diff --git a/src/Eccube/Command/ComposerInstallCommand.php b/src/Eccube/Command/ComposerInstallCommand.php
index a572545c48e..ec7983dcc95 100644
--- a/src/Eccube/Command/ComposerInstallCommand.php
+++ b/src/Eccube/Command/ComposerInstallCommand.php
@@ -33,15 +33,15 @@ public function __construct(ComposerApiService $composerService)
         $this->composerService = $composerService;
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this->addOption('dry-run');
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $this->composerService->execInstall($input->getOption('dry-run'), $output);
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/ComposerRemoveCommand.php b/src/Eccube/Command/ComposerRemoveCommand.php
index 01957eb082d..1a27f160831 100644
--- a/src/Eccube/Command/ComposerRemoveCommand.php
+++ b/src/Eccube/Command/ComposerRemoveCommand.php
@@ -36,12 +36,12 @@ public function __construct(ComposerApiService $composerService)
         $this->composerService = $composerService;
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this->addArgument('package', InputArgument::REQUIRED);
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $this->composerService->execRemove($input->getArgument('package'), $output);
 
@@ -57,7 +57,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
         } catch (\Exception $e) {
             $io->error($e->getMessage());
 
-            return 1;
+            return Command::FAILURE;
         }
     }
 }
diff --git a/src/Eccube/Command/ComposerRequireAlreadyInstalledPluginsCommand.php b/src/Eccube/Command/ComposerRequireAlreadyInstalledPluginsCommand.php
index f2bf5cfda9a..95c3a4f7edb 100644
--- a/src/Eccube/Command/ComposerRequireAlreadyInstalledPluginsCommand.php
+++ b/src/Eccube/Command/ComposerRequireAlreadyInstalledPluginsCommand.php
@@ -59,12 +59,12 @@ public function __construct(
         $this->pluginRepository = $pluginRepository;
     }
 
-    public function initialize(InputInterface $input, OutputInterface $output)
+    public function initialize(InputInterface $input, OutputInterface $output): void
     {
         $this->io = new SymfonyStyle($input, $output);
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $packageNames = [];
         $unSupportedPlugins = [];
@@ -90,7 +90,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
             ]);
             $question = new ConfirmationQuestion($message);
             if (!$this->io->askQuestion($question)) {
-                return;
+                return Command::FAILURE;
             }
         }
 
@@ -98,6 +98,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
             $this->composerService->execRequire(implode(' ', $packageNames), $this->io);
         }
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/ComposerRequireCommand.php b/src/Eccube/Command/ComposerRequireCommand.php
index 4c74c21c03e..9a9f5b5789f 100644
--- a/src/Eccube/Command/ComposerRequireCommand.php
+++ b/src/Eccube/Command/ComposerRequireCommand.php
@@ -35,14 +35,14 @@ public function __construct(ComposerApiService $composerService)
         $this->composerService = $composerService;
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this->addArgument('package', InputArgument::REQUIRED)
             ->addArgument('version', InputArgument::OPTIONAL)
             ->addOption('from', null, InputOption::VALUE_OPTIONAL, 'Path of composer repository');
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $packageName = $input->getArgument('package');
         if ($input->getArgument('version')) {
@@ -51,6 +51,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
 
         $this->composerService->execRequire($packageName, $output, $input->getOption('from'));
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/ComposerUpdateCommand.php b/src/Eccube/Command/ComposerUpdateCommand.php
index cc71b5276a9..11a8dee7e8e 100644
--- a/src/Eccube/Command/ComposerUpdateCommand.php
+++ b/src/Eccube/Command/ComposerUpdateCommand.php
@@ -33,15 +33,15 @@ public function __construct(ComposerApiService $composerService)
         $this->composerService = $composerService;
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this->addOption('dry-run');
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $this->composerService->execUpdate($input->getOption('dry-run'), $output);
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/DeleteCartsCommand.php b/src/Eccube/Command/DeleteCartsCommand.php
index b53ec11e68b..689e4c6648f 100644
--- a/src/Eccube/Command/DeleteCartsCommand.php
+++ b/src/Eccube/Command/DeleteCartsCommand.php
@@ -69,14 +69,14 @@ public function __construct(EccubeConfig $eccubeConfig, EntityManagerInterface $
         $this->cartRepository = $cartRepository;
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->setDescription('Delete Carts from the database')
             ->addArgument('date', InputArgument::REQUIRED, 'Deletes carts before the specified date');
     }
 
-    protected function interact(InputInterface $input, OutputInterface $output)
+    protected function interact(InputInterface $input, OutputInterface $output): void
     {
         if (null !== $input->getArgument('date')) {
             return;
@@ -102,7 +102,7 @@ protected function interact(InputInterface $input, OutputInterface $output)
         $input->setArgument('date', $dateStr);
     }
 
-    protected function initialize(InputInterface $input, OutputInterface $output)
+    protected function initialize(InputInterface $input, OutputInterface $output): void
     {
         $this->io = new SymfonyStyle($input, $output);
         $this->locale = $this->eccubeConfig->get('locale');
@@ -110,7 +110,7 @@ protected function initialize(InputInterface $input, OutputInterface $output)
         $this->formatter = $this->createIntlFormatter();
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $dateStr = $input->getArgument('date');
         $timestamp = $this->formatter->parse($dateStr);
@@ -120,7 +120,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
 
         $this->io->success('Delete carts successful.');
 
-        return 0;
+        return Command::SUCCESS;
     }
 
     protected function deleteCarts(\DateTime $dateTime)
diff --git a/src/Eccube/Command/GenerateDummyDataCommand.php b/src/Eccube/Command/GenerateDummyDataCommand.php
index 023d210612b..56c74223743 100644
--- a/src/Eccube/Command/GenerateDummyDataCommand.php
+++ b/src/Eccube/Command/GenerateDummyDataCommand.php
@@ -57,7 +57,7 @@ public function __construct(Generator $generator = null, EntityManagerInterface
         $this->productRepository = $productRepository;
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->setDescription('Dummy data generator')
@@ -81,7 +81,7 @@ protected function configure()
             );
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $locale = $input->getOption('with-locale');
         $notImage = $input->getOption('without-image');
@@ -189,6 +189,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
         $output->writeln('');
         $output->writeln(sprintf('%s <info>success</info>', 'eccube:fixtures:generate'));
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/GenerateProxyCommand.php b/src/Eccube/Command/GenerateProxyCommand.php
index 664517e1efa..fb1590324bb 100644
--- a/src/Eccube/Command/GenerateProxyCommand.php
+++ b/src/Eccube/Command/GenerateProxyCommand.php
@@ -41,13 +41,13 @@ public function __construct(EntityProxyService $entityProxyService, EccubeConfig
         $this->eccubeConfig = $eccubeConfig;
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->setDescription('Generate entity proxies');
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $projectDir = $this->eccubeConfig->get('kernel.project_dir');
         $includeDirs = [$projectDir.'/app/Customize/Entity'];
@@ -66,6 +66,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
             $output
         );
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/InstallerCommand.php b/src/Eccube/Command/InstallerCommand.php
index 78351292174..c63ad450163 100644
--- a/src/Eccube/Command/InstallerCommand.php
+++ b/src/Eccube/Command/InstallerCommand.php
@@ -105,13 +105,13 @@ public function updateEnvFile()
         };
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->setDescription('Install EC-CUBE');
     }
 
-    protected function interact(InputInterface $input, OutputInterface $output)
+    protected function interact(InputInterface $input, OutputInterface $output): void
     {
         $this->io->title('EC-CUBE Installer Interactive Wizard');
         $this->io->text([
@@ -209,12 +209,12 @@ protected function interact(InputInterface $input, OutputInterface $output)
         $this->envFileUpdater->updateEnvFile();
     }
 
-    protected function initialize(InputInterface $input, OutputInterface $output)
+    protected function initialize(InputInterface $input, OutputInterface $output): void
     {
         $this->io = new SymfonyStyle($input, $output);
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         // Process実行時に, APP_ENV/APP_DEBUGが子プロセスに引き継がれてしまうため,
         // 生成された.envをロードして上書きする.
@@ -254,13 +254,13 @@ protected function execute(InputInterface $input, OutputInterface $output)
             } catch (ProcessFailedException $e) {
                 $this->io->error($e->getMessage());
 
-                return 1;
+                return Command::FAILURE;
             }
         }
 
         $this->io->success('EC-CUBE installation successful.');
 
-        return 0;
+        return Command::SUCCESS;
     }
 
     protected function getDatabaseName($databaseUrl)
diff --git a/src/Eccube/Command/LoadDataFixturesEccubeCommand.php b/src/Eccube/Command/LoadDataFixturesEccubeCommand.php
index e0eaaf2923f..f00cced79e0 100644
--- a/src/Eccube/Command/LoadDataFixturesEccubeCommand.php
+++ b/src/Eccube/Command/LoadDataFixturesEccubeCommand.php
@@ -18,6 +18,7 @@
 use Eccube\Common\EccubeConfig;
 use Eccube\Entity\Member;
 use Eccube\Security\PasswordHasher\PasswordHasher;
+use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\Filesystem\Filesystem;
@@ -44,7 +45,7 @@ public function __construct(ManagerRegistry $registry, EccubeConfig $eccubeConfi
         $this->passwordHasher = $passwordHasher;
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->setDescription('Load data fixtures to your database.')
@@ -56,7 +57,7 @@ protected function configure()
             );
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $em = $this->getEntityManager(null);
 
@@ -142,6 +143,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
 
         $output->writeln(sprintf('  <comment>></comment> <info>%s</info>', 'Finished Successful!'));
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/PluginDisableCommand.php b/src/Eccube/Command/PluginDisableCommand.php
index c6f0ef1e6f6..559a27e9625 100644
--- a/src/Eccube/Command/PluginDisableCommand.php
+++ b/src/Eccube/Command/PluginDisableCommand.php
@@ -24,13 +24,13 @@ class PluginDisableCommand extends Command
     use PluginCommandTrait;
     protected static $defaultName = 'eccube:plugin:disable';
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addOption('code', null, InputOption::VALUE_OPTIONAL, 'plugin code');
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $io = new SymfonyStyle($input, $output);
 
@@ -39,14 +39,14 @@ protected function execute(InputInterface $input, OutputInterface $output)
         if (empty($code)) {
             $io->error('code is required.');
 
-            return 1;
+            return Command::FAILURE;
         }
 
         $plugin = $this->pluginRepository->findByCode($code);
         if (is_null($plugin)) {
             $io->error("Plugin `$code` is not found.");
 
-            return 1;
+            return Command::FAILURE;
         }
 
         $this->pluginService->disable($plugin);
@@ -54,6 +54,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
 
         $io->success('Plugin Disabled.');
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/PluginEnableCommand.php b/src/Eccube/Command/PluginEnableCommand.php
index 01cc0fbd1e2..237e01bad6f 100644
--- a/src/Eccube/Command/PluginEnableCommand.php
+++ b/src/Eccube/Command/PluginEnableCommand.php
@@ -24,13 +24,13 @@ class PluginEnableCommand extends Command
     use PluginCommandTrait;
     protected static $defaultName = 'eccube:plugin:enable';
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addOption('code', null, InputOption::VALUE_OPTIONAL, 'plugin code');
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $io = new SymfonyStyle($input, $output);
 
@@ -39,14 +39,14 @@ protected function execute(InputInterface $input, OutputInterface $output)
         if (empty($code)) {
             $io->error('code is required.');
 
-            return 1;
+            return Command::FAILURE;
         }
 
         $plugin = $this->pluginRepository->findByCode($code);
         if (is_null($plugin)) {
             $io->error("Plugin `$code` is not found.");
 
-            return 1;
+            return Command::FAILURE;
         }
 
         if (!$plugin->isInitialized()) {
@@ -58,6 +58,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
 
         $io->success('Plugin Enabled.');
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/PluginGenerateCommand.php b/src/Eccube/Command/PluginGenerateCommand.php
index 36541335038..55ab4f7bed7 100644
--- a/src/Eccube/Command/PluginGenerateCommand.php
+++ b/src/Eccube/Command/PluginGenerateCommand.php
@@ -48,7 +48,7 @@ public function __construct(EccubeConfig $eccubeConfig)
         $this->eccubeConfig = $eccubeConfig;
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addArgument('name', InputOption::VALUE_REQUIRED, 'plugin name')
@@ -57,13 +57,13 @@ protected function configure()
             ->setDescription('Generate plugin skeleton.');
     }
 
-    protected function initialize(InputInterface $input, OutputInterface $output)
+    protected function initialize(InputInterface $input, OutputInterface $output): void
     {
         $this->io = new SymfonyStyle($input, $output);
         $this->fs = new Filesystem();
     }
 
-    protected function interact(InputInterface $input, OutputInterface $output)
+    protected function interact(InputInterface $input, OutputInterface $output): void
     {
         if (null !== $input->getArgument('name') && null !== $input->getArgument('code') && null !== $input->getArgument('ver')) {
             return;
@@ -99,7 +99,7 @@ protected function interact(InputInterface $input, OutputInterface $output)
         }
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $name = $input->getArgument('name');
         $code = $input->getArgument('code');
@@ -121,7 +121,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
 
         $this->io->success(sprintf('Plugin was successfully created: %s %s %s', $name, $code, $version));
 
-        return 0;
+        return Command::SUCCESS;
     }
 
     public function validateCode($code)
@@ -315,7 +315,7 @@ class Event implements EventSubscriberInterface
     /**
      * @return array
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [];
     }
diff --git a/src/Eccube/Command/PluginInstallCommand.php b/src/Eccube/Command/PluginInstallCommand.php
index a55a4aa249b..3a4f1e9c0c7 100644
--- a/src/Eccube/Command/PluginInstallCommand.php
+++ b/src/Eccube/Command/PluginInstallCommand.php
@@ -24,7 +24,7 @@ class PluginInstallCommand extends Command
     use PluginCommandTrait;
     protected static $defaultName = 'eccube:plugin:install';
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addOption('path', null, InputOption::VALUE_OPTIONAL, 'path of tar or zip')
@@ -33,7 +33,7 @@ protected function configure()
             ->setDescription('Install plugin from local.');
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $io = new SymfonyStyle($input, $output);
 
@@ -46,7 +46,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
             if ($this->pluginService->install($path, $ifNotExists)) {
                 $io->success('Installed.');
 
-                return 0;
+                return Command::SUCCESS;
             }
         }
 
@@ -56,11 +56,11 @@ protected function execute(InputInterface $input, OutputInterface $output)
             $this->clearCache($io);
             $io->success('Installed.');
 
-            return 0;
+            return Command::SUCCESS;
         }
 
         $io->error('path or code is required.');
 
