diff --git a/src/Bridges/Dibi/Dibi3Adapter.php b/src/Bridges/Dibi/Dibi3Adapter.php
index 684c296..05dd5c3 100644
--- a/src/Bridges/Dibi/Dibi3Adapter.php
+++ b/src/Bridges/Dibi/Dibi3Adapter.php
@@ -9,7 +9,7 @@
 
 namespace Nextras\Migrations\Bridges\Dibi;
 
-use DateTime;
+use DateTimeInterface;
 use Dibi;
 use Nextras\Migrations\IDbal;
 
@@ -26,7 +26,7 @@ public function __construct(Dibi\Connection $dibi)
 	}
 
 
-	public function query($sql)
+	public function query(string $sql): array
 	{
 		$result = $this->conn->nativeQuery($sql);
 		$result->setRowClass(null);
@@ -34,37 +34,38 @@ public function query($sql)
 	}
 
 
-	public function exec($sql)
+	public function exec(string $sql): int
 	{
-		return $this->conn->nativeQuery($sql);
+		$this->conn->nativeQuery($sql);
+		return $this->conn->getAffectedRows();
 	}
 
 
-	public function escapeString($value)
+	public function escapeString(string $value): string
 	{
 		return $this->conn->getDriver()->escapeText($value);
 	}
 
 
-	public function escapeInt($value)
+	public function escapeInt(int $value): string
 	{
-		return (string) (int) $value;
+		return (string) $value;
 	}
 
 
-	public function escapeBool($value)
+	public function escapeBool(bool $value): string
 	{
-		return $this->conn->getDriver()->escapeBool($value);
+		return (string) $this->conn->getDriver()->escapeBool($value);
 	}
 
 
-	public function escapeDateTime(DateTime $value)
+	public function escapeDateTime(DateTimeInterface $value): string
 	{
 		return $this->conn->getDriver()->escapeDateTime($value);
 	}
 
 
-	public function escapeIdentifier($value)
+	public function escapeIdentifier(string $value): string
 	{
 		return $this->conn->getDriver()->escapeIdentifier($value);
 	}
diff --git a/src/Bridges/Dibi/DibiAdapter.php b/src/Bridges/Dibi/DibiAdapter.php
index ea8f8aa..e8807e2 100644
--- a/src/Bridges/Dibi/DibiAdapter.php
+++ b/src/Bridges/Dibi/DibiAdapter.php
@@ -9,8 +9,9 @@
 
 namespace Nextras\Migrations\Bridges\Dibi;
 
-use DateTime;
+use DateTimeInterface;
 use dibi;
+use Dibi\Connection;
 use LogicException;
 use Nextras\Migrations\IDbal;
 
@@ -21,7 +22,7 @@ class DibiAdapter implements IDbal
 	private $innerAdapter;
 
 
-	public function __construct($conn)
+	public function __construct(Connection $conn)
 	{
 		if (version_compare(dibi::VERSION, '3.0.0', '>=')) {
 			$this->innerAdapter = new Dibi3Adapter($conn);
@@ -32,43 +33,43 @@ public function __construct($conn)
 	}
 
 
-	public function query($sql)
+	public function query(string $sql): array
 	{
 		return $this->innerAdapter->query($sql);
 	}
 
 
-	public function exec($sql)
+	public function exec(string $sql): int
 	{
 		return $this->innerAdapter->exec($sql);
 	}
 
 
-	public function escapeString($value)
+	public function escapeString(string $value): string
 	{
 		return $this->innerAdapter->escapeString($value);
 	}
 
 
-	public function escapeInt($value)
+	public function escapeInt(int $value): string
 	{
 		return $this->innerAdapter->escapeInt($value);
 	}
 
 
-	public function escapeBool($value)
+	public function escapeBool(bool $value): string
 	{
 		return $this->innerAdapter->escapeBool($value);
 	}
 
 
-	public function escapeDateTime(DateTime $value)
+	public function escapeDateTime(DateTimeInterface $value): string
 	{
 		return $this->innerAdapter->escapeDateTime($value);
 	}
 
 
-	public function escapeIdentifier($value)
+	public function escapeIdentifier(string $value): string
 	{
 		return $this->innerAdapter->escapeIdentifier($value);
 	}
diff --git a/src/Bridges/DoctrineDbal/DoctrineAdapter.php b/src/Bridges/DoctrineDbal/DoctrineAdapter.php
index 3896244..64d9da5 100644
--- a/src/Bridges/DoctrineDbal/DoctrineAdapter.php
+++ b/src/Bridges/DoctrineDbal/DoctrineAdapter.php
@@ -9,7 +9,7 @@
 
 namespace Nextras\Migrations\Bridges\DoctrineDbal;
 
-use DateTime;
+use DateTimeInterface;
 use Doctrine;
 use Nextras\Migrations\IDbal;
 
@@ -26,7 +26,7 @@ public function __construct(Doctrine\DBAL\Connection $conn)
 	}
 
 
-	public function query($sql)
+	public function query(string $sql): array
 	{
 		return method_exists($this->conn, 'fetchAllAssociative')
 			? $this->conn->fetchAllAssociative($sql)
@@ -34,7 +34,7 @@ public function query($sql)
 	}
 
 
-	public function exec($sql)
+	public function exec(string $sql): int
 	{
 		return method_exists($this->conn, 'executeStatement')
 			? $this->conn->executeStatement($sql)
@@ -42,31 +42,31 @@ public function exec($sql)
 	}
 
 
-	public function escapeString($value)
+	public function escapeString(string $value): string
 	{
 		return $this->conn->quote($value, 'string');
 	}
 
 
-	public function escapeInt($value)
+	public function escapeInt(int $value): string
 	{
 		return $this->conn->quote($value, 'integer');
 	}
 
 
-	public function escapeBool($value)
+	public function escapeBool(bool $value): string
 	{
 		return $this->conn->quote($value, 'boolean');
 	}
 
 
-	public function escapeDateTime(DateTime $value)
+	public function escapeDateTime(DateTimeInterface $value): string
 	{
 		return $this->conn->quote($value, 'datetime');
 	}
 
 
-	public function escapeIdentifier($value)
+	public function escapeIdentifier(string $value): string
 	{
 		return $this->conn->quoteIdentifier($value);
 	}
diff --git a/src/Bridges/DoctrineOrm/StructureDiffGenerator.php b/src/Bridges/DoctrineOrm/StructureDiffGenerator.php
index 80c7e5c..daf1f80 100644
--- a/src/Bridges/DoctrineOrm/StructureDiffGenerator.php
+++ b/src/Bridges/DoctrineOrm/StructureDiffGenerator.php
@@ -25,30 +25,20 @@ class StructureDiffGenerator implements IDiffGenerator
 	private $ignoredQueriesFile;
 
 
-	/**
-	 * @param  EntityManagerInterface $entityManager
-	 * @param  string|NULL            $ignoredQueriesFile
-	 */
-	public function __construct(EntityManagerInterface $entityManager, $ignoredQueriesFile = null)
+	public function __construct(EntityManagerInterface $entityManager, ?string $ignoredQueriesFile = null)
 	{
 		$this->entityManager = $entityManager;
 		$this->ignoredQueriesFile = $ignoredQueriesFile;
 	}
 
