diff --git a/composer.json b/composer.json
index 57826fba1e..e501cf35dd 100644
--- a/composer.json
+++ b/composer.json
@@ -36,7 +36,7 @@
         "myclabs/php-enum": "^1.6.6",
         "php-coveralls/php-coveralls": "^2.1",
         "phpstan/extension-installer": "^1.1",
-        "phpstan/phpstan": "^1.0",
+        "phpstan/phpstan": "^1.9",
         "phpunit/phpunit": "^8.5.19 || ^9.5.8",
         "symfony/var-dumper": "^5.4 || ^6.0",
         "thecodingmachine/phpstan-strict-rules": "^1.0"
diff --git a/src/AggregateControllerQueryProvider.php b/src/AggregateControllerQueryProvider.php
index 61135bacb7..a85e97bc1f 100644
--- a/src/AggregateControllerQueryProvider.php
+++ b/src/AggregateControllerQueryProvider.php
@@ -29,7 +29,7 @@ class AggregateControllerQueryProvider implements QueryProviderInterface
      * @param iterable<string>   $controllers          A list of controllers name in the container.
      * @param ContainerInterface $controllersContainer The container we will fetch controllers from.
      */
-    public function __construct(private iterable $controllers, private FieldsBuilder $fieldsBuilder, private ContainerInterface $controllersContainer)
+    public function __construct(private readonly iterable $controllers, private readonly FieldsBuilder $fieldsBuilder, private readonly ContainerInterface $controllersContainer)
     {
     }
 
diff --git a/src/AggregateControllerQueryProviderFactory.php b/src/AggregateControllerQueryProviderFactory.php
index 56e549a69b..1eb77795e8 100644
--- a/src/AggregateControllerQueryProviderFactory.php
+++ b/src/AggregateControllerQueryProviderFactory.php
@@ -15,7 +15,7 @@ class AggregateControllerQueryProviderFactory implements QueryProviderFactoryInt
      * @param iterable<string> $controllers A list of controllers name in the container.
      * @param ContainerInterface $controllersContainer The container we will fetch controllers from.
      */
-    public function __construct(private iterable $controllers, private ContainerInterface $controllersContainer)
+    public function __construct(private readonly iterable $controllers, private readonly ContainerInterface $controllersContainer)
     {
     }
 
diff --git a/src/AnnotationReader.php b/src/AnnotationReader.php
index 2e9164ab1d..a65d15ac10 100644
--- a/src/AnnotationReader.php
+++ b/src/AnnotationReader.php
@@ -67,7 +67,7 @@ class AnnotationReader
      * @param string $mode One of self::LAX_MODE or self::STRICT_MODE. If true, no exceptions will be thrown for incorrect annotations in code coming from the "vendor/" directory.
      * @param array<int,string> $strictNamespaces Classes in those namespaces MUST have valid annotations (otherwise, an error is thrown).
      */
-    public function __construct(private Reader $reader, private string $mode = self::STRICT_MODE, private array $strictNamespaces = [])
+    public function __construct(private readonly Reader $reader, private readonly string $mode = self::STRICT_MODE, private readonly array $strictNamespaces = [])
     {
         if (! in_array($mode, [self::LAX_MODE, self::STRICT_MODE], true)) {
             throw new InvalidArgumentException('The mode passed must be one of AnnotationReader::LAX_MODE, AnnotationReader::STRICT_MODE');
@@ -100,20 +100,11 @@ private function getClassAnnotation(ReflectionClass $refClass, string $annotatio
             assert($type === null || $type instanceof $annotationClass);
             return $type;
         } catch (AnnotationException $e) {
-            switch ($this->mode) {
-                case self::STRICT_MODE:
-                    throw $e;
-
-                case self::LAX_MODE:
-                    if ($this->isErrorImportant($annotationClass, $refClass->getDocComment() ?: '', $refClass->getName())) {
-                        throw $e;
-                    }
-
-                    return null;
-
-                default:
-                    throw new RuntimeException("Unexpected mode '" . $this->mode . "'."); // @codeCoverageIgnore
-            }
+            return match ($this->mode) {
+                self::STRICT_MODE=> throw $e,
+                self::LAX_MODE=>$this->isErrorImportant($annotationClass, $refClass->getDocComment() ?: '', $refClass->getName()) ? throw $e : null,
+                default=>throw new RuntimeException("Unexpected mode '" . $this->mode . "'.") // @codeCoverageIgnore
+            };
         }
     }
 
@@ -139,20 +130,11 @@ private function getMethodAnnotation(ReflectionMethod $refMethod, string $annota
 
             return $this->methodAnnotationCache[$cacheKey] = $this->reader->getMethodAnnotation($refMethod, $annotationClass);
         } catch (AnnotationException $e) {
-            switch ($this->mode) {
-                case self::STRICT_MODE:
-                    throw $e;
-
-                case self::LAX_MODE:
-                    if ($this->isErrorImportant($annotationClass, $refMethod->getDocComment() ?: '', $refMethod->getDeclaringClass()->getName())) {
-                        throw $e;
-                    }
-
-                    return null;
-
-                default:
-                    throw new RuntimeException("Unexpected mode '" . $this->mode . "'."); // @codeCoverageIgnore
-            }
+            return match ($this->mode) {
+                self::STRICT_MODE=> throw $e,
+                self::LAX_MODE=>$this->isErrorImportant($annotationClass, $refMethod->getDocComment() ?: '', $refMethod->getName()) ? throw $e : null,
+                default=>throw new RuntimeException("Unexpected mode '" . $this->mode . "'.") // @codeCoverageIgnore
+            };
         }
     }
 
diff --git a/src/FactoryContext.php b/src/FactoryContext.php
index 4985a2040a..a59dafd668 100644
--- a/src/FactoryContext.php
+++ b/src/FactoryContext.php
@@ -18,19 +18,19 @@
 final class FactoryContext
 {
     public function __construct(
-        private AnnotationReader $annotationReader,
-        private TypeResolver $typeResolver,
-        private NamingStrategyInterface $namingStrategy,
-        private TypeRegistry $typeRegistry,
-        private FieldsBuilder $fieldsBuilder,
-        private TypeGenerator $typeGenerator,
-        private InputTypeGenerator $inputTypeGenerator,
-        private RecursiveTypeMapperInterface $recursiveTypeMapper,
-        private ContainerInterface $container,
-        private CacheInterface $cache,
-        private InputTypeValidatorInterface|null $inputTypeValidator,
-        private int|null $globTTL,
-        private int|null $mapTTL = null,
+        private readonly AnnotationReader $annotationReader,
+        private readonly TypeResolver $typeResolver,
+        private readonly NamingStrategyInterface $namingStrategy,
+        private readonly TypeRegistry $typeRegistry,
+        private readonly FieldsBuilder $fieldsBuilder,
+        private readonly TypeGenerator $typeGenerator,
+        private readonly InputTypeGenerator $inputTypeGenerator,
+        private readonly RecursiveTypeMapperInterface $recursiveTypeMapper,
+        private readonly ContainerInterface $container,
+        private readonly CacheInterface $cache,
+        private readonly InputTypeValidatorInterface|null $inputTypeValidator,
+        private readonly int|null $globTTL,
+        private readonly int|null $mapTTL = null,
     ) {
     }
 
diff --git a/src/FieldsBuilder.php b/src/FieldsBuilder.php
index b1781ff325..b126d410b1 100644
--- a/src/FieldsBuilder.php
+++ b/src/FieldsBuilder.php
@@ -62,7 +62,7 @@
 use function key;
 use function reset;
 use function rtrim;
-use function strpos;
+use function str_starts_with;
 use function trim;
 
 use const PHP_EOL;
@@ -75,16 +75,16 @@ class FieldsBuilder
     private TypeHandler $typeMapper;
 
     public function __construct(
-        private AnnotationReader $annotationReader,
-        private RecursiveTypeMapperInterface $recursiveTypeMapper,
-        private ArgumentResolver $argumentResolver,
-        private TypeResolver $typeResolver,
-        private CachedDocBlockFactory $cachedDocBlockFactory,
-        private NamingStrategyInterface $namingStrategy,
-        private RootTypeMapperInterface $rootTypeMapper,
-        private ParameterMiddlewareInterface $parameterMapper,
-        private FieldMiddlewareInterface $fieldMiddleware,
-        private InputFieldMiddlewareInterface $inputFieldMiddleware,
+        private readonly AnnotationReader $annotationReader,
+        private readonly RecursiveTypeMapperInterface $recursiveTypeMapper,
+        private readonly ArgumentResolver $argumentResolver,
+        private readonly TypeResolver $typeResolver,
+        private readonly CachedDocBlockFactory $cachedDocBlockFactory,
+        private readonly NamingStrategyInterface $namingStrategy,
+        private readonly RootTypeMapperInterface $rootTypeMapper,
+        private readonly ParameterMiddlewareInterface $parameterMapper,
+        private readonly FieldMiddlewareInterface $fieldMiddleware,
+        private readonly InputFieldMiddlewareInterface $inputFieldMiddleware,
     )
     {
         $this->typeMapper = new TypeHandler($this->argumentResolver, $this->rootTypeMapper, $this->typeResolver);
@@ -342,7 +342,7 @@ private function getFieldsByMethodAnnotations(string|object $controller, Reflect
             $methodName = $refMethod->getName();
 
             if ($queryAnnotation instanceof Field) {
-                if (strpos($methodName, 'set') === 0) {
+                if (str_starts_with($methodName, 'set')) {
                     continue;
                 }
                 $for = $queryAnnotation->getFor();
@@ -673,12 +673,8 @@ private function getMagicGetMethodFromSourceClassOrProxy(ReflectionClass $proxyR
         return $sourceRefClass->getMethod($magicGet);
     }
 