-        return 1;
+        return Command::FAILURE;
     }
 }
diff --git a/src/Eccube/Command/PluginSchemaUpdateCommand.php b/src/Eccube/Command/PluginSchemaUpdateCommand.php
index 6d094eed079..e001831b97c 100644
--- a/src/Eccube/Command/PluginSchemaUpdateCommand.php
+++ b/src/Eccube/Command/PluginSchemaUpdateCommand.php
@@ -26,14 +26,14 @@ class PluginSchemaUpdateCommand extends Command
 
     protected static $defaultName = 'eccube:plugin:schema-update';
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addArgument('code', InputArgument::REQUIRED, 'Plugin code')
             ->setDescription('Execute plugin schema update.');
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $io = new SymfonyStyle($input, $output);
 
@@ -44,7 +44,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
         if (!$Plugin) {
             $io->error("No such plugin `{$code}`.");
 
-            return 1;
+            return Command::FAILURE;
         }
 
         $config = $this->pluginService->readConfig($this->pluginService->calcPluginDir($code));
@@ -53,6 +53,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
 
         $io->success('Schema Updated.');
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/PluginUninstallCommand.php b/src/Eccube/Command/PluginUninstallCommand.php
index 30582d10995..d946917a106 100644
--- a/src/Eccube/Command/PluginUninstallCommand.php
+++ b/src/Eccube/Command/PluginUninstallCommand.php
@@ -24,7 +24,7 @@ class PluginUninstallCommand extends Command
     use PluginCommandTrait;
     protected static $defaultName = 'eccube:plugin:uninstall';
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addOption('code', null, InputOption::VALUE_OPTIONAL, 'plugin code')
@@ -32,7 +32,7 @@ protected function configure()
             ->setDescription('Uninstall plugin.');
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $io = new SymfonyStyle($input, $output);
 
@@ -42,14 +42,14 @@ protected function execute(InputInterface $input, OutputInterface $output)
         if (empty($code)) {
             $io->error('code is required.');
 
-            return 1;
+            return Command::FAILURE;
         }
 
         $plugin = $this->pluginRepository->findByCode($code);
         if (is_null($plugin)) {
             $io->error("Plugin `$code` is not installed.");
 
-            return 1;
+            return Command::FAILURE;
         }
 
         $this->pluginService->uninstall($plugin, $uninstallForce);
@@ -57,6 +57,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
 
         $io->success('Uninstalled.');
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Command/PluginUpdateCommand.php b/src/Eccube/Command/PluginUpdateCommand.php
index c81c5c0660f..3cccc6234cc 100644
--- a/src/Eccube/Command/PluginUpdateCommand.php
+++ b/src/Eccube/Command/PluginUpdateCommand.php
@@ -25,14 +25,14 @@ class PluginUpdateCommand extends Command
     use PluginCommandTrait;
     protected static $defaultName = 'eccube:plugin:update';
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addArgument('code', InputArgument::REQUIRED, 'Plugin code')
             ->setDescription('Execute plugin update process.');
     }
 
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $io = new SymfonyStyle($input, $output);
 
@@ -44,7 +44,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
         if (!$Plugin) {
             $io->error("No such plugin `{$code}`.");
 
-            return 1;
+            return Command::FAILURE;
         }
 
         $config = $this->pluginService->readConfig($this->pluginService->calcPluginDir($code));
@@ -53,6 +53,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
 
         $io->success('Updated.');
 
-        return 0;
+        return Command::SUCCESS;
     }
 }
diff --git a/src/Eccube/Common/EccubeConfig.php b/src/Eccube/Common/EccubeConfig.php
index 013f541b239..46fdf22f942 100644
--- a/src/Eccube/Common/EccubeConfig.php
+++ b/src/Eccube/Common/EccubeConfig.php
@@ -53,7 +53,7 @@ public function has($key)
      * @return bool
      */
     #[\ReturnTypeWillChange]
-    public function offsetExists($offset)
+    public function offsetExists($offset): bool
     {
         return $this->has($offset);
     }
@@ -64,7 +64,7 @@ public function offsetExists($offset)
      * @return mixed
      */
     #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    public function offsetGet($offset): mixed
     {
         return $this->get($offset);
     }
@@ -74,7 +74,7 @@ public function offsetGet($offset)
      * @param mixed $value
      */
     #[\ReturnTypeWillChange]
-    public function offsetSet($offset, $value)
+    public function offsetSet($offset, $value): void
     {
         throw new \LogicException();
     }
@@ -85,7 +85,7 @@ public function offsetSet($offset, $value)
      * @throws \LogicException
      */
     #[\ReturnTypeWillChange]
-    public function offsetUnset($offset)
+    public function offsetUnset($offset): void
     {
         throw new \LogicException();
     }
diff --git a/src/Eccube/DataCollector/EccubeDataCollector.php b/src/Eccube/DataCollector/EccubeDataCollector.php
index 584735736d7..2e2746c6fe9 100644
--- a/src/Eccube/DataCollector/EccubeDataCollector.php
+++ b/src/Eccube/DataCollector/EccubeDataCollector.php
@@ -106,7 +106,7 @@ public function getDefaultLocaleCode()
     /**
      * {@inheritdoc}
      */
-    public function collect(Request $request, Response $response, \Throwable $exception = null)
+    public function collect(Request $request, Response $response, \Throwable $exception = null): void
     {
         $this->data['base_currency_code'] = $this->eccubeConfig->get('currency');
         $this->data['currency_code'] = $this->eccubeConfig->get('currency');
@@ -144,7 +144,7 @@ public function collect(Request $request, Response $response, \Throwable $except
         }
     }
 
-    public function reset()
+    public function reset(): void
     {
         $this->data = [];
     }
@@ -152,7 +152,7 @@ public function reset()
     /**
      * {@inheritdoc}
      */
-    public function getName()
+    public function getName(): string
     {
         return 'eccube_core';
     }
diff --git a/src/Eccube/DependencyInjection/Compiler/AutoConfigurationTagPass.php b/src/Eccube/DependencyInjection/Compiler/AutoConfigurationTagPass.php
index 6f42cdb8f0f..a5b9a488b10 100644
--- a/src/Eccube/DependencyInjection/Compiler/AutoConfigurationTagPass.php
+++ b/src/Eccube/DependencyInjection/Compiler/AutoConfigurationTagPass.php
@@ -31,7 +31,7 @@
  */
 class AutoConfigurationTagPass implements CompilerPassInterface
 {
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         foreach ($container->getDefinitions() as $id => $definition) {
             $this->configureDoctrineEventSubscriberTag($definition);
diff --git a/src/Eccube/DependencyInjection/Compiler/NavCompilerPass.php b/src/Eccube/DependencyInjection/Compiler/NavCompilerPass.php
index 0dfbe0268a5..4a066281751 100644
--- a/src/Eccube/DependencyInjection/Compiler/NavCompilerPass.php
+++ b/src/Eccube/DependencyInjection/Compiler/NavCompilerPass.php
@@ -21,7 +21,7 @@ class NavCompilerPass implements CompilerPassInterface
 {
     public const NAV_TAG = 'eccube.nav';
 
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $ids = $container->findTaggedServiceIds(self::NAV_TAG);
         $nav = $container->getParameter('eccube_nav');
diff --git a/src/Eccube/DependencyInjection/Compiler/PaymentMethodPass.php b/src/Eccube/DependencyInjection/Compiler/PaymentMethodPass.php
index 396ac41618c..59a3ede3a68 100644
--- a/src/Eccube/DependencyInjection/Compiler/PaymentMethodPass.php
+++ b/src/Eccube/DependencyInjection/Compiler/PaymentMethodPass.php
@@ -21,7 +21,7 @@ class PaymentMethodPass implements CompilerPassInterface
 {
     public const PAYMENT_METHOD_TAG = 'eccube.payment.method';
 
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $ids = $container->findTaggedServiceIds(self::PAYMENT_METHOD_TAG);
 
diff --git a/src/Eccube/DependencyInjection/Compiler/PluginPass.php b/src/Eccube/DependencyInjection/Compiler/PluginPass.php
index f3343b1a6c1..17f9b6a4fd7 100644
--- a/src/Eccube/DependencyInjection/Compiler/PluginPass.php
+++ b/src/Eccube/DependencyInjection/Compiler/PluginPass.php
@@ -31,7 +31,7 @@ class PluginPass implements CompilerPassInterface
      *
      * @param ContainerBuilder $container
      */
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         // 無効状態のプラグインコード一覧を取得.
         // 無効なプラグインの一覧はEccubeExtensionで定義している.
diff --git a/src/Eccube/DependencyInjection/Compiler/PurchaseFlowPass.php b/src/Eccube/DependencyInjection/Compiler/PurchaseFlowPass.php
index c8215ed443d..42a7afbf99c 100644
--- a/src/Eccube/DependencyInjection/Compiler/PurchaseFlowPass.php
+++ b/src/Eccube/DependencyInjection/Compiler/PurchaseFlowPass.php
@@ -37,7 +37,7 @@ class PurchaseFlowPass implements CompilerPassInterface
     public const ITEM_HOLDER_POST_VALIDATOR_TAG = 'eccube.item.holder.post.validator';
     public const PURCHASE_PROCESSOR_TAG = 'eccube.purchase.processor';
 
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $flowTypes = [
             PurchaseContext::CART_FLOW => $container->findDefinition('eccube.purchase.flow.cart'),
diff --git a/src/Eccube/DependencyInjection/Compiler/QueryCustomizerPass.php b/src/Eccube/DependencyInjection/Compiler/QueryCustomizerPass.php
index 88de3a28ba0..bb88f72f29b 100644
--- a/src/Eccube/DependencyInjection/Compiler/QueryCustomizerPass.php
+++ b/src/Eccube/DependencyInjection/Compiler/QueryCustomizerPass.php
@@ -23,7 +23,7 @@ class QueryCustomizerPass implements CompilerPassInterface
 {
     public const QUERY_CUSTOMIZER_TAG = 'eccube.query_customizer';
 
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $queries = $container->getDefinition(Queries::class);
         $ids = $container->findTaggedServiceIds(self::QUERY_CUSTOMIZER_TAG);
diff --git a/src/Eccube/DependencyInjection/Compiler/TwigBlockPass.php b/src/Eccube/DependencyInjection/Compiler/TwigBlockPass.php
index ee56c77c840..3141d596ae9 100644
--- a/src/Eccube/DependencyInjection/Compiler/TwigBlockPass.php
+++ b/src/Eccube/DependencyInjection/Compiler/TwigBlockPass.php
@@ -21,7 +21,7 @@ class TwigBlockPass implements CompilerPassInterface
 {
     public const TWIG_BLOCK_TAG = 'eccube.twig_block';
 
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $ids = $container->findTaggedServiceIds(self::TWIG_BLOCK_TAG);
         $templates = $container->getParameter('eccube_twig_block_templates');
diff --git a/src/Eccube/DependencyInjection/Compiler/TwigExtensionPass.php b/src/Eccube/DependencyInjection/Compiler/TwigExtensionPass.php
index acda9133d99..827be829148 100644
--- a/src/Eccube/DependencyInjection/Compiler/TwigExtensionPass.php
+++ b/src/Eccube/DependencyInjection/Compiler/TwigExtensionPass.php
@@ -20,7 +20,7 @@
 
 class TwigExtensionPass implements CompilerPassInterface
 {
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         // 本番時はtwigのurl(), path()を差し替える.
         if (!$container->getParameter('kernel.debug')) {
diff --git a/src/Eccube/DependencyInjection/Compiler/WebServerDocumentRootPass.php b/src/Eccube/DependencyInjection/Compiler/WebServerDocumentRootPass.php
index 986e1b49834..42db4b00259 100644
--- a/src/Eccube/DependencyInjection/Compiler/WebServerDocumentRootPass.php
+++ b/src/Eccube/DependencyInjection/Compiler/WebServerDocumentRootPass.php
@@ -28,7 +28,7 @@ public function __construct($docroot = '%kernel.project_dir%/')
         $this->docroot = $docroot;
     }
 
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         if (!$container->hasDefinition('web_server.command.server_run')) {
             return;
diff --git a/src/Eccube/DependencyInjection/EccubeExtension.php b/src/Eccube/DependencyInjection/EccubeExtension.php
index 4bf9a009f63..68d970ff35e 100644
--- a/src/Eccube/DependencyInjection/EccubeExtension.php
+++ b/src/Eccube/DependencyInjection/EccubeExtension.php
@@ -16,6 +16,7 @@
 use Doctrine\Bundle\DoctrineBundle\DependencyInjection\Configuration as DoctrineBundleConfiguration;
 use Doctrine\DBAL\Connection;
 use Doctrine\DBAL\DriverManager;
+use Symfony\Component\Config\Definition\ConfigurationInterface;
 use Symfony\Component\Config\Definition\Processor;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Extension\PrependExtensionInterface;
@@ -29,7 +30,7 @@ class EccubeExtension extends Extension implements PrependExtensionInterface
      *
      * @throws \InvalidArgumentException When provided tag is not defined in this extension
      */
-    public function load(array $configs, ContainerBuilder $container)
+    public function load(array $configs, ContainerBuilder $container): void
     {
         $configuration = new Configuration();
         $configs = $this->processConfiguration($configuration, $configs);
@@ -40,7 +41,7 @@ public function getAlias(): string
         return 'eccube';
     }
 
-    public function getConfiguration(array $config, ContainerBuilder $container)
+    public function getConfiguration(array $config, ContainerBuilder $container): ?ConfigurationInterface
     {
         return parent::getConfiguration($config, $container);
     }
@@ -48,7 +49,7 @@ public function getConfiguration(array $config, ContainerBuilder $container)
     /**
      * Allow an extension to prepend the extension configurations.
      */
-    public function prepend(ContainerBuilder $container)
+    public function prepend(ContainerBuilder $container): void
     {
         // FrameworkBundleの設定を動的に変更する.
         $this->configureFramework($container);
@@ -57,7 +58,7 @@ public function prepend(ContainerBuilder $container)
         $this->configurePlugins($container);
     }
 
-    protected function configureFramework(ContainerBuilder $container)
+    protected function configureFramework(ContainerBuilder $container): void
     {
         $forceSSL = $container->resolveEnvPlaceholders('%env(ECCUBE_FORCE_SSL)%', true);
         // envから取得した内容が文字列のため, booleanに変換
@@ -119,7 +120,7 @@ protected function configureFramework(ContainerBuilder $container)
         $container->setParameter('eccube_rate_limiter_configs', $rateLimiterConfigs);
     }
 
