diff --git a/src/Composer/Repository/AsyncRepositoryInterface.php b/src/Composer/Repository/AsyncRepositoryInterface.php
index 91f543dbf..5804694ec 100644
--- a/src/Composer/Repository/AsyncRepositoryInterface.php
+++ b/src/Composer/Repository/AsyncRepositoryInterface.php
@@ -25,13 +25,13 @@ interface AsyncRepositoryInterface
 {
     /**
      * @param array $names Names of packages to retrieve data for
-     * @return scalar Id to be passed to later loadPackages call
+     * @return mixed Id to be passed to later loadPackages call
      */
     public function requestPackages(array $names);
 
     /**
      * @param array $names
-     * @return scalar id for load call
+     * @return mixed id for load call
      */
     public function returnPackages($loadId);
 }