociation($classMetadata, $mapping)
+    private function remapAssociation(ClassMetadata $classMetadata, array $mapping): void
     {
         $newMapping              = $this->resolveTargetEntities[$mapping['targetEntity']];
         $newMapping              = array_replace_recursive($mapping, $newMapping);
diff --git a/lib/Doctrine/ORM/Tools/SchemaTool.php b/lib/Doctrine/ORM/Tools/SchemaTool.php
index 2ccbede124c..f952ba1475c 100644
--- a/lib/Doctrine/ORM/Tools/SchemaTool.php
+++ b/lib/Doctrine/ORM/Tools/SchemaTool.php
@@ -422,12 +422,8 @@ static function (ClassMetadata $class) use ($idMapping): bool {
     /**
      * Gets a portable column definition as required by the DBAL for the discriminator
      * column of a class.
-     *
-     * @param ClassMetadata $class
-     *
-     * @return void
      */
-    private function addDiscriminatorColumnDefinition($class, Table $table)
+    private function addDiscriminatorColumnDefinition(ClassMetadata $class, Table $table): void
     {
         $discrColumn = $class->discriminatorColumn;
 
@@ -454,12 +450,8 @@ private function addDiscriminatorColumnDefinition($class, Table $table)
     /**
      * Gathers the column definitions as required by the DBAL of all field mappings
      * found in the given class.
-     *
-     * @param ClassMetadata $class
-     *
-     * @return void
      */
-    private function gatherColumns($class, Table $table)
+    private function gatherColumns(ClassMetadata $class, Table $table): void
     {
         $pkColumns = [];
 
diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index 4ab5f4af187..c5bbe79a763 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -513,10 +513,8 @@ private function postCommitCleanup($entity): void
 
     /**
      * Computes the changesets of all entities scheduled for insertion.
-     *
-     * @return void
      */
-    private function computeScheduleInsertsChangeSets()
+    private function computeScheduleInsertsChangeSets(): void
     {
         foreach ($this->entityInsertions as $entity) {
             $class = $this->em->getClassMetadata(get_class($entity));
@@ -535,11 +533,9 @@ private function computeScheduleInsertsChangeSets()
      *
      * @param object $entity
      *
-     * @return void
-     *
      * @throws InvalidArgumentException
      */
-    private function computeSingleEntityChangeSet($entity)
+    private function computeSingleEntityChangeSet($entity): void
     {
         $state = $this->getEntityState($entity);
 
@@ -964,12 +960,9 @@ private function computeAssociationChanges(array $assoc, $value): void
     }
 
     /**
-     * @param ClassMetadata $class
-     * @param object        $entity
-     *
-     * @return void
+     * @param object $entity
      */
-    private function persistNew($class, $entity)
+    private function persistNew(ClassMetadata $class, $entity): void
     {
         $oid    = spl_object_hash($entity);
         $invoke = $this->listenersInvoker->getSubscribedSystems($class, Events::prePersist);
@@ -1091,12 +1084,8 @@ public function recomputeSingleEntityChangeSet(ClassMetadata $class, $entity)
 
     /**
      * Executes all entity insertions for entities of the specified type.
-     *
-     * @param ClassMetadata $class
-     *
-     * @return void
      */
-    private function executeInserts($class)
+    private function executeInserts(ClassMetadata $class): void
     {
         $entities  = [];
         $className = $class->name;
@@ -1158,8 +1147,11 @@ private function executeInserts($class)
     /**
      * @param object $entity
      */
-    private function addToEntityIdentifiersAndEntityMap(ClassMetadata $class, string $oid, $entity): void
-    {
+    private function addToEntityIdentifiersAndEntityMap(
+        ClassMetadata $class,
+        string $oid,
+        $entity
+    ): void {
         $identifier = [];
 
         foreach ($class->getIdentifierFieldNames() as $idField) {
@@ -1181,12 +1173,8 @@ private function addToEntityIdentifiersAndEntityMap(ClassMetadata $class, string
 