-    protected function configurePlugins(ContainerBuilder $container)
+    protected function configurePlugins(ContainerBuilder $container): void
     {
         $pluginDir = $container->getParameter('kernel.project_dir').'/app/Plugin';
         $pluginDirs = $this->getPluginDirectories($pluginDir);
@@ -181,7 +182,7 @@ protected function configurePlugins(ContainerBuilder $container)
     /**
      * @param string $pluginDir
      */
-    protected function configureTwigPaths(ContainerBuilder $container, $enabled, $pluginDir)
+    protected function configureTwigPaths(ContainerBuilder $container, $enabled, $pluginDir): void
     {
         $paths = [];
         $projectDir = $container->getParameter('kernel.project_dir');
@@ -209,7 +210,7 @@ protected function configureTwigPaths(ContainerBuilder $container, $enabled, $pl
     /**
      * @param string $pluginDir
      */
-    protected function configureTranslations(ContainerBuilder $container, $enabled, $pluginDir)
+    protected function configureTranslations(ContainerBuilder $container, $enabled, $pluginDir): void
     {
         $paths = [];
 
diff --git a/src/Eccube/Doctrine/Filter/NoStockHiddenFilter.php b/src/Eccube/Doctrine/Filter/NoStockHiddenFilter.php
index c1510c19af6..99dacdbd2dd 100644
--- a/src/Eccube/Doctrine/Filter/NoStockHiddenFilter.php
+++ b/src/Eccube/Doctrine/Filter/NoStockHiddenFilter.php
@@ -18,7 +18,7 @@
 
 class NoStockHiddenFilter extends SQLFilter
 {
-    public function addFilterConstraint(ClassMetadata $targetEntity, $targetTableAlias)
+    public function addFilterConstraint(ClassMetadata $targetEntity, $targetTableAlias): string
     {
         if ($targetEntity->reflClass->getName() === 'Eccube\Entity\ProductClass') {
             return $targetTableAlias.'.stock >= 1 OR '.$targetTableAlias.'.stock_unlimited = true';
diff --git a/src/Eccube/Doctrine/Filter/OrderStatusFilter.php b/src/Eccube/Doctrine/Filter/OrderStatusFilter.php
index 0d4dfac8ce6..f0444ae04eb 100644
--- a/src/Eccube/Doctrine/Filter/OrderStatusFilter.php
+++ b/src/Eccube/Doctrine/Filter/OrderStatusFilter.php
@@ -19,7 +19,7 @@
 
 class OrderStatusFilter extends SQLFilter
 {
-    public function addFilterConstraint(ClassMetadata $targetEntity, $targetTableAlias)
+    public function addFilterConstraint(ClassMetadata $targetEntity, $targetTableAlias): string
     {
         // 決済処理中/購入処理中を除く.
         if ($targetEntity->reflClass->getName() === 'Eccube\Entity\Order') {
diff --git a/src/Eccube/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php b/src/Eccube/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php
index a898ea58535..7cf9d80b6a9 100644
--- a/src/Eccube/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php
+++ b/src/Eccube/Doctrine/ORM/Mapping/Driver/AnnotationDriver.php
@@ -27,7 +27,7 @@ public function setTraitProxiesDirectory($dir)
     /**
      * {@inheritdoc}
      */
-    public function getAllClassNames()
+    public function getAllClassNames(): array
     {
         if ($this->classNames !== null) {
             return $this->classNames;
diff --git a/src/Eccube/Doctrine/ORM/Mapping/Driver/NopAnnotationDriver.php b/src/Eccube/Doctrine/ORM/Mapping/Driver/NopAnnotationDriver.php
index d3a704db0cb..e38df65680c 100644
--- a/src/Eccube/Doctrine/ORM/Mapping/Driver/NopAnnotationDriver.php
+++ b/src/Eccube/Doctrine/ORM/Mapping/Driver/NopAnnotationDriver.php
@@ -15,7 +15,7 @@
 
 class NopAnnotationDriver extends \Doctrine\ORM\Mapping\Driver\AnnotationDriver
 {
-    public function getAllClassNames()
+    public function getAllClassNames(): array
     {
         return [];
     }
diff --git a/src/Eccube/Doctrine/ORM/Mapping/Driver/ReloadSafeAnnotationDriver.php b/src/Eccube/Doctrine/ORM/Mapping/Driver/ReloadSafeAnnotationDriver.php
index 820e0b11cd5..d209a4f6730 100644
--- a/src/Eccube/Doctrine/ORM/Mapping/Driver/ReloadSafeAnnotationDriver.php
+++ b/src/Eccube/Doctrine/ORM/Mapping/Driver/ReloadSafeAnnotationDriver.php
@@ -51,7 +51,7 @@ public function setOutputDir($outputDir)
     /**
      * {@inheritdoc}
      */
-    public function getAllClassNames()
+    public function getAllClassNames(): array
     {
         if ($this->classNames !== null) {
             return $this->classNames;
diff --git a/src/Eccube/Doctrine/ORM/Query/Extract.php b/src/Eccube/Doctrine/ORM/Query/Extract.php
index f82c50d7969..30b016a101b 100644
--- a/src/Eccube/Doctrine/ORM/Query/Extract.php
+++ b/src/Eccube/Doctrine/ORM/Query/Extract.php
@@ -61,7 +61,7 @@ class Extract extends FunctionNode
         'TIME',
     ];
 
-    public function parse(Parser $parser)
+    public function parse(Parser $parser): void
     {
         $lexer = $parser->getLexer();
         $parser->match(Lexer::T_IDENTIFIER);
@@ -90,7 +90,7 @@ public function parse(Parser $parser)
         $parser->match(Lexer::T_CLOSE_PARENTHESIS);
     }
 
-    public function getSql(SqlWalker $sqlWalker)
+    public function getSql(SqlWalker $sqlWalker): string
     {
         $driver = $sqlWalker->getConnection()->getDriver()->getDatabasePlatform()->getName();
         // UTCとの時差(秒数)
diff --git a/src/Eccube/Doctrine/ORM/Query/Normalize.php b/src/Eccube/Doctrine/ORM/Query/Normalize.php
index b731be77901..a058e16ae18 100644
--- a/src/Eccube/Doctrine/ORM/Query/Normalize.php
+++ b/src/Eccube/Doctrine/ORM/Query/Normalize.php
@@ -24,7 +24,7 @@ class Normalize extends FunctionNode
     public const FROM = 'あいうえおかきくけこさしすせそたちつてとなにぬねのはひふへほまみむめもやゆよらりるれろわをんがぎぐげござじずぜぞだぢづでどばびぶべぼぱぴぷぺぽぁぃぅぇぉっゃゅょゎゐゑー';
     public const TO = 'アイウエオカキクケコサシスセソタチツテトナニヌネノハヒフヘホマミムメモヤユヨラリルレロワヲンガギグゲゴザジズゼゾダヂヅデドバビブベボパピプペポァィゥェォッャュョヮヰヱー';
 
-    public function parse(Parser $parser)
+    public function parse(Parser $parser): void
     {
         $parser->match(Lexer::T_IDENTIFIER);
         $parser->match(Lexer::T_OPEN_PARENTHESIS);
@@ -32,7 +32,7 @@ public function parse(Parser $parser)
         $parser->match(Lexer::T_CLOSE_PARENTHESIS);
     }
 
-    public function getSql(SqlWalker $sqlWalker)
+    public function getSql(SqlWalker $sqlWalker): string
     {
         switch ($sqlWalker->getConnection()->getDriver()->getDatabasePlatform()->getName()) {
             case 'postgresql':
diff --git a/src/Eccube/Entity/AbstractEntity.php b/src/Eccube/Entity/AbstractEntity.php
index 1adda0f693f..70566035820 100644
--- a/src/Eccube/Entity/AbstractEntity.php
+++ b/src/Eccube/Entity/AbstractEntity.php
@@ -29,7 +29,7 @@
 abstract class AbstractEntity implements \ArrayAccess
 {
     #[\ReturnTypeWillChange]
-    public function offsetExists($offset)
+    public function offsetExists($offset): bool
     {
         $inflector = new Inflector(new NoopWordInflector(), new NoopWordInflector());
         $method = $inflector->classify($offset);
@@ -41,12 +41,12 @@ public function offsetExists($offset)
     }
 
     #[\ReturnTypeWillChange]
-    public function offsetSet($offset, $value)
+    public function offsetSet($offset, $value): void
     {
     }
 
     #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    public function offsetGet($offset): mixed
     {
         $inflector = new Inflector(new NoopWordInflector(), new NoopWordInflector());
         $method = $inflector->classify($offset);
@@ -60,10 +60,12 @@ public function offsetGet($offset)
         } elseif (method_exists($this, "has$method")) {
             return $this->{"has$method"}();
         }
+
+        return null;
     }
 
     #[\ReturnTypeWillChange]
-    public function offsetUnset($offset)
+    public function offsetUnset($offset): void
     {
     }
 
diff --git a/src/Eccube/Entity/Customer.php b/src/Eccube/Entity/Customer.php
index 9f7d4ae3f97..1261eea4191 100644
--- a/src/Eccube/Entity/Customer.php
+++ b/src/Eccube/Entity/Customer.php
@@ -330,7 +330,7 @@ public function getUsername()
         /**
          * {@inheritdoc}
          */
-        public function eraseCredentials()
+        public function eraseCredentials(): void
         {
         }
 
diff --git a/src/Eccube/Entity/Member.php b/src/Eccube/Entity/Member.php
index 14b91b68a90..1617d52a421 100644
--- a/src/Eccube/Entity/Member.php
+++ b/src/Eccube/Entity/Member.php
@@ -68,7 +68,7 @@ public function getUsername()
         /**
          * {@inheritdoc}
          */
-        public function eraseCredentials()
+        public function eraseCredentials(): void
         {
         }
 
diff --git a/src/Eccube/EventListener/ExceptionListener.php b/src/Eccube/EventListener/ExceptionListener.php
index d58eff19f75..e675e285f4b 100644
--- a/src/Eccube/EventListener/ExceptionListener.php
+++ b/src/Eccube/EventListener/ExceptionListener.php
@@ -126,7 +126,7 @@ public function onKernelException(ExceptionEvent $event)
      *
      * @return array The event names to listen to
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             KernelEvents::EXCEPTION => ['onKernelException'],
diff --git a/src/Eccube/EventListener/ForwardOnlyListener.php b/src/Eccube/EventListener/ForwardOnlyListener.php
index 4ee86df4127..b9196e7ef6d 100644
--- a/src/Eccube/EventListener/ForwardOnlyListener.php
+++ b/src/Eccube/EventListener/ForwardOnlyListener.php
@@ -56,7 +56,7 @@ public function onController(ControllerEvent $event)
      *
      * @return array
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             KernelEvents::CONTROLLER => 'onController',
diff --git a/src/Eccube/EventListener/IpAddrListener.php b/src/Eccube/EventListener/IpAddrListener.php
index 3c948a54b3a..6cd56097744 100644
--- a/src/Eccube/EventListener/IpAddrListener.php
+++ b/src/Eccube/EventListener/IpAddrListener.php
@@ -89,7 +89,7 @@ private function isClientIpInList($hostList, $clientIp)
         return true;
     }
 
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             'kernel.request' => ['onKernelRequest', 512],
diff --git a/src/Eccube/EventListener/LogListener.php b/src/Eccube/EventListener/LogListener.php
index 25fdfb552c2..68132c2ee9e 100644
--- a/src/Eccube/EventListener/LogListener.php
+++ b/src/Eccube/EventListener/LogListener.php
@@ -41,7 +41,7 @@ public function __construct(LoggerInterface $logger)
     /**
      * {@inheritdoc}
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             KernelEvents::REQUEST => [
diff --git a/src/Eccube/EventListener/LoginHistoryListener.php b/src/Eccube/EventListener/LoginHistoryListener.php
index 5e46ef1fd53..5eb1769c67e 100644
--- a/src/Eccube/EventListener/LoginHistoryListener.php
+++ b/src/Eccube/EventListener/LoginHistoryListener.php
@@ -70,7 +70,7 @@ public function __construct(
     /**
      * @return array
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             SecurityEvents::INTERACTIVE_LOGIN => 'onInteractiveLogin',
diff --git a/src/Eccube/EventListener/MaintenanceListener.php b/src/Eccube/EventListener/MaintenanceListener.php
index 33df2c9a2a3..9455548f986 100644
--- a/src/Eccube/EventListener/MaintenanceListener.php
+++ b/src/Eccube/EventListener/MaintenanceListener.php
@@ -35,7 +35,7 @@ public function __construct(Context $requestContext, SystemService $systemServic
         $this->systemService = $systemService;
     }
 
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             KernelEvents::RESPONSE => ['onResponse'],
diff --git a/src/Eccube/EventListener/MobileTemplatePathListener.php b/src/Eccube/EventListener/MobileTemplatePathListener.php
index 0d83c68b7cf..7fe9fc33898 100644
--- a/src/Eccube/EventListener/MobileTemplatePathListener.php
+++ b/src/Eccube/EventListener/MobileTemplatePathListener.php
@@ -83,7 +83,7 @@ public function onKernelRequest(RequestEvent $event)
         $this->twig->setLoader($loader);
     }
 
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             'kernel.request' => ['onKernelRequest', 512],
diff --git a/src/Eccube/EventListener/RateLimiterListener.php b/src/Eccube/EventListener/RateLimiterListener.php
index a15a0ea39f2..9016bc63296 100644
--- a/src/Eccube/EventListener/RateLimiterListener.php
+++ b/src/Eccube/EventListener/RateLimiterListener.php
@@ -98,7 +98,7 @@ public function onController(ControllerEvent $event)
     /**
      * {@inheritdoc}
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             KernelEvents::CONTROLLER => ['onController', 0],
diff --git a/src/Eccube/EventListener/RestrictFileUploadListener.php b/src/Eccube/EventListener/RestrictFileUploadListener.php
index 14a9f960a61..e1571c3d5a8 100644
--- a/src/Eccube/EventListener/RestrictFileUploadListener.php
+++ b/src/Eccube/EventListener/RestrictFileUploadListener.php
@@ -54,7 +54,7 @@ public function onKernelRequest(RequestEvent $event)
         }
     }
 