-    /**
-     * @param ReflectionClass<object> $refClass
-     *
-     * @return OutputType&Type
-     */
-    private function resolveOutputType(string $outputType, ReflectionClass $refClass, SourceFieldInterface $sourceField): OutputType
+    /** @param ReflectionClass<object> $refClass */
+    private function resolveOutputType(string $outputType, ReflectionClass $refClass, SourceFieldInterface $sourceField): OutputType&Type
     {
         try {
             return $this->typeResolver->mapNameToOutputType($outputType);
@@ -688,12 +684,8 @@ private function resolveOutputType(string $outputType, ReflectionClass $refClass
         }
     }
 
-    /**
-     * @param ReflectionClass<object> $refClass
-     *
-     * @return OutputType&Type
-     */
-    private function resolvePhpType(string $phpTypeStr, ReflectionClass $refClass, ReflectionMethod $refMethod): OutputType
+    /** @param ReflectionClass<object> $refClass */
+    private function resolvePhpType(string $phpTypeStr, ReflectionClass $refClass, ReflectionMethod $refMethod): OutputType&Type
     {
         $typeResolver = new \phpDocumentor\Reflection\TypeResolver();
 
@@ -850,7 +842,7 @@ private function getInputFieldsByMethodAnnotations(string|object $controller, Re
 
             $docBlockObj = $this->cachedDocBlockFactory->getDocBlock($refMethod);
             $methodName = $refMethod->getName();
-            if (strpos($methodName, 'set') !== 0) {
+            if (! str_starts_with($methodName, 'set')) {
                 continue;
             }
             $name = $fieldAnnotations->getName() ?: $this->namingStrategy->getInputFieldNameFromMethodName($methodName);
diff --git a/src/Http/WebonyxGraphqlMiddleware.php b/src/Http/WebonyxGraphqlMiddleware.php
index acc02a2fa8..82e0485e7b 100644
--- a/src/Http/WebonyxGraphqlMiddleware.php
+++ b/src/Http/WebonyxGraphqlMiddleware.php
@@ -42,11 +42,11 @@ final class WebonyxGraphqlMiddleware implements MiddlewareInterface
     ];
 
     public function __construct(
-        private ServerConfig $config,
-        private ResponseFactoryInterface $responseFactory,
-        private StreamFactoryInterface $streamFactory,
-        private HttpCodeDeciderInterface $httpCodeDecider,
-        private string $graphqlUri = '/graphql',
+        private readonly ServerConfig $config,
+        private readonly ResponseFactoryInterface $responseFactory,
+        private readonly StreamFactoryInterface $streamFactory,
+        private readonly HttpCodeDeciderInterface $httpCodeDecider,
+        private readonly string $graphqlUri = '/graphql',
         StandardServer|null $handler = null,
     )
     {
diff --git a/src/InputField.php b/src/InputField.php
index 6507fa8b20..367ff96d55 100644
--- a/src/InputField.php
+++ b/src/InputField.php
@@ -29,7 +29,7 @@
  * @phpstan-import-type InputObjectFieldConfig from InputObjectField
  * @phpstan-import-type ArgumentType from InputObjectField
  */
-class InputField extends InputObjectField
+final class InputField extends InputObjectField
 {
     /** @var callable */
     private $resolve;
diff --git a/src/InputFieldDescriptor.php b/src/InputFieldDescriptor.php
index aa909ce49c..d7e79f5620 100644
--- a/src/InputFieldDescriptor.php
+++ b/src/InputFieldDescriptor.php
@@ -27,7 +27,7 @@ class InputFieldDescriptor
 {
     private string $name;
     /** @var (InputType&Type)|(InputType&Type&NullableType) */
-    private InputType $type;
+    private InputType&Type $type;
     /** @var array<string, ParameterInterface> */
     private array $parameters = [];
     /** @var callable|null */
@@ -96,13 +96,12 @@ public function setName(string $name): void
     }
 
     /** @return ((InputType&Type)|(InputType&Type&NullableType))  */
-    public function getType(): InputType
+    public function getType(): InputType&Type
     {
         return $this->type;
     }
 
-    /** @param (InputType&Type)  $type */
-    public function setType(InputType $type): void
+    public function setType(InputType&Type $type): void
     {
         $this->type = $type;
     }
diff --git a/src/InputTypeUtils.php b/src/InputTypeUtils.php
index c96899e0f1..3c38de38aa 100644
--- a/src/InputTypeUtils.php
+++ b/src/InputTypeUtils.php
@@ -33,8 +33,8 @@
 class InputTypeUtils
 {
     public function __construct(
-        private AnnotationReader $annotationReader,
-        private NamingStrategyInterface $namingStrategy,
+        private readonly AnnotationReader $annotationReader,
+        private readonly NamingStrategyInterface $namingStrategy,
     )
     {
     }
diff --git a/src/Mappers/AbstractTypeMapper.php b/src/Mappers/AbstractTypeMapper.php
index 60828ee63f..95c20f4f29 100644
--- a/src/Mappers/AbstractTypeMapper.php
+++ b/src/Mappers/AbstractTypeMapper.php
@@ -56,16 +56,16 @@ abstract class AbstractTypeMapper implements TypeMapperInterface
 
     public function __construct(
         string $cachePrefix,
-        private TypeGenerator $typeGenerator,
-        private InputTypeGenerator $inputTypeGenerator,
-        private InputTypeUtils $inputTypeUtils,
-        private ContainerInterface $container,
-        private AnnotationReader $annotationReader,
-        private NamingStrategyInterface $namingStrategy,
-        private RecursiveTypeMapperInterface $recursiveTypeMapper,
-        private CacheInterface $cache,
+        private readonly TypeGenerator $typeGenerator,
+        private readonly InputTypeGenerator $inputTypeGenerator,
+        private readonly InputTypeUtils $inputTypeUtils,
+        private readonly ContainerInterface $container,
+        private readonly AnnotationReader $annotationReader,
+        private readonly NamingStrategyInterface $namingStrategy,
+        private readonly RecursiveTypeMapperInterface $recursiveTypeMapper,
+        private readonly CacheInterface $cache,
         protected int|null $globTTL = 2,
-        private int|null $mapTTL = null,
+        private readonly int|null $mapTTL = null,
     )
     {
         $this->cacheContract = new Psr16Adapter($this->cache, $cachePrefix, $this->globTTL ?? 0);
@@ -185,7 +185,7 @@ private function buildMapClassToExtendTypeArray(): GlobExtendTypeMapperCache
         $globExtendTypeMapperCache = new GlobExtendTypeMapperCache();
 
         $classes = $this->getClassList();
-        foreach ($classes as $className => $refClass) {
+        foreach ($classes as $refClass) {
             $annotationsCache = $this->mapClassToExtendAnnotationsCache->get($refClass, function () use ($refClass) {
                 $extendAnnotationsCache = new GlobExtendAnnotationsCache();
 
