diff --git a/autoload.php b/autoload.php
index d7d655e8ed..3d54ee409d 100644
--- a/autoload.php
+++ b/autoload.php
@@ -73,7 +73,7 @@ public static function load($class)
                 // Make sure we don't try to load any of Composer's classes
                 // while the autoloader is being setup.
                 if (strpos($class, 'Composer\\') === 0) {
-                    return;
+                    return false;
                 }
 
                 if (strpos(__DIR__, 'phar://') !== 0