diff --git a/phpBB/phpbb/finder/factory.php b/phpBB/phpbb/finder/factory.php
index 3022f5ea9d..0ce087b061 100644
--- a/phpBB/phpbb/finder/factory.php
+++ b/phpBB/phpbb/finder/factory.php
@@ -13,6 +13,8 @@
 
 namespace phpbb\finder;
 
+use phpbb\cache\service;
+
 /**
 * The finder provides a simple way to locate files in the core and a set of extensions
 */
@@ -26,12 +28,12 @@ class factory
 	/**
 	* Creates a new finder instance with its dependencies
 	*
-	* @param \phpbb\cache\service		$cache A cache instance or null
+	* @param service|null		$cache A cache instance or null
 	* @param bool $use_cache		Use cache or not
 	* @param string $phpbb_root_path	Path to the phpbb root directory
 	* @param string $php_ext			php file extension
 	*/
-	public function __construct(/*\phpbb\cache\service */ $cache, $use_cache, $phpbb_root_path, $php_ext)
+	public function __construct(?service $cache, bool $use_cache, string $phpbb_root_path, string $php_ext)
 	{
 		$this->cache = $cache;
 		$this->use_cache = $use_cache;
@@ -44,10 +46,10 @@ class factory
 	*
 	* Allows the use of multiple differently configured finders with the same cache.
 	*
-	* @param string $cache_name The name of the cache variable, defaults to
-	* _ext_finder
+	* @param string $cache_name The name of the cache variable, defaults to _ext_finder
+	* @return finder New instance of finder
 	*/
-	public function get($cache_name = '_ext_finder')
+	public function get(string $cache_name = '_ext_finder'): finder
 	{
 		return new finder($this->cache, $this->use_cache, $this->phpbb_root_path, $this->php_ext, $cache_name);
 	}
diff --git a/phpBB/phpbb/finder/finder.php b/phpBB/phpbb/finder/finder.php
index 5c88396299..6b0baef19f 100644
--- a/phpBB/phpbb/finder/finder.php
+++ b/phpBB/phpbb/finder/finder.php
@@ -13,6 +13,7 @@
 
 namespace phpbb\finder;
 
+use phpbb\cache\service;
 use phpbb\filesystem\helper as filesystem_helper;
 
 /**
@@ -51,12 +52,13 @@ class finder
 	* Creates a new finder instance with its dependencies
 	*
 	* @param string $phpbb_root_path Path to the phpbb root directory
-	* @param \phpbb\cache\service|null $cache A cache instance or null
+	* @param service|null $cache A cache instance or null
+	* @param bool $use_cache Flag whether cache should be used
 	* @param string $php_ext php file extension
 	* @param string $cache_name The name of the cache variable, defaults to
-	*                           _ext_finder
+	*							_ext_finder
 	*/
-	public function __construct(/*\phpbb\cache\service */ $cache, $use_cache, $phpbb_root_path, $php_ext, $cache_name = '_ext_finder')
+	public function __construct(?service $cache, bool $use_cache, string $phpbb_root_path, string $php_ext, string $cache_name = '_ext_finder')
 	{
 		$this->phpbb_root_path = $phpbb_root_path;
 		$this->cache = $cache;
diff --git a/phpBB/phpbb/install/module/install_database/task/create_schema_file.php b/phpBB/phpbb/install/module/install_database/task/create_schema_file.php
index 695ec86143..984ca3461e 100644
--- a/phpBB/phpbb/install/module/install_database/task/create_schema_file.php
+++ b/phpBB/phpbb/install/module/install_database/task/create_schema_file.php
@@ -46,7 +46,7 @@ class create_schema_file extends \phpbb\install\task_base
 	protected $php_ext;
 
 	/**
-	 * @var string
+	 * @var bool
 	 */
 	protected $finder_cache;
 
@@ -58,6 +58,7 @@ class create_schema_file extends \phpbb\install\task_base
 	 * @param \phpbb\filesystem\filesystem_interface				$filesystem			Filesystem service
 	 * @param string												$phpbb_root_path	Path phpBB's root
 	 * @param string												$php_ext			Extension of PHP files
+	 * @param bool													$finder_cache		Flag whether to cache finder
 	 */
 	public function __construct(\phpbb\install\helper\config $config,
 								\phpbb\install\helper\database $db_helper,
@@ -124,7 +125,8 @@ class create_schema_file extends \phpbb\install\task_base
 				include ($this->phpbb_root_path . 'includes/constants.' . $this->php_ext);
 			}
 
-			$finder = new \phpbb\finder\finder(null, $this->finder_cache, $this->phpbb_root_path, $this->php_ext);
+			$finder_factory = new \phpbb\finder\factory(null, $this->finder_cache, $this->phpbb_root_path, $this->php_ext);
+			$finder = $finder_factory->get();
 			$migrator_classes = $finder->core_path('phpbb/db/migration/data/')->get_classes();
 			$factory = new \phpbb\db\tools\factory();
 			$db_tools = $factory->get($this->db, true);