diff --git a/src/Plugin/HookablePluginDependant.php b/src/Plugin/HookablePluginDependant.php
index 9f2da43096dd7f01e47bdbdc05b5d59f91227d55..e335c53732b39717d1cae65048538715467ca4e6 100644
--- a/src/Plugin/HookablePluginDependant.php
+++ b/src/Plugin/HookablePluginDependant.php
@@ -11,7 +11,7 @@ interface HookablePluginDependant extends Hookable {
 	 *
 	 * @return null
 	 */
-	public function set_plugin( $plugin );
+	public function set_plugin( AbstractPlugin $plugin );
 
 	/**
 	 * Get plugin.