     /**
      * Executes all entity updates for entities of the specified type.
-     *
-     * @param ClassMetadata $class
-     *
-     * @return void
      */
-    private function executeUpdates($class)
+    private function executeUpdates(ClassMetadata $class): void
     {
         $className        = $class->name;
         $persister        = $this->getEntityPersister($className);
@@ -1218,12 +1206,8 @@ private function executeUpdates($class)
 
     /**
      * Executes all entity deletions for entities of the specified type.
-     *
-     * @param ClassMetadata $class
-     *
-     * @return void
      */
-    private function executeDeletions($class)
+    private function executeDeletions(ClassMetadata $class): void
     {
         $className = $class->name;
         $persister = $this->getEntityPersister($className);
@@ -1931,6 +1915,7 @@ public function merge($entity)
     /**
      * Executes a merge operation on an entity.
      *
+     * @param object   $entity
      * @param string[] $assoc
      * @psalm-param array<string, object> $visited
      *
@@ -2038,12 +2023,13 @@ private function doMerge(
      * @param object $entity
      * @param object $managedCopy
      *
-     * @return void
-     *
      * @throws OptimisticLockException
      */
-    private function ensureVersionMatch(ClassMetadata $class, $entity, $managedCopy)
-    {
+    private function ensureVersionMatch(
+        ClassMetadata $class,
+        $entity,
+        $managedCopy
+    ): void {
         if (! ($class->isVersioned && $this->isLoaded($managedCopy) && $this->isLoaded($entity))) {
             return;
         }
@@ -2065,10 +2051,8 @@ private function ensureVersionMatch(ClassMetadata $class, $entity, $managedCopy)
      * Tests if an entity is loaded - must either be a loaded proxy or not a proxy
      *
      * @param object $entity
-     *
-     * @return bool
      */
-    private function isLoaded($entity)
+    private function isLoaded($entity): bool
     {
         return ! ($entity instanceof Proxy) || $entity->__isInitialized();
     }
@@ -2076,6 +2060,7 @@ private function isLoaded($entity)
     /**
      * Sets/adds associated managed copies into the previous entity's association field
      *
+     * @param object   $entity
      * @param string[] $association
      */
     private function updateAssociationWithMergedEntity(
@@ -2124,11 +2109,12 @@ public function detach($entity)
      * @param object  $entity
      * @param mixed[] $visited
      * @param bool    $noCascade if true, don't cascade detach operation.
-     *
-     * @return void
      */
-    private function doDetach($entity, array &$visited, $noCascade = false)
-    {
+    private function doDetach(
+        $entity,
+        array &$visited,
+        bool $noCascade = false
+    ): void {
         $oid = spl_object_hash($entity);
 
         if (isset($visited[$oid])) {
@@ -2302,6 +2288,8 @@ static function ($assoc) {
     /**
      * Cascades a merge operation to associated entities.
      *
+     * @param object $entity
+     * @param object $managedCopy
      * @psalm-param array<string, object> $visited
      */
     private function cascadeMerge($entity, $managedCopy, array &$visited): void
@@ -2615,11 +2603,9 @@ public function isCollectionScheduledForDeletion(PersistentCollection $coll)
     }
 
     /**
-     * @param ClassMetadata $class
-     *
-     * @return ObjectManagerAware|object
+     * @return object
      */
-    private function newInstance($class)
+    private function newInstance(ClassMetadata $class)
     {
         $entity = $class->newInstance();
 
diff --git a/lib/Doctrine/ORM/Utility/IdentifierFlattener.php b/lib/Doctrine/ORM/Utility/IdentifierFlattener.php
index 954501d4a4b..216fd66cb05 100644
--- a/lib/Doctrine/ORM/Utility/IdentifierFlattener.php
+++ b/lib/Doctrine/ORM/Utility/IdentifierFlattener.php
@@ -64,7 +64,7 @@ public function __construct(UnitOfWork $unitOfWork, ClassMetadataFactory $metada
      *
      * @psalm-return array<string, mixed>
      */
-    public function flattenIdentifier(ClassMetadata $class, array $id)
+    public function flattenIdentifier(ClassMetadata $class, array $id): array
     {
         $flatId = [];
 
