diff --git a/core/lib/Drupal/Component/DependencyInjection/Dumper/OptimizedPhpArrayDumper.php b/core/lib/Drupal/Component/DependencyInjection/Dumper/OptimizedPhpArrayDumper.php
index 11768d0c20..d42b4c6d1d 100644
--- a/core/lib/Drupal/Component/DependencyInjection/Dumper/OptimizedPhpArrayDumper.php
+++ b/core/lib/Drupal/Component/DependencyInjection/Dumper/OptimizedPhpArrayDumper.php
@@ -309,10 +309,10 @@ protected function dumpCollection($collection, &$resolve = FALSE) {
         }
       }
       else {
-        if (is_object($value)) {
+        $code[$key] = $this->dumpValue($value);
+        if (is_object($code[$key])) {
           $resolve = TRUE;
         }
-        $code[$key] = $this->dumpValue($value);
       }
     }
 
@@ -403,6 +403,9 @@ protected function dumpValue($value) {
     elseif ($value instanceof Parameter) {
       return $this->getParameterCall((string) $value);
     }
+    elseif (preg_match('/^\%(.*)\%$/', $value, $matches)) {
+      return $this->getParameterCall($matches[1]);
+    }
     elseif ($value instanceof Expression) {
       throw new RuntimeException('Unable to use expressions as the Symfony ExpressionLanguage component is not installed.');
     }