diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 0c037e6..98ceb8c 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -89,3 +89,6 @@ jobs:
 
             - name: Run unit test suite
               run: composer test
+
+            - name: Run PHPStan analysis
+              run: composer run-script phpstan
diff --git a/composer.json b/composer.json
index dc2c6c8..889158c 100644
--- a/composer.json
+++ b/composer.json
@@ -34,6 +34,9 @@
         "ibexa/doctrine-schema": "~5.0.x-dev",
         "ibexa/rector": "~5.0.x-dev",
         "mikey179/vfsstream": "^1.6",
+        "phpstan/phpstan": "^2.0",
+        "phpstan/phpstan-phpunit": "^2.0",
+        "phpstan/phpstan-symfony": "^2.0",
         "phpunit/phpunit": "^9.6"
     },
     "autoload": {
@@ -52,7 +55,8 @@
     "scripts": {
         "fix-cs": "php-cs-fixer fix --config=.php-cs-fixer.php -v --show-progress=dots",
         "check-cs": "@fix-cs --dry-run",
-        "test": "phpunit"
+        "test": "phpunit",
+        "phpstan": "phpstan analyse"
     },
     "extra": {
         "branch-alias": {
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
new file mode 100644
index 0000000..635a1df
--- /dev/null
+++ b/phpstan-baseline.neon
@@ -0,0 +1,31 @@
+parameters:
+	ignoreErrors:
+		-
+			message: '#^Class Ibexa\\Bundle\\DesignEngine\\DataCollector\\TwigDataCollector extends @final class Symfony\\Bridge\\Twig\\DataCollector\\TwigDataCollector\.$#'
+			identifier: class.extendsFinalByPhpDoc
+			count: 1
+			path: src/bundle/DataCollector/TwigDataCollector.php
+
+		-
+			message: '#^Parameter \#1 \$provisioner of method Ibexa\\Bundle\\DesignEngine\\DependencyInjection\\Compiler\\AssetPathResolutionPass\:\:preResolveAssetsPaths\(\) expects Ibexa\\DesignEngine\\Asset\\AssetPathProvisionerInterface, object given\.$#'
+			identifier: argument.type
+			count: 1
+			path: src/bundle/DependencyInjection/Compiler/AssetPathResolutionPass.php
+
+		-
+			message: '#^Parameter \#2 \$designPathMap of method Ibexa\\Bundle\\DesignEngine\\DependencyInjection\\Compiler\\AssetPathResolutionPass\:\:preResolveAssetsPaths\(\) expects array\<string, list\<string\>\>, array\|bool\|float\|int\|string\|null given\.$#'
+			identifier: argument.type
+			count: 1
+			path: src/bundle/DependencyInjection/Compiler/AssetPathResolutionPass.php
+
+		-
+			message: '#^Parameter \#3 \$length of function substr expects int\|null, int\|false given\.$#'
+			identifier: argument.type
+			count: 1
+			path: src/bundle/DependencyInjection/Compiler/AssetThemePass.php
+
+		-
+			message: '#^PHPDoc tag @var with type SplFileInfo is not subtype of native type Symfony\\Component\\Finder\\SplFileInfo\.$#'
+			identifier: varTag.nativeType
+			count: 1
+			path: src/lib/Asset/ProvisionedPathResolver.php
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..cf9e462
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,11 @@
+includes:
+    - phpstan-baseline.neon
+    - vendor/phpstan/phpstan-phpunit/extension.neon
+    - vendor/phpstan/phpstan-symfony/extension.neon
+
+parameters:
+    level: 8
+    paths:
+        - src
+        - tests
+    treatPhpDocTypesAsCertain: false
diff --git a/src/bundle/DataCollector/TwigDataCollector.php b/src/bundle/DataCollector/TwigDataCollector.php
index c842b1f..848de31 100644
--- a/src/bundle/DataCollector/TwigDataCollector.php
+++ b/src/bundle/DataCollector/TwigDataCollector.php
@@ -14,29 +14,30 @@
 
 class TwigDataCollector extends BaseCollector
 {
-    private TemplatePathRegistryInterface $templatePathRegistry;
-
-    public function __construct(Profile $profile, Environment $environment, TemplatePathRegistryInterface $templatePathRegistry)
-    {
+    public function __construct(
+        Profile $profile,
+        Environment $environment,
+        private TemplatePathRegistryInterface $templatePathRegistry
+    ) {
         parent::__construct($profile, $environment);
-        $this->templatePathRegistry = $templatePathRegistry;
     }
 
