diff --git a/Command/DebugCommand.php b/Command/DebugCommand.php
index 510a22fd..320de536 100644
--- a/Command/DebugCommand.php
+++ b/Command/DebugCommand.php
@@ -113,8 +113,8 @@ protected function outputMailer($name)
 
         $tableRows[] = ['Name', $name];
         $tableRows[] = ['Service', $service];
-        $tableRows[] = ['Class', get_class($mailer)];
-        $tableRows[] = ['Transport', sprintf('%s (%s)', sprintf('swiftmailer.mailer.%s.transport.name', $name), get_class($transport))];
+        $tableRows[] = ['Class', \get_class($mailer)];
+        $tableRows[] = ['Transport', sprintf('%s (%s)', sprintf('swiftmailer.mailer.%s.transport.name', $name), \get_class($transport))];
         $tableRows[] = ['Spool', $spool];
         if ($this->getContainer()->hasParameter(sprintf('swiftmailer.spool.%s.file.path', $name))) {
             $tableRows[] = ['Spool file', $this->getContainer()->getParameter(sprintf('swiftmailer.spool.%s.file.path', $name))];
diff --git a/DataCollector/MessageDataCollector.php b/DataCollector/MessageDataCollector.php
index a4f5b85a..594a4d71 100644
--- a/DataCollector/MessageDataCollector.php
+++ b/DataCollector/MessageDataCollector.php
@@ -110,7 +110,7 @@ public function getMailers()
     public function getMailerData($name)
     {
         if (!isset($this->data['mailer'][$name])) {
-            throw new \LogicException(sprintf('Missing "%s" data in "%s".', $name, get_class($this)));
+            throw new \LogicException(sprintf('Missing "%s" data in "%s".', $name, \get_class($this)));
         }
 
         return $this->data['mailer'][$name];
diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index 02d8ee18..e1c11db5 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -50,7 +50,7 @@ public function getConfigTreeBuilder()
             ->end()
             ->beforeNormalization()
                 ->ifTrue(function ($v) {
-                    return is_array($v) && !array_key_exists('mailers', $v) && !array_key_exists('mailer', $v);
+                    return \is_array($v) && !\array_key_exists('mailers', $v) && !\array_key_exists('mailer', $v);
                 })
                 ->then(function ($v) {
                     $mailer = [];
diff --git a/DependencyInjection/SwiftmailerExtension.php b/DependencyInjection/SwiftmailerExtension.php
index 778c8167..6419ca91 100644
--- a/DependencyInjection/SwiftmailerExtension.php
+++ b/DependencyInjection/SwiftmailerExtension.php
@@ -118,7 +118,7 @@ protected function configureMailer($name, array $mailer, ContainerBuilder $conta
 
             $container->setParameter(sprintf('swiftmailer.mailer.%s.transport.name', $name), $transport);
 
-            $transportId = in_array($transport, ['smtp', 'sendmail', 'null'])
+            $transportId = \in_array($transport, ['smtp', 'sendmail', 'null'])
                 ? sprintf('swiftmailer.mailer.%s.transport.%s', $name, $transport)
                 : $transport;
 
@@ -333,7 +333,7 @@ protected function configureMailerAntiFlood($name, array $mailer, ContainerBuild
 
     protected function configureMailerDeliveryAddress($name, array $mailer, ContainerBuilder $container, $isDefaultMailer = false)
     {
-        if (count($mailer['delivery_addresses']) > 0) {
+        if (\count($mailer['delivery_addresses']) > 0) {
             $container->setParameter(sprintf('swiftmailer.mailer.%s.single_address', $name), $mailer['delivery_addresses'][0]);
             $container->setParameter(sprintf('swiftmailer.mailer.%s.delivery_addresses', $name), $mailer['delivery_addresses']);
             $container->setParameter(sprintf('swiftmailer.mailer.%s.delivery_whitelist', $name), $mailer['delivery_whitelist']);
diff --git a/DependencyInjection/SwiftmailerTransportFactory.php b/DependencyInjection/SwiftmailerTransportFactory.php
index 563a0873..dc73b68e 100644
--- a/DependencyInjection/SwiftmailerTransportFactory.php
+++ b/DependencyInjection/SwiftmailerTransportFactory.php
@@ -148,11 +148,11 @@ public static function resolveOptions(array $options)
      */
     public static function validateConfig($options)
     {
-        if (!in_array($options['encryption'], ['tls', 'ssl', null], true)) {
+        if (!\in_array($options['encryption'], ['tls', 'ssl', null], true)) {
             throw new \InvalidArgumentException(sprintf('The %s encryption is not supported', $options['encryption']));
         }
 
-        if (!in_array($options['auth_mode'], ['plain', 'login', 'cram-md5', 'ntlm', null], true)) {
+        if (!\in_array($options['auth_mode'], ['plain', 'login', 'cram-md5', 'ntlm', null], true)) {
             throw new \InvalidArgumentException(sprintf('The %s authentication mode is not supported', $options['auth_mode']));
         }
     }
diff --git a/SwiftmailerBundle.php b/SwiftmailerBundle.php
index 5a4b61cc..5dc6b5cd 100644
--- a/SwiftmailerBundle.php
+++ b/SwiftmailerBundle.php
@@ -31,7 +31,7 @@ public function build(ContainerBuilder $container)
 