 
-	/**
-	 * @return string
-	 */
-	public function getExtension()
+	public function getExtension(): string
 	{
 		return 'sql';
 	}
 
 
-	/**
-	 * @return string
-	 */
-	public function generateContent()
+	public function generateContent(): string
 	{
 		$queries = array_diff($this->getUpdateQueries(), $this->getIgnoredQueries());
 		$content = $queries ? (implode(";\n", $queries) . ";\n") : '';
@@ -58,9 +48,9 @@ public function generateContent()
 
 
 	/**
-	 * @return string[]
+	 * @return list<string>
 	 */
-	protected function getUpdateQueries()
+	protected function getUpdateQueries(): array
 	{
 		$cache = $this->entityManager->getConfiguration()->getMetadataCacheImpl();
 		if ($cache instanceof ClearableCache) {
@@ -76,9 +66,9 @@ protected function getUpdateQueries()
 
 
 	/**
-	 * @return string[]
+	 * @return list<string>
 	 */
-	protected function getIgnoredQueries()
+	protected function getIgnoredQueries(): array
 	{
 		if ($this->ignoredQueriesFile === null) {
 			return [];
diff --git a/src/Bridges/NetteDI/MigrationsExtension.php b/src/Bridges/NetteDI/MigrationsExtension.php
index 931dad2..c837f07 100644
--- a/src/Bridges/NetteDI/MigrationsExtension.php
+++ b/src/Bridges/NetteDI/MigrationsExtension.php
@@ -13,6 +13,8 @@
 use Dibi;
 use Nette;
 use Nette\DI\ContainerBuilder;
+use Nette\DI\ServiceDefinition;
+use Nette\DI\Statement;
 use Nette\Utils\Strings;
 use Nette\Utils\Validators;
 use Nextras;
@@ -27,7 +29,7 @@ class MigrationsExtension extends Nette\DI\CompilerExtension
 	/** attributes = ['for' => names of target migration extensions, 'extension' => name of handled file extension] */
 	const TAG_EXTENSION_HANDLER = 'nextras.migrations.extensionHandler';
 
-	/** @var array */
+	/** @var array<string, mixed> */
 	public $defaults = [
 		'dir' => null,
 		'phpParams' => [],
@@ -40,7 +42,7 @@ class MigrationsExtension extends Nette\DI\CompilerExtension
 		'ignoredQueriesFile' => null,
 	];
 
-	/** @var array */
+	/** @var array<string, class-string> */
 	protected $dbals = [
 		'dibi' => Nextras\Migrations\Bridges\Dibi\DibiAdapter::class,
 		'dibi3' => Nextras\Migrations\Bridges\Dibi\Dibi3Adapter::class,
@@ -50,20 +52,20 @@ class MigrationsExtension extends Nette\DI\CompilerExtension
 		'nextras' => Nextras\Migrations\Bridges\NextrasDbal\NextrasAdapter::class,
 	];
 
-	/** @var array */
+	/** @var array<string, class-string> */
 	protected $drivers = [
 		'mysql' => Nextras\Migrations\Drivers\MySqlDriver::class,
 		'pgsql' => Nextras\Migrations\Drivers\PgSqlDriver::class,
 	];
 
-	/** @var array */
+	/** @var array<string, class-string> */
 	protected $printers = [
 		'console' => Nextras\Migrations\Printers\Console::class,
 		'psrLog' => Nextras\Migrations\Bridges\PsrLog\PsrLogPrinter::class,
 	];
 
 
-	public function loadConfiguration()
+	public function loadConfiguration(): void
 	{
 		$config = $this->validateConfig($this->defaults);
 
@@ -109,7 +111,7 @@ public function loadConfiguration()
 	}
 
 
-	public function beforeCompile()
+	public function beforeCompile(): void
 	{
 		$builder = $this->getContainerBuilder();
 		$config = $this->validateConfig($this->defaults);
@@ -160,6 +162,10 @@ public function beforeCompile()
 	}
 
 
+	/**
+	 * @param  null|string|Statement $dbal
+	 * @return string|ServiceDefinition
+	 */
 	private function getDbalDefinition($dbal)
 	{
 		$factory = $this->getDbalFactory($dbal);
@@ -179,9 +185,13 @@ private function getDbalDefinition($dbal)
 	}
 
 
+	/**
+	 * @param  null|string|Statement $dbal
+	 * @return string|Statement|null
+	 */
 	private function getDbalFactory($dbal)
 	{
-		if ($dbal instanceof Nette\DI\Statement) {
+		if ($dbal instanceof Statement) {
 			return $this->filterArguments([$dbal])[0];
 
 		} elseif (is_string($dbal) && isset($this->dbals[$dbal])) {
@@ -196,6 +206,11 @@ private function getDbalFactory($dbal)
 	}
 
 
+	/**
+	 * @param  null|string|Statement    $driver
+	 * @param  string|ServiceDefinition $dbal
+	 * @return string|ServiceDefinition
+	 */
 	private function getDriverDefinition($driver, $dbal)
 	{
 		$factory = $this->getDriverFactory($driver, $dbal);
@@ -215,13 +230,18 @@ private function getDriverDefinition($driver, $dbal)
 	}
 
 
+	/**
+	 * @param  null|string|Statement    $driver
+	 * @param  string|ServiceDefinition $dbal
+	 * @return string|Statement|null
+	 */
 	private function getDriverFactory($driver, $dbal)
 	{
-		if ($driver instanceof Nette\DI\Statement) {
+		if ($driver instanceof Statement) {
 			return $this->filterArguments([$driver])[0];
 
 		} elseif (is_string($driver) && isset($this->drivers[$driver])) {
-			return new Nette\DI\Statement($this->drivers[$driver], [$dbal]);
+			return new Statement($this->drivers[$driver], [$dbal]);
 
 		} else {
 			return null;
@@ -229,6 +249,10 @@ private function getDriverFactory($driver, $dbal)
 	}
 
 
+	/**
+	 * @param  null|string|Statement $printer
+	 * @return string|ServiceDefinition
+	 */
 	private function getPrinterDefinition($printer)
 	{
 		$factory = $this->getPrinterFactory($printer);
@@ -248,9 +272,13 @@ private function getPrinterDefinition($printer)
 	}
 
 
+	/**
+	 * @param  null|string|Statement $printer
+	 * @return string|Statement|null
+	 */
 	private function getPrinterFactory($printer)
 	{
-		if ($printer instanceof Nette\DI\Statement) {
+		if ($printer instanceof Statement) {
 			return $this->filterArguments([$printer])[0];
 
 		} elseif (is_string($printer) && isset($this->printers[$printer])) {
@@ -265,15 +293,19 @@ private function getPrinterFactory($printer)
 	}
 