-    private function getTemplatePathRegistry()
+    private function getTemplatePathRegistry(): TemplatePathRegistryInterface
     {
-        if (!isset($this->templatePathRegistry)) {
-            $this->templatePathRegistry = unserialize($this->data['template_path_registry']);
-        }
-
         return $this->templatePathRegistry;
     }
 
+    #[\Override]
     public function lateCollect(): void
     {
         parent::lateCollect();
         $this->data['template_path_registry'] = serialize($this->templatePathRegistry);
     }
 
+    /**
+     * @return array<string, int>
+     */
+    #[\Override]
     public function getTemplates(): array
     {
         $registry = $this->getTemplatePathRegistry();
diff --git a/src/bundle/DependencyInjection/Compiler/AssetPathResolutionPass.php b/src/bundle/DependencyInjection/Compiler/AssetPathResolutionPass.php
index f719cd8..41906ce 100644
--- a/src/bundle/DependencyInjection/Compiler/AssetPathResolutionPass.php
+++ b/src/bundle/DependencyInjection/Compiler/AssetPathResolutionPass.php
@@ -42,6 +42,11 @@ public function process(ContainerBuilder $container): void
         $container->setAlias('ibexadesign.asset_path_resolver', new Alias(ProvisionedPathResolver::class));
     }
 
+    /**
+     * @param array<string, list<string>> $designPathMap
+     *
+     * @return array<string, array<string, string>>
+     */
     private function preResolveAssetsPaths(AssetPathProvisionerInterface $provisioner, array $designPathMap): array
     {
         $resolvedPathsByDesign = [];
diff --git a/src/bundle/DependencyInjection/Compiler/AssetThemePass.php b/src/bundle/DependencyInjection/Compiler/AssetThemePass.php
index 858692e..03e0ba8 100644
--- a/src/bundle/DependencyInjection/Compiler/AssetThemePass.php
+++ b/src/bundle/DependencyInjection/Compiler/AssetThemePass.php
@@ -21,17 +21,20 @@ public function process(ContainerBuilder $container): void
             return;
         }
 
+        $overridePaths = $container->getParameter('ibexa.design.assets.override_paths');
         $themesPathMap = [
             '_override' => array_merge(
                 ['assets'],
-                $container->getParameter('ibexa.design.assets.override_paths')
+                (array)$overridePaths,
             ),
         ];
         $finder = new Finder();
         // Look for assets themes in bundles.
-        foreach ($container->getParameter('kernel.bundles') as $bundleName => $bundleClass) {
+        foreach ((array)$container->getParameter('kernel.bundles') as $bundleName => $bundleClass) {
             $bundleReflection = new \ReflectionClass($bundleClass);
-            $bundleViewsDir = \dirname($bundleReflection->getFileName()) . '/Resources/public';
+            $fileName = $bundleReflection->getFileName();
+            assert(is_string($fileName));
+            $bundleViewsDir = \dirname($fileName) . '/Resources/public';
             $themeDir = $bundleViewsDir . '/themes';
             if (!is_dir($themeDir)) {
                 continue;
@@ -46,7 +49,9 @@ public function process(ContainerBuilder $container): void
         }
 
         // Look for assets themes at application level (web/assets/themes).
-        $appLevelThemeDir = $container->getParameter('webroot_dir') . '/assets/themes';
+        $webrootDir = $container->getParameter('webroot_dir');
+        assert(is_string($webrootDir));
+        $appLevelThemeDir = $webrootDir . '/assets/themes';
         if (is_dir($appLevelThemeDir)) {
             foreach ((new Finder())->directories()->in($appLevelThemeDir)->depth('== 0') as $directoryInfo) {
                 $theme = $directoryInfo->getBasename();
@@ -62,7 +67,7 @@ public function process(ContainerBuilder $container): void
         }
 