@@ -320,7 +320,7 @@ public function mapClassToInputType(string $className): ResolvableMutableInputIn
      * @throws CannotMapTypeExceptionInterface
      * @throws ReflectionException
      */
-    public function mapNameToType(string $typeName): Type
+    public function mapNameToType(string $typeName): Type&NamedType
     {
         $typeClassName = $this->getMaps()->getTypeByGraphQLTypeName($typeName);
 
diff --git a/src/Mappers/CompositeTypeMapper.php b/src/Mappers/CompositeTypeMapper.php
index 44302d6ca2..74a290d6e8 100644
--- a/src/Mappers/CompositeTypeMapper.php
+++ b/src/Mappers/CompositeTypeMapper.php
@@ -132,7 +132,7 @@ public function mapClassToInputType(string $className): ResolvableMutableInputIn
      *
      * @return NamedType&Type&((ResolvableMutableInputInterface&InputObjectType)|MutableInterface)
      */
-    public function mapNameToType(string $typeName): Type
+    public function mapNameToType(string $typeName): Type&NamedType
     {
         foreach ($this->typeMappers as $typeMapper) {
             if ($typeMapper->canMapNameToType($typeName)) {
diff --git a/src/Mappers/GlobExtendAnnotationsCache.php b/src/Mappers/GlobExtendAnnotationsCache.php
index d99bf1e47b..4ed59fe6de 100644
--- a/src/Mappers/GlobExtendAnnotationsCache.php
+++ b/src/Mappers/GlobExtendAnnotationsCache.php
@@ -9,7 +9,7 @@
  *
  * @internal
  */
-class GlobExtendAnnotationsCache
+final class GlobExtendAnnotationsCache
 {
     private string|null $extendTypeClassName = null;
 
diff --git a/src/Mappers/Parameters/ContainerParameterHandler.php b/src/Mappers/Parameters/ContainerParameterHandler.php
index 7988189d01..e75a0d9b9a 100644
--- a/src/Mappers/Parameters/ContainerParameterHandler.php
+++ b/src/Mappers/Parameters/ContainerParameterHandler.php
@@ -21,12 +21,8 @@
  */
 class ContainerParameterHandler implements ParameterMiddlewareInterface
 {
-    /** @var ContainerInterface */
-    private $container;
-
-    public function __construct(ContainerInterface $container)
+    public function __construct(private readonly ContainerInterface $container)
     {
-        $this->container = $container;
     }
 
     public function mapParameter(ReflectionParameter $parameter, DocBlock $docBlock, Type|null $paramTagType, ParameterAnnotations $parameterAnnotations, ParameterHandlerInterface $next): ParameterInterface
diff --git a/src/Mappers/Parameters/InjectUserParameterHandler.php b/src/Mappers/Parameters/InjectUserParameterHandler.php
index d794544daa..b7fe0ddd76 100644
--- a/src/Mappers/Parameters/InjectUserParameterHandler.php
+++ b/src/Mappers/Parameters/InjectUserParameterHandler.php
@@ -18,7 +18,7 @@
  */
 class InjectUserParameterHandler implements ParameterMiddlewareInterface
 {
-    public function __construct(private AuthenticationServiceInterface $authenticationService)
+    public function __construct(private readonly AuthenticationServiceInterface $authenticationService)
     {
     }
 
diff --git a/src/Mappers/Parameters/TypeHandler.php b/src/Mappers/Parameters/TypeHandler.php
index 810e971b39..47ceea4681 100644
--- a/src/Mappers/Parameters/TypeHandler.php
+++ b/src/Mappers/Parameters/TypeHandler.php
@@ -63,16 +63,15 @@ class TypeHandler implements ParameterHandlerInterface
     private PhpDocumentorTypeResolver $phpDocumentorTypeResolver;
 
     public function __construct(
-        private ArgumentResolver $argumentResolver,
-        private RootTypeMapperInterface $rootTypeMapper,
-        private TypeResolver $typeResolver,
+        private readonly ArgumentResolver $argumentResolver,
+        private readonly RootTypeMapperInterface $rootTypeMapper,
+        private readonly TypeResolver $typeResolver,
     )
     {
         $this->phpDocumentorTypeResolver = new PhpDocumentorTypeResolver();
     }
 
-    /** @return GraphQLType&OutputType */
-    public function mapReturnType(ReflectionMethod $refMethod, DocBlock $docBlockObj): GraphQLType
+    public function mapReturnType(ReflectionMethod $refMethod, DocBlock $docBlockObj): GraphQLType&OutputType
     {
         $returnType = $refMethod->getReturnType();
         if ($returnType !== null) {
diff --git a/src/Mappers/PorpaginasTypeMapper.php b/src/Mappers/PorpaginasTypeMapper.php
index 7fee55162a..6fd520a862 100644
--- a/src/Mappers/PorpaginasTypeMapper.php
+++ b/src/Mappers/PorpaginasTypeMapper.php
@@ -138,7 +138,7 @@ public function canMapNameToType(string $typeName): bool
      *
      * @throws CannotMapTypeExceptionInterface
      */
-    public function mapNameToType(string $typeName): Type
+    public function mapNameToType(string $typeName): Type&NamedType
     {
         if (! $this->canMapNameToType($typeName)) {
             throw CannotMapTypeException::createForName($typeName);
diff --git a/src/Mappers/Proxys/MutableInterfaceTypeAdapter.php b/src/Mappers/Proxys/MutableInterfaceTypeAdapter.php
index 4d5ccc7985..2f179ab4e1 100644
--- a/src/Mappers/Proxys/MutableInterfaceTypeAdapter.php
+++ b/src/Mappers/Proxys/MutableInterfaceTypeAdapter.php
@@ -25,7 +25,7 @@
  *
  * @internal
  */
-class MutableInterfaceTypeAdapter extends MutableInterfaceType implements MutableInterface
+final class MutableInterfaceTypeAdapter extends MutableInterfaceType
 {
     /** @use MutableAdapterTrait */
     use MutableAdapterTrait;
diff --git a/src/Mappers/Proxys/MutableObjectTypeAdapter.php b/src/Mappers/Proxys/MutableObjectTypeAdapter.php
index 4e15a064f1..cae384e1e0 100644
--- a/src/Mappers/Proxys/MutableObjectTypeAdapter.php
+++ b/src/Mappers/Proxys/MutableObjectTypeAdapter.php
@@ -26,7 +26,7 @@
  *
  * @internal
  */
-class MutableObjectTypeAdapter extends MutableObjectType implements MutableInterface
+final class MutableObjectTypeAdapter extends MutableObjectType
 {
     /** @use MutableAdapterTrait */
     use MutableAdapterTrait;
diff --git a/src/Mappers/RecursiveTypeMapper.php b/src/Mappers/RecursiveTypeMapper.php
index 9df69bafa5..0b3415740f 100644
--- a/src/Mappers/RecursiveTypeMapper.php
+++ b/src/Mappers/RecursiveTypeMapper.php
@@ -341,11 +341,9 @@ public function mapClassToType(string $className, OutputType|null $subType): Mut
      * @param class-string<object> $className The exact class name to look for (this function does not look into parent classes).
      * @param (OutputType&Type&NamedType)|null $subType A subtype (if the main className is an iterator)
      *
-     * @return OutputType&Type&NamedType
-     *
      * @throws CannotMapTypeExceptionInterface
      */
-    public function mapClassToInterfaceOrType(string $className, OutputType|null $subType): OutputType
+    public function mapClassToInterfaceOrType(string $className, OutputType|null $subType): OutputType&Type&NamedType
     {
         $closestClassName = $this->findClosestMatchingParent($className);
         if ($closestClassName === null) {
@@ -478,7 +476,7 @@ public function canMapNameToType(string $typeName): bool
      *
      * @return NamedType&Type&(InputType|OutputType)
      */
-    public function mapNameToType(string $typeName): Type
+    public function mapNameToType(string $typeName): Type&NamedType
     {
         if ($this->typeRegistry->hasType($typeName)) {
             return $this->typeRegistry->getType($typeName);
diff --git a/src/Mappers/RecursiveTypeMapperInterface.php b/src/Mappers/RecursiveTypeMapperInterface.php
index 549405db9e..b90b6b5ec1 100644
--- a/src/Mappers/RecursiveTypeMapperInterface.php
+++ b/src/Mappers/RecursiveTypeMapperInterface.php
@@ -47,11 +47,9 @@ public function mapClassToType(string $className, OutputType|null $subType): Mut
      * @param string      $className                                   The exact class name to look for (this function does not look into parent classes).
      * @param (OutputType&Type)|null $subType A subtype (if the main className is an iterator)
      *
-     * @return OutputType&Type
-     *
      * @throws CannotMapTypeExceptionInterface
      */
-    public function mapClassToInterfaceOrType(string $className, OutputType|null $subType): OutputType;
+    public function mapClassToInterfaceOrType(string $className, OutputType|null $subType): OutputType&Type;
 
     /**
      * Finds the list of interfaces returned by $className.
diff --git a/src/Mappers/Root/BaseTypeMapper.php b/src/Mappers/Root/BaseTypeMapper.php
index 22ec7a8ff6..d30bd239a0 100644
--- a/src/Mappers/Root/BaseTypeMapper.php
+++ b/src/Mappers/Root/BaseTypeMapper.php
@@ -45,12 +45,12 @@
  */
 class BaseTypeMapper implements RootTypeMapperInterface
 {
-    public function __construct(private RootTypeMapperInterface $next, private RecursiveTypeMapperInterface $recursiveTypeMapper, private RootTypeMapperInterface $topRootTypeMapper)
+    public function __construct(private readonly RootTypeMapperInterface $next, private readonly RecursiveTypeMapperInterface $recursiveTypeMapper, private readonly RootTypeMapperInterface $topRootTypeMapper)
     {
     }
 