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             'kernel.request' => ['onKernelRequest', 7], // RouterListener より必ず後で実行する
diff --git a/src/Eccube/EventListener/SecurityListener.php b/src/Eccube/EventListener/SecurityListener.php
index cad6b71a54c..bbb23c07597 100644
--- a/src/Eccube/EventListener/SecurityListener.php
+++ b/src/Eccube/EventListener/SecurityListener.php
@@ -103,7 +103,7 @@ public function onAuthenticationFailure(LoginFailureEvent $event)
      *
      * @return array The event names to listen to
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             SecurityEvents::INTERACTIVE_LOGIN => 'onInteractiveLogin',
diff --git a/src/Eccube/EventListener/TransactionListener.php b/src/Eccube/EventListener/TransactionListener.php
index d75b4ac9a5c..07bffbb61cf 100644
--- a/src/Eccube/EventListener/TransactionListener.php
+++ b/src/Eccube/EventListener/TransactionListener.php
@@ -143,7 +143,7 @@ public function onKernelTerminate(TerminateEvent $event)
      *
      * @return array
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             KernelEvents::REQUEST => 'onKernelRequest',
diff --git a/src/Eccube/EventListener/TwigInitializeListener.php b/src/Eccube/EventListener/TwigInitializeListener.php
index 4913fb76b2a..f1c2c39cd5e 100644
--- a/src/Eccube/EventListener/TwigInitializeListener.php
+++ b/src/Eccube/EventListener/TwigInitializeListener.php
@@ -306,7 +306,7 @@ private function getDisplayEccubeNav($parentNav, $AuthorityRoles, $baseUrl)
     /**
      * {@inheritdoc}
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             KernelEvents::REQUEST => [
diff --git a/src/Eccube/EventListener/TwoFactorAuthListener.php b/src/Eccube/EventListener/TwoFactorAuthListener.php
index b06596639f6..03edb220892 100644
--- a/src/Eccube/EventListener/TwoFactorAuthListener.php
+++ b/src/Eccube/EventListener/TwoFactorAuthListener.php
@@ -113,7 +113,7 @@ public function onKernelController(ControllerArgumentsEvent $event)
     /**
      * @return array
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             KernelEvents::CONTROLLER_ARGUMENTS => ['onKernelController', 7],
diff --git a/src/Eccube/Form/DataTransformer/EntityToIdTransformer.php b/src/Eccube/Form/DataTransformer/EntityToIdTransformer.php
index a311000b137..0ba79de18cb 100644
--- a/src/Eccube/Form/DataTransformer/EntityToIdTransformer.php
+++ b/src/Eccube/Form/DataTransformer/EntityToIdTransformer.php
@@ -39,7 +39,7 @@ public function __construct(ObjectManager $om, $className)
         $this->className = $className;
     }
 
-    public function transform($entity)
+    public function transform($entity): mixed
     {
         if (null === $entity) {
             return '';
@@ -48,7 +48,7 @@ public function transform($entity)
         return $entity->getId();
     }
 
-    public function reverseTransform($id)
+    public function reverseTransform($id): mixed
     {
         if ('' === $id || null === $id) {
             return null;
diff --git a/src/Eccube/Form/EventListener/ConvertKanaListener.php b/src/Eccube/Form/EventListener/ConvertKanaListener.php
index 2ed4292a26d..013b053d97d 100644
--- a/src/Eccube/Form/EventListener/ConvertKanaListener.php
+++ b/src/Eccube/Form/EventListener/ConvertKanaListener.php
@@ -35,14 +35,14 @@ public function __construct($option = 'a', $encoding = 'utf-8')
         $this->encoding = $encoding;
     }
 
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             FormEvents::PRE_SUBMIT => 'onPreSubmit',
         ];
     }
 
-    public function onPreSubmit(FormEvent $event)
+    public function onPreSubmit(FormEvent $event): void
     {
         $data = $event->getData();
 
diff --git a/src/Eccube/Form/EventListener/TruncateHyphenListener.php b/src/Eccube/Form/EventListener/TruncateHyphenListener.php
index 45b34f6fdd1..61b0ff46019 100644
--- a/src/Eccube/Form/EventListener/TruncateHyphenListener.php
+++ b/src/Eccube/Form/EventListener/TruncateHyphenListener.php
@@ -22,7 +22,7 @@ class TruncateHyphenListener implements EventSubscriberInterface
     /**
      * @return array
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             FormEvents::PRE_SUBMIT => 'onPreSubmit',
diff --git a/src/Eccube/Form/Extension/DoctrineOrmExtension.php b/src/Eccube/Form/Extension/DoctrineOrmExtension.php
index 1669d9fb4ae..59c91d77c0e 100644
--- a/src/Eccube/Form/Extension/DoctrineOrmExtension.php
+++ b/src/Eccube/Form/Extension/DoctrineOrmExtension.php
@@ -52,7 +52,7 @@ public function __construct(EntityManagerInterface $em, Reader $reader)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->addEventListener(
             FormEvents::PRE_SET_DATA,
@@ -91,7 +91,7 @@ function (FormEvent $event) {
         );
     }
 
-    public function buildView(FormView $view, FormInterface $form, array $options)
+    public function buildView(FormView $view, FormInterface $form, array $options): void
     {
         $options = $form->getConfig()->getOption('eccube_form_options');
 
@@ -110,7 +110,7 @@ public function buildView(FormView $view, FormInterface $form, array $options)
         $view->vars['eccube_form_options'] = $options;
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefault(
             'eccube_form_options',
diff --git a/src/Eccube/Form/Extension/HTMLPurifierTextTypeExtension.php b/src/Eccube/Form/Extension/HTMLPurifierTextTypeExtension.php
index 9f26379e365..87d7ecb0d16 100644
--- a/src/Eccube/Form/Extension/HTMLPurifierTextTypeExtension.php
+++ b/src/Eccube/Form/Extension/HTMLPurifierTextTypeExtension.php
@@ -32,7 +32,7 @@ public function __construct(Context $context)
         $this->context = $context;
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         if ($this->context->isFront()) {
             $resolver->setDefault('purify_html', true);
@@ -55,7 +55,7 @@ public static function getExtendedTypes(): iterable
         yield TextType::class;
     }
 
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         if ($this->context->isFront() && $options['purify_html']) {
             $builder->addEventSubscriber(
diff --git a/src/Eccube/Form/Extension/HelpTypeExtension.php b/src/Eccube/Form/Extension/HelpTypeExtension.php
index cd4504b9cbc..434f41355ae 100644
--- a/src/Eccube/Form/Extension/HelpTypeExtension.php
+++ b/src/Eccube/Form/Extension/HelpTypeExtension.php
@@ -29,7 +29,7 @@ class HelpTypeExtension extends AbstractTypeExtension
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->setAttribute('help', $options['help']);
     }
@@ -37,7 +37,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function buildView(FormView $view, FormInterface $form, array $options)
+    public function buildView(FormView $view, FormInterface $form, array $options): void
     {
         $view->vars['help'] = $form->getConfig()->getAttribute('help');
     }
@@ -45,7 +45,7 @@ public function buildView(FormView $view, FormInterface $form, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'help' => null,
diff --git a/src/Eccube/Form/Type/AddCartType.php b/src/Eccube/Form/Type/AddCartType.php
index a791e21ddb2..44d71071451 100644
--- a/src/Eccube/Form/Type/AddCartType.php
+++ b/src/Eccube/Form/Type/AddCartType.php
@@ -66,7 +66,7 @@ public function __construct(ManagerRegistry $doctrine, EccubeConfig $config)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         /** @var \Eccube\Entity\Product $Product */
         $Product = $options['product'];
@@ -157,7 +157,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setRequired('product');
         $resolver->setDefaults([
@@ -172,7 +172,7 @@ public function configureOptions(OptionsResolver $resolver)
     /*
      * {@inheritdoc}
      */
-    public function finishView(FormView $view, FormInterface $form, array $options)
+    public function finishView(FormView $view, FormInterface $form, array $options): void
     {
         if ($options['id_add_product_id']) {
             foreach ($view->vars['form']->children as $child) {
@@ -184,7 +184,7 @@ public function finishView(FormView $view, FormInterface $form, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'add_cart';
     }
diff --git a/src/Eccube/Form/Type/AddressType.php b/src/Eccube/Form/Type/AddressType.php
index 68d19cf1e80..04e0c39d6c1 100644
--- a/src/Eccube/Form/Type/AddressType.php
+++ b/src/Eccube/Form/Type/AddressType.php
@@ -45,7 +45,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $options['pref_options']['required'] = $options['required'];
         $options['addr01_options']['required'] = $options['required'];
@@ -84,7 +84,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function buildView(FormView $view, FormInterface $form, array $options)
+    public function buildView(FormView $view, FormInterface $form, array $options): void
     {
         $builder = $form->getConfig();
         $view->vars['pref_name'] = $builder->getAttribute('pref_name');
@@ -95,7 +95,7 @@ public function buildView(FormView $view, FormInterface $form, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'options' => [],
@@ -127,7 +127,7 @@ public function configureOptions(OptionsResolver $resolver)
         ]);
     }
 
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'address';
     }
diff --git a/src/Eccube/Form/Type/Admin/AuthenticationType.php b/src/Eccube/Form/Type/Admin/AuthenticationType.php
index ed5994b5b35..4194146b356 100644
--- a/src/Eccube/Form/Type/Admin/AuthenticationType.php
+++ b/src/Eccube/Form/Type/Admin/AuthenticationType.php
@@ -41,7 +41,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->add(
             'authentication_key', TextType::class,
@@ -67,7 +67,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => BaseInfo::class,
@@ -77,7 +77,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_authentication';
     }
diff --git a/src/Eccube/Form/Type/Admin/AuthorityRoleType.php b/src/Eccube/Form/Type/Admin/AuthorityRoleType.php
index af2385e47a3..6a20ee2dc90 100644
--- a/src/Eccube/Form/Type/Admin/AuthorityRoleType.php
+++ b/src/Eccube/Form/Type/Admin/AuthorityRoleType.php
@@ -32,7 +32,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('Authority', EntityType::class, [
@@ -69,7 +69,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\AuthorityRole',
@@ -79,7 +79,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_authority_role';
     }
diff --git a/src/Eccube/Form/Type/Admin/BlockType.php b/src/Eccube/Form/Type/Admin/BlockType.php
index 8885d1998f7..b0fb72ac571 100644
--- a/src/Eccube/Form/Type/Admin/BlockType.php
+++ b/src/Eccube/Form/Type/Admin/BlockType.php
@@ -55,7 +55,7 @@ public function __construct(EntityManagerInterface $entityManager, EccubeConfig
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -126,7 +126,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => Block::class,
@@ -136,7 +136,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'block';
     }
diff --git a/src/Eccube/Form/Type/Admin/CalendarType.php b/src/Eccube/Form/Type/Admin/CalendarType.php
index 81819959ba3..fe15419c38b 100644
--- a/src/Eccube/Form/Type/Admin/CalendarType.php
+++ b/src/Eccube/Form/Type/Admin/CalendarType.php
@@ -60,7 +60,7 @@ public function __construct(EccubeConfig $eccubeConfig, ValidatorInterface $vali
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('title', TextType::class, [
@@ -133,7 +133,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => Calendar::class,
@@ -143,7 +143,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'calendar';
     }
diff --git a/src/Eccube/Form/Type/Admin/CategoryType.php b/src/Eccube/Form/Type/Admin/CategoryType.php
index 97b3f75a5c4..9342e50b994 100644
--- a/src/Eccube/Form/Type/Admin/CategoryType.php
+++ b/src/Eccube/Form/Type/Admin/CategoryType.php
@@ -40,7 +40,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -57,7 +57,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\Category',
@@ -67,7 +67,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_category';
     }
diff --git a/src/Eccube/Form/Type/Admin/ChangePasswordType.php b/src/Eccube/Form/Type/Admin/ChangePasswordType.php
index 4ac23e206d0..a60e765c7be 100644
--- a/src/Eccube/Form/Type/Admin/ChangePasswordType.php
+++ b/src/Eccube/Form/Type/Admin/ChangePasswordType.php
@@ -42,7 +42,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('current_password', PasswordType::class, [
@@ -77,14 +77,14 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
     }
 
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_change_password';
     }
diff --git a/src/Eccube/Form/Type/Admin/ClassCategoryType.php b/src/Eccube/Form/Type/Admin/ClassCategoryType.php
index 543c0deb85b..7647e4c1c62 100644
--- a/src/Eccube/Form/Type/Admin/ClassCategoryType.php
+++ b/src/Eccube/Form/Type/Admin/ClassCategoryType.php
@@ -36,7 +36,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -68,7 +68,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\ClassCategory',
@@ -78,7 +78,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_class_category';
     }
diff --git a/src/Eccube/Form/Type/Admin/ClassNameType.php b/src/Eccube/Form/Type/Admin/ClassNameType.php
index dacfe42ba19..2675975f6f6 100644
--- a/src/Eccube/Form/Type/Admin/ClassNameType.php
+++ b/src/Eccube/Form/Type/Admin/ClassNameType.php
@@ -42,7 +42,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -67,7 +67,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\ClassName',
@@ -77,7 +77,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_class_name';
     }
diff --git a/src/Eccube/Form/Type/Admin/CsvImportType.php b/src/Eccube/Form/Type/Admin/CsvImportType.php
index 290a1deca14..afb0f21ff8f 100644
--- a/src/Eccube/Form/Type/Admin/CsvImportType.php
+++ b/src/Eccube/Form/Type/Admin/CsvImportType.php
@@ -41,7 +41,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('import_file', FileType::class, [
@@ -70,7 +70,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_csv_import';
     }
diff --git a/src/Eccube/Form/Type/Admin/CustomerType.php b/src/Eccube/Form/Type/Admin/CustomerType.php
index c97d89d8dd4..8b62a52b9f7 100644
--- a/src/Eccube/Form/Type/Admin/CustomerType.php
+++ b/src/Eccube/Form/Type/Admin/CustomerType.php
@@ -58,7 +58,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', NameType::class, [
@@ -171,7 +171,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\Customer',
@@ -181,7 +181,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_customer';
     }
diff --git a/src/Eccube/Form/Type/Admin/DeliveryFeeType.php b/src/Eccube/Form/Type/Admin/DeliveryFeeType.php
index 30aac73ce02..8418fcf65ff 100644
--- a/src/Eccube/Form/Type/Admin/DeliveryFeeType.php
+++ b/src/Eccube/Form/Type/Admin/DeliveryFeeType.php
@@ -23,7 +23,7 @@ class DeliveryFeeType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('fee', PriceType::class, [
@@ -35,7 +35,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\DeliveryFee',
@@ -45,7 +45,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'delivery_fee';
     }
diff --git a/src/Eccube/Form/Type/Admin/DeliveryTimeType.php b/src/Eccube/Form/Type/Admin/DeliveryTimeType.php
index 7d7fb20623a..e75635539cc 100644
--- a/src/Eccube/Form/Type/Admin/DeliveryTimeType.php
+++ b/src/Eccube/Form/Type/Admin/DeliveryTimeType.php
@@ -30,7 +30,7 @@ class DeliveryTimeType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('delivery_time', TextType::class, [
@@ -67,7 +67,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\DeliveryTime',
@@ -82,7 +82,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'delivery_time';
     }
diff --git a/src/Eccube/Form/Type/Admin/DeliveryType.php b/src/Eccube/Form/Type/Admin/DeliveryType.php
index f7820b0d8fb..ccbdb66e57d 100644
--- a/src/Eccube/Form/Type/Admin/DeliveryType.php
+++ b/src/Eccube/Form/Type/Admin/DeliveryType.php
@@ -41,7 +41,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -115,7 +115,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\Delivery',
@@ -125,7 +125,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'delivery';
     }
diff --git a/src/Eccube/Form/Type/Admin/LayoutType.php b/src/Eccube/Form/Type/Admin/LayoutType.php
index 671443461c8..24855aca9ce 100644
--- a/src/Eccube/Form/Type/Admin/LayoutType.php
+++ b/src/Eccube/Form/Type/Admin/LayoutType.php
@@ -31,7 +31,7 @@ class LayoutType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $layout_id = $options['layout_id'];
 