         $pathsByDesign = [];
-        foreach ($container->getParameter('ibexa.design.list') as $designName => $themeFallback) {
+        foreach ((array)$container->getParameter('ibexa.design.list') as $designName => $themeFallback) {
             // Always add _override theme first.
             array_unshift($themeFallback, '_override');
             foreach ($themeFallback as $theme) {
@@ -77,7 +82,7 @@ public function process(ContainerBuilder $container): void
             }
         }
 
-        $themesList = $container->getParameter('ibexa.design.themes.list');
+        $themesList = (array)$container->getParameter('ibexa.design.themes.list');
         $container->setParameter(
             'ibexa.design.themes.list',
             array_unique(
diff --git a/src/bundle/DependencyInjection/Compiler/TwigThemePass.php b/src/bundle/DependencyInjection/Compiler/TwigThemePass.php
index 159bf59..1d22f84 100644
--- a/src/bundle/DependencyInjection/Compiler/TwigThemePass.php
+++ b/src/bundle/DependencyInjection/Compiler/TwigThemePass.php
@@ -33,13 +33,15 @@ public function process(ContainerBuilder $container): void
         }
 
         $themesPathMap = [
-            '_override' => $container->getParameter('ibexa.design.templates.override_paths'),
+            '_override' => (array)$container->getParameter('ibexa.design.templates.override_paths'),
         ];
         $finder = new Finder();
         // Look for themes in bundles.
-        foreach ($container->getParameter('kernel.bundles') as $bundleName => $bundleClass) {
+        foreach ((array)$container->getParameter('kernel.bundles') as $bundleName => $bundleClass) {
             $bundleReflection = new ReflectionClass($bundleClass);
-            $bundleViewsDir = \dirname($bundleReflection->getFileName()) . '/Resources/views';
+            $filename = $bundleReflection->getFileName();
+            assert(is_string($filename));
+            $bundleViewsDir = \dirname($filename) . '/Resources/views';
             $themeDir = $bundleViewsDir . '/themes';
             if (!is_dir($themeDir)) {
                 continue;
@@ -53,9 +55,9 @@ public function process(ContainerBuilder $container): void
 
         $twigLoaderDef = $container->findDefinition(TwigThemeLoader::class);
         // Now look for themes at application level
-        $appLevelThemesDir = $container->getParameterBag()->resolveValue(
-            $container->getParameter('twig.default_path') . '/themes'
-        );
+        $twigDefaultPath = $container->getParameter('twig.default_path');
+        assert(is_string($twigDefaultPath));
+        $appLevelThemesDir = $container->getParameterBag()->resolveValue($twigDefaultPath . '/themes');
 
         if (is_dir($appLevelThemesDir)) {
             foreach ((new Finder())->directories()->in($appLevelThemesDir)->depth('== 0') as $directoryInfo) {
@@ -69,14 +71,17 @@ public function process(ContainerBuilder $container): void
 
         // Now merge with already configured template theme paths
         // Template theme paths defined via config will always have less priority than convention based paths
-        $themesPathMap = array_merge_recursive($themesPathMap, $container->getParameter('ibexa.design.templates.path_map'));
+        $themesPathMap = array_merge_recursive(
+            $themesPathMap,
+            (array)$container->getParameter('ibexa.design.templates.path_map'),
+        );
 
         // De-duplicate the map
         foreach ($themesPathMap as $theme => &$paths) {
             $paths = array_unique($paths);
         }
 
-        foreach ($container->getParameter('ibexa.design.list') as $designName => $themeFallback) {
+        foreach ((array)$container->getParameter('ibexa.design.list') as $designName => $themeFallback) {
             // Always add _override theme first.
             array_unshift($themeFallback, '_override');
             foreach ($themeFallback as $theme) {
@@ -91,7 +96,7 @@ public function process(ContainerBuilder $container): void
             }
         }
 