 
-	private function createDefaultGroupConfiguration($dir, $withDummyData)
+	/**
+	 * @param  string|Nette\PhpGenerator\PhpLiteral $dir
+	 * @return array<string, array{enabled?: bool, directory: string, dependencies?: list<string>, generator?: ServiceDefinition|null}>
+	 */
+	private function createDefaultGroupConfiguration($dir, bool $withDummyData): array
 	{
 		if ($dir instanceof Nette\PhpGenerator\PhpLiteral) {
-			$append = function ($path) use ($dir) {
+			$append = function (string $path) use ($dir): Nette\PhpGenerator\PhpLiteral {
 				return ContainerBuilder::literal('? . ?', [$dir, $path]);
 			};
 
 		} else {
-			$append = function ($path) use ($dir) {
+			$append = function (string $path) use ($dir): string {
 				return $dir . $path;
 			};
 		}
@@ -305,7 +337,11 @@ private function createDefaultGroupConfiguration($dir, $withDummyData)
 	}
 
 
-	private function createGroupDefinitions(array $groups)
+	/**
+	 * @param  array<string, array{enabled?: bool, directory: string, dependencies?: list<string>, generator?: ServiceDefinition}> $groups
+	 * @return list<ServiceDefinition>
+	 */
+	private function createGroupDefinitions(array $groups): array
 	{
 		$builder = $this->getContainerBuilder();
 		$groupDefinitions = [];
@@ -334,7 +370,12 @@ private function createGroupDefinitions(array $groups)
 	}
 
 
-	private function createExtensionHandlerDefinitions($driver, $phpParams)
+	/**
+	 * @param  string|ServiceDefinition $driver
+	 * @param  array<string, mixed>     $phpParams
+	 * @return list<ServiceDefinition>
+	 */
+	private function createExtensionHandlerDefinitions($driver, array $phpParams): array
 	{
 		$builder = $this->getContainerBuilder();
 
@@ -354,7 +395,7 @@ private function createExtensionHandlerDefinitions($driver, $phpParams)
 	}
 
 
-	private function createConfigurationDefinition()
+	private function createConfigurationDefinition(): ServiceDefinition
 	{
 		return $this->getContainerBuilder()
 			->addDefinition($this->prefix('configuration'))
@@ -363,7 +404,7 @@ private function createConfigurationDefinition()
 	}
 
 
-	private function createDoctrineStructureDiffGeneratorDefinition($ignoredQueriesFile)
+	private function createDoctrineStructureDiffGeneratorDefinition(?string $ignoredQueriesFile): ServiceDefinition
 	{
 		$builder = $this->getContainerBuilder();
 
@@ -375,7 +416,12 @@ private function createDoctrineStructureDiffGeneratorDefinition($ignoredQueriesF
 	}
 
 
-	private function createSymfonyCommandDefinitions($driver, $configuration, $printer)
+	/**
+	 * @param  string|ServiceDefinition $driver
+	 * @param  string|ServiceDefinition $configuration
+	 * @param  string|ServiceDefinition $printer
+	 */
+	private function createSymfonyCommandDefinitions($driver, $configuration, $printer): void
 	{
 		$builder = $this->getContainerBuilder();
 		$builder->addExcludedClasses([Nextras\Migrations\Bridges\SymfonyConsole\BaseCommand::class]);
@@ -397,7 +443,7 @@ private function createSymfonyCommandDefinitions($driver, $configuration, $print
 	}
 
 
-	private function filterArguments(array $arguments)
+	private function filterArguments(array $arguments): array
 	{
 		if (method_exists(Nette\DI\Helpers::class, 'filterArguments')) {
 			return Nette\DI\Helpers::filterArguments($arguments);
diff --git a/src/Bridges/NetteDatabase/NetteAdapter.php b/src/Bridges/NetteDatabase/NetteAdapter.php
index 0d0073e..5327528 100644
--- a/src/Bridges/NetteDatabase/NetteAdapter.php
+++ b/src/Bridges/NetteDatabase/NetteAdapter.php
@@ -9,7 +9,7 @@
 
 namespace Nextras\Migrations\Bridges\NetteDatabase;
 
-use DateTime;
+use DateTimeInterface;
 use Nette;
 use Nextras\Migrations\IDbal;
 use PDO;
@@ -27,7 +27,7 @@ public function __construct(Nette\Database\Connection $ndb)
 	}
 
 
-	public function query($sql)
+	public function query(string $sql): array
 	{
 		return array_map(
 			function ($row) { return (array) $row; },
@@ -36,37 +36,37 @@ function ($row) { return (array) $row; },
 	}
 
 
-	public function exec($sql)
+	public function exec(string $sql): int
 	{
 		return $this->conn->query($sql)->getRowCount();
 	}
 
 
-	public function escapeString($value)
+	public function escapeString(string $value): string
 	{
 		return $this->conn->quote($value, PDO::PARAM_STR);
 	}
 
 
-	public function escapeInt($value)
+	public function escapeInt(int $value): string
 	{
 		return $this->conn->quote((string) $value, PDO::PARAM_INT);
 	}
 
 
-	public function escapeBool($value)
+	public function escapeBool(bool $value): string
 	{
 		return $this->escapeString((string) (int) $value);
 	}
 
 
-	public function escapeDateTime(DateTime $value)
+	public function escapeDateTime(DateTimeInterface $value): string
 	{
 		return $this->conn->getSupplementalDriver()->formatDateTime($value);
 	}
 
 
-	public function escapeIdentifier($value)
+	public function escapeIdentifier(string $value): string
 	{
 		return $this->conn->getSupplementalDriver()->delimite($value);
 	}
diff --git a/src/Bridges/NextrasDbal/NextrasAdapter.php b/src/Bridges/NextrasDbal/NextrasAdapter.php
index ebb5912..1cacb0e 100644
--- a/src/Bridges/NextrasDbal/NextrasAdapter.php
+++ b/src/Bridges/NextrasDbal/NextrasAdapter.php
@@ -9,7 +9,7 @@
 
 namespace Nextras\Migrations\Bridges\NextrasDbal;
 
-use DateTime;
+use DateTimeInterface;
 use Nextras\Dbal\Connection;
 use Nextras\Dbal\Drivers\IDriver;
 use Nextras\Dbal\Result\Row;
@@ -42,7 +42,7 @@ public function __construct(Connection $connection)
 	}
 
 
-	public function query($sql)
+	public function query(string $sql): array
 	{
 		return array_map(
 			function (Row $row) { return $row->toArray(); },
@@ -51,14 +51,14 @@ function (Row $row) { return $row->toArray(); },
 	}
 
 
-	public function exec($sql)
+	public function exec(string $sql): int
 	{
 		$this->conn->query('%raw', $sql);
 		return $this->conn->getAffectedRows();
 	}
 
 
-	public function escapeString($value)
+	public function escapeString(string $value): string
 	{
 		if ($this->version >= 2) {
 			return $this->conn->getDriver()->convertStringToSql($value);
@@ -68,13 +68,13 @@ public function escapeString($value)
 	}
 
 
-	public function escapeInt($value)
+	public function escapeInt(int $value): string
 	{
 		return (string) (int) $value;
 	}
 