@@ -73,7 +73,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\Layout',
@@ -84,7 +84,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_layout';
     }
diff --git a/src/Eccube/Form/Type/Admin/LogType.php b/src/Eccube/Form/Type/Admin/LogType.php
index c8a0f2d437f..d13d059b53e 100644
--- a/src/Eccube/Form/Type/Admin/LogType.php
+++ b/src/Eccube/Form/Type/Admin/LogType.php
@@ -50,7 +50,7 @@ public function __construct(EccubeConfig $eccubeConfig, KernelInterface $kernel)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $files = [];
         $finder = new Finder();
@@ -92,7 +92,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_system_log';
     }
diff --git a/src/Eccube/Form/Type/Admin/LoginType.php b/src/Eccube/Form/Type/Admin/LoginType.php
index e9206af6e17..eaa3959851d 100644
--- a/src/Eccube/Form/Type/Admin/LoginType.php
+++ b/src/Eccube/Form/Type/Admin/LoginType.php
@@ -45,7 +45,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->add('login_id', TextType::class, [
             'attr' => [
@@ -69,7 +69,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'csrf_protection' => false,
@@ -79,7 +79,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_login';
     }
diff --git a/src/Eccube/Form/Type/Admin/MailType.php b/src/Eccube/Form/Type/Admin/MailType.php
index 950c3edcba5..a55f3eecea1 100644
--- a/src/Eccube/Form/Type/Admin/MailType.php
+++ b/src/Eccube/Form/Type/Admin/MailType.php
@@ -43,7 +43,7 @@ public function __construct(MailTemplateRepository $mailTemplateRepository, Eccu
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('template', MailTemplateType::class, [
@@ -114,7 +114,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => MailTemplate::class,
@@ -124,7 +124,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'mail';
     }
diff --git a/src/Eccube/Form/Type/Admin/MainEditType.php b/src/Eccube/Form/Type/Admin/MainEditType.php
index 8255527a7f4..b80ea8b4cf3 100644
--- a/src/Eccube/Form/Type/Admin/MainEditType.php
+++ b/src/Eccube/Form/Type/Admin/MainEditType.php
@@ -69,7 +69,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -283,7 +283,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => Page::class,
@@ -293,7 +293,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'main_edit';
     }
diff --git a/src/Eccube/Form/Type/Admin/MasterdataDataType.php b/src/Eccube/Form/Type/Admin/MasterdataDataType.php
index 004b4b4b3d7..f47bae48983 100644
--- a/src/Eccube/Form/Type/Admin/MasterdataDataType.php
+++ b/src/Eccube/Form/Type/Admin/MasterdataDataType.php
@@ -45,7 +45,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('id', TextType::class, [
@@ -75,7 +75,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_system_masterdata_data';
     }
diff --git a/src/Eccube/Form/Type/Admin/MasterdataEditType.php b/src/Eccube/Form/Type/Admin/MasterdataEditType.php
index ddd2b096d81..4932fccf521 100644
--- a/src/Eccube/Form/Type/Admin/MasterdataEditType.php
+++ b/src/Eccube/Form/Type/Admin/MasterdataEditType.php
@@ -26,7 +26,7 @@ class MasterdataEditType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('data', CollectionType::class, [
@@ -68,7 +68,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_system_masterdata_edit';
     }
diff --git a/src/Eccube/Form/Type/Admin/MasterdataType.php b/src/Eccube/Form/Type/Admin/MasterdataType.php
index 30d36f5a535..ee6711460bf 100644
--- a/src/Eccube/Form/Type/Admin/MasterdataType.php
+++ b/src/Eccube/Form/Type/Admin/MasterdataType.php
@@ -48,7 +48,7 @@ public function __construct(EntityManagerInterface $entityManager)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $masterdata = [];
 
@@ -97,7 +97,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_system_masterdata';
     }
diff --git a/src/Eccube/Form/Type/Admin/MemberType.php b/src/Eccube/Form/Type/Admin/MemberType.php
index c97b163a84a..8c0affb680e 100755
--- a/src/Eccube/Form/Type/Admin/MemberType.php
+++ b/src/Eccube/Form/Type/Admin/MemberType.php
@@ -59,7 +59,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -171,7 +171,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\Member',
@@ -181,7 +181,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_member';
     }
diff --git a/src/Eccube/Form/Type/Admin/NewsType.php b/src/Eccube/Form/Type/Admin/NewsType.php
index d6e6084b088..870c1f06cf8 100644
--- a/src/Eccube/Form/Type/Admin/NewsType.php
+++ b/src/Eccube/Form/Type/Admin/NewsType.php
@@ -40,7 +40,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('publish_date', DateTimeType::class, [
@@ -96,7 +96,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => News::class,
@@ -106,7 +106,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_news';
     }
diff --git a/src/Eccube/Form/Type/Admin/OrderItemType.php b/src/Eccube/Form/Type/Admin/OrderItemType.php
index 4312524f22a..ef24952fa3c 100644
--- a/src/Eccube/Form/Type/Admin/OrderItemType.php
+++ b/src/Eccube/Form/Type/Admin/OrderItemType.php
@@ -121,7 +121,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('product_name', TextType::class, [
@@ -300,7 +300,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => OrderItem::class,
@@ -310,7 +310,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'order_item';
     }
diff --git a/src/Eccube/Form/Type/Admin/OrderMailType.php b/src/Eccube/Form/Type/Admin/OrderMailType.php
index 2eacf4b9540..b6c30d0ed53 100644
--- a/src/Eccube/Form/Type/Admin/OrderMailType.php
+++ b/src/Eccube/Form/Type/Admin/OrderMailType.php
@@ -44,7 +44,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('template', MailTemplateType::class, [
@@ -75,7 +75,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_order_mail';
     }
diff --git a/src/Eccube/Form/Type/Admin/OrderPdfType.php b/src/Eccube/Form/Type/Admin/OrderPdfType.php
index 69c68944d01..61a2bfd3c44 100644
--- a/src/Eccube/Form/Type/Admin/OrderPdfType.php
+++ b/src/Eccube/Form/Type/Admin/OrderPdfType.php
@@ -55,7 +55,7 @@ public function __construct(EccubeConfig $eccubeConfig, EntityManagerInterface $
      * @param FormBuilderInterface $builder
      * @param array                $options
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $config = $this->eccubeConfig;
         $builder
diff --git a/src/Eccube/Form/Type/Admin/OrderStatusSettingType.php b/src/Eccube/Form/Type/Admin/OrderStatusSettingType.php
index f7470aa23fc..25a09f76ec2 100644
--- a/src/Eccube/Form/Type/Admin/OrderStatusSettingType.php
+++ b/src/Eccube/Form/Type/Admin/OrderStatusSettingType.php
@@ -57,7 +57,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -109,7 +109,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => OrderStatus::class,
diff --git a/src/Eccube/Form/Type/Admin/OrderType.php b/src/Eccube/Form/Type/Admin/OrderType.php
index d98a637be29..dd58e1df696 100644
--- a/src/Eccube/Form/Type/Admin/OrderType.php
+++ b/src/Eccube/Form/Type/Admin/OrderType.php
@@ -88,7 +88,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', NameType::class, [
@@ -253,7 +253,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => Order::class,
@@ -263,7 +263,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'order';
     }
diff --git a/src/Eccube/Form/Type/Admin/PageType.php b/src/Eccube/Form/Type/Admin/PageType.php
index afa27580098..1e9b9ebfcc9 100644
--- a/src/Eccube/Form/Type/Admin/PageType.php
+++ b/src/Eccube/Form/Type/Admin/PageType.php
@@ -23,7 +23,7 @@ class PageType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('layout', EntityType::class, [
@@ -42,7 +42,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_page';
     }
diff --git a/src/Eccube/Form/Type/Admin/PaymentRegisterType.php b/src/Eccube/Form/Type/Admin/PaymentRegisterType.php
index 9f9497a9594..dce7d9db7d1 100644
--- a/src/Eccube/Form/Type/Admin/PaymentRegisterType.php
+++ b/src/Eccube/Form/Type/Admin/PaymentRegisterType.php
@@ -46,7 +46,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('method', TextType::class, [
@@ -106,7 +106,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\Payment',
@@ -116,7 +116,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'payment_register';
     }
diff --git a/src/Eccube/Form/Type/Admin/PluginLocalInstallType.php b/src/Eccube/Form/Type/Admin/PluginLocalInstallType.php
index 99bb230b289..b9a1580a4ad 100644
--- a/src/Eccube/Form/Type/Admin/PluginLocalInstallType.php
+++ b/src/Eccube/Form/Type/Admin/PluginLocalInstallType.php
@@ -23,7 +23,7 @@ class PluginLocalInstallType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('plugin_archive', FileType::class, [
@@ -43,7 +43,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'plugin_local_install';
     }
diff --git a/src/Eccube/Form/Type/Admin/PluginManagementType.php b/src/Eccube/Form/Type/Admin/PluginManagementType.php
index ca84d5c0d2b..112bed1a524 100644
--- a/src/Eccube/Form/Type/Admin/PluginManagementType.php
+++ b/src/Eccube/Form/Type/Admin/PluginManagementType.php
@@ -29,7 +29,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $plugin_id = $options['plugin_id'];
 
@@ -57,7 +57,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'plugin_management';
     }
@@ -65,7 +65,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setRequired(['plugin_id']);
     }
diff --git a/src/Eccube/Form/Type/Admin/ProductClassEditType.php b/src/Eccube/Form/Type/Admin/ProductClassEditType.php
index 5b07f3e780b..4f44f4a9f7f 100644
--- a/src/Eccube/Form/Type/Admin/ProductClassEditType.php
+++ b/src/Eccube/Form/Type/Admin/ProductClassEditType.php
@@ -82,7 +82,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('checked', CheckboxType::class, [
@@ -151,7 +151,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => ProductClass::class,
diff --git a/src/Eccube/Form/Type/Admin/ProductClassMatrixType.php b/src/Eccube/Form/Type/Admin/ProductClassMatrixType.php
index b030e8feb86..7bd56d6c7d5 100644
--- a/src/Eccube/Form/Type/Admin/ProductClassMatrixType.php
+++ b/src/Eccube/Form/Type/Admin/ProductClassMatrixType.php
@@ -30,7 +30,7 @@
 
 class ProductClassMatrixType extends AbstractType
 {
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('class_name1', EntityType::class, [
@@ -98,7 +98,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
         }
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'product_classes_exist' => false,
diff --git a/src/Eccube/Form/Type/Admin/ProductClassType.php b/src/Eccube/Form/Type/Admin/ProductClassType.php
index de01ecdcb87..7ec3ecf8f7f 100644
--- a/src/Eccube/Form/Type/Admin/ProductClassType.php
+++ b/src/Eccube/Form/Type/Admin/ProductClassType.php
@@ -59,7 +59,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('code', TextType::class, [
@@ -150,7 +150,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\ProductClass',
@@ -160,7 +160,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_product_class';
     }
diff --git a/src/Eccube/Form/Type/Admin/ProductTag.php b/src/Eccube/Form/Type/Admin/ProductTag.php
index 89d48a1d624..9565aaa476f 100644
--- a/src/Eccube/Form/Type/Admin/ProductTag.php
+++ b/src/Eccube/Form/Type/Admin/ProductTag.php
@@ -39,7 +39,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -55,7 +55,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_product_tag';
     }
diff --git a/src/Eccube/Form/Type/Admin/ProductType.php b/src/Eccube/Form/Type/Admin/ProductType.php
index aafe36d378b..1af89ab3b21 100644
--- a/src/Eccube/Form/Type/Admin/ProductType.php
+++ b/src/Eccube/Form/Type/Admin/ProductType.php
@@ -66,7 +66,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             // 商品規格情報
@@ -223,14 +223,14 @@ private function validateFilePath($form, $dirs)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
     }
 
