Merge branch '3.1' into 3.2

* 3.1:
  [Config] ConfigCache::isFresh() should return false on __PHP_Incomplete_Class
  mark alias as private during creation
  [Serializer] Remove unused GetSetMethodNormalizer::denormalize

Author: nicolas-grekas

DependencyInjection/FrameworkExtension.php

@@ -14,6 +14,7 @@
 use Doctrine\Common\Annotations\Reader;
 use Symfony\Bridge\Monolog\Processor\DebugProcessor;
 use Symfony\Component\Cache\Adapter\AdapterInterface;
+use Symfony\Component\DependencyInjection\Alias;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Definition;
@@ -1248,8 +1249,7 @@ private function registerCacheConfiguration(array $config, ContainerBuilder $con
         }
         foreach (array('doctrine', 'psr6', 'redis') as $name) {
             if (isset($config[$name = 'default_'.$name.'_provider'])) {
-                $container->setAlias('cache.'.$name, Compiler\CachePoolPass::getServiceProvider($container, $config[$name]));
-                $container->getAlias('cache.'.$name)->setPublic(false);
+                $container->setAlias('cache.'.$name, new Alias(Compiler\CachePoolPass::getServiceProvider($container, $config[$name]), false));
             }
         }
         foreach (array('app', 'system') as $name) {