 
-	public function escapeBool($value)
+	public function escapeBool(bool $value): string
 	{
 		if ($this->version >= 5) {
 			return $this->conn->getPlatform()->formatBool($value);
@@ -86,7 +86,7 @@ public function escapeBool($value)
 	}
 
 
-	public function escapeDateTime(DateTime $value)
+	public function escapeDateTime(DateTimeInterface $value): string
 	{
 		if ($this->version >= 5) {
 			return $this->conn->getPlatform()->formatDateTime($value);
@@ -98,7 +98,7 @@ public function escapeDateTime(DateTime $value)
 	}
 
 
-	public function escapeIdentifier($value)
+	public function escapeIdentifier(string $value): string
 	{
 		if ($this->version >= 5) {
 			return $this->conn->getPlatform()->formatIdentifier($value);
diff --git a/src/Bridges/PsrLog/PsrLogPrinter.php b/src/Bridges/PsrLog/PsrLogPrinter.php
index f601c67..fc1539d 100644
--- a/src/Bridges/PsrLog/PsrLogPrinter.php
+++ b/src/Bridges/PsrLog/PsrLogPrinter.php
@@ -27,13 +27,13 @@ public function __construct(LoggerInterface $logger)
 	}
 
 
-	public function printIntro($mode)
+	public function printIntro(string $mode): void
 	{
 		$this->logger->info("Nextras Migrations: started in $mode mode");
 	}
 
 
-	public function printToExecute(array $toExecute)
+	public function printToExecute(array $toExecute): void
 	{
 		$count = count($toExecute);
 
@@ -46,7 +46,7 @@ public function printToExecute(array $toExecute)
 	}
 
 
-	public function printExecute(File $file, $count, $time)
+	public function printExecute(File $file, int $count, float $time): void
 	{
 		$this->logger->info("Nextras Migrations: {$file->group->name}/{$file->name} successfully executed", [
 			'queryCount' => $count,
@@ -55,19 +55,19 @@ public function printExecute(File $file, $count, $time)
 	}
 
 
-	public function printDone()
+	public function printDone(): void
 	{
 		$this->logger->info('Nextras Migrations: done');
 	}
 
 
-	public function printError(Exception $e)
+	public function printError(Exception $e): void
 	{
 		throw $e;
 	}
 
 
-	public function printSource($code)
+	public function printSource(string $code): void
 	{
 		$this->logger->debug("Nextras Migrations: init source:\n\n$code");
 	}
diff --git a/src/Bridges/SymfonyBundle/DependencyInjection/Configuration.php b/src/Bridges/SymfonyBundle/DependencyInjection/Configuration.php
index df19575..d422257 100644
--- a/src/Bridges/SymfonyBundle/DependencyInjection/Configuration.php
+++ b/src/Bridges/SymfonyBundle/DependencyInjection/Configuration.php
@@ -15,7 +15,7 @@
 
 class Configuration implements ConfigurationInterface
 {
-	public function getConfigTreeBuilder()
+	public function getConfigTreeBuilder(): TreeBuilder
 	{
 		if (!method_exists(TreeBuilder::class, '__construct')) { // Symfony < 4.2.0
 			$treeBuilder = new TreeBuilder();
diff --git a/src/Bridges/SymfonyBundle/DependencyInjection/NextrasMigrationsExtension.php b/src/Bridges/SymfonyBundle/DependencyInjection/NextrasMigrationsExtension.php
index d8192c0..1e29673 100644
--- a/src/Bridges/SymfonyBundle/DependencyInjection/NextrasMigrationsExtension.php
+++ b/src/Bridges/SymfonyBundle/DependencyInjection/NextrasMigrationsExtension.php
@@ -17,7 +17,7 @@
 
 class NextrasMigrationsExtension extends Extension
 {
-	/** @var array */
+	/** @var array<string, class-string> */
 	protected $dbals = [
 		'dibi' => Nextras\Migrations\Bridges\Dibi\DibiAdapter::class,
 		'dibi3' => Nextras\Migrations\Bridges\Dibi\Dibi3Adapter::class,
@@ -27,20 +27,20 @@ class NextrasMigrationsExtension extends Extension
 		'nextras' => Nextras\Migrations\Bridges\NextrasDbal\NextrasAdapter::class,
 	];
 
-	/** @var array */
+	/** @var array<string, class-string> */
 	protected $drivers = [
 		'mysql' => Nextras\Migrations\Drivers\MySqlDriver::class,
 		'pgsql' => Nextras\Migrations\Drivers\PgSqlDriver::class,
 	];
 
-	/** @var array */
+	/** @var array<string, class-string> */
 	protected $printers = [
 		'console' => Nextras\Migrations\Printers\Console::class,
 		'psrLog' => Nextras\Migrations\Bridges\PsrLog\PsrLogPrinter::class,
 	];
 
 
-	public function load(array $configs, ContainerBuilder $container)
+	public function load(array $configs, ContainerBuilder $container): void
 	{
 		$config = $this->processConfiguration(new Configuration(), $configs);
 
diff --git a/src/Bridges/SymfonyConsole/BaseCommand.php b/src/Bridges/SymfonyConsole/BaseCommand.php
index c7a25c6..13a3f16 100644
--- a/src/Bridges/SymfonyConsole/BaseCommand.php
+++ b/src/Bridges/SymfonyConsole/BaseCommand.php
@@ -29,26 +29,19 @@ abstract class BaseCommand extends Command
 	protected $printer;
 
 
-	/**
-	 * @param  IDriver        $driver
-	 * @param  IConfiguration $config
-	 * @param  IPrinter|NULL  $printer
-	 */
-	public function __construct(IDriver $driver, IConfiguration $config, IPrinter $printer = NULL)
+	public function __construct(IDriver $driver, IConfiguration $config, ?IPrinter $printer = null)
 	{
 		$this->driver = $driver;
 		$this->config = $config;
-		$this->printer = $printer ?: new Console();
+		$this->printer = $printer ?? new Console();
 		parent::__construct();
 	}
 
 
 	/**
-	 * @param  string         $mode Runner::MODE_*
-	 * @param  IConfiguration $config
-	 * @return int
+	 * @param  Runner::MODE_* $mode
 	 */
-	protected function runMigrations($mode, $config)
+	protected function runMigrations(string $mode, IConfiguration $config): int
 	{
 		$runner = new Runner($this->driver, $this->printer);
 		$runner->run($mode, $config);
diff --git a/src/Bridges/SymfonyConsole/ContinueCommand.php b/src/Bridges/SymfonyConsole/ContinueCommand.php
index b329e5c..88821b1 100644
--- a/src/Bridges/SymfonyConsole/ContinueCommand.php
+++ b/src/Bridges/SymfonyConsole/ContinueCommand.php
@@ -22,7 +22,8 @@ class ContinueCommand extends BaseCommand
 	/** @var string */
 	protected static $defaultDescription = 'Updates database schema by running all new migrations';
 
-	protected function configure()
+
+	protected function configure(): void
 	{
 		$this->setName(self::$defaultName);
 		$this->setDescription(self::$defaultDescription);
@@ -30,7 +31,7 @@ protected function configure()
 	}
 