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_product';
     }
diff --git a/src/Eccube/Form/Type/Admin/SearchCustomerType.php b/src/Eccube/Form/Type/Admin/SearchCustomerType.php
index 7adc88cdbbe..68cbec0e2ca 100644
--- a/src/Eccube/Form/Type/Admin/SearchCustomerType.php
+++ b/src/Eccube/Form/Type/Admin/SearchCustomerType.php
@@ -64,7 +64,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $months = range(1, 12);
         $builder
@@ -438,7 +438,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_search_customer';
     }
diff --git a/src/Eccube/Form/Type/Admin/SearchLoginHistoryType.php b/src/Eccube/Form/Type/Admin/SearchLoginHistoryType.php
index 708c61ec35d..12c86e70868 100644
--- a/src/Eccube/Form/Type/Admin/SearchLoginHistoryType.php
+++ b/src/Eccube/Form/Type/Admin/SearchLoginHistoryType.php
@@ -40,7 +40,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             // ログインID・IPアドレス
@@ -111,7 +111,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_search_login_history';
     }
diff --git a/src/Eccube/Form/Type/Admin/SearchOrderType.php b/src/Eccube/Form/Type/Admin/SearchOrderType.php
index 518f314d83c..a403fb89bdb 100644
--- a/src/Eccube/Form/Type/Admin/SearchOrderType.php
+++ b/src/Eccube/Form/Type/Admin/SearchOrderType.php
@@ -46,7 +46,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             // 受注ID・注文者名・注文者（フリガナ）・注文者会社名
@@ -465,7 +465,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_search_order';
     }
diff --git a/src/Eccube/Form/Type/Admin/SearchPluginApiType.php b/src/Eccube/Form/Type/Admin/SearchPluginApiType.php
index cb0e0f74a28..7d391a6fc2a 100644
--- a/src/Eccube/Form/Type/Admin/SearchPluginApiType.php
+++ b/src/Eccube/Form/Type/Admin/SearchPluginApiType.php
@@ -26,7 +26,7 @@ class SearchPluginApiType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $category = $options['category'];
         // Todo: constant for the API key
@@ -79,7 +79,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'category' => [],
@@ -89,7 +89,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'search_plugin';
     }
diff --git a/src/Eccube/Form/Type/Admin/SearchProductType.php b/src/Eccube/Form/Type/Admin/SearchProductType.php
index bb947c6773b..20660e51d02 100644
--- a/src/Eccube/Form/Type/Admin/SearchProductType.php
+++ b/src/Eccube/Form/Type/Admin/SearchProductType.php
@@ -72,7 +72,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('id', TextType::class, [
@@ -301,7 +301,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_search_product';
     }
diff --git a/src/Eccube/Form/Type/Admin/SecurityType.php b/src/Eccube/Form/Type/Admin/SecurityType.php
index f48ad6f6545..e6ab81a8fc1 100644
--- a/src/Eccube/Form/Type/Admin/SecurityType.php
+++ b/src/Eccube/Form/Type/Admin/SecurityType.php
@@ -67,7 +67,7 @@ public function __construct(EccubeConfig $eccubeConfig, ValidatorInterface $vali
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $allowHosts = $this->eccubeConfig->get('eccube_admin_allow_hosts');
         $allowHosts = implode("\n", $allowHosts);
@@ -246,7 +246,7 @@ private function getRouteCollection(): string
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_security';
     }
diff --git a/src/Eccube/Form/Type/Admin/ShippingType.php b/src/Eccube/Form/Type/Admin/ShippingType.php
index 057518ee592..c9d7f6f7c12 100644
--- a/src/Eccube/Form/Type/Admin/ShippingType.php
+++ b/src/Eccube/Form/Type/Admin/ShippingType.php
@@ -87,7 +87,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', NameType::class, [
@@ -341,7 +341,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\Shipping',
@@ -351,7 +351,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'shipping';
     }
diff --git a/src/Eccube/Form/Type/Admin/ShopMasterType.php b/src/Eccube/Form/Type/Admin/ShopMasterType.php
index 64a65618d50..2058433a7a5 100644
--- a/src/Eccube/Form/Type/Admin/ShopMasterType.php
+++ b/src/Eccube/Form/Type/Admin/ShopMasterType.php
@@ -54,7 +54,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('company_name', TextType::class, [
@@ -258,7 +258,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => \Eccube\Entity\BaseInfo::class,
@@ -268,7 +268,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'shop_master';
     }
diff --git a/src/Eccube/Form/Type/Admin/TagType.php b/src/Eccube/Form/Type/Admin/TagType.php
index 3b9bf3df860..7755a8a7643 100644
--- a/src/Eccube/Form/Type/Admin/TagType.php
+++ b/src/Eccube/Form/Type/Admin/TagType.php
@@ -33,7 +33,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -50,7 +50,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\Tag',
@@ -60,7 +60,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_tag';
     }
diff --git a/src/Eccube/Form/Type/Admin/TaxRuleType.php b/src/Eccube/Form/Type/Admin/TaxRuleType.php
index 3228c2877be..e8fa780eba9 100644
--- a/src/Eccube/Form/Type/Admin/TaxRuleType.php
+++ b/src/Eccube/Form/Type/Admin/TaxRuleType.php
@@ -41,7 +41,7 @@ public function __construct(TaxRuleRepository $taxRuleRepository)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('tax_rate', IntegerType::class, [
@@ -97,7 +97,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => TaxRule::class,
@@ -107,7 +107,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'tax_rule';
     }
diff --git a/src/Eccube/Form/Type/Admin/TemplateType.php b/src/Eccube/Form/Type/Admin/TemplateType.php
index c1efc930e08..373fa958564 100644
--- a/src/Eccube/Form/Type/Admin/TemplateType.php
+++ b/src/Eccube/Form/Type/Admin/TemplateType.php
@@ -36,7 +36,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('code', TextType::class, [
@@ -76,7 +76,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\Template',
@@ -86,7 +86,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_template';
     }
diff --git a/src/Eccube/Form/Type/Admin/TradeLawType.php b/src/Eccube/Form/Type/Admin/TradeLawType.php
index 0e19496e759..1a35c389b9a 100644
--- a/src/Eccube/Form/Type/Admin/TradeLawType.php
+++ b/src/Eccube/Form/Type/Admin/TradeLawType.php
@@ -38,7 +38,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', TextType::class, [
@@ -68,7 +68,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => TradeLaw::class,
diff --git a/src/Eccube/Form/Type/Admin/TwoFactorAuthType.php b/src/Eccube/Form/Type/Admin/TwoFactorAuthType.php
index 88d2df8b1ae..22c975518f9 100644
--- a/src/Eccube/Form/Type/Admin/TwoFactorAuthType.php
+++ b/src/Eccube/Form/Type/Admin/TwoFactorAuthType.php
@@ -24,7 +24,7 @@ class TwoFactorAuthType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add(
@@ -55,7 +55,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'admin_two_factor_auth';
     }
diff --git a/src/Eccube/Form/Type/Front/ContactType.php b/src/Eccube/Form/Type/Front/ContactType.php
index 5f014a2d4d1..0dc128eeccc 100644
--- a/src/Eccube/Form/Type/Front/ContactType.php
+++ b/src/Eccube/Form/Type/Front/ContactType.php
@@ -46,7 +46,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', NameType::class, [
@@ -83,7 +83,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'contact';
     }
diff --git a/src/Eccube/Form/Type/Front/CustomerAddressType.php b/src/Eccube/Form/Type/Front/CustomerAddressType.php
index e676b2139f5..e075b1a1e75 100644
--- a/src/Eccube/Form/Type/Front/CustomerAddressType.php
+++ b/src/Eccube/Form/Type/Front/CustomerAddressType.php
@@ -43,7 +43,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', NameType::class, [
@@ -70,7 +70,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\CustomerAddress',
@@ -80,7 +80,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'customer_address';
     }
diff --git a/src/Eccube/Form/Type/Front/CustomerLoginType.php b/src/Eccube/Form/Type/Front/CustomerLoginType.php
index 6dd331edfcd..02ad4718c83 100644
--- a/src/Eccube/Form/Type/Front/CustomerLoginType.php
+++ b/src/Eccube/Form/Type/Front/CustomerLoginType.php
@@ -44,7 +44,7 @@ public function __construct(AuthenticationUtils $authenticationUtils, EccubeConf
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->add('login_email', EmailType::class, [
             'attr' => [
@@ -72,7 +72,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'customer_login';
     }
diff --git a/src/Eccube/Form/Type/Front/EntryType.php b/src/Eccube/Form/Type/Front/EntryType.php
index 199a3a9fecd..a1b979982d8 100644
--- a/src/Eccube/Form/Type/Front/EntryType.php
+++ b/src/Eccube/Form/Type/Front/EntryType.php
@@ -55,7 +55,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', NameType::class, [
@@ -127,7 +127,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\Customer',
@@ -137,7 +137,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         // todo entry,mypageで共有されているので名前を変更する
         return 'entry';
diff --git a/src/Eccube/Form/Type/Front/ForgotType.php b/src/Eccube/Form/Type/Front/ForgotType.php
index 3bac4a9a017..d4211ab0b0c 100644
--- a/src/Eccube/Form/Type/Front/ForgotType.php
+++ b/src/Eccube/Form/Type/Front/ForgotType.php
@@ -43,7 +43,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->add('login_email', EmailType::class, [
             'attr' => [
@@ -59,7 +59,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'forgot';
     }
diff --git a/src/Eccube/Form/Type/Front/NonMemberType.php b/src/Eccube/Form/Type/Front/NonMemberType.php
index 6ad5fbabfb8..a6afa9d3ae8 100644
--- a/src/Eccube/Form/Type/Front/NonMemberType.php
+++ b/src/Eccube/Form/Type/Front/NonMemberType.php
@@ -45,7 +45,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('name', NameType::class, [
@@ -77,7 +77,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'nonmember';
     }
diff --git a/src/Eccube/Form/Type/Front/PasswordResetType.php b/src/Eccube/Form/Type/Front/PasswordResetType.php
index cb9fba6782b..c2baae42f5b 100644
--- a/src/Eccube/Form/Type/Front/PasswordResetType.php
+++ b/src/Eccube/Form/Type/Front/PasswordResetType.php
@@ -44,7 +44,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->add('login_email', EmailType::class, [
             'attr' => [
@@ -67,7 +67,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'forgot_reset';
     }
diff --git a/src/Eccube/Form/Type/Front/ShoppingShippingType.php b/src/Eccube/Form/Type/Front/ShoppingShippingType.php
index 8f634dc0f75..63a201faa95 100644
--- a/src/Eccube/Form/Type/Front/ShoppingShippingType.php
+++ b/src/Eccube/Form/Type/Front/ShoppingShippingType.php
@@ -22,14 +22,14 @@ class ShoppingShippingType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
     }
 
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'data_class' => 'Eccube\Entity\CustomerAddress',
@@ -39,7 +39,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return CustomerAddressType::class;
     }
@@ -47,7 +47,7 @@ public function getParent()
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'shopping_shipping';
     }
diff --git a/src/Eccube/Form/Type/Install/Step1Type.php b/src/Eccube/Form/Type/Install/Step1Type.php
index e17f452a1fc..66c99ecd3c3 100644
--- a/src/Eccube/Form/Type/Install/Step1Type.php
+++ b/src/Eccube/Form/Type/Install/Step1Type.php
@@ -22,7 +22,7 @@ class Step1Type extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('agree', CheckboxType::class, [
@@ -34,7 +34,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'install_step1';
     }
diff --git a/src/Eccube/Form/Type/Install/Step3Type.php b/src/Eccube/Form/Type/Install/Step3Type.php
index 4c8038f7adf..4e7a0d49131 100644
--- a/src/Eccube/Form/Type/Install/Step3Type.php
+++ b/src/Eccube/Form/Type/Install/Step3Type.php
@@ -48,7 +48,7 @@ public function __construct(ValidatorInterface $validator, EccubeConfig $eccubeC
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('shop_name', TextType::class, [
@@ -162,7 +162,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'install_step3';
     }
diff --git a/src/Eccube/Form/Type/Install/Step4Type.php b/src/Eccube/Form/Type/Install/Step4Type.php
index e3831768291..55359bd836a 100644
--- a/src/Eccube/Form/Type/Install/Step4Type.php
+++ b/src/Eccube/Form/Type/Install/Step4Type.php
@@ -45,7 +45,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $database = [];
         if (extension_loaded('pdo_pgsql')) {
@@ -126,7 +126,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'install_step4';
     }
diff --git a/src/Eccube/Form/Type/Install/Step5Type.php b/src/Eccube/Form/Type/Install/Step5Type.php
index 31c523b783d..df3f55383c2 100644
--- a/src/Eccube/Form/Type/Install/Step5Type.php
+++ b/src/Eccube/Form/Type/Install/Step5Type.php
@@ -22,7 +22,7 @@ class Step5Type extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('no_update', CheckboxType::class, [
@@ -35,7 +35,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'install_step5';
     }
diff --git a/src/Eccube/Form/Type/KanaType.php b/src/Eccube/Form/Type/KanaType.php
index 9a5666886dd..ca0586011ff 100644
--- a/src/Eccube/Form/Type/KanaType.php
+++ b/src/Eccube/Form/Type/KanaType.php
@@ -39,7 +39,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // ひらがなをカタカナに変換する
         // 引数はmb_convert_kanaのもの
@@ -49,7 +49,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'lastname_options' => [
@@ -86,7 +86,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return NameType::class;
     }
@@ -94,7 +94,7 @@ public function getParent()
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'kana';
     }
diff --git a/src/Eccube/Form/Type/Master/CategoryType.php b/src/Eccube/Form/Type/Master/CategoryType.php
index 2d8b001cb51..c8ed30c1cfd 100644
--- a/src/Eccube/Form/Type/Master/CategoryType.php
+++ b/src/Eccube/Form/Type/Master/CategoryType.php
@@ -23,7 +23,7 @@ class CategoryType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Category',
@@ -36,12 +36,12 @@ public function configureOptions(OptionsResolver $resolver)
         ]);
     }
 
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
 
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'category';
     }
diff --git a/src/Eccube/Form/Type/Master/CsvType.php b/src/Eccube/Form/Type/Master/CsvType.php
index 256cbcc0d3c..bb35253503f 100644
--- a/src/Eccube/Form/Type/Master/CsvType.php
+++ b/src/Eccube/Form/Type/Master/CsvType.php
@@ -22,7 +22,7 @@ class CsvType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Master\CsvType',
@@ -35,7 +35,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'csv_type';
     }
@@ -43,7 +43,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/CustomerStatusType.php b/src/Eccube/Form/Type/Master/CustomerStatusType.php
index e43862374cb..9935bd8159c 100644
--- a/src/Eccube/Form/Type/Master/CustomerStatusType.php
+++ b/src/Eccube/Form/Type/Master/CustomerStatusType.php
@@ -23,13 +23,13 @@ class CustomerStatusType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // todo ???
         $options['sex_options']['required'] = $options['required'];
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Master\CustomerStatus',
@@ -37,12 +37,12 @@ public function configureOptions(OptionsResolver $resolver)
         ]);
     }
 