         // Older supported versions of Symfony don't have the parent class that EnsureNoHotPathPass extends from.
         // But they don't have the hot_path optimization either, so not being able to register our pass is not an issue.
-        if (\class_exists('Symfony\Component\DependencyInjection\Compiler\AbstractRecursivePass')) {
+        if (class_exists('Symfony\Component\DependencyInjection\Compiler\AbstractRecursivePass')) {
             $container->addCompilerPass(new EnsureNoHotPathPass(), PassConfig::TYPE_AFTER_REMOVING);
         }
     }
diff --git a/Tests/Command/SendEmailCommandTest.php b/Tests/Command/SendEmailCommandTest.php
index f141da25..14ce2a0d 100644
--- a/Tests/Command/SendEmailCommandTest.php
+++ b/Tests/Command/SendEmailCommandTest.php
@@ -56,7 +56,7 @@ public function testTimeLimitNull()
         $container = $this->buildContainer($spoolTransport, $realTransport);
         $this->executeCommand($container);
 
-        $this->assertSame(null, $spool->getTimeLimit());
+        $this->assertNull($spool->getTimeLimit());
     }
 
     public function testMessageLimitInteger()
@@ -84,7 +84,7 @@ public function testMessageLimitNull()
         $container = $this->buildContainer($spoolTransport, $realTransport);
         $this->executeCommand($container);
 
-        $this->assertSame(null, $spool->getMessageLimit());
+        $this->assertNull($spool->getMessageLimit());
     }
 
     public function testRecoverLoadbalancedTransportWithSpool()
@@ -129,11 +129,11 @@ private function buildContainer(\Swift_Transport $transport, \Swift_Transport $r
     /**
      * @return CommandTester
      */
-    private function executeCommand(ContainerInterface $container, $input = array(), $options = array())
+    private function executeCommand(ContainerInterface $container, $input = [], $options = [])
     {
         $kernel = $this->getMockBuilder(KernelInterface::class)->getMock();
         $kernel->expects($this->any())->method('getContainer')->willReturn($container);
-        $kernel->expects($this->any())->method('getBundles')->willReturn(array());
+        $kernel->expects($this->any())->method('getBundles')->willReturn([]);
 
         $application = new Application($kernel);
         $application->add(new SendEmailCommand());
@@ -149,12 +149,26 @@ private function executeCommand(ContainerInterface $container, $input = array(),
      */
     private function configurableSpool(): \Swift_ConfigurableSpool
     {
-        return new class extends \Swift_ConfigurableSpool {
-            public function start() {}
-            public function stop() {}
-            public function isStarted() {}
-            public function queueMessage(\Swift_Mime_SimpleMessage $message) {}
-            public function flushQueue(\Swift_Transport $transport, &$failedRecipients = null) {}
+        return new class() extends \Swift_ConfigurableSpool {
+            public function start()
+            {
+            }
+
+            public function stop()
+            {
+            }
+
+            public function isStarted()
+            {
+            }
+
+            public function queueMessage(\Swift_Mime_SimpleMessage $message)
+            {
+            }
+
+            public function flushQueue(\Swift_Transport $transport, &$failedRecipients = null)
+            {
+            }
         };
     }
 }
diff --git a/Tests/DependencyInjection/Fixtures/config/php/sendmail_no_command.php b/Tests/DependencyInjection/Fixtures/config/php/sendmail_no_command.php
index d1d41506..822b9c5f 100644
--- a/Tests/DependencyInjection/Fixtures/config/php/sendmail_no_command.php
+++ b/Tests/DependencyInjection/Fixtures/config/php/sendmail_no_command.php
@@ -1,6 +1,6 @@
 <?php
 
-$container->loadFromExtension('swiftmailer', array(
+$container->loadFromExtension('swiftmailer', [
     'transport' => 'sendmail',
     'url' => '%env(SWIFTMAILER_URL)%',
-));
+]);
diff --git a/Tests/DependencyInjection/SwiftmailerExtensionTest.php b/Tests/DependencyInjection/SwiftmailerExtensionTest.php
index 27d1e9ed..7dd9b6dc 100644
--- a/Tests/DependencyInjection/SwiftmailerExtensionTest.php
+++ b/Tests/DependencyInjection/SwiftmailerExtensionTest.php
@@ -99,7 +99,7 @@ public function testSendmailConfig($type)
      */
     public function testSendmailDynamicConfigWithoutCommand($type)
     {
-        $container = $this->loadContainerFromFile('sendmail_no_command', $type, array(), true);
+        $container = $this->loadContainerFromFile('sendmail_no_command', $type, [], true);
         $container->getAlias('swiftmailer.transport')->setPublic(true);
 
         /** @var \Swift_SendmailTransport $transport */