diff --git a/src/Config.php b/src/Config.php
index 3518e4cd..63fcbf42 100644
--- a/src/Config.php
+++ b/src/Config.php
@@ -61,8 +61,9 @@ public function getShared()
 
     public function configureServiceManager(ServiceManager $serviceManager)
     {
-        $allowOverride = $this->getAllowOverride();
-        isset($allowOverride) ? $serviceManager->setAllowOverride($allowOverride) : null;
+        if (($allowOverride = $this->getAllowOverride()) !== null) {
+            $serviceManager->setAllowOverride($allowOverride);
+        }
 
         foreach ($this->getFactories() as $name => $factory) {
             $serviceManager->setFactory($name, $factory);