-        $themesList = $container->getParameter('ibexa.design.themes.list');
+        $themesList = (array)$container->getParameter('ibexa.design.themes.list');
         $container->setParameter(
             'ibexa.design.themes.list',
             array_unique(
diff --git a/src/bundle/DependencyInjection/DesignConfigParser.php b/src/bundle/DependencyInjection/DesignConfigParser.php
index c1d83eb..69f637b 100644
--- a/src/bundle/DependencyInjection/DesignConfigParser.php
+++ b/src/bundle/DependencyInjection/DesignConfigParser.php
@@ -13,6 +13,10 @@
 
 class DesignConfigParser implements ParserInterface
 {
+    /**
+     * @param array<string, mixed> $scopeSettings
+     * @param string $currentScope
+     */
     public function mapConfig(array &$scopeSettings, $currentScope, ContextualizerInterface $contextualizer): void
     {
         if (isset($scopeSettings['design'])) {
@@ -20,11 +24,17 @@ public function mapConfig(array &$scopeSettings, $currentScope, ContextualizerIn
         }
     }
 
+    /**
+     * @param array<string, mixed> $config
+     */
     public function preMap(array $config, ContextualizerInterface $contextualizer): void
     {
         // Nothing to map
     }
 
+    /**
+     * @param array<string, mixed> $config
+     */
     public function postMap(array $config, ContextualizerInterface $contextualizer): void
     {
         // Nothing to map
diff --git a/src/bundle/DependencyInjection/IbexaDesignEngineExtension.php b/src/bundle/DependencyInjection/IbexaDesignEngineExtension.php
index 7992f3e..49a013a 100644
--- a/src/bundle/DependencyInjection/IbexaDesignEngineExtension.php
+++ b/src/bundle/DependencyInjection/IbexaDesignEngineExtension.php
@@ -7,7 +7,6 @@
 
 namespace Ibexa\Bundle\DesignEngine\DependencyInjection;
 
-use Ibexa\Bundle\Core\DependencyInjection\Configuration\SiteAccessAware\ConfigurationProcessor;
 use Symfony\Component\Config\Definition\ConfigurationInterface;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
@@ -18,11 +17,16 @@ class IbexaDesignEngineExtension extends Extension
 {
     public const string EXTENSION_NAME = 'ibexa_design_engine';
 
+    #[\Override]
     public function getAlias(): string
     {
         return self::EXTENSION_NAME;
     }
 
+    /**
+     * @param array<string, mixed> $config
+     */
+    #[\Override]
     public function getConfiguration(array $config, ContainerBuilder $container): ?ConfigurationInterface
     {
         return new Configuration();
@@ -40,12 +44,14 @@ public function load(array $configs, ContainerBuilder $container): void
         $configuration = $this->getConfiguration($configs, $container);
         assert(null !== $configuration);
         $config = $this->processConfiguration($configuration, $configs);
-        $processor = new ConfigurationProcessor($container, 'ezdesign');
 
-        $this->configureDesigns($config, $processor, $container);
+        $this->configureDesigns($config, $container);
     }
 
-    private function configureDesigns(array $config, ConfigurationProcessor $processor, ContainerBuilder $container): void
+    /**
+     * @param array<string, mixed> $config
+     */
+    private function configureDesigns(array $config, ContainerBuilder $container): void
     {
         // Always add "standard" design to the list (defaults to application level & override paths only)
         $config['design_list'] += ['standard' => []];
diff --git a/src/bundle/IbexaDesignEngineBundle.php b/src/bundle/IbexaDesignEngineBundle.php
index 065c3bb..850b8ba 100644
--- a/src/bundle/IbexaDesignEngineBundle.php
+++ b/src/bundle/IbexaDesignEngineBundle.php
@@ -34,12 +34,13 @@ public function build(ContainerBuilder $container): void
         $container->addCompilerPass(new AssetPathResolutionPass(), PassConfig::TYPE_OPTIMIZE);
     }
 
+    #[\Override]
     public function getContainerExtension(): ?ExtensionInterface
     {
         if (!isset($this->extension)) {
             $this->extension = new IbexaDesignEngineExtension();
         }
 
