diff --git a/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php b/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php
index eca801fa87e38..c60b3b44f44ca 100644
--- a/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php
+++ b/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php
@@ -2047,7 +2047,7 @@ private function getAutoloadFile(): ?string
 
             foreach (get_declared_classes() as $class) {
                 if (0 === strpos($class, 'ComposerAutoloaderInit') && $class::getLoader() === $autoloader[0]) {
-                    $file = (new \ReflectionClass($class))->getFileName();
+                    $file = \dirname((new \ReflectionClass($class))->getFileName(), 2).'/autoload.php';
 
                     if (preg_match($this->targetDirRegex.'A', $file)) {
                         return $file;
diff --git a/src/Symfony/Component/DependencyInjection/ExpressionLanguage.php b/src/Symfony/Component/DependencyInjection/ExpressionLanguage.php
index 4be1ae70858c6..24bf94a0667ac 100644
--- a/src/Symfony/Component/DependencyInjection/ExpressionLanguage.php
+++ b/src/Symfony/Component/DependencyInjection/ExpressionLanguage.php
@@ -14,6 +14,10 @@
 use Psr\Cache\CacheItemPoolInterface;
 use Symfony\Component\ExpressionLanguage\ExpressionLanguage as BaseExpressionLanguage;
 
+if (!class_exists(BaseExpressionLanguage::class)) {
+    throw new \ReflectionException(BaseExpressionLanguage::class.' not found.');
+}
+
 /**
  * Adds some function to the default ExpressionLanguage.
  *