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
 
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'customer_status';
     }
diff --git a/src/Eccube/Form/Type/Master/DeliveryDurationType.php b/src/Eccube/Form/Type/Master/DeliveryDurationType.php
index 8f0985ba447..bff07a72976 100644
--- a/src/Eccube/Form/Type/Master/DeliveryDurationType.php
+++ b/src/Eccube/Form/Type/Master/DeliveryDurationType.php
@@ -26,7 +26,7 @@ class DeliveryDurationType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\DeliveryDuration',
@@ -44,7 +44,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'delivery_duration';
     }
@@ -52,7 +52,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return EntityType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/DeviceTypeType.php b/src/Eccube/Form/Type/Master/DeviceTypeType.php
index 129e1ff87df..e3bba3dfc3f 100644
--- a/src/Eccube/Form/Type/Master/DeviceTypeType.php
+++ b/src/Eccube/Form/Type/Master/DeviceTypeType.php
@@ -23,7 +23,7 @@ class DeviceTypeType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => DeviceType::class,
@@ -35,7 +35,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
@@ -43,7 +43,7 @@ public function getParent()
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'device_type';
     }
diff --git a/src/Eccube/Form/Type/Master/JobType.php b/src/Eccube/Form/Type/Master/JobType.php
index d2643746bc6..43f66440fe5 100644
--- a/src/Eccube/Form/Type/Master/JobType.php
+++ b/src/Eccube/Form/Type/Master/JobType.php
@@ -22,7 +22,7 @@ class JobType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Master\Job',
@@ -33,7 +33,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'job';
     }
@@ -41,7 +41,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/LoginHistoryStatusType.php b/src/Eccube/Form/Type/Master/LoginHistoryStatusType.php
index 6216a6d8d5f..1e9d0932917 100644
--- a/src/Eccube/Form/Type/Master/LoginHistoryStatusType.php
+++ b/src/Eccube/Form/Type/Master/LoginHistoryStatusType.php
@@ -22,7 +22,7 @@ class LoginHistoryStatusType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Master\LoginHistoryStatus',
@@ -33,7 +33,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
@@ -41,7 +41,7 @@ public function getParent()
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'login_history_status';
     }
diff --git a/src/Eccube/Form/Type/Master/MailTemplateType.php b/src/Eccube/Form/Type/Master/MailTemplateType.php
index 7d6836868b0..af57d314fbb 100644
--- a/src/Eccube/Form/Type/Master/MailTemplateType.php
+++ b/src/Eccube/Form/Type/Master/MailTemplateType.php
@@ -26,7 +26,7 @@ class MailTemplateType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\MailTemplate',
@@ -42,7 +42,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'mail_template';
     }
@@ -50,7 +50,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/OrderStatusType.php b/src/Eccube/Form/Type/Master/OrderStatusType.php
index 6c04527f2f9..09997ea4ce2 100644
--- a/src/Eccube/Form/Type/Master/OrderStatusType.php
+++ b/src/Eccube/Form/Type/Master/OrderStatusType.php
@@ -41,7 +41,7 @@ public function __construct(OrderRepository $orderRepository)
     /**
      * {@inheritdoc}
      */
-    public function buildView(FormView $view, FormInterface $form, array $options)
+    public function buildView(FormView $view, FormInterface $form, array $options): void
     {
         /** @var OrderStatus[] $OrderStatuses */
         $OrderStatuses = $options['choice_loader']->loadChoiceList()->getChoices();
@@ -61,7 +61,7 @@ public function buildView(FormView $view, FormInterface $form, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => OrderStatus::class,
@@ -71,7 +71,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'order_status';
     }
@@ -79,7 +79,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/PageMaxType.php b/src/Eccube/Form/Type/Master/PageMaxType.php
index 758f654ad30..04081ab84a7 100644
--- a/src/Eccube/Form/Type/Master/PageMaxType.php
+++ b/src/Eccube/Form/Type/Master/PageMaxType.php
@@ -35,7 +35,7 @@ public function __construct(EntityManagerInterface $entityManager)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) {
             $options = $event->getForm()->getConfig()->getOptions();
@@ -57,7 +57,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => PageMax::class,
@@ -67,7 +67,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'page_max';
     }
@@ -75,7 +75,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/PaymentType.php b/src/Eccube/Form/Type/Master/PaymentType.php
index 48ba5afeda5..6b4df66056c 100644
--- a/src/Eccube/Form/Type/Master/PaymentType.php
+++ b/src/Eccube/Form/Type/Master/PaymentType.php
@@ -23,7 +23,7 @@ class PaymentType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Payment',
@@ -40,7 +40,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'payment';
     }
@@ -48,7 +48,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/PrefType.php b/src/Eccube/Form/Type/Master/PrefType.php
index 740414b0ba6..18cfee987ed 100644
--- a/src/Eccube/Form/Type/Master/PrefType.php
+++ b/src/Eccube/Form/Type/Master/PrefType.php
@@ -25,7 +25,7 @@ class PrefType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Master\Pref',
@@ -36,7 +36,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'pref';
     }
@@ -44,7 +44,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/ProductListMaxType.php b/src/Eccube/Form/Type/Master/ProductListMaxType.php
index 15ee9b024aa..c681fc36bfd 100644
--- a/src/Eccube/Form/Type/Master/ProductListMaxType.php
+++ b/src/Eccube/Form/Type/Master/ProductListMaxType.php
@@ -26,7 +26,7 @@ class ProductListMaxType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->addEventListener(FormEvents::PRE_SUBMIT, function (FormEvent $event) {
             $options = $event->getForm()->getConfig()->getOptions();
@@ -39,7 +39,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => ProductListMax::class,
@@ -49,7 +49,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'product_list_max';
     }
@@ -57,7 +57,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/ProductListOrderByType.php b/src/Eccube/Form/Type/Master/ProductListOrderByType.php
index dd91cf327bf..dc586b57428 100644
--- a/src/Eccube/Form/Type/Master/ProductListOrderByType.php
+++ b/src/Eccube/Form/Type/Master/ProductListOrderByType.php
@@ -26,7 +26,7 @@ class ProductListOrderByType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->addEventListener(FormEvents::PRE_SUBMIT, function (FormEvent $event) {
             $options = $event->getForm()->getConfig()->getOptions();
@@ -39,7 +39,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => ProductListOrderBy::class,
@@ -49,7 +49,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'product_list_order_by';
     }
@@ -57,7 +57,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/ProductStatusType.php b/src/Eccube/Form/Type/Master/ProductStatusType.php
index cb4c1489044..45c9481acec 100644
--- a/src/Eccube/Form/Type/Master/ProductStatusType.php
+++ b/src/Eccube/Form/Type/Master/ProductStatusType.php
@@ -22,7 +22,7 @@ class ProductStatusType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Master\ProductStatus',
@@ -33,7 +33,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
@@ -41,7 +41,7 @@ public function getParent()
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'product_status';
     }
diff --git a/src/Eccube/Form/Type/Master/RoundingTypeType.php b/src/Eccube/Form/Type/Master/RoundingTypeType.php
index d2df58c2612..e4856526144 100644
--- a/src/Eccube/Form/Type/Master/RoundingTypeType.php
+++ b/src/Eccube/Form/Type/Master/RoundingTypeType.php
@@ -19,7 +19,7 @@
 
 class RoundingTypeType extends AbstractType
 {
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Master\RoundingType',
@@ -27,12 +27,12 @@ public function configureOptions(OptionsResolver $resolver)
         ]);
     }
 
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
 
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'rounding_type';
     }
diff --git a/src/Eccube/Form/Type/Master/SaleTypeType.php b/src/Eccube/Form/Type/Master/SaleTypeType.php
index 85628f8105d..66db098ba50 100644
--- a/src/Eccube/Form/Type/Master/SaleTypeType.php
+++ b/src/Eccube/Form/Type/Master/SaleTypeType.php
@@ -25,7 +25,7 @@ class SaleTypeType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Master\SaleType',
@@ -36,7 +36,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'sale_type';
     }
@@ -44,7 +44,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
diff --git a/src/Eccube/Form/Type/Master/SexType.php b/src/Eccube/Form/Type/Master/SexType.php
index e5278059d06..2ef4988b03c 100644
--- a/src/Eccube/Form/Type/Master/SexType.php
+++ b/src/Eccube/Form/Type/Master/SexType.php
@@ -23,12 +23,12 @@ class SexType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $options['sex_options']['required'] = $options['required'];
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'class' => 'Eccube\Entity\Master\Sex',
@@ -37,12 +37,12 @@ public function configureOptions(OptionsResolver $resolver)
         ]);
     }
 
-    public function getParent()
+    public function getParent(): ?string
     {
         return MasterType::class;
     }
 
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'sex';
     }
diff --git a/src/Eccube/Form/Type/MasterType.php b/src/Eccube/Form/Type/MasterType.php
index f812000a4e5..d34d756d626 100644
--- a/src/Eccube/Form/Type/MasterType.php
+++ b/src/Eccube/Form/Type/MasterType.php
@@ -23,7 +23,7 @@ class MasterType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'multiple' => false,
@@ -40,7 +40,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'master';
     }
@@ -48,7 +48,7 @@ public function getBlockPrefix()
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return EntityType::class;
     }
diff --git a/src/Eccube/Form/Type/NameType.php b/src/Eccube/Form/Type/NameType.php
index 13b82e45028..5fac215aa57 100644
--- a/src/Eccube/Form/Type/NameType.php
+++ b/src/Eccube/Form/Type/NameType.php
@@ -43,7 +43,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $options['lastname_options']['required'] = $options['required'];
         $options['firstname_options']['required'] = $options['required'];
@@ -82,7 +82,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function buildView(FormView $view, FormInterface $form, array $options)
+    public function buildView(FormView $view, FormInterface $form, array $options): void
     {
         $builder = $form->getConfig();
         $view->vars['lastname_name'] = $builder->getAttribute('lastname_name');
@@ -92,7 +92,7 @@ public function buildView(FormView $view, FormInterface $form, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'options' => [],
@@ -135,7 +135,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'name';
     }
diff --git a/src/Eccube/Form/Type/PhoneNumberType.php b/src/Eccube/Form/Type/PhoneNumberType.php
index 029b69db11c..0b529d559e4 100644
--- a/src/Eccube/Form/Type/PhoneNumberType.php
+++ b/src/Eccube/Form/Type/PhoneNumberType.php
@@ -43,7 +43,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // 全角英数を事前に半角にする
         $builder->addEventSubscriber(new \Eccube\Form\EventListener\ConvertKanaListener());
@@ -53,7 +53,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setNormalizer('constraints', function($options, $value) {
             $constraints = [];
@@ -85,7 +85,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return TelType::class;
     }
@@ -93,7 +93,7 @@ public function getParent()
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'phone_number';
     }
diff --git a/src/Eccube/Form/Type/PostalType.php b/src/Eccube/Form/Type/PostalType.php
index f0dfc5c08ca..868fa8357ae 100644
--- a/src/Eccube/Form/Type/PostalType.php
+++ b/src/Eccube/Form/Type/PostalType.php
@@ -43,7 +43,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->addEventSubscriber(new \Eccube\Form\EventListener\ConvertKanaListener());
         $builder->addEventSubscriber(new \Eccube\Form\EventListener\TruncateHyphenListener());
@@ -52,7 +52,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setNormalizer('constraints', function($options, $value) {
             $constraints = [];
@@ -86,7 +86,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return TelType::class;
     }
@@ -94,7 +94,7 @@ public function getParent()
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'postal';
     }
diff --git a/src/Eccube/Form/Type/PriceType.php b/src/Eccube/Form/Type/PriceType.php
index e9dc7ee1b28..3c692484a57 100644
--- a/src/Eccube/Form/Type/PriceType.php
+++ b/src/Eccube/Form/Type/PriceType.php
@@ -42,7 +42,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $currency = $this->eccubeConfig->get('currency');
         $scale = Currencies::getFractionDigits($currency);
@@ -82,7 +82,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return MoneyType::class;
     }
@@ -90,7 +90,7 @@ public function getParent()
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'price';
     }
diff --git a/src/Eccube/Form/Type/RepeatedEmailType.php b/src/Eccube/Form/Type/RepeatedEmailType.php
index 64a11b4316f..b0fd39a45b4 100644
--- a/src/Eccube/Form/Type/RepeatedEmailType.php
+++ b/src/Eccube/Form/Type/RepeatedEmailType.php
@@ -42,7 +42,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'entry_type' => EmailType::class,
@@ -78,7 +78,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return RepeatedType::class;
     }
@@ -86,7 +86,7 @@ public function getParent()
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'repeated_email';
     }
diff --git a/src/Eccube/Form/Type/RepeatedPasswordType.php b/src/Eccube/Form/Type/RepeatedPasswordType.php
index b465d27a256..5a0b43ce1e5 100644
--- a/src/Eccube/Form/Type/RepeatedPasswordType.php
+++ b/src/Eccube/Form/Type/RepeatedPasswordType.php
@@ -45,7 +45,7 @@ public function __construct(EccubeConfig $eccubeConfig)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'type' => TextType::class, // type password だと入力欄を空にされてしまうので、widgetで対応
@@ -85,7 +85,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getParent()
+    public function getParent(): ?string
     {
         return RepeatedType::class;
     }
@@ -93,7 +93,7 @@ public function getParent()
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'repeated_password';
     }
diff --git a/src/Eccube/Form/Type/SearchProductBlockType.php b/src/Eccube/Form/Type/SearchProductBlockType.php
index 476a829a639..8655defbe7b 100644
--- a/src/Eccube/Form/Type/SearchProductBlockType.php
+++ b/src/Eccube/Form/Type/SearchProductBlockType.php
@@ -35,7 +35,7 @@ public function __construct(CategoryRepository $categoryRepository)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $Categories = $this->categoryRepository
             ->getList(null, true);
@@ -59,7 +59,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'csrf_protection' => false,
@@ -70,7 +70,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'search_product_block';
     }
diff --git a/src/Eccube/Form/Type/SearchProductType.php b/src/Eccube/Form/Type/SearchProductType.php
index 6c5548e3f57..a2715e6b880 100644
--- a/src/Eccube/Form/Type/SearchProductType.php
+++ b/src/Eccube/Form/Type/SearchProductType.php
@@ -52,7 +52,7 @@ public function __construct(CategoryRepository $categoryRepository, EntityManage
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $Categories = $this->categoryRepository
             ->getList(null, true);
@@ -87,7 +87,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'csrf_protection' => false,
@@ -98,7 +98,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'search_product';
     }
diff --git a/src/Eccube/Form/Type/ShippingMultipleItemType.php b/src/Eccube/Form/Type/ShippingMultipleItemType.php
index 6d32fa42431..1c28e6dfa4e 100644
--- a/src/Eccube/Form/Type/ShippingMultipleItemType.php
+++ b/src/Eccube/Form/Type/ShippingMultipleItemType.php
@@ -96,7 +96,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('quantity', IntegerType::class, [
@@ -183,7 +183,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'shipping_multiple_item';
     }
diff --git a/src/Eccube/Form/Type/ShippingMultipleType.php b/src/Eccube/Form/Type/ShippingMultipleType.php
index 71905ab7a08..bc13c7300f4 100644
--- a/src/Eccube/Form/Type/ShippingMultipleType.php
+++ b/src/Eccube/Form/Type/ShippingMultipleType.php
@@ -39,7 +39,7 @@ public function __construct(ShippingRepository $shippingRepository)
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->addEventListener(FormEvents::POST_SET_DATA, function ($event) {
@@ -72,7 +72,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'shipping_multiple';
     }
diff --git a/src/Eccube/Form/Type/Shopping/CustomerAddressType.php b/src/Eccube/Form/Type/Shopping/CustomerAddressType.php
index c099ab06e91..f338c5553e4 100644
--- a/src/Eccube/Form/Type/Shopping/CustomerAddressType.php
+++ b/src/Eccube/Form/Type/Shopping/CustomerAddressType.php
@@ -24,7 +24,7 @@
 
 class CustomerAddressType extends AbstractType
 {
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // 会員住所とお届け先住所をマージして選択肢を作成
         /** @var Customer $Customer */
@@ -52,7 +52,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
         ]);
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults(['customer' => null, 'shipping' => null]);
     }
diff --git a/src/Eccube/Form/Type/Shopping/OrderItemType.php b/src/Eccube/Form/Type/Shopping/OrderItemType.php
index de258df63a1..6d67dc44b9a 100644
--- a/src/Eccube/Form/Type/Shopping/OrderItemType.php
+++ b/src/Eccube/Form/Type/Shopping/OrderItemType.php
@@ -26,11 +26,11 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults(
             [
@@ -39,7 +39,7 @@ public function configureOptions(OptionsResolver $resolver)
         );
     }
 
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return '_shopping_order_item';
     }
diff --git a/src/Eccube/Form/Type/Shopping/OrderType.php b/src/Eccube/Form/Type/Shopping/OrderType.php
index 7409d9bd2b9..dfccd42f318 100644
--- a/src/Eccube/Form/Type/Shopping/OrderType.php
+++ b/src/Eccube/Form/Type/Shopping/OrderType.php
@@ -90,7 +90,7 @@ public function __construct(
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // ShoppingController::checkoutから呼ばれる場合は, フォーム項目の定義をスキップする.
         if ($options['skip_add_form']) {
@@ -179,7 +179,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
         });
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults(
             [
@@ -189,7 +189,7 @@ public function configureOptions(OptionsResolver $resolver)
         );
     }
 