-        return $this->extension;
+        return $this->extension === false ? null : $this->extension;
     }
 }
diff --git a/src/lib/Asset/AssetPathProvisionerInterface.php b/src/lib/Asset/AssetPathProvisionerInterface.php
index 589e380..13bfe8b 100644
--- a/src/lib/Asset/AssetPathProvisionerInterface.php
+++ b/src/lib/Asset/AssetPathProvisionerInterface.php
@@ -14,7 +14,7 @@ interface AssetPathProvisionerInterface
      * Returns a map with asset logical path as key and its resolved path (relative to webroot dir) as value.
      * Example => ['images/foo.png' => 'asset/themes/some_theme/images/foo.png'].
      *
-     * @param string[] $assetsPaths
+     * @param list<string> $assetsPaths
      *
      * @return array<string, string>
      */
diff --git a/src/lib/Asset/AssetPathResolver.php b/src/lib/Asset/AssetPathResolver.php
index 4df890c..1abebb0 100644
--- a/src/lib/Asset/AssetPathResolver.php
+++ b/src/lib/Asset/AssetPathResolver.php
@@ -12,18 +12,14 @@
 
 class AssetPathResolver implements AssetPathResolverInterface
 {
-    /** @var array<string, string> */
-    private array $designPaths;
-
-    private string $webRootDir;
-
-    private ?LoggerInterface $logger;
-
-    public function __construct(array $designPaths, string $webRootDir, LoggerInterface $logger = null)
-    {
-        $this->designPaths = $designPaths;
-        $this->webRootDir = $webRootDir;
-        $this->logger = $logger;
+    /**
+     * @param array<string, array<int, string>> $designPaths
+     */
+    public function __construct(
+        private readonly array $designPaths,
+        private readonly string $webRootDir,
+        private readonly ?LoggerInterface $logger = null
+    ) {
     }
 
     public function resolveAssetPath(string $path, string $design): string
diff --git a/src/lib/Asset/ProvisionedPathResolver.php b/src/lib/Asset/ProvisionedPathResolver.php
index 900df2e..8f28b60 100644
--- a/src/lib/Asset/ProvisionedPathResolver.php
+++ b/src/lib/Asset/ProvisionedPathResolver.php
@@ -9,29 +9,21 @@
 
 use Symfony\Component\Finder\Finder;
 
-class ProvisionedPathResolver implements AssetPathResolverInterface, AssetPathProvisionerInterface
+readonly class ProvisionedPathResolver implements AssetPathResolverInterface, AssetPathProvisionerInterface
 {
     /**
-     * @var array<string, array<string, string>>
+     * @param array<string, array<string, string>> $resolvedPaths
      */
-    private array $resolvedPaths;
-
-    private AssetPathResolverInterface $innerResolver;
-
-    private string $webRootDir;
-
-    public function __construct(array $resolvedPaths, AssetPathResolverInterface $innerResolver, string $webRootDir)
-    {
-        $this->resolvedPaths = $resolvedPaths;
-        $this->innerResolver = $innerResolver;
-        $this->webRootDir = $webRootDir;
+    public function __construct(
+        private array $resolvedPaths,
+        private AssetPathResolverInterface $innerResolver,
+        private string $webRootDir
+    ) {
     }
 
     /**
      * Looks for $path within pre-resolved paths for provided design.
      * If it cannot be found, fallbacks to original resolver.
-     *
-     * {@inheritdoc}
      */
     public function resolveAssetPath(string $path, string $design): string
     {
diff --git a/src/lib/Asset/ThemePackage.php b/src/lib/Asset/ThemePackage.php
index c7e82b2..178f6fb 100644
--- a/src/lib/Asset/ThemePackage.php
+++ b/src/lib/Asset/ThemePackage.php
@@ -15,23 +15,25 @@ class ThemePackage implements PackageInterface, DesignAwareInterface
 {
     use DesignAwareTrait;
 