     /** @throws CannotMapTypeExceptionInterface */
-    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType
+    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType&GraphQLType
     {
         $mappedType = $this->mapBaseType($type);
         if ($mappedType !== null) {
@@ -78,7 +78,7 @@ public function toGraphQLOutputType(Type $type, OutputType|null $subType, Reflec
      * @throws CannotMapTypeException
      * @throws CannotMapTypeExceptionInterface
      */
-    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType
+    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType&GraphQLType
     {
         $mappedType = $this->mapBaseType($type);
         if ($mappedType !== null) {
@@ -127,23 +127,23 @@ private function mapBaseType(Type $type): BooleanType|FloatType|IDType|IntType|S
 
         if ($type instanceof Object_) {
             $fqcn = (string) $type->getFqsen();
-            switch ($fqcn) {
-                case '\\' . DateTimeImmutable::class:
-                case '\\' . DateTimeInterface::class:
-                    return self::getDateTimeType();
+            return match ($fqcn) {
+                 '\\' . DateTimeImmutable::class,
+                 '\\' . DateTimeInterface::class=>
+                     self::getDateTimeType(),
 
-                case '\\' . UploadedFileInterface::class:
-                    return self::getUploadType();
+                 '\\' . UploadedFileInterface::class=>
+                     self::getUploadType(),
 
-                case '\\' . DateTime::class:
-                    throw CannotMapTypeException::createForDateTime();
+                 '\\' . DateTime::class=>
+                    throw CannotMapTypeException::createForDateTime(),
 
-                case '\\' . ID::class:
-                    return GraphQLType::id();
+                 '\\' . ID::class
+                    => GraphQLType::id(),
 
-                default:
-                    return null;
-            }
+                default=>
+                     null
+            };
         }
 
         return null;
@@ -178,17 +178,13 @@ private static function getDateTimeType(): DateTimeType
      *
      * @param string $typeName The name of the GraphQL type
      */
-    public function mapNameToType(string $typeName): NamedType
+    public function mapNameToType(string $typeName): NamedType&GraphQLType
     {
         // No need to map base types, only types added by us.
-        if ($typeName === 'Upload') {
-            return self::getUploadType();
-        }
-
-        if ($typeName === 'DateTime') {
-            return self::getDateTimeType();
-        }
-
-        return $this->next->mapNameToType($typeName);
+        return match ($typeName) {
+            'Upload'=>self::getUploadType(),
+            'DateTime'=>self::getDateTimeType(),
+            default=>$this->next->mapNameToType($typeName)
+        };
     }
 }
diff --git a/src/Mappers/Root/CompoundTypeMapper.php b/src/Mappers/Root/CompoundTypeMapper.php
index 70323ae80a..c3e7389874 100644
--- a/src/Mappers/Root/CompoundTypeMapper.php
+++ b/src/Mappers/Root/CompoundTypeMapper.php
@@ -40,15 +40,15 @@
 class CompoundTypeMapper implements RootTypeMapperInterface
 {
     public function __construct(
-        private RootTypeMapperInterface $next,
-        private RootTypeMapperInterface $topRootTypeMapper,
-        private NamingStrategyInterface $namingStrategy,
-        private TypeRegistry $typeRegistry,
-        private RecursiveTypeMapperInterface $recursiveTypeMapper,
+        private readonly RootTypeMapperInterface $next,
+        private readonly RootTypeMapperInterface $topRootTypeMapper,
+        private readonly NamingStrategyInterface $namingStrategy,
+        private readonly TypeRegistry $typeRegistry,
+        private readonly RecursiveTypeMapperInterface $recursiveTypeMapper,
     ) {
     }
 
-    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType
+    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType&GraphQLType
     {
         if (! $type instanceof Compound) {
             return $this->next->toGraphQLOutputType($type, $subType, $reflector, $docBlockObj);
@@ -87,7 +87,7 @@ public function toGraphQLOutputType(Type $type, OutputType|null $subType, Reflec
         return $return;
     }
 
-    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType
+    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType&GraphQLType
     {
         if (! $type instanceof Compound) {
             return $this->next->toGraphQLInputType($type, $subType, $argumentName, $reflector, $docBlockObj);
@@ -165,7 +165,7 @@ private function getTypeFromUnion(array $unionTypes): GraphQLType
      *
      * @param string $typeName The name of the GraphQL type
      */
-    public function mapNameToType(string $typeName): NamedType
+    public function mapNameToType(string $typeName): NamedType&GraphQLType
     {
         return $this->next->mapNameToType($typeName);
     }
diff --git a/src/Mappers/Root/EnumTypeMapper.php b/src/Mappers/Root/EnumTypeMapper.php
index fbe6e6802f..13b7519240 100644
--- a/src/Mappers/Root/EnumTypeMapper.php
+++ b/src/Mappers/Root/EnumTypeMapper.php
@@ -38,24 +38,20 @@ class EnumTypeMapper implements RootTypeMapperInterface
 
     /** @param NS[] $namespaces List of namespaces containing enums. Used when searching an enum by name. */
     public function __construct(
-        private RootTypeMapperInterface $next,
-        private AnnotationReader $annotationReader,
-        private CacheInterface $cacheService,
-        private array $namespaces,
+        private readonly RootTypeMapperInterface $next,
+        private readonly AnnotationReader $annotationReader,
+        private readonly CacheInterface $cacheService,
+        private readonly array $namespaces,
     ) {
     }
 
-    /**
-     * @param (OutputType&GraphQLType)|null $subType
-     *
-     * @return OutputType&GraphQLType
-     */
+    /** @param (OutputType&GraphQLType)|null $subType */
     public function toGraphQLOutputType(
         Type $type,
         OutputType|null $subType,
         ReflectionMethod|ReflectionProperty $reflector,
         DocBlock $docBlockObj,
-    ): OutputType {
+    ): OutputType&GraphQLType {
         $result = $this->map($type);
         return $result ?? $this->next->toGraphQLOutputType($type, $subType, $reflector, $docBlockObj);
     }
@@ -69,7 +65,7 @@ public function toGraphQLInputType(
         string $argumentName,
         ReflectionMethod|ReflectionProperty $reflector,
         DocBlock $docBlockObj,
-    ): InputType
+    ): InputType&GraphQLType
     {
         $result = $this->map($type);
         if ($result === null) {
@@ -140,7 +136,7 @@ private function getTypeName(ReflectionClass $reflectionClass): string
      *
      * @param string $typeName The name of the GraphQL type
      */
-    public function mapNameToType(string $typeName): NamedType
+    public function mapNameToType(string $typeName): NamedType&GraphQLType
     {
         // This is a hack to make sure "$schema->assertValid()" returns true.
         // The mapNameToType will fail if the mapByClassName method was not called before.
diff --git a/src/Mappers/Root/FinalRootTypeMapper.php b/src/Mappers/Root/FinalRootTypeMapper.php
index e7881c5843..e3f7a2ba11 100644
--- a/src/Mappers/Root/FinalRootTypeMapper.php
+++ b/src/Mappers/Root/FinalRootTypeMapper.php
@@ -23,24 +23,22 @@
  */
 final class FinalRootTypeMapper implements RootTypeMapperInterface
 {
-    public function __construct(private RecursiveTypeMapperInterface $recursiveTypeMapper)
+    public function __construct(private readonly RecursiveTypeMapperInterface $recursiveTypeMapper)
     {
     }
 
     /**
      * @param (OutputType&GraphQLType)|null $subType
      *
-     * @return OutputType&GraphQLType
-     *
      * @throws CannotMapTypeException
      */
-    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType
+    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType&GraphQLType
     {
         throw CannotMapTypeException::createForPhpDocType($type);
     }
 
     /** @throws CannotMapTypeException */
-    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType
+    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType&GraphQLType
     {
         throw CannotMapTypeException::createForPhpDocType($type);
     }
@@ -52,7 +50,7 @@ public function toGraphQLInputType(Type $type, InputType|null $subType, string $
      *
      * @param string $typeName The name of the GraphQL type
      */
-    public function mapNameToType(string $typeName): NamedType
+    public function mapNameToType(string $typeName): NamedType&GraphQLType
     {
         return $this->recursiveTypeMapper->mapNameToType($typeName);
     }
diff --git a/src/Mappers/Root/IteratorTypeMapper.php b/src/Mappers/Root/IteratorTypeMapper.php
index f0eaca1ab7..8d9f9fb1da 100644
--- a/src/Mappers/Root/IteratorTypeMapper.php
+++ b/src/Mappers/Root/IteratorTypeMapper.php
@@ -34,11 +34,11 @@
  */
 class IteratorTypeMapper implements RootTypeMapperInterface
 {
-    public function __construct(private RootTypeMapperInterface $next, private RootTypeMapperInterface $topRootTypeMapper)
+    public function __construct(private readonly RootTypeMapperInterface $next, private readonly RootTypeMapperInterface $topRootTypeMapper)
     {
     }
 