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 55eeb6e351c..ad4d20c9521 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -395,11 +395,6 @@ parameters:
 			count: 1
 			path: lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php
 
-		-
-			message: "#^Strict comparison using \\=\\=\\= between array and null will always evaluate to false\\.$#"
-			count: 1
-			path: lib/Doctrine/ORM/Internal/Hydration/ArrayHydrator.php
-
 		-
 			message: "#^Access to an undefined property Doctrine\\\\ORM\\\\Proxy\\\\Proxy\\:\\:\\$__isInitialized__\\.$#"
 			count: 1
@@ -607,7 +602,7 @@ parameters:
 
 		-
 			message: "#^Negated boolean expression is always false\\.$#"
-			count: 4
+			count: 3
 			path: lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
 
 		-
@@ -1385,14 +1380,9 @@ parameters:
 			count: 2
 			path: lib/Doctrine/ORM/PersistentCollection.php
 
-		-
-			message: "#^Property Doctrine\\\\ORM\\\\PersistentCollection\\<TKey,T\\>\\:\\:\\$owner \\(object\\) does not accept null\\.$#"
-			count: 1
-			path: lib/Doctrine/ORM/PersistentCollection.php
-
 		-
 			message: "#^Right side of && is always true\\.$#"
-			count: 7
+			count: 2
 			path: lib/Doctrine/ORM/PersistentCollection.php
 
 		-
@@ -1410,31 +1400,11 @@ parameters:
 			count: 1
 			path: lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php
 
-		-
-			message: "#^Method Doctrine\\\\ORM\\\\Persisters\\\\Entity\\\\BasicEntityPersister\\:\\:getManyToManyStatement\\(\\) should return Doctrine\\\\DBAL\\\\Driver\\\\Statement but returns Doctrine\\\\DBAL\\\\Driver\\\\ResultStatement&Doctrine\\\\DBAL\\\\Result\\.$#"
-			count: 1
-			path: lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php
-
-		-
-			message: "#^Method Doctrine\\\\ORM\\\\Persisters\\\\Entity\\\\BasicEntityPersister\\:\\:getOneToManyStatement\\(\\) should return Doctrine\\\\DBAL\\\\Statement but returns Doctrine\\\\DBAL\\\\Driver\\\\ResultStatement&Doctrine\\\\DBAL\\\\Result\\.$#"
-			count: 1
-			path: lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php
-
 		-
 			message: "#^Parameter \\#1 \\$em of method Doctrine\\\\ORM\\\\Id\\\\AbstractIdGenerator\\:\\:generate\\(\\) expects Doctrine\\\\ORM\\\\EntityManager, Doctrine\\\\ORM\\\\EntityManagerInterface given\\.$#"
 			count: 1
 			path: lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php
 
-		-
-			message: "#^Parameter \\#2 \\$stmt of method Doctrine\\\\ORM\\\\Persisters\\\\Entity\\\\BasicEntityPersister\\:\\:loadArrayFromStatement\\(\\) expects Doctrine\\\\DBAL\\\\Statement, Doctrine\\\\DBAL\\\\Driver\\\\Statement given\\.$#"
-			count: 1
-			path: lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php
-
-		-
-			message: "#^Parameter \\#2 \\$stmt of method Doctrine\\\\ORM\\\\Persisters\\\\Entity\\\\BasicEntityPersister\\:\\:loadCollectionFromStatement\\(\\) expects Doctrine\\\\DBAL\\\\Statement, Doctrine\\\\DBAL\\\\Driver\\\\Statement given\\.$#"
-			count: 1
-			path: lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php
-
 		-
 			message: "#^Parameter \\#3 \\$hints of method Doctrine\\\\ORM\\\\Internal\\\\Hydration\\\\AbstractHydrator\\:\\:hydrateAll\\(\\) expects array\\<string, string\\>, array\\<string, Doctrine\\\\ORM\\\\PersistentCollection\\|true\\> given\\.$#"
 			count: 1
@@ -1505,21 +1475,6 @@ parameters:
 			count: 1
 			path: lib/Doctrine/ORM/Query.php
 