 
-	protected function execute(InputInterface $input, OutputInterface $output)
+	protected function execute(InputInterface $input, OutputInterface $output): int
 	{
 		return $this->runMigrations(Runner::MODE_CONTINUE, $this->config);
 	}
diff --git a/src/Bridges/SymfonyConsole/CreateCommand.php b/src/Bridges/SymfonyConsole/CreateCommand.php
index de1294d..8dfe188 100644
--- a/src/Bridges/SymfonyConsole/CreateCommand.php
+++ b/src/Bridges/SymfonyConsole/CreateCommand.php
@@ -37,20 +37,13 @@ class CreateCommand extends BaseCommand
 	protected $defaultContentSource = self::CONTENT_SOURCE_DIFF;
 
 
-	/**
-	 * @param  string $defaultContentSource
-	 * @return void
-	 */
-	public function setDefaultContentSource($defaultContentSource)
+	public function setDefaultContentSource(string $defaultContentSource): void
 	{
 		$this->defaultContentSource = $defaultContentSource;
 	}
 
 
-	/**
-	 * @return void
-	 */
-	protected function configure()
+	protected function configure(): void
 	{
 		$this->setName(self::$defaultName);
 		$this->setDescription(self::$defaultDescription);
@@ -65,12 +58,7 @@ protected function configure()
 	}
 
 
-	/**
-	 * @param  InputInterface  $input
-	 * @param  OutputInterface $output
-	 * @return int
-	 */
-	protected function execute(InputInterface $input, OutputInterface $output)
+	protected function execute(InputInterface $input, OutputInterface $output): int
 	{
 		$group = $this->getGroup($input->getArgument('type'));
 		$path = $this->getPath($group, $input->getArgument('label'));
@@ -83,12 +71,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
 	}
 
 
-	/**
-	 * @param  Group  $group
-	 * @param  string $label
-	 * @return string
-	 */
-	protected function getPath(Group $group, $label)
+	protected function getPath(Group $group, string $label): string
 	{
 		$dir = $group->directory;
 		$extension = $group->generator ? $group->generator->getExtension() : 'sql';
@@ -108,11 +91,7 @@ protected function getPath(Group $group, $label)
 	}
 
 
-	/**
-	 * @param  string $type
-	 * @return Group
-	 */
-	protected function getGroup($type)
+	protected function getGroup(string $type): Group
 	{
 		$groupNamePattern = preg_quote($type, '~');
 		$groupNamePattern = str_replace('\\-', '\\w*+\\-', $groupNamePattern);
@@ -143,12 +122,7 @@ protected function getGroup($type)
 	}
 
 
-	/**
-	 * @param  string $label
-	 * @param  string $extension
-	 * @return string
-	 */
-	protected function getFileName($label, $extension)
+	protected function getFileName(string $label, string $extension): string
 	{
 		if (preg_match('#^[a-z0-9.-]++$#i', $label)) {
 			$slug = strtolower($label);
@@ -171,12 +145,7 @@ class_exists(AsciiSlugger::class)
 	}
 
 
-	/**
-	 * @param  string      $dir
-	 * @param  string|NULL $found
-	 * @return bool
-	 */
-	protected function hasNumericSubdirectory($dir, &$found)
+	protected function hasNumericSubdirectory(string $dir, ?string &$found): bool
 	{
 		$items = @scandir($dir); // directory may not exist
 
@@ -193,10 +162,7 @@ protected function hasNumericSubdirectory($dir, &$found)
 	}
 
 
-	/**
-	 * @return string
-	 */
-	protected function getTypeArgDescription()
+	protected function getTypeArgDescription(): string
 	{
 		$options = [];
 		$groups = $this->config->getGroups();
@@ -222,11 +188,7 @@ protected function getTypeArgDescription()
 	}
 
 
-	/**
-	 * @param  InputInterface $input
-	 * @return string
-	 */
-	protected function getFileContentSource(InputInterface $input)
+	protected function getFileContentSource(InputInterface $input): string
 	{
 		if ($input->getOption('diff')) {
 			return self::CONTENT_SOURCE_DIFF;
@@ -243,12 +205,7 @@ protected function getFileContentSource(InputInterface $input)
 	}
 
 
-	/**
-	 * @param  Group  $group
-	 * @param  string $source
-	 * @return string
-	 */
-	protected function getFileContent(Group $group, $source)
+	protected function getFileContent(Group $group, string $source): string
 	{
 		if ($source === self::CONTENT_SOURCE_DIFF && $group->generator !== null) {
 			return $group->generator->generateContent();
@@ -262,13 +219,7 @@ protected function getFileContent(Group $group, $source)
 	}
 
 
-	/**
-	 * @param  string          $path
-	 * @param  string          $content
-	 * @param  OutputInterface $output
-	 * @return void
-	 */
-	protected function createFile($path, $content, OutputInterface $output)
+	protected function createFile(string $path, string $content, OutputInterface $output): void
 	{
 		@mkdir(dirname($path), 0777, true); // directory may already exist
 
diff --git a/src/Bridges/SymfonyConsole/ResetCommand.php b/src/Bridges/SymfonyConsole/ResetCommand.php
index 05d9aaa..405f800 100644
--- a/src/Bridges/SymfonyConsole/ResetCommand.php
+++ b/src/Bridges/SymfonyConsole/ResetCommand.php
@@ -23,7 +23,7 @@ class ResetCommand extends BaseCommand
 	protected static $defaultDescription = 'Drops current database and recreates it from scratch';
 
 
-	protected function configure()
+	protected function configure(): void
 	{
 		$this->setName(self::$defaultName);
 		$this->setDescription(self::$defaultDescription);
@@ -31,7 +31,7 @@ protected function configure()
 	}
 
 
-	protected function execute(InputInterface $input, OutputInterface $output)
+	protected function execute(InputInterface $input, OutputInterface $output): int
 	{
 		return $this->runMigrations(Runner::MODE_RESET, $this->config);
 	}
diff --git a/src/Configurations/Configuration.php b/src/Configurations/Configuration.php
index 217ac42..567d2f7 100644
--- a/src/Configurations/Configuration.php
+++ b/src/Configurations/Configuration.php
@@ -19,16 +19,16 @@
  */
 class Configuration implements IConfiguration
 {
-	/** @var Group[] */
+	/** @var list<Group> */
 	private $groups;
 
-	/** @var IExtensionHandler[] (extension => IExtensionHandler) */
+	/** @var array<string, IExtensionHandler> (extension => IExtensionHandler) */
 	private $extensionHandlers;
 
 
 	/**
-	 * @param  Group[]             $groups
-	 * @param  IExtensionHandler[] $extensionHandlers (extension => IExtensionHandler)
+	 * @param  list<Group>                      $groups
+	 * @param  array<string, IExtensionHandler> $extensionHandlers (extension => IExtensionHandler)
 	 */
 	public function __construct(array $groups, array $extensionHandlers)
 	{
@@ -37,19 +37,13 @@ public function __construct(array $groups, array $extensionHandlers)
 	}
 