-    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType
+    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType&GraphQLType
     {
         if (! $type instanceof Compound) {
             try {
@@ -70,7 +70,7 @@ public function toGraphQLOutputType(Type $type, OutputType|null $subType, Reflec
         return $result;
     }
 
-    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType
+    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType&GraphQLType
     {
         if (! $type instanceof Compound) {
             //try {
@@ -102,7 +102,7 @@ public function toGraphQLInputType(Type $type, InputType|null $subType, string $
      *
      * @param string $typeName The name of the GraphQL type
      */
-    public function mapNameToType(string $typeName): NamedType
+    public function mapNameToType(string $typeName): NamedType&GraphQLType
     {
         // TODO: how to handle this? Do we need?
         return $this->next->mapNameToType($typeName);
@@ -125,7 +125,7 @@ private function getTypeInArray(Type $typeHint): Type|null
      *
      * @return (OutputType&GraphQLType)|(InputType&GraphQLType)|null
      */
-    private function toGraphQLType(Compound $type, Closure $topToGraphQLType, bool $isOutputType)
+    private function toGraphQLType(Compound $type, Closure $topToGraphQLType, bool $isOutputType): GraphQLType|null
     {
         $types = iterator_to_array($type);
 
diff --git a/src/Mappers/Root/MyCLabsEnumTypeMapper.php b/src/Mappers/Root/MyCLabsEnumTypeMapper.php
index 1797e27720..7ad0d1f9d8 100644
--- a/src/Mappers/Root/MyCLabsEnumTypeMapper.php
+++ b/src/Mappers/Root/MyCLabsEnumTypeMapper.php
@@ -35,17 +35,17 @@ class MyCLabsEnumTypeMapper implements RootTypeMapperInterface
     private array $cacheByName = [];
 
     /** @param NS[] $namespaces List of namespaces containing enums. Used when searching an enum by name. */
-    public function __construct(private RootTypeMapperInterface $next, private AnnotationReader $annotationReader, private CacheInterface $cacheService, private array $namespaces)
+    public function __construct(private readonly RootTypeMapperInterface $next, private readonly AnnotationReader $annotationReader, private readonly CacheInterface $cacheService, private readonly array $namespaces)
     {
     }
 
-    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType
+    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType&\GraphQL\Type\Definition\Type
     {
         $result = $this->map($type);
         return $result ?? $this->next->toGraphQLOutputType($type, $subType, $reflector, $docBlockObj);
     }
 
-    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType
+    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType&\GraphQL\Type\Definition\Type
     {
         $result = $this->map($type);
         return $result ?? $this->next->toGraphQLInputType($type, $subType, $argumentName, $reflector, $docBlockObj);
@@ -102,7 +102,7 @@ private function getTypeName(ReflectionClass $refClass): string
      *
      * @param string $typeName The name of the GraphQL type
      */
-    public function mapNameToType(string $typeName): NamedType
+    public function mapNameToType(string $typeName): NamedType&\GraphQL\Type\Definition\Type
     {
         // This is a hack to make sure "$schema->assertValid()" returns true.
         // The mapNameToType will fail if the mapByClassName method was not called before.
diff --git a/src/Mappers/Root/NullableTypeMapperAdapter.php b/src/Mappers/Root/NullableTypeMapperAdapter.php
index 09260e0d16..42d478bd79 100644
--- a/src/Mappers/Root/NullableTypeMapperAdapter.php
+++ b/src/Mappers/Root/NullableTypeMapperAdapter.php
@@ -39,7 +39,7 @@ public function setNext(RootTypeMapperInterface $next): void
         $this->next = $next;
     }
 
-    public function toGraphQLOutputType(Type $type, OutputType|GraphQLType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType
+    public function toGraphQLOutputType(Type $type, OutputType|GraphQLType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType&GraphQLType
     {
         // Let's check a "null" value in the docblock
         $isNullable = $this->isNullable($type);
@@ -65,7 +65,7 @@ public function toGraphQLOutputType(Type $type, OutputType|GraphQLType|null $sub
         return $graphQlType;
     }
 
-    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType
+    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType&GraphQLType
     {
         // Let's check a "null" value in the docblock
         $isNullable = $this->isNullable($type);
@@ -99,7 +99,7 @@ public function toGraphQLInputType(Type $type, InputType|null $subType, string $
      *
      * @param string $typeName The name of the GraphQL type
      */
-    public function mapNameToType(string $typeName): NamedType
+    public function mapNameToType(string $typeName): NamedType&GraphQLType
     {
         return $this->next->mapNameToType($typeName);
     }
diff --git a/src/Mappers/Root/RootTypeMapperFactoryContext.php b/src/Mappers/Root/RootTypeMapperFactoryContext.php
index 5a6f27d28f..254a5ac081 100644
--- a/src/Mappers/Root/RootTypeMapperFactoryContext.php
+++ b/src/Mappers/Root/RootTypeMapperFactoryContext.php
@@ -19,15 +19,15 @@
 final class RootTypeMapperFactoryContext
 {
     public function __construct(
-        private AnnotationReader $annotationReader,
-        private TypeResolver $typeResolver,
-        private NamingStrategyInterface $namingStrategy,
-        private TypeRegistry $typeRegistry,
-        private RecursiveTypeMapperInterface $recursiveTypeMapper,
-        private ContainerInterface $container,
-        private CacheInterface $cache,
-        private int|null $globTTL,
-        private int|null $mapTTL = null,
+        private readonly AnnotationReader $annotationReader,
+        private readonly TypeResolver $typeResolver,
+        private readonly NamingStrategyInterface $namingStrategy,
+        private readonly TypeRegistry $typeRegistry,
+        private readonly RecursiveTypeMapperInterface $recursiveTypeMapper,
+        private readonly ContainerInterface $container,
+        private readonly CacheInterface $cache,
+        private readonly int|null $globTTL,
+        private readonly int|null $mapTTL = null,
     ) {
     }
 
diff --git a/src/Mappers/Root/RootTypeMapperInterface.php b/src/Mappers/Root/RootTypeMapperInterface.php
index 03fc11aa11..237768c969 100644
--- a/src/Mappers/Root/RootTypeMapperInterface.php
+++ b/src/Mappers/Root/RootTypeMapperInterface.php
@@ -25,19 +25,11 @@
  */
 interface RootTypeMapperInterface
 {
-    /**
-     * @param (OutputType&GraphQLType)|null $subType
-     *
-     * @return OutputType&GraphQLType
-     */
-    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType;
+    /** @param (OutputType&GraphQLType)|null $subType */
+    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType&GraphQLType;
 
-    /**
-     * @param (InputType&GraphQLType)|null $subType
-     *
-     * @return InputType&GraphQLType
-     */
-    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType;
+    /** @param (InputType&GraphQLType)|null $subType */
+    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType&GraphQLType;
 
     /**
      * Returns a GraphQL type by name.
@@ -46,5 +38,5 @@ public function toGraphQLInputType(Type $type, InputType|null $subType, string $
      *
      * @param string $typeName The name of the GraphQL type
      */
-    public function mapNameToType(string $typeName): NamedType;
+    public function mapNameToType(string $typeName): NamedType&GraphQLType;
 }
diff --git a/src/Mappers/StaticTypeMapper.php b/src/Mappers/StaticTypeMapper.php
index 916fc66ead..d41d7cdb37 100644
--- a/src/Mappers/StaticTypeMapper.php
+++ b/src/Mappers/StaticTypeMapper.php
@@ -161,7 +161,7 @@ public function mapClassToInputType(string $className): ResolvableMutableInputIn
      *
      * @throws CannotMapTypeExceptionInterface
      */
-    public function mapNameToType(string $typeName): Type
+    public function mapNameToType(string $typeName): Type&NamedType
     {
         if (isset($this->notMappedTypes[$typeName])) {
             return $this->notMappedTypes[$typeName];
diff --git a/src/Mappers/TypeMapperInterface.php b/src/Mappers/TypeMapperInterface.php
index c402e230de..c3c32e3a4d 100644
--- a/src/Mappers/TypeMapperInterface.php
+++ b/src/Mappers/TypeMapperInterface.php
@@ -53,7 +53,7 @@ public function canMapNameToType(string $typeName): bool;
      *
      * @return NamedType&Type&((ResolvableMutableInputInterface&InputObjectType)|MutableObjectType|MutableInterfaceType)
      */
-    public function mapNameToType(string $typeName): Type;
+    public function mapNameToType(string $typeName): Type&NamedType;
 