-    private AssetPathResolverInterface $pathResolver;
-
-    private PackageInterface $innerPackage;
-
-    public function __construct(AssetPathResolverInterface $pathResolver, PackageInterface $innerPackage)
-    {
-        $this->pathResolver = $pathResolver;
-        $this->innerPackage = $innerPackage;
+    public function __construct(
+        private AssetPathResolverInterface $pathResolver,
+        private PackageInterface $innerPackage
+    ) {
     }
 
     public function getUrl(string $path): string
     {
-        return $this->innerPackage->getUrl($this->pathResolver->resolveAssetPath($path, $this->getCurrentDesign()));
+        $currentDesign = $this->getCurrentDesign();
+        assert(is_string($currentDesign));
+
+        return $this->innerPackage->getUrl($this->pathResolver->resolveAssetPath($path, $currentDesign));
     }
 
     public function getVersion(string $path): string
     {
-        return $this->innerPackage->getVersion($this->pathResolver->resolveAssetPath($path, $this->getCurrentDesign()));
+        $currentDesign = $this->getCurrentDesign();
+        assert(is_string($currentDesign));
+
+        return $this->innerPackage->getVersion($this->pathResolver->resolveAssetPath($path, $currentDesign));
     }
 }
diff --git a/src/lib/Templating/TemplatePathRegistry.php b/src/lib/Templating/TemplatePathRegistry.php
index 93e4216..b62f86e 100644
--- a/src/lib/Templating/TemplatePathRegistry.php
+++ b/src/lib/Templating/TemplatePathRegistry.php
@@ -14,11 +14,9 @@ class TemplatePathRegistry implements TemplatePathRegistryInterface, Serializabl
     /** @var array<string, string> */
     private array $pathMap = [];
 
-    private string $kernelRootDir;
-
-    public function __construct(string $kernelRootDir)
-    {
-        $this->kernelRootDir = $kernelRootDir;
+    public function __construct(
+        private string $kernelRootDir
+    ) {
     }
 
     public function mapTemplatePath(string $templateName, string $path): void
@@ -41,16 +39,22 @@ public function serialize(): ?string
         return serialize([$this->pathMap, $this->kernelRootDir]);
     }
 
-    public function unserialize($serialized): void
+    public function unserialize(string $serialized): void
     {
         [$this->pathMap, $this->kernelRootDir] = unserialize($serialized);
     }
 
+    /**
+     * @return array{array<string, string>, string}
+     */
     public function __serialize(): array
     {
         return [$this->pathMap, $this->kernelRootDir];
     }
 
+    /**
+     * @param array{array<string, string>, string} $data
+     */
     public function __unserialize(array $data): void
     {
         [$this->pathMap, $this->kernelRootDir] = $data;
diff --git a/src/lib/Templating/Twig/TwigThemeLoader.php b/src/lib/Templating/Twig/TwigThemeLoader.php
index 9b51256..7fd14b6 100644
--- a/src/lib/Templating/Twig/TwigThemeLoader.php
+++ b/src/lib/Templating/Twig/TwigThemeLoader.php
@@ -17,28 +17,13 @@
  * Decorates regular Twig FilesystemLoader.
  * It resolves generic @ibexadesign namespace to the actual current namespace.
  */
-class TwigThemeLoader implements LoaderInterface
+readonly class TwigThemeLoader implements LoaderInterface
 {
-    /**
-     * @var \Ibexa\DesignEngine\Templating\TemplateNameResolverInterface
-     */
-    private TemplateNameResolverInterface $nameResolver;
-
-    /**
-     * @var \Ibexa\DesignEngine\Templating\TemplatePathRegistryInterface
-     */
-    private TemplatePathRegistryInterface $pathRegistry;
-
-    private FilesystemLoader $innerFilesystemLoader;
-
     public function __construct(
-        TemplateNameResolverInterface $templateNameResolver,
-        TemplatePathRegistryInterface $templatePathRegistry,
-        FilesystemLoader $innerFilesystemLoader
+        private TemplateNameResolverInterface $nameResolver,
+        private TemplatePathRegistryInterface $pathRegistry,
+        private FilesystemLoader $innerFilesystemLoader
     ) {
-        $this->innerFilesystemLoader = $innerFilesystemLoader;
-        $this->nameResolver = $templateNameResolver;
-        $this->pathRegistry = $templatePathRegistry;
     }
 
     public function exists(string $name): bool
@@ -64,11 +49,17 @@ public function isFresh(string $name, int $time): bool
         return $this->innerFilesystemLoader->isFresh($this->nameResolver->resolveTemplateName($name), $time);
     }
 
