Merge branch '4.4' into 5.2

* 4.4:
  Simplify some code with null coalesce operator

Author: derrabus

Compiler/MergeExtensionConfigurationPass.php

@@ -143,7 +143,7 @@ public function freezeAfterProcessing(Extension $extension, ContainerBuilder $co
      */
     public function getEnvPlaceholders(): array
     {
-        return null !== $this->processedEnvPlaceholders ? $this->processedEnvPlaceholders : parent::getEnvPlaceholders();
+        return $this->processedEnvPlaceholders ?? parent::getEnvPlaceholders();
     }
 
     public function getUnusedEnvPlaceholders(): array

ContainerBuilder.php

@@ -1560,7 +1560,7 @@ private function callMethod(object $service, array $call, array &$inlineServices
      */
     private function shareService(Definition $definition, $service, ?string $id, array &$inlineServices)
     {
-        $inlineServices[null !== $id ? $id : spl_object_hash($definition)] = $service;
+        $inlineServices[$id ?? spl_object_hash($definition)] = $service;
 
         if (null !== $id && $definition->isShared()) {
             $this->services[$id] = $service;