     /**
      * Returns the list of classes that have matching GraphQL types.
diff --git a/src/Middlewares/AuthorizationInputFieldMiddleware.php b/src/Middlewares/AuthorizationInputFieldMiddleware.php
index 5d1676db03..c31e6c276b 100644
--- a/src/Middlewares/AuthorizationInputFieldMiddleware.php
+++ b/src/Middlewares/AuthorizationInputFieldMiddleware.php
@@ -20,8 +20,8 @@
 class AuthorizationInputFieldMiddleware implements InputFieldMiddlewareInterface
 {
     public function __construct(
-        private AuthenticationServiceInterface $authenticationService,
-        private AuthorizationServiceInterface $authorizationService,
+        private readonly AuthenticationServiceInterface $authenticationService,
+        private readonly AuthorizationServiceInterface $authorizationService,
     )
     {
     }
diff --git a/src/Middlewares/InputNext.php b/src/Middlewares/InputNext.php
index 80f8b4f82e..f7f1493090 100644
--- a/src/Middlewares/InputNext.php
+++ b/src/Middlewares/InputNext.php
@@ -23,7 +23,7 @@ final class InputNext implements InputFieldHandlerInterface
      * @param InputFieldHandlerInterface $fallbackHandler Fallback handler to
      *     invoke when the queue is exhausted.
      */
-    public function __construct(SplQueue $queue, private InputFieldHandlerInterface $fallbackHandler)
+    public function __construct(SplQueue $queue, private readonly InputFieldHandlerInterface $fallbackHandler)
     {
         $this->queue = clone $queue;
     }
diff --git a/src/Middlewares/MagicPropertyResolver.php b/src/Middlewares/MagicPropertyResolver.php
index 9c1e3826cc..502ba1afcf 100644
--- a/src/Middlewares/MagicPropertyResolver.php
+++ b/src/Middlewares/MagicPropertyResolver.php
@@ -16,7 +16,7 @@
  *
  * @internal
  */
-class MagicPropertyResolver implements SourceResolverInterface
+final class MagicPropertyResolver implements SourceResolverInterface
 {
     private object|null $object = null;
 
diff --git a/src/Middlewares/Next.php b/src/Middlewares/Next.php
index fb9a1ddc7c..ef0925454a 100644
--- a/src/Middlewares/Next.php
+++ b/src/Middlewares/Next.php
@@ -21,7 +21,7 @@ final class Next implements FieldHandlerInterface
      * @param FieldHandlerInterface $fallbackHandler Fallback handler to
      *     invoke when the queue is exhausted.
      */
-    public function __construct(SplQueue $queue, private FieldHandlerInterface $fallbackHandler)
+    public function __construct(SplQueue $queue, private readonly FieldHandlerInterface $fallbackHandler)
     {
         $this->queue           = clone $queue;
     }
diff --git a/src/Middlewares/SecurityFieldMiddleware.php b/src/Middlewares/SecurityFieldMiddleware.php
index 6dbb07c8ae..a6a9bde9d9 100644
--- a/src/Middlewares/SecurityFieldMiddleware.php
+++ b/src/Middlewares/SecurityFieldMiddleware.php
@@ -26,7 +26,7 @@
  */
 class SecurityFieldMiddleware implements FieldMiddlewareInterface
 {
-    public function __construct(private ExpressionLanguage $language, private AuthenticationServiceInterface $authenticationService, private AuthorizationServiceInterface $authorizationService/*, ?LoggerInterface $logger = null*/)
+    public function __construct(private readonly ExpressionLanguage $language, private readonly AuthenticationServiceInterface $authenticationService, private readonly AuthorizationServiceInterface $authorizationService/*, ?LoggerInterface $logger = null*/)
     {
         /*$this->logger = $logger;*/
     }
diff --git a/src/Middlewares/SecurityInputFieldMiddleware.php b/src/Middlewares/SecurityInputFieldMiddleware.php
index 89a93bb5cb..bc21fa57bf 100644
--- a/src/Middlewares/SecurityInputFieldMiddleware.php
+++ b/src/Middlewares/SecurityInputFieldMiddleware.php
@@ -25,9 +25,9 @@
 class SecurityInputFieldMiddleware implements InputFieldMiddlewareInterface
 {
     public function __construct(
-        private ExpressionLanguage $language,
-        private AuthenticationServiceInterface $authenticationService,
-        private AuthorizationServiceInterface $authorizationService,
+        private readonly ExpressionLanguage $language,
+        private readonly AuthenticationServiceInterface $authenticationService,
+        private readonly AuthorizationServiceInterface $authorizationService,
     ) {
     }
 
diff --git a/src/Middlewares/ServiceResolver.php b/src/Middlewares/ServiceResolver.php
index f1135fae8d..1f0c9f8c39 100644
--- a/src/Middlewares/ServiceResolver.php
+++ b/src/Middlewares/ServiceResolver.php
@@ -12,7 +12,7 @@
  *
  * @internal
  */
-class ServiceResolver implements ResolverInterface
+final class ServiceResolver implements ResolverInterface
 {
     /** @var callable&array{0:object, 1:string} */
     private $callable;
diff --git a/src/Middlewares/SourceInputPropertyResolver.php b/src/Middlewares/SourceInputPropertyResolver.php
index ad5607c9c9..66b76ee459 100644
--- a/src/Middlewares/SourceInputPropertyResolver.php
+++ b/src/Middlewares/SourceInputPropertyResolver.php
@@ -15,11 +15,11 @@
  *
  * @internal
  */
-class SourceInputPropertyResolver implements SourceResolverInterface
+final class SourceInputPropertyResolver implements SourceResolverInterface
 {
     private object|null $object = null;
 
-    public function __construct(private string $propertyName)
+    public function __construct(private readonly string $propertyName)
     {
     }
 
diff --git a/src/Middlewares/SourcePropertyResolver.php b/src/Middlewares/SourcePropertyResolver.php
index 5444070400..29582ab0c1 100644
--- a/src/Middlewares/SourcePropertyResolver.php
+++ b/src/Middlewares/SourcePropertyResolver.php
@@ -15,11 +15,11 @@
  *
  * @internal
  */
-class SourcePropertyResolver implements SourceResolverInterface
+final class SourcePropertyResolver implements SourceResolverInterface
 {
     private object|null $object = null;
 
-    public function __construct(private string $propertyName)
+    public function __construct(private readonly string $propertyName)
     {
     }
 
diff --git a/src/Middlewares/SourceResolver.php b/src/Middlewares/SourceResolver.php
index 51618d721a..8f4b6e5cc4 100644
--- a/src/Middlewares/SourceResolver.php
+++ b/src/Middlewares/SourceResolver.php
@@ -15,11 +15,11 @@
  *
  * @internal
  */
-class SourceResolver implements SourceResolverInterface
+final class SourceResolver implements SourceResolverInterface
 {
     private object|null $object = null;
 
-    public function __construct(private string $methodName)
+    public function __construct(private readonly string $methodName)
     {
     }
 
diff --git a/src/Parameters/ContainerParameter.php b/src/Parameters/ContainerParameter.php
index 4937d23619..1e926618a2 100644
--- a/src/Parameters/ContainerParameter.php
+++ b/src/Parameters/ContainerParameter.php
@@ -12,7 +12,7 @@
  */
 class ContainerParameter implements ParameterInterface
 {
-    public function __construct(private ContainerInterface $container, private string $identifier)
+    public function __construct(private readonly ContainerInterface $container, private readonly string $identifier)
     {
     }
 
diff --git a/src/Parameters/DefaultValueParameter.php b/src/Parameters/DefaultValueParameter.php
index 39866b1f34..78e86b86dd 100644
--- a/src/Parameters/DefaultValueParameter.php
+++ b/src/Parameters/DefaultValueParameter.php
@@ -11,7 +11,7 @@
  */
 class DefaultValueParameter implements ParameterInterface
 {
-    public function __construct(private mixed $defaultValue)
+    public function __construct(private readonly mixed $defaultValue)
     {
     }
 
diff --git a/src/Parameters/InjectUserParameter.php b/src/Parameters/InjectUserParameter.php
index d6fad0a51a..32755a32ce 100644
--- a/src/Parameters/InjectUserParameter.php
+++ b/src/Parameters/InjectUserParameter.php
@@ -12,7 +12,7 @@
  */
 class InjectUserParameter implements ParameterInterface
 {
-    public function __construct(private AuthenticationServiceInterface $authenticationService)
+    public function __construct(private readonly AuthenticationServiceInterface $authenticationService)
     {
     }
 
diff --git a/src/Parameters/InputTypeParameter.php b/src/Parameters/InputTypeParameter.php
index 60cc458316..67a62ee009 100644
--- a/src/Parameters/InputTypeParameter.php
+++ b/src/Parameters/InputTypeParameter.php
@@ -15,8 +15,7 @@ class InputTypeParameter implements InputTypeParameterInterface
     private bool $doesHaveDefaultValue;
     private string|null $description = null;
 
