diff --git a/apps/files_sharing/lib/ISharedStorage.php b/apps/files_sharing/lib/ISharedStorage.php
index 07c012fd6ff..cbed54b3a45 100644
--- a/apps/files_sharing/lib/ISharedStorage.php
+++ b/apps/files_sharing/lib/ISharedStorage.php
@@ -24,5 +24,7 @@
 
 namespace OCA\Files_Sharing;
 
-interface ISharedStorage {
+use OCP\Files\Storage\IStorage;
+
+interface ISharedStorage extends IStorage {
 }
diff --git a/lib/public/Files/IHomeStorage.php b/lib/public/Files/IHomeStorage.php
index 074e7a09301..96aefd17f01 100644
--- a/lib/public/Files/IHomeStorage.php
+++ b/lib/public/Files/IHomeStorage.php
@@ -32,10 +32,12 @@
 
 namespace OCP\Files;
 
+use OCP\Files\Storage\IStorage;
+
 /**
  * Interface IHomeStorage
  *
  * @since 7.0.0
  */
-interface IHomeStorage {
+interface IHomeStorage extends IStorage {
 }
diff --git a/lib/public/Files/Storage/IDisableEncryptionStorage.php b/lib/public/Files/Storage/IDisableEncryptionStorage.php
index 761f636b068..e070244094d 100644
--- a/lib/public/Files/Storage/IDisableEncryptionStorage.php
+++ b/lib/public/Files/Storage/IDisableEncryptionStorage.php
@@ -29,5 +29,5 @@ namespace OCP\Files\Storage;
  *
  * @since 16.0.0
  */
-interface IDisableEncryptionStorage {
+interface IDisableEncryptionStorage extends IStorage {
 }
diff --git a/lib/public/Files/Storage/IStorage.php b/lib/public/Files/Storage/IStorage.php
index 5e70e319c40..96bc7ea616d 100644
--- a/lib/public/Files/Storage/IStorage.php
+++ b/lib/public/Files/Storage/IStorage.php
@@ -362,9 +362,12 @@ interface IStorage {
 	/**
 	 * Check if the storage is an instance of $class or is a wrapper for a storage that is an instance of $class
 	 *
+	 * @template T of IStorage
 	 * @param string $class
+	 * @psalm-param class-string<T> $class
 	 * @return bool
 	 * @since 9.0.0
+	 * @psalm-assert-if-true T $this
 	 */
 	public function instanceOfStorage($class);