Merge branch '3.4' into 4.0

* 3.4:
  PHP CS Fixer: clean up repo and adjust config
  use interface_exists instead of class_exists
  [DX] [DI] Improve exception for invalid setter injection arguments
  Dumper shouldn't use html format for phpdbg
  [Validator] Fix access to root object when using composite constraint

Author: nicolas-grekas

Loader/YamlFileLoader.php

@@ -454,6 +454,9 @@ private function parseDefinition($id, $service, $file, array $defaults)
                     $args = isset($call[1]) ? $this->resolveServices($call[1], $file) : array();
                 }
 
+                if (!is_array($args)) {
+                    throw new InvalidArgumentException(sprintf('The second parameter for function call "%s" must be an array of its arguments for service "%s" in %s. Check your YAML syntax.', $method, $id, $file));
+                }
                 $definition->addMethodCall($method, $args);
             }
         }