-    /** @param InputType&Type $type */
-    public function __construct(private string $name, private InputType $type, bool $hasDefaultValue, private mixed $defaultValue, private ArgumentResolver $argumentResolver)
+    public function __construct(private readonly string $name, private readonly InputType&Type $type, bool $hasDefaultValue, private readonly mixed $defaultValue, private readonly ArgumentResolver $argumentResolver)
     {
         $this->doesHaveDefaultValue = $hasDefaultValue;
     }
@@ -46,8 +45,7 @@ public function getName(): string
         return $this->name;
     }
 
-    /** @return InputType&Type */
-    public function getType(): InputType
+    public function getType(): InputType&Type
     {
         return $this->type;
     }
diff --git a/src/Parameters/InputTypeParameterInterface.php b/src/Parameters/InputTypeParameterInterface.php
index 55a0906731..221640e514 100644
--- a/src/Parameters/InputTypeParameterInterface.php
+++ b/src/Parameters/InputTypeParameterInterface.php
@@ -14,8 +14,7 @@ interface InputTypeParameterInterface extends ParameterInterface
     /** @param array<string, mixed> $args */
     public function resolve(object|null $source, array $args, mixed $context, ResolveInfo $info): mixed;
 
-    /** @return InputType&Type */
-    public function getType(): InputType;
+    public function getType(): InputType&Type;
 
     public function hasDefaultValue(): bool;
 
diff --git a/src/Parameters/InputTypeProperty.php b/src/Parameters/InputTypeProperty.php
index 88170be42c..ee62a0245d 100644
--- a/src/Parameters/InputTypeProperty.php
+++ b/src/Parameters/InputTypeProperty.php
@@ -10,8 +10,7 @@
 
 class InputTypeProperty extends InputTypeParameter
 {
-    /** @param InputType&Type $type */
-    public function __construct(private string $propertyName, string $fieldName, InputType $type, bool $hasDefaultValue, mixed $defaultValue, ArgumentResolver $argumentResolver)
+    public function __construct(private readonly string $propertyName, string $fieldName, InputType&Type $type, bool $hasDefaultValue, mixed $defaultValue, ArgumentResolver $argumentResolver)
     {
         parent::__construct($fieldName, $type, $hasDefaultValue, $defaultValue, $argumentResolver);
     }
diff --git a/src/QueryField.php b/src/QueryField.php
index f6ae0b92ad..df02c837db 100644
--- a/src/QueryField.php
+++ b/src/QueryField.php
@@ -37,7 +37,7 @@
  * @phpstan-import-type ArgumentListConfig from FieldDefinition
  * @phpstan-import-type ComplexityFn from FieldDefinition
  */
-class QueryField extends FieldDefinition
+final class QueryField extends FieldDefinition
 {
     /**
      * @param OutputType&Type $type
diff --git a/src/QueryFieldDescriptor.php b/src/QueryFieldDescriptor.php
index 12c3514f7a..52252dab25 100644
--- a/src/QueryFieldDescriptor.php
+++ b/src/QueryFieldDescriptor.php
@@ -67,8 +67,7 @@ public function getType(): Type|null
         return $this->type;
     }
 
-    /** @param OutputType&Type $type */
-    public function setType(Type $type): void
+    public function setType(OutputType&Type $type): void
     {
         $this->type = $type;
     }
diff --git a/src/Reflection/CachedDocBlockFactory.php b/src/Reflection/CachedDocBlockFactory.php
index 31be932ce0..70b5c6699c 100644
--- a/src/Reflection/CachedDocBlockFactory.php
+++ b/src/Reflection/CachedDocBlockFactory.php
@@ -32,7 +32,7 @@ class CachedDocBlockFactory
     private ContextFactory $contextFactory;
 
     /** @param CacheInterface $cache The cache we fetch data from. Note this is a SAFE cache. It does not need to be purged. */
-    public function __construct(private CacheInterface $cache, DocBlockFactory|null $docBlockFactory = null)
+    public function __construct(private readonly CacheInterface $cache, DocBlockFactory|null $docBlockFactory = null)
     {
         $this->docBlockFactory = $docBlockFactory ?: DocBlockFactory::createInstance();
         $this->contextFactory  = new ContextFactory();
diff --git a/src/ResolveUtils.php b/src/ResolveUtils.php
index 0d6d2bbeb8..b3aa657668 100644
--- a/src/ResolveUtils.php
+++ b/src/ResolveUtils.php
@@ -19,7 +19,7 @@
  *
  * @internal
  */
-class ResolveUtils
+final class ResolveUtils
 {
     public static function assertInnerReturnType(mixed $result, Type $type): void
     {
diff --git a/src/Types/ArgumentResolver.php b/src/Types/ArgumentResolver.php
index 0025e5076a..7f5f5fb53a 100644
--- a/src/Types/ArgumentResolver.php
+++ b/src/Types/ArgumentResolver.php
@@ -26,13 +26,11 @@
 class ArgumentResolver
 {
     /**
-     * Casts a value received from GraphQL into an argument passed to a method.
-     *
-     * @param InputType&Type $type
+     * Casts a value received from GraphQL into an argument passed to a method.*
      *
      * @throws Error
      */
-    public function resolve(object|null $source, mixed $val, mixed $context, ResolveInfo $resolveInfo, InputType $type): mixed
+    public function resolve(object|null $source, mixed $val, mixed $context, ResolveInfo $resolveInfo, InputType&Type $type): mixed
     {
         $type = $this->stripNonNullType($type);
         if ($type instanceof ListOfType) {
@@ -68,10 +66,12 @@ public function resolve(object|null $source, mixed $val, mixed $context, Resolve
         throw new RuntimeException('Unexpected type: ' . $type::class);
     }
 
-    private function stripNonNullType(Type $type): Type
+    private function stripNonNullType(InputType&Type $type): InputType&Type
     {
         if ($type instanceof NonNull) {
-            return $this->stripNonNullType($type->getWrappedType());
+            $wrapped = $type->getWrappedType();
+            assert($wrapped instanceof InputType);
+            return $this->stripNonNullType($wrapped);
         }
 
         return $type;
diff --git a/src/Types/EnumType.php b/src/Types/EnumType.php
index 4962f3162b..f04c02b1ae 100644
--- a/src/Types/EnumType.php
+++ b/src/Types/EnumType.php
@@ -18,7 +18,7 @@
 class EnumType extends BaseEnumType
 {
     /** @param class-string<UnitEnum> $enumName */
-    public function __construct(string $enumName, string $typeName, private bool $useValues = false)
+    public function __construct(string $enumName, string $typeName, private readonly bool $useValues = false)
     {
         $values = [];
         foreach ($enumName::cases() as $case) {
diff --git a/src/Types/ID.php b/src/Types/ID.php
index 363585a911..950214a4ed 100644
--- a/src/Types/ID.php
+++ b/src/Types/ID.php
@@ -19,7 +19,7 @@ class ID
     /**
      * Note: if $value is an object, it has a __toString method on it.
      */
-    public function __construct(private bool|float|int|string|object $value)
+    public function __construct(private readonly bool|float|int|string|object $value)
     {
         if (! is_scalar($value) && (! is_object($value) || ! method_exists($value, '__toString'))) {
             throw new InvalidArgumentException('ID constructor cannot be passed a non scalar value.');
diff --git a/src/Types/TypeResolver.php b/src/Types/TypeResolver.php
index c5fc455049..5edb635a01 100644
--- a/src/Types/TypeResolver.php
+++ b/src/Types/TypeResolver.php
@@ -52,8 +52,7 @@ public function mapNameToType(string $typeName): Type
         return $type;
     }
 
-    /** @return OutputType&Type */
-    public function mapNameToOutputType(string $typeName): OutputType
+    public function mapNameToOutputType(string $typeName): OutputType&Type
     {
         $type = $this->mapNameToType($typeName);
         if (! $type instanceof OutputType || ($type instanceof WrappingType && ! $type->getWrappedType() instanceof OutputType)) {
@@ -63,8 +62,7 @@ public function mapNameToOutputType(string $typeName): OutputType
         return $type;
     }
 
-    /** @return InputType&Type */
-    public function mapNameToInputType(string $typeName): InputType
+    public function mapNameToInputType(string $typeName): InputType&Type
     {
         $type = $this->mapNameToType($typeName);
         if (! $type instanceof InputType || ($type instanceof WrappingType && ! $type->getWrappedType() instanceof InputType)) {
diff --git a/src/Utils/NamespacedCache.php b/src/Utils/NamespacedCache.php
index 00fc886e03..209e6efb23 100644
--- a/src/Utils/NamespacedCache.php
+++ b/src/Utils/NamespacedCache.php
@@ -20,7 +20,7 @@ class NamespacedCache implements CacheInterface
 
     private string $namespace;
 