-		-
-			message: "#^Method Doctrine\\\\ORM\\\\QueryBuilder\\:\\:getEntityManager\\(\\) should return Doctrine\\\\ORM\\\\EntityManager but returns Doctrine\\\\ORM\\\\EntityManagerInterface\\.$#"
-			count: 1
-			path: lib/Doctrine/ORM/QueryBuilder.php
-
-		-
-			message: "#^PHPDoc tag @param references unknown parameter\\: \\$where$#"
-			count: 2
-			path: lib/Doctrine/ORM/QueryBuilder.php
-
-		-
-			message: "#^Parameter \\#2 \\$dqlPart of method Doctrine\\\\ORM\\\\QueryBuilder\\:\\:add\\(\\) expects array\\<'join'\\|int, array\\<int\\|string, object\\>\\|string\\>\\|object\\|string, array\\<string, Doctrine\\\\ORM\\\\Query\\\\Expr\\\\Join\\> given\\.$#"
-			count: 2
-			path: lib/Doctrine/ORM/QueryBuilder.php
-
 		-
 			message: "#^Access to an undefined property Doctrine\\\\ORM\\\\Query\\\\AST\\\\Node\\:\\:\\$value\\.$#"
 			count: 1
@@ -1685,11 +1640,6 @@ parameters:
 			count: 1
 			path: lib/Doctrine/ORM/Query/Parser.php
 
-		-
-			message: "#^Method Doctrine\\\\ORM\\\\Query\\\\Parser\\:\\:CustomFunctionDeclaration\\(\\) should return Doctrine\\\\ORM\\\\Query\\\\AST\\\\Functions\\\\FunctionNode but returns null\\.$#"
-			count: 1
-			path: lib/Doctrine/ORM/Query/Parser.php
-
 		-
 			message:
 				"""
@@ -1727,13 +1677,13 @@ parameters:
 			path: lib/Doctrine/ORM/Query/Parser.php
 
 		-
-			message: "#^Method Doctrine\\\\ORM\\\\Query\\\\ResultSetMappingBuilder\\:\\:getColumnAlias\\(\\) should return string but return statement is missing\\.$#"
+			message: "#^Parameter \\#2 \\$class of static method Doctrine\\\\ORM\\\\Utility\\\\PersisterHelper\\:\\:getTypeOfColumn\\(\\) expects Doctrine\\\\ORM\\\\Mapping\\\\ClassMetadata, Doctrine\\\\ORM\\\\Mapping\\\\ClassMetadataInfo given\\.$#"
 			count: 1
 			path: lib/Doctrine/ORM/Query/ResultSetMappingBuilder.php
 
 		-
-			message: "#^Parameter \\#2 \\$class of static method Doctrine\\\\ORM\\\\Utility\\\\PersisterHelper\\:\\:getTypeOfColumn\\(\\) expects Doctrine\\\\ORM\\\\Mapping\\\\ClassMetadata, Doctrine\\\\ORM\\\\Mapping\\\\ClassMetadataInfo given\\.$#"
-			count: 1
+			message: "#^Parameter \\#2 \\$mode of method Doctrine\\\\ORM\\\\Query\\\\ResultSetMappingBuilder\\:\\:getColumnAliasMap\\(\\) expects 1\\|2\\|3, int given\\.$#"
+			count: 2
 			path: lib/Doctrine/ORM/Query/ResultSetMappingBuilder.php
 
 		-
@@ -2276,6 +2226,16 @@ parameters:
 			count: 1
 			path: lib/Doctrine/ORM/Query/TreeWalkerChainIterator.php
 
