diff --git a/core/lib/Drupal/Core/Composer/Composer.php b/core/lib/Drupal/Core/Composer/Composer.php
index 3f9e3bb..3d500df 100644
--- a/core/lib/Drupal/Core/Composer/Composer.php
+++ b/core/lib/Drupal/Core/Composer/Composer.php
@@ -153,7 +153,7 @@ public static function vendorTestCodeCleanup(PackageEvent $event) {
   /**
    * Find the array key for a given package name with a case-insensitive search.
    *
-   * @param $package_name
+   * @param string $package_name
    *   The package name from composer. This is always already lower case.
    *
    * @return NULL|string