 
-	/**
-	 * @return Group[]
-	 */
-	public function getGroups()
+	public function getGroups(): array
 	{
 		return $this->groups;
 	}
 
 
-	/**
-	 * @return IExtensionHandler[] (extension => IExtensionHandler)
-	 */
-	public function getExtensionHandlers()
+	public function getExtensionHandlers(): array
 	{
 		return $this->extensionHandlers;
 	}
diff --git a/src/Configurations/DefaultConfiguration.php b/src/Configurations/DefaultConfiguration.php
index 12fbacd..fc71bbb 100644
--- a/src/Configurations/DefaultConfiguration.php
+++ b/src/Configurations/DefaultConfiguration.php
@@ -33,29 +33,26 @@ class DefaultConfiguration implements IConfiguration
 	/** @var bool */
 	protected $withDummyData;
 
-	/** @var array */
+	/** @var array<string, mixed> */
 	protected $phpParams;
 
-	/** @var Group[] */
+	/** @var list<Group> */
 	protected $groups;
 
-	/** @var IExtensionHandler[] */
+	/** @var array<string, IExtensionHandler> */
 	protected $handlers;
 
-	/** @var IDiffGenerator|NULL */
+	/** @var ?IDiffGenerator */
 	protected $structureDiffGenerator;
 
-	/** @var IDiffGenerator|NULL */
+	/** @var ?IDiffGenerator */
 	protected $dummyDataDiffGenerator;
 
 
 	/**
-	 * @param  string  $dir
-	 * @param  IDriver $driver
-	 * @param  bool    $withDummyData
-	 * @param  array   $phpParams
+	 * @param  array<string, mixed> $phpParams
 	 */
-	public function __construct($dir, IDriver $driver, $withDummyData = true, array $phpParams = [])
+	public function __construct(string $dir, IDriver $driver, bool $withDummyData = true, array $phpParams = [])
 	{
 		$this->dir = $dir;
 		$this->driver = $driver;
@@ -64,10 +61,7 @@ public function __construct($dir, IDriver $driver, $withDummyData = true, array
 	}
 
 
-	/**
-	 * @return Group[]
-	 */
-	public function getGroups()
+	public function getGroups(): array
 	{
 		if ($this->groups === null) {
 			$structures = new Group();
@@ -97,10 +91,7 @@ public function getGroups()
 	}
 
 
-	/**
-	 * @return array|IExtensionHandler[] (extension => IExtensionHandler)
-	 */
-	public function getExtensionHandlers()
+	public function getExtensionHandlers(): array
 	{
 		if ($this->handlers === null) {
 			$this->handlers = [
@@ -113,21 +104,13 @@ public function getExtensionHandlers()
 	}
 
 
-	/**
-	 * @param  IDiffGenerator|NULL $generator
-	 * @return void
-	 */
-	public function setStructureDiffGenerator(IDiffGenerator $generator = null)
+	public function setStructureDiffGenerator(?IDiffGenerator $generator = null): void
 	{
 		$this->structureDiffGenerator = $generator;
 	}
 
 
-	/**
-	 * @param  IDiffGenerator|NULL $generator
-	 * @return void
-	 */
-	public function setDummyDataDiffGenerator(IDiffGenerator $generator = null)
+	public function setDummyDataDiffGenerator(?IDiffGenerator $generator = null): void
 	{
 		$this->dummyDataDiffGenerator = $generator;
 	}
diff --git a/src/Controllers/BaseController.php b/src/Controllers/BaseController.php
index 9fc20bf..2295c10 100644
--- a/src/Controllers/BaseController.php
+++ b/src/Controllers/BaseController.php
@@ -13,6 +13,7 @@
 use Nextras\Migrations\Entities\Group;
 use Nextras\Migrations\IDriver;
 use Nextras\Migrations\IExtensionHandler;
+use Nextras\Migrations\IPrinter;
 
 
 abstract class BaseController
@@ -23,7 +24,7 @@ abstract class BaseController
 	/** @var string */
 	protected $mode;
 
-	/** @var array (name => Group) */
+	/** @var array<string, Group> (name => Group) */
 	protected $groups;
 
 
@@ -36,10 +37,13 @@ public function __construct(IDriver $driver)
 	}
 
 
-	abstract public function run();
+	abstract public function run(): void;
 
 
-	public function addGroup($name, $dir, array $dependencies = [])
+    /**
+     * @param  list<string>  $dependencies
+     */
+	public function addGroup(string $name, string $dir, array $dependencies = []): self
 	{
 		$group = new Group;
 		$group->name = $name;
@@ -52,32 +56,38 @@ public function addGroup($name, $dir, array $dependencies = [])
 	}
 
 
-	public function addExtension($extension, IExtensionHandler $handler)
+	public function addExtension(string $extension, IExtensionHandler $handler): self
 	{
 		$this->runner->addExtensionHandler($extension, $handler);
 		return $this;
 	}
 
 
-	protected function registerGroups()
+    /**
+     * @return list<string>
+     */
+	protected function registerGroups(): array
 	{
 		$enabled = [];
+
 		foreach ($this->groups as $group) {
 			$this->runner->addGroup($group);
+
 			if ($group->enabled) {
 				$enabled[] = $group->name;
 			}
 		}
+
 		return $enabled;
 	}
 
 
-	protected function setupPhp()
+	protected function setupPhp(): void
 	{
 		@set_time_limit(0);
 		@ini_set('memory_limit', '1G');
 	}
 
 
-	abstract protected function createPrinter();
+	abstract protected function createPrinter(): IPrinter;
 }
diff --git a/src/Controllers/ConsoleController.php b/src/Controllers/ConsoleController.php
index 3f4dde7..08a8caf 100644
--- a/src/Controllers/ConsoleController.php
+++ b/src/Controllers/ConsoleController.php
@@ -10,12 +10,13 @@
 namespace Nextras\Migrations\Controllers;
 
 use Nextras\Migrations\Engine;
+use Nextras\Migrations\IPrinter;
 use Nextras\Migrations\Printers;
 
 
 class ConsoleController extends BaseController
 {
-	public function run()
+	public function run(): void
 	{
 		$this->processArguments();
 		$this->printHeader();
@@ -24,7 +25,7 @@ public function run()
 	}
 
 
-	private function printHeader()
+	private function printHeader(): void
 	{
 		if ($this->mode === Engine\Runner::MODE_INIT) {
 			printf("-- Migrations init\n");
@@ -35,7 +36,7 @@ private function printHeader()
 	}
 
 
-	private function processArguments()
+	private function processArguments(): void
 	{
 		$arguments = array_slice($_SERVER['argv'], 1);
 		$help = count($arguments) === 0;
@@ -88,7 +89,7 @@ private function processArguments()
 	}
 
 
-	protected function createPrinter()
+	protected function createPrinter(): IPrinter
 	{
 		return new Printers\Console();
 	}
diff --git a/src/Controllers/HttpController.php b/src/Controllers/HttpController.php
index 8176a55..8857f1e 100644
--- a/src/Controllers/HttpController.php
+++ b/src/Controllers/HttpController.php
@@ -10,6 +10,7 @@
 namespace Nextras\Migrations\Controllers;
 
 use Nextras\Migrations\Engine;
+use Nextras\Migrations\IPrinter;
 use Nextras\Migrations\Printers;
 