+		-
+			message: "#^PHPDoc tag @param references unknown parameter\\: \\$where$#"
+			count: 2
+			path: lib/Doctrine/ORM/QueryBuilder.php
+
+		-
+			message: "#^Parameter \\#2 \\$dqlPart of method Doctrine\\\\ORM\\\\QueryBuilder\\:\\:add\\(\\) expects array\\<'join'\\|int, array\\<int\\|string, object\\>\\|string\\>\\|object\\|string, array\\<string, Doctrine\\\\ORM\\\\Query\\\\Expr\\\\Join\\> given\\.$#"
+			count: 2
+			path: lib/Doctrine/ORM/QueryBuilder.php
+
 		-
 			message: "#^Else branch is unreachable because ternary operator condition is always true\\.$#"
 			count: 1
@@ -2536,11 +2496,6 @@ parameters:
 			count: 1
 			path: lib/Doctrine/ORM/UnitOfWork.php
 
-		-
-			message: "#^Strict comparison using \\=\\=\\= between object and null will always evaluate to false\\.$#"
-			count: 1
-			path: lib/Doctrine/ORM/UnitOfWork.php
-
 		-
 			message: "#^Strict comparison using \\=\\=\\= between string and 4 will always evaluate to false\\.$#"
 			count: 1
diff --git a/psalm-baseline.xml b/psalm-baseline.xml
index b8283906d46..39b4287aecc 100644
--- a/psalm-baseline.xml
+++ b/psalm-baseline.xml
@@ -368,10 +368,6 @@
     </UndefinedInterfaceMethod>
   </file>
   <file src="lib/Doctrine/ORM/Query.php">
-    <InvalidArgument occurrences="2">
-      <code>$paramMappings</code>
-      <code>$sqlPositions</code>
-    </InvalidArgument>
     <LessSpecificImplementedReturnType occurrences="1">
       <code>mixed</code>
     </LessSpecificImplementedReturnType>
@@ -379,9 +375,6 @@
       <code>$hydrationMode</code>
       <code>$parameters</code>
     </MoreSpecificImplementedParamType>
-    <UndefinedMethod occurrences="1">
-      <code>$sqlPositions</code>
-    </UndefinedMethod>
   </file>
   <file src="lib/Doctrine/ORM/Query/AST/Functions/DateAddFunction.php">
     <UndefinedPropertyFetch occurrences="1">
@@ -426,8 +419,7 @@
       <code>$this-&gt;identVariableExpressions[$dqlAlias]</code>
       <code>$this-&gt;queryComponents[$dqlAlias]</code>
     </InvalidArrayOffset>
-    <InvalidNullableReturnType occurrences="2">
-      <code>FunctionNode</code>
+    <InvalidNullableReturnType occurrences="1">
       <code>SelectStatement|UpdateStatement|DeleteStatement</code>
     </InvalidNullableReturnType>
     <InvalidPropertyAssignmentValue occurrences="1">
@@ -448,7 +440,7 @@
       <code>AST\BetweenExpression|</code>
       <code>ArithmeticFactor</code>
     </InvalidReturnType>
-    <NullableReturnStatement occurrences="10">
+    <NullableReturnStatement occurrences="9">
       <code>$aliasIdentVariable</code>
       <code>$factors[0]</code>
       <code>$identVariable</code>
@@ -458,14 +450,8 @@
       <code>$terms[0]</code>
       <code>$this-&gt;lexer-&gt;token['value']</code>
       <code>$this-&gt;lexer-&gt;token['value']</code>
-      <code>null</code>
     </NullableReturnStatement>
   </file>
-  <file src="lib/Doctrine/ORM/Query/ResultSetMappingBuilder.php">
-    <InvalidNullableReturnType occurrences="1">
-      <code>string</code>
-    </InvalidNullableReturnType>
-  </file>
   <file src="lib/Doctrine/ORM/Query/SqlWalker.php">
     <InvalidArgument occurrences="1">
       <code>$selectedClass['class']-&gt;name</code>