[DI] fix related to preloading

Author: nicolas-grekas

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;

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.
  *