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return '_shopping_order';
     }
diff --git a/src/Eccube/Form/Type/Shopping/ShippingType.php b/src/Eccube/Form/Type/Shopping/ShippingType.php
index 9f710a1779c..2cc6a8a72df 100644
--- a/src/Eccube/Form/Type/Shopping/ShippingType.php
+++ b/src/Eccube/Form/Type/Shopping/ShippingType.php
@@ -63,7 +63,7 @@ public function __construct(EccubeConfig $eccubeConfig, DeliveryRepository $deli
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add(
@@ -269,7 +269,7 @@ function (FormEvent $event) {
         });
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults(
             [
@@ -278,7 +278,7 @@ public function configureOptions(OptionsResolver $resolver)
         );
     }
 
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return '_shopping_shipping';
     }
diff --git a/src/Eccube/Form/Type/ShoppingMultipleType.php b/src/Eccube/Form/Type/ShoppingMultipleType.php
index 07f8294a54e..2bc21b67de1 100644
--- a/src/Eccube/Form/Type/ShoppingMultipleType.php
+++ b/src/Eccube/Form/Type/ShoppingMultipleType.php
@@ -24,7 +24,7 @@ class ShoppingMultipleType extends AbstractType
     /**
      * {@inheritdoc}
      */
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $deliveries = $options['deliveries'];
         $delivery = $options['delivery'];
@@ -51,7 +51,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
             ]);
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'deliveries' => [],
@@ -63,7 +63,7 @@ public function configureOptions(OptionsResolver $resolver)
     /**
      * {@inheritdoc}
      */
-    public function getBlockPrefix()
+    public function getBlockPrefix(): string
     {
         return 'shopping_multiple';
     }
diff --git a/src/Eccube/Form/Type/ToggleSwitchType.php b/src/Eccube/Form/Type/ToggleSwitchType.php
index 55d125140a9..3b5538c500a 100644
--- a/src/Eccube/Form/Type/ToggleSwitchType.php
+++ b/src/Eccube/Form/Type/ToggleSwitchType.php
@@ -21,13 +21,13 @@
 
 class ToggleSwitchType extends AbstractType
 {
-    public function buildView(FormView $view, FormInterface $form, array $options)
+    public function buildView(FormView $view, FormInterface $form, array $options): void
     {
         $view->vars['label_on'] = $options['label_on'];
         $view->vars['label_off'] = $options['label_off'];
     }
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'label' => false,
@@ -36,7 +36,7 @@ public function configureOptions(OptionsResolver $resolver)
         ]);
     }
 
-    public function getParent()
+    public function getParent(): ?string
     {
         return CheckboxType::class;
     }
diff --git a/src/Eccube/Form/Validator/EmailValidator.php b/src/Eccube/Form/Validator/EmailValidator.php
index dc61d8befd9..7d9a04bc657 100644
--- a/src/Eccube/Form/Validator/EmailValidator.php
+++ b/src/Eccube/Form/Validator/EmailValidator.php
@@ -31,7 +31,7 @@ class EmailValidator extends ConstraintValidator
     /**
      * {@inheritdoc}
      */
-    public function validate($value, Constraint $constraint)
+    public function validate($value, Constraint $constraint): void
     {
         if (!$constraint instanceof Email) {
             throw new UnexpectedTypeException($constraint, __NAMESPACE__.'\Email');
diff --git a/src/Eccube/Form/Validator/TwigLintValidator.php b/src/Eccube/Form/Validator/TwigLintValidator.php
index 4f336f1bcad..89734d035a1 100644
--- a/src/Eccube/Form/Validator/TwigLintValidator.php
+++ b/src/Eccube/Form/Validator/TwigLintValidator.php
@@ -40,7 +40,7 @@ public function __construct(\Twig\Environment $twig)
      * @param mixed $value
      * @param Constraint $constraint
      */
-    public function validate($value, Constraint $constraint)
+    public function validate($value, Constraint $constraint): void
     {
         // valueがnullの場合は "Template is not defined"のエラーが投げられるので, 空文字でチェックする.
         if (is_null($value)) {
diff --git a/src/Eccube/Log/Logger.php b/src/Eccube/Log/Logger.php
index 4794acc36e4..3ae1decdd92 100644
--- a/src/Eccube/Log/Logger.php
+++ b/src/Eccube/Log/Logger.php
@@ -58,7 +58,7 @@ public function __construct(
      * @param string $message
      * @param array $context
      */
-    public function log($level, $message, array $context = [])
+    public function log($level, $message, array $context = []): void
     {
         if ($this->context->isAdmin()) {
             $this->adminLogger->log($level, $message, $context);
diff --git a/src/Eccube/Security/Http/Authentication/EccubeLogoutSuccessHandler.php b/src/Eccube/Security/Http/Authentication/EccubeLogoutSuccessHandler.php
index 5c6e589bae9..223e61b3d4b 100644
--- a/src/Eccube/Security/Http/Authentication/EccubeLogoutSuccessHandler.php
+++ b/src/Eccube/Security/Http/Authentication/EccubeLogoutSuccessHandler.php
@@ -37,7 +37,7 @@ public function onLogout(LogoutEvent $event)
         }
     }
 
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [LogoutEvent::class => 'onLogout'];
     }
diff --git a/src/Eccube/Security/Voter/AuthorityVoter.php b/src/Eccube/Security/Voter/AuthorityVoter.php
index d13f65ac8c4..0e0d6033b2c 100644
--- a/src/Eccube/Security/Voter/AuthorityVoter.php
+++ b/src/Eccube/Security/Voter/AuthorityVoter.php
@@ -47,7 +47,7 @@ public function __construct(
         $this->eccubeConfig = $eccubeConfig;
     }
 
-    public function vote(TokenInterface $token, $object, array $attributes)
+    public function vote(TokenInterface $token, $object, array $attributes): int
     {
         $path = null;
 
diff --git a/src/Eccube/Service/CsvImportService.php b/src/Eccube/Service/CsvImportService.php
index bc62d17fd70..b6a13dc2e84 100644
--- a/src/Eccube/Service/CsvImportService.php
+++ b/src/Eccube/Service/CsvImportService.php
@@ -234,7 +234,7 @@ public function rewind()
      * {@inheritdoc}
      */
     #[\ReturnTypeWillChange]
-    public function count()
+    public function count(): int
     {
         if (null === $this->count) {
             $position = $this->key();
@@ -278,7 +278,7 @@ public function key()
      * {@inheritdoc}
      */
     #[\ReturnTypeWillChange]
-    public function seek($pointer)
+    public function seek($pointer): void
     {
         $this->file->seek($pointer);
     }
diff --git a/src/Eccube/Service/OrderStateMachine.php b/src/Eccube/Service/OrderStateMachine.php
index e74c40ca134..a0fb8bad47d 100644
--- a/src/Eccube/Service/OrderStateMachine.php
+++ b/src/Eccube/Service/OrderStateMachine.php
@@ -98,7 +98,7 @@ private function getTransition(OrderStateMachineContext $context, OrderStatus $O
     /**
      * {@inheritdoc}
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [
             'workflow.order.completed' => ['onCompleted'],
diff --git a/src/Eccube/Service/SystemService.php b/src/Eccube/Service/SystemService.php
index c22f01f19f5..86662a19d13 100644
--- a/src/Eccube/Service/SystemService.php
+++ b/src/Eccube/Service/SystemService.php
@@ -228,7 +228,7 @@ public function isMaintenanceMode()
     /**
      * {@inheritdoc}
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [KernelEvents::TERMINATE => 'disableMaintenanceEvent'];
     }
diff --git a/src/Eccube/Session/Session.php b/src/Eccube/Session/Session.php
index cce1d0b4d06..5faebc9ee9c 100644
--- a/src/Eccube/Session/Session.php
+++ b/src/Eccube/Session/Session.php
@@ -44,7 +44,7 @@ public function getId(): string
         return $this->getSession()->getId();
     }
 
-    public function setId(string $id)
+    public function setId(string $id): void
     {
         $this->getSession()->setId($id);
     }
@@ -54,7 +54,7 @@ public function getName(): string
         return $this->getSession()->getName();
     }
 
-    public function setName(string $name)
+    public function setName(string $name): void
     {
         $this->getSession()->setName($name);
     }
@@ -69,7 +69,7 @@ public function migrate(bool $destroy = false, int $lifetime = null): bool
         return $this->getSession()->migrate($destroy, $lifetime);
     }
 
-    public function save()
+    public function save(): void
     {
         $this->getSession()->save();
     }
@@ -84,9 +84,9 @@ public function get(string $name, mixed $default = null): mixed
         return $this->getSession()->get($name, $default);
     }
 
-    public function set(string $name, mixed $value)
+    public function set(string $name, mixed $value): void
     {
-        return $this->getSession()->set($name, $value);
+        $this->getSession()->set($name, $value);
     }
 
     public function all(): array
@@ -94,9 +94,9 @@ public function all(): array
         return $this->getSession()->all();
     }
 
-    public function replace(array $attributes)
+    public function replace(array $attributes): void
     {
-        return $this->getSession()->replace($attributes);
+        $this->getSession()->replace($attributes);
     }
 
     public function remove(string $name): mixed
@@ -104,7 +104,7 @@ public function remove(string $name): mixed
         return $this->getSession()->remove($name);
     }
 
-    public function clear()
+    public function clear(): void
     {
         $this->getSession()->clear();
     }
@@ -114,7 +114,7 @@ public function isStarted(): bool
         return $this->getSession()->isStarted();
     }
 
-    public function registerBag(SessionBagInterface $bag)
+    public function registerBag(SessionBagInterface $bag): void
     {
         $this->getSession()->registerBag($bag);
     }
diff --git a/src/Eccube/Twig/Extension/CartServiceExtension.php b/src/Eccube/Twig/Extension/CartServiceExtension.php
index 9a709f48229..d44391cd012 100644
--- a/src/Eccube/Twig/Extension/CartServiceExtension.php
+++ b/src/Eccube/Twig/Extension/CartServiceExtension.php
@@ -30,7 +30,7 @@ public function __construct(CartService $cartService)
         $this->cartService = $cartService;
     }
 
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('get_cart', [$this, 'get_cart'], ['is_safe' => ['all']]),
diff --git a/src/Eccube/Twig/Extension/EccubeBlockExtension.php b/src/Eccube/Twig/Extension/EccubeBlockExtension.php
index 824ac13d591..eb9dfb94065 100644
--- a/src/Eccube/Twig/Extension/EccubeBlockExtension.php
+++ b/src/Eccube/Twig/Extension/EccubeBlockExtension.php
@@ -29,7 +29,7 @@ public function __construct(Environment $twig, array $blockTemplates)
         $this->blockTemplates = $blockTemplates;
     }
 
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('eccube_block_*', function ($context, $name, array $parameters = []) {
diff --git a/src/Eccube/Twig/Extension/IntlExtension.php b/src/Eccube/Twig/Extension/IntlExtension.php
index 1802c9b90af..317d0717367 100644
--- a/src/Eccube/Twig/Extension/IntlExtension.php
+++ b/src/Eccube/Twig/Extension/IntlExtension.php
@@ -22,7 +22,7 @@ class IntlExtension extends AbstractExtension
     /**
      * {@inheritdoc}
      */
-    public function getFilters()
+    public function getFilters(): array
     {
         return [
             new TwigFilter('date_day', [$this, 'date_day'], ['needs_environment' => true]),
diff --git a/src/Eccube/Twig/Extension/RepositoryExtension.php b/src/Eccube/Twig/Extension/RepositoryExtension.php
index 8e0b35f937f..9643f00bbae 100644
--- a/src/Eccube/Twig/Extension/RepositoryExtension.php
+++ b/src/Eccube/Twig/Extension/RepositoryExtension.php
@@ -29,7 +29,7 @@ public function __construct(EntityManagerInterface $em)
         $this->em = $em;
     }
 
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('repository', function ($entity) {
diff --git a/src/Eccube/Twig/Extension/TemplateEventExtension.php b/src/Eccube/Twig/Extension/TemplateEventExtension.php
index 7bf8ed255d8..bbb216fcbf5 100644
--- a/src/Eccube/Twig/Extension/TemplateEventExtension.php
+++ b/src/Eccube/Twig/Extension/TemplateEventExtension.php
@@ -11,7 +11,7 @@
 
 class TemplateEventExtension extends AbstractExtension
 {
-    public function getNodeVisitors()
+    public function getNodeVisitors(): array
     {
         return [new TemplateEventNodeVisiror()];
     }
diff --git a/src/Eccube/Twig/Extension/TwigIncludeExtension.php b/src/Eccube/Twig/Extension/TwigIncludeExtension.php
index 4214756d215..1ffb37709af 100644
--- a/src/Eccube/Twig/Extension/TwigIncludeExtension.php
+++ b/src/Eccube/Twig/Extension/TwigIncludeExtension.php
@@ -25,7 +25,7 @@ public function __construct(\Twig\Environment $twig)
         $this->twig = $twig;
     }
 
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new TwigFunction('include_dispatch', [$this, 'include_dispatch'],
diff --git a/src/Eccube/Twig/Template.php b/src/Eccube/Twig/Template.php
index caa561e8650..d67dd3b0ad2 100644
--- a/src/Eccube/Twig/Template.php
+++ b/src/Eccube/Twig/Template.php
@@ -45,7 +45,7 @@ public function display(array $context, array $blocks = [])
         }
     }
 
-    public function getTemplateName()
+    public function getTemplateName(): string
     {
         // Templateのキャッシュ作成時に動的に作成されるメソッド
         // デバッグツールバーでエラーが発生するため空文字を返しておく。
@@ -53,7 +53,7 @@ public function getTemplateName()
         return '';
     }
 
-    public function getDebugInfo()
+    public function getDebugInfo(): array
     {
         // Templateのキャッシュ作成時に動的に作成されるメソッド
         return [];
@@ -64,7 +64,7 @@ protected function doDisplay(array $context, array $blocks = [])
         // Templateのキャッシュ作成時に動的に作成されるメソッド
     }
 
-    public function getSourceContext()
+    public function getSourceContext(): Source
     {
         // FIXME Twig\Loader\FilesystemLoader の実装を持ってきたが,これで問題ないか要確認
         return new Source('', $this->getTemplateName(), '');
diff --git a/src/Eccube/Util/CacheUtil.php b/src/Eccube/Util/CacheUtil.php
index 9da97fa58fd..f8554c4a76c 100644
--- a/src/Eccube/Util/CacheUtil.php
+++ b/src/Eccube/Util/CacheUtil.php
@@ -220,7 +220,7 @@ public static function clear($app, $isAll, $isTwig = false)
     /**
      * {@inheritdoc}
      */
-    public static function getSubscribedEvents()
+    public static function getSubscribedEvents(): array
     {
         return [KernelEvents::TERMINATE => 'forceClearCache'];
     }