+    /**
+     * @return list<string>
+     */
     public function getPaths(string $namespace = FilesystemLoader::MAIN_NAMESPACE): array
     {
         return $this->innerFilesystemLoader->getPaths($namespace);
     }
 
+    /**
+     * @return list<string>
+     */
     public function getNamespaces(): array
     {
         return $this->innerFilesystemLoader->getNamespaces();
diff --git a/tests/lib/Asset/AssetPathResolverTest.php b/tests/lib/Asset/AssetPathResolverTest.php
index 8ac953f..2388052 100644
--- a/tests/lib/Asset/AssetPathResolverTest.php
+++ b/tests/lib/Asset/AssetPathResolverTest.php
@@ -38,6 +38,14 @@ public function testResolveInvalidDesign(): void
         self::assertSame($assetPath, $resolver->resolveAssetPath($assetPath, 'foo'));
     }
 
+    /**
+     * @return list<array{
+     *     0: array{foo: list<string>},
+     *     1: list<string>,
+     *     2: string,
+     *     3: string
+     * }>
+     */
     public function resolveAssetPathProvider(): array
     {
         return [
@@ -106,6 +114,9 @@ public function resolveAssetPathProvider(): array
 
     /**
      * @dataProvider resolveAssetPathProvider
+     *
+     * @param array{foo: array<string>} $designPaths
+     * @param list<string> $existingPaths
      */
     public function testResolveAssetPath(array $designPaths, array $existingPaths, string $path, string $resolvedPath): void
     {
diff --git a/tests/lib/Asset/ProvisionedPathResolverTest.php b/tests/lib/Asset/ProvisionedPathResolverTest.php
index d9b97d3..94c4cf4 100644
--- a/tests/lib/Asset/ProvisionedPathResolverTest.php
+++ b/tests/lib/Asset/ProvisionedPathResolverTest.php
@@ -11,6 +11,7 @@
 use Ibexa\DesignEngine\Asset\AssetPathResolverInterface;
 use Ibexa\DesignEngine\Asset\ProvisionedPathResolver;
 use org\bovigo\vfs\vfsStream;
+use org\bovigo\vfs\vfsStreamDirectory;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
@@ -18,10 +19,7 @@ class ProvisionedPathResolverTest extends TestCase
 {
     private AssetPathResolverInterface&MockObject $innerResolver;
 
-    /**
-     * @var \org\bovigo\vfs\vfsStreamDirectory
-     */
-    private $webrootDir;
+    private vfsStreamDirectory $webrootDir;
 
     protected function setUp(): void
     {
diff --git a/tests/lib/Templating/ThemeTemplateNameResolverTest.php b/tests/lib/Templating/ThemeTemplateNameResolverTest.php
index 42a2ec7..f4dd494 100644
--- a/tests/lib/Templating/ThemeTemplateNameResolverTest.php
+++ b/tests/lib/Templating/ThemeTemplateNameResolverTest.php
@@ -23,6 +23,13 @@ protected function setUp(): void
         $this->configResolver = $this->createMock(ConfigResolverInterface::class);
     }
 
+    /**
+     * @return list<array{
+     *     0: ?string,
+     *     1: string,
+     *     2: string
+     * }>
+     */
     public function templateNameProvider(): array
     {
         return [
@@ -45,6 +52,13 @@ public function testResolveTemplateName(?string $currentDesign, string $template
         self::assertSame($expectedTemplateName, $resolver->resolveTemplateName($templateName));
     }
 
+    /**
+     * @return list<array{
+     *     0: ?string,
+     *     1: string,
+     *     2: bool
+     * }>
+     */
     public function isTemplateDesignNamespacedProvider(): array
     {
         return [