 
@@ -22,14 +23,14 @@ class HttpController extends BaseController
 	private $error;
 
 
-	public function run()
+	public function run(): void
 	{
 		$this->processArguments();
 		$this->executeAction();
 	}
 
 
-	private function processArguments()
+	private function processArguments(): void
 	{
 		if (isset($_GET['action'])) {
 			if ($_GET['action'] === 'run' || $_GET['action'] === 'css') {
@@ -87,14 +88,14 @@ private function processArguments()
 	}
 
 
-	private function executeAction()
+	private function executeAction(): void
 	{
 		$method = 'action' . ucfirst($this->action);
 		$this->$method();
 	}
 
 
-	private function actionIndex()
+	private function actionIndex(): void
 	{
 		$combinations = $this->getGroupsCombinations();
 		$this->printHeader();
@@ -122,7 +123,7 @@ private function actionIndex()
 	}
 
 
-	private function actionRun()
+	private function actionRun(): void
 	{
 		$groups = $this->registerGroups();
 		$groups = implode(' + ', $groups);
@@ -135,14 +136,14 @@ private function actionRun()
 	}
 
 
-	private function actionCss()
+	private function actionCss(): void
 	{
 		header('Content-Type: text/css', true);
 		readfile(__DIR__ . '/templates/main.css');
 	}
 
 
-	private function actionError()
+	private function actionError(): void
 	{
 		$this->printHeader();
 		echo "<h1>Migrations – error</h1>\n";
@@ -150,7 +151,10 @@ private function actionError()
 	}
 
 
-	private function getGroupsCombinations()
+    /**
+     * @return list<list<string>>
+     */
+	private function getGroupsCombinations(): array
 	{
 		$groups = [];
 		$index = 1;
@@ -183,13 +187,13 @@ private function getGroupsCombinations()
 	}
 
 
-	private function printHeader()
+	private function printHeader(): void
 	{
 		readfile(__DIR__ . '/templates/header.phtml');
 	}
 
 
-	protected function createPrinter()
+	protected function createPrinter(): IPrinter
 	{
 		return new Printers\HtmlDump();
 	}
diff --git a/src/Drivers/BaseDriver.php b/src/Drivers/BaseDriver.php
index 508edbe..6c942d7 100644
--- a/src/Drivers/BaseDriver.php
+++ b/src/Drivers/BaseDriver.php
@@ -31,18 +31,14 @@ abstract class BaseDriver implements IDriver
 	protected $tableNameQuoted;
 
 
-	/**
-	 * @param  IDbal  $dbal
-	 * @param  string $tableName
-	 */
-	public function __construct(IDbal $dbal, $tableName = 'migrations')
+	public function __construct(IDbal $dbal, string $tableName = 'migrations')
 	{
 		$this->dbal = $dbal;
 		$this->tableName = $tableName;
 	}
 
 
-	public function setupConnection()
+	public function setupConnection(): void
 	{
 		$this->tableNameQuoted = $this->dbal->escapeIdentifier($this->tableName);
 	}
@@ -56,11 +52,8 @@ public function setupConnection()
 	 * @author   Michael Moravec
 	 * @author   Jan Skrasek
 	 * @license  Apache License
-	 *
-	 * @param  string $path
-	 * @return int number of executed queries
 	 */
-	public function loadFile($path)
+	public function loadFile(string $path): int
 	{
 		$content = @file_get_contents($path);
 		if ($content === false) {
@@ -103,7 +96,7 @@ public function loadFile($path)
 					break;
 
 				} elseif ($found) { // find matching quote or comment end
-					$endRe = isset($endReTable[$found]) ? $endReTable[$found] : '(' . (preg_match('~^-- |^#~', $found) ? "\n" : preg_quote($found) . "|\\\\.") . '|\z)s';
+					$endRe = $endReTable[$found] ?? '(' . (preg_match('~^-- |^#~', $found) ? "\n" : preg_quote($found) . "|\\\\.") . '|\z)s';
 					while (preg_match($endRe, $content, $match, PREG_OFFSET_CAPTURE, $parseOffset)) { //! respect sql_mode NO_BACKSLASH_ESCAPES
 						$s = $match[0][0];
 						if (strlen($s) === 0) {
diff --git a/src/Drivers/MySqlDriver.php b/src/Drivers/MySqlDriver.php
index 8130539..0534380 100644
--- a/src/Drivers/MySqlDriver.php
+++ b/src/Drivers/MySqlDriver.php
@@ -22,7 +22,10 @@
  */
 class MySqlDriver extends BaseDriver implements IDriver
 {
-	public function setupConnection()
+	private const LOCK_NAME = 'Nextras.Migrations';
+
+
+	public function setupConnection(): void
 	{
 		parent::setupConnection();
 		$this->dbal->exec('SET NAMES "utf8mb4"');
@@ -32,7 +35,7 @@ public function setupConnection()
 	}
 
 
-	public function emptyDatabase()
+	public function emptyDatabase(): void
 	{
 		$rows = $this->dbal->query('SELECT DATABASE() AS `name`');
 		$dbName = $this->dbal->escapeIdentifier($rows[0]['name']);
@@ -46,25 +49,25 @@ public function emptyDatabase()
 	}
 
 
-	public function beginTransaction()
+	public function beginTransaction(): void
 	{
 		$this->dbal->exec('START TRANSACTION');
 	}
 
 
-	public function commitTransaction()
+	public function commitTransaction(): void
 	{
 		$this->dbal->exec('COMMIT');
 	}
 
 
-	public function rollbackTransaction()
+	public function rollbackTransaction(): void
 	{
 		$this->dbal->exec('ROLLBACK');
 	}
 
 
-	public function lock()
+	public function lock(): void
 	{
 		$lock = $this->dbal->escapeString(self::LOCK_NAME);
 		$result = (int) $this->dbal->query("SELECT GET_LOCK(SHA1(CONCAT($lock, '-', DATABASE())), 3) AS `result`")[0]['result'];
@@ -74,7 +77,7 @@ public function lock()
 	}
 
 
-	public function unlock()
+	public function unlock(): void
 	{
 		$lock = $this->dbal->escapeString(self::LOCK_NAME);
 		$result = (int) $this->dbal->query("SELECT RELEASE_LOCK(SHA1(CONCAT($lock, '-', DATABASE()))) AS `result`")[0]['result'];
@@ -84,19 +87,19 @@ public function unlock()
 	}
 
 
-	public function createTable()
+	public function createTable(): void
 	{
 		$this->dbal->exec($this->getInitTableSource());
 	}
 
 
-	public function dropTable()
+	public function dropTable(): void
 	{
 		$this->dbal->exec("DROP TABLE {$this->tableNameQuoted}");
 	}
 
 
-	public function insertMigration(Migration $migration)
+	public function insertMigration(Migration $migration): void
 	{
 		$this->dbal->exec("
 			INSERT INTO {$this->tableNameQuoted}
@@ -113,7 +116,7 @@ public function insertMigration(Migration $migration)
 	}
 