-    public function __construct(private CacheInterface $cache)
+    public function __construct(private readonly CacheInterface $cache)
     {
         $this->namespace = substr(md5(Versions::getVersion('thecodingmachine/graphqlite')), 0, 8);
     }
diff --git a/src/Utils/Namespaces/NS.php b/src/Utils/Namespaces/NS.php
index 65c1b59c7f..5c8f3bf9ec 100644
--- a/src/Utils/Namespaces/NS.php
+++ b/src/Utils/Namespaces/NS.php
@@ -30,7 +30,7 @@ final class NS
     private array|null $classes = null;
 
     /** @param string $namespace The namespace that contains the GraphQL types (they must have a `@Type` annotation) */
-    public function __construct(private string $namespace, private CacheInterface $cache, private ClassNameMapper $classNameMapper, private int|null $globTTL, private bool $recursive)
+    public function __construct(private readonly string $namespace, private readonly CacheInterface $cache, private readonly ClassNameMapper $classNameMapper, private readonly int|null $globTTL, private readonly bool $recursive)
     {
     }
 
@@ -44,8 +44,8 @@ public function getClassList(): array
     {
         if ($this->classes === null) {
             $this->classes = [];
-            $explorer      = new GlobClassExplorer($this->namespace, $this->cache, $this->globTTL, $this->classNameMapper, $this->recursive);
-            $classes       = $explorer->getClassMap();
+            $explorer = new GlobClassExplorer($this->namespace, $this->cache, $this->globTTL, $this->classNameMapper, $this->recursive);
+            $classes = $explorer->getClassMap();
             foreach ($classes as $className => $phpFile) {
                 if (! class_exists($className, false) && ! interface_exists($className, false)) {
                     // Let's try to load the file if it was not imported yet.
diff --git a/src/Utils/Namespaces/NamespaceFactory.php b/src/Utils/Namespaces/NamespaceFactory.php
index b10b087a52..9d1c6d32cf 100644
--- a/src/Utils/Namespaces/NamespaceFactory.php
+++ b/src/Utils/Namespaces/NamespaceFactory.php
@@ -16,7 +16,7 @@ final class NamespaceFactory
 {
     private ClassNameMapper $classNameMapper;
 
-    public function __construct(private CacheInterface $cache, ClassNameMapper|null $classNameMapper = null, private int|null $globTTL = 2)
+    public function __construct(private readonly CacheInterface $cache, ClassNameMapper|null $classNameMapper = null, private int|null $globTTL = 2)
     {
         $this->classNameMapper = $classNameMapper ?? ClassNameMapper::createFromComposerFile(null, null, true);
     }
diff --git a/tests/AbstractQueryProviderTest.php b/tests/AbstractQueryProviderTest.php
index 2c1ba84bc8..cd40b3cb21 100644
--- a/tests/AbstractQueryProviderTest.php
+++ b/tests/AbstractQueryProviderTest.php
@@ -5,6 +5,7 @@
 
 use Doctrine\Common\Annotations\AnnotationReader as DoctrineAnnotationReader;
 use GraphQL\Type\Definition\InputObjectType;
+use GraphQL\Type\Definition\NamedType;
 use GraphQL\Type\Definition\ObjectType;
 use GraphQL\Type\Definition\OutputType;
 use GraphQL\Type\Definition\Type;
@@ -180,7 +181,7 @@ public function getSupportedClasses(): array
                     return [TestObject::class, TestObject2::class];
                 }
 
-                public function mapNameToType(string $typeName): Type
+                public function mapNameToType(string $typeName): Type&NamedType
                 {
                     return match ($typeName) {
                         'TestObject' => $this->testObjectType,
@@ -432,8 +433,7 @@ protected function getTypeRegistry(): TypeRegistry
 
     protected function resolveType(string $type): \phpDocumentor\Reflection\Type
     {
-        $phpDocumentorTypeResolver = new PhpDocumentorTypeResolver();
-        return $phpDocumentorTypeResolver->resolve($type);
+        return (new PhpDocumentorTypeResolver())->resolve($type);
     }
 
     protected function getNamespaceFactory(): NamespaceFactory
diff --git a/tests/Mappers/CompositeTypeMapperTest.php b/tests/Mappers/CompositeTypeMapperTest.php
index 553e0fc4e2..f26e46f916 100644
--- a/tests/Mappers/CompositeTypeMapperTest.php
+++ b/tests/Mappers/CompositeTypeMapperTest.php
@@ -78,19 +78,17 @@ public function getSupportedClasses(): array
              * @param string $typeName The name of the GraphQL type
              * @return NamedType&Type&((ResolvableMutableInputInterface&InputObjectType)|MutableObjectType)
              */
-            public function mapNameToType(string $typeName): Type
+            public function mapNameToType(string $typeName): Type&NamedType
             {
-                switch ($typeName) {
-                    case 'TestObject':
-                        return new MutableObjectType([
-                            'name'    => 'TestObject',
-                            'fields'  => [
-                                'test'   => Type::string(),
-                            ],
-                        ]);
-                    default:
-                        throw CannotMapTypeException::createForName($typeName);
-                }
+                return match ($typeName) {
+                    'TestObject' => new MutableObjectType([
+                        'name' => 'TestObject',
+                        'fields' => [
+                            'test' => Type::string(),
+                        ],
+                    ]),
+                    default => throw CannotMapTypeException::createForName($typeName),
+                };
             }
 
             /**
diff --git a/tests/Mappers/Root/NullableTypeMapperAdapterTest.php b/tests/Mappers/Root/NullableTypeMapperAdapterTest.php
index 447d12f503..66b02bee74 100644
--- a/tests/Mappers/Root/NullableTypeMapperAdapterTest.php
+++ b/tests/Mappers/Root/NullableTypeMapperAdapterTest.php
@@ -50,17 +50,17 @@ public function testNonNullableReturnedByWrappedMapper(): void
 
         $typeMapper->setNext(new class implements RootTypeMapperInterface {
 
-            public function toGraphQLOutputType(Type $type, ?OutputType $subType, $reflector, DocBlock $docBlockObj): OutputType
+            public function toGraphQLOutputType(Type $type, ?OutputType $subType, $reflector, DocBlock $docBlockObj): OutputType&GraphQLType
             {
                 return new NonNull(new StringType());
             }
 
-            public function toGraphQLInputType(Type $type, null|InputType $subType, string $argumentName, $reflector, DocBlock $docBlockObj): InputType
+            public function toGraphQLInputType(Type $type, null|InputType $subType, string $argumentName, $reflector, DocBlock $docBlockObj): InputType&GraphQLType
             {
                 throw new \RuntimeException('Not implemented');
             }
 
-            public function mapNameToType(string $typeName): NamedType
+            public function mapNameToType(string $typeName): NamedType&GraphQLType
             {
                 throw new \RuntimeException('Not implemented');
             }
diff --git a/tests/Mappers/Root/VoidRootTypeMapper.php b/tests/Mappers/Root/VoidRootTypeMapper.php
index 42b0c17906..23d4874d1b 100644
--- a/tests/Mappers/Root/VoidRootTypeMapper.php
+++ b/tests/Mappers/Root/VoidRootTypeMapper.php
@@ -15,30 +15,18 @@
 
 class VoidRootTypeMapper implements RootTypeMapperInterface
 {
-    /** @var RootTypeMapperInterface */
-    private $next;
-
-    public function __construct(RootTypeMapperInterface $next)
+    public function __construct(private readonly RootTypeMapperInterface $next)
     {
-        $this->next = $next;
     }
 
-    /**
-     * @param (OutputType&GraphQLType)|null $subType
-     *
-     * @return OutputType&GraphQLType
-     */
-    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType
+    /** @param (OutputType&GraphQLType)|null $subType */
+    public function toGraphQLOutputType(Type $type, OutputType|null $subType, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): OutputType&GraphQLType
     {
         return $this->next->toGraphQLOutputType($type, $subType, $reflector, $docBlockObj);
     }
 
-    /**
-     * @param (InputType&GraphQLType)|null $subType
-     *
-     * @return InputType&GraphQLType
-     */
-    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType
+    /** @param (InputType&GraphQLType)|null $subType */
+    public function toGraphQLInputType(Type $type, InputType|null $subType, string $argumentName, ReflectionMethod|ReflectionProperty $reflector, DocBlock $docBlockObj): InputType&GraphQLType
     {
         return $this->next->toGraphQLInputType($type, $subType, $argumentName, $reflector, $docBlockObj);
     }
@@ -50,7 +38,7 @@ public function toGraphQLInputType(Type $type, InputType|null $subType, string $
      *
      * @param string $typeName The name of the GraphQL type
      */
-    public function mapNameToType(string $typeName): NamedType
+    public function mapNameToType(string $typeName): NamedType&GraphQLType
     {
         return $this->next->mapNameToType($typeName);
     }