minor #18025 [2.7] Don't use reflection when possible (Ener-Getick)

This PR was merged into the 2.7 branch.

Discussion
----------

[2.7] Don't use reflection when possible

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

See symfony/symfony#18021

Commits
-------

35be501 Don't use reflections when possible

Author: fabpot

DependencyInjection/Compiler/FragmentRendererPass.php

@@ -37,9 +37,8 @@ public function process(ContainerBuilder $container)
             // We must assume that the class value has been correctly filled, even if the service is created by a factory
             $class = $container->getDefinition($id)->getClass();
 
-            $refClass = new \ReflectionClass($class);
             $interface = 'Symfony\Component\HttpKernel\Fragment\FragmentRendererInterface';
-            if (!$refClass->implementsInterface($interface)) {
+            if (!is_subclass_of($class, $interface)) {
                 throw new \InvalidArgumentException(sprintf('Service "%s" must implement interface "%s".', $id, $interface));
             }
 

DependencyInjection/Compiler/LoggingTranslatorPass.php

@@ -36,8 +36,7 @@ public function process(ContainerBuilder $container)
             $definition = $container->getDefinition((string) $translatorAlias);
             $class = $container->getParameterBag()->resolveValue($definition->getClass());
 
-            $refClass = new \ReflectionClass($class);
-            if ($refClass->implementsInterface('Symfony\Component\Translation\TranslatorInterface') && $refClass->implementsInterface('Symfony\Component\Translation\TranslatorBagInterface')) {
+            if (is_subclass_of($class, 'Symfony\Component\Translation\TranslatorInterface') && is_subclass_of($class, 'Symfony\Component\Translation\TranslatorBagInterface')) {
                 $container->getDefinition('translator.logging')->setDecoratedService('translator');
                 $container->getDefinition('translation.warmer')->replaceArgument(0, new Reference('translator.logging.inner'));
             }