symfony
diff --git a/‎src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
+4Lines changed: 4 additions & 0 deletions b/‎src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
+4Lines changed: 4 additions & 0 deletions
diff --git a/‎src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
+4Lines changed: 4 additions & 0 deletions b/‎src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
+4Lines changed: 4 additions & 0 deletions
@@ -506,6 +506,10 @@ private function getArgumentsAsPhp(\DOMElement $node, $name, $file, $lowercase =
                     $arguments[$key] = new Reference($arg->getAttribute('id'), $invalidBehavior);
                     break;
                 case 'expression':
+                    if (!class_exists(Expression::class)) {
+                        throw new \LogicException(sprintf('The type="expression" attribute cannot be used without the ExpressionLanguage component. Try running "composer require symfony/expression-language".'));
+                    }
+
                     $arguments[$key] = new Expression($arg->nodeValue);
                     break;
                 case 'collection':
 
@@ -775,6 +775,10 @@ private function resolveServices($value, $file, $isParameter = false)
                 $value[$k] = $this->resolveServices($v, $file, $isParameter);
             }
         } elseif (is_string($value) && 0 === strpos($value, '@=')) {
+            if (!class_exists(Expression::class)) {
+                throw new \LogicException(sprintf('The "@=" expression syntax cannot be used without the ExpressionLanguage component. Try running "composer require symfony/expression-language".'));
+            }
+
             return new Expression(substr($value, 2));
         } elseif (is_string($value) && 0 === strpos($value, '@')) {
             if (0 === strpos($value, '@@')) {