diff --git a/includes/api/ApiQueryInfo.php b/includes/api/ApiQueryInfo.php
index 6f1e2e5bc7a..db9ad90b6f6 100644
--- a/includes/api/ApiQueryInfo.php
+++ b/includes/api/ApiQueryInfo.php
@@ -37,7 +37,14 @@ class ApiQueryInfo extends ApiQueryBase {
 		$fld_notificationtimestamp = false,
 		$fld_preload = false, $fld_displaytitle = false;
 
-	private $params, $titles, $missing, $everything;
+	private $params;
+
+	/** @var Title[] */
+	private $titles;
+	/** @var Title[] */
+	private $missing;
+	/** @var Title[] */
+	private $everything;
 
 	private $pageRestrictions, $pageIsRedir, $pageIsNew, $pageTouched,
 		$pageLatest, $pageLength;