 
-	public function markMigrationAsReady(Migration $migration)
+	public function markMigrationAsReady(Migration $migration): void
 	{
 		$this->dbal->exec("
 			UPDATE {$this->tableNameQuoted}
@@ -123,7 +126,7 @@ public function markMigrationAsReady(Migration $migration)
 	}
 
 
-	public function getAllMigrations()
+	public function getAllMigrations(): array
 	{
 		$migrations = [];
 		$result = $this->dbal->query("SELECT * FROM {$this->tableNameQuoted} ORDER BY `executed`");
@@ -153,7 +156,7 @@ public function getAllMigrations()
 	}
 
 
-	public function getInitTableSource()
+	public function getInitTableSource(): string
 	{
 		return preg_replace('#^\t{3}#m', '', trim("
 			CREATE TABLE IF NOT EXISTS {$this->tableNameQuoted} (
@@ -170,7 +173,7 @@ public function getInitTableSource()
 	}
 
 
-	public function getInitMigrationsSource(array $files)
+	public function getInitMigrationsSource(array $files): string
 	{
 		$out = '';
 		foreach ($files as $file) {
diff --git a/src/Drivers/PgSqlDriver.php b/src/Drivers/PgSqlDriver.php
index 398ba79..acb4905 100644
--- a/src/Drivers/PgSqlDriver.php
+++ b/src/Drivers/PgSqlDriver.php
@@ -30,51 +30,46 @@ class PgSqlDriver extends BaseDriver implements IDriver
 	protected $schemaQuoted;
 
 
-	/**
-	 * @param  IDbal  $dbal
-	 * @param  string $tableName
-	 * @param  string $schema
-	 */
-	public function __construct(IDbal $dbal, $tableName = 'migrations', $schema = 'public')
+	public function __construct(IDbal $dbal, string $tableName = 'migrations', string $schema = 'public')
 	{
 		parent::__construct($dbal, $tableName);
 		$this->schema = $schema;
 	}
 
 
-	public function setupConnection()
+	public function setupConnection(): void
 	{
 		parent::setupConnection();
 		$this->schemaQuoted = $this->dbal->escapeIdentifier($this->schema);
 	}
 
 
-	public function emptyDatabase()
+	public function emptyDatabase(): void
 	{
 		$this->dbal->exec("DROP SCHEMA IF EXISTS {$this->schemaQuoted} CASCADE");
 		$this->dbal->exec("CREATE SCHEMA {$this->schemaQuoted}");
 	}
 
 
-	public function beginTransaction()
+	public function beginTransaction(): void
 	{
 		$this->dbal->exec('START TRANSACTION');
 	}
 
 
-	public function commitTransaction()
+	public function commitTransaction(): void
 	{
 		$this->dbal->exec('COMMIT');
 	}
 
 
-	public function rollbackTransaction()
+	public function rollbackTransaction(): void
 	{
 		$this->dbal->exec('ROLLBACK');
 	}
 
 
-	public function lock()
+	public function lock(): void
 	{
 		try {
 			$this->dbal->exec('SELECT pg_advisory_lock(-2099128779216184107)');
@@ -85,7 +80,7 @@ public function lock()
 	}
 
 
-	public function unlock()
+	public function unlock(): void
 	{
 		try {
 			$this->dbal->exec('SELECT pg_advisory_unlock(-2099128779216184107)');
@@ -96,19 +91,19 @@ public function unlock()
 	}
 
 
-	public function createTable()
+	public function createTable(): void
 	{
 		$this->dbal->exec($this->getInitTableSource());
 	}
 
 
-	public function dropTable()
+	public function dropTable(): void
 	{
 		$this->dbal->exec("DROP TABLE {$this->schemaQuoted}.{$this->tableNameQuoted}");
 	}
 
 
-	public function insertMigration(Migration $migration)
+	public function insertMigration(Migration $migration): void
 	{
 		$rows = $this->dbal->query("
 			INSERT INTO {$this->schemaQuoted}.{$this->tableNameQuoted}" . '
@@ -126,7 +121,7 @@ public function insertMigration(Migration $migration)
 	}
 
 
-	public function markMigrationAsReady(Migration $migration)
+	public function markMigrationAsReady(Migration $migration): void
 	{
 		$this->dbal->exec("
 			UPDATE {$this->schemaQuoted}.{$this->tableNameQuoted}" . '
@@ -136,7 +131,7 @@ public function markMigrationAsReady(Migration $migration)
 	}
 
 
-	public function getAllMigrations()
+	public function getAllMigrations(): array
 	{
 		$migrations = [];
 		$result = $this->dbal->query("SELECT * FROM {$this->schemaQuoted}.{$this->tableNameQuoted} ORDER BY \"executed\"");
@@ -166,7 +161,7 @@ public function getAllMigrations()
 	}
 
 
-	public function getInitTableSource()
+	public function getInitTableSource(): string
 	{
 		return preg_replace('#^\t{3}#m', '', trim("
 			CREATE TABLE IF NOT EXISTS {$this->schemaQuoted}.{$this->tableNameQuoted} (" . '
@@ -183,7 +178,7 @@ public function getInitTableSource()
 	}
 
 
-	public function getInitMigrationsSource(array $files)
+	public function getInitMigrationsSource(array $files): string
 	{
 		$out = '';
 		foreach ($files as $file) {
diff --git a/src/Engine/Finder.php b/src/Engine/Finder.php
index 9a1b552..0687864 100644
--- a/src/Engine/Finder.php
+++ b/src/Engine/Finder.php
@@ -21,12 +21,12 @@ class Finder
 	/**
 	 * Finds files.
 	 *
-	 * @param  Group[]  $groups
-	 * @param  string[] $extensions
-	 * @return File[]
+	 * @param  list<Group>  $groups
+	 * @param  list<string> $extensions
+	 * @return list<File>
 	 * @throws Exception
 	 */
-	public function find(array $groups, array $extensions)
+	public function find(array $groups, array $extensions): array
 	{
 		$files = [];
 		foreach ($groups as $group) {
@@ -53,9 +53,8 @@ public function find(array $groups, array $extensions)
 	 * Returns logical name of migration file.
 	 *
 	 * @param  string $path relative path to group directory
-	 * @return string
 	 */
-	protected function getName($path)
+	protected function getName(string $path): string
 	{
 		$parts = explode('/', $path);
 		$dirName = implode('-', array_slice($parts, 0, -1));
@@ -68,12 +67,10 @@ protected function getName($path)
 	/**
 	 * Returns file extension.
 	 *
-	 * @param  File     $file
-	 * @param  string[] $extensions
-	 * @return string
+	 * @param  list<string> $extensions
 	 * @throws Exception
 	 */
-	protected function getExtension(File $file, array $extensions)
+	protected function getExtension(File $file, array $extensions): string
 	{
 		$fileExt = null;
 
@@ -102,11 +99,7 @@ protected function getExtension(File $file, array $extensions)
 	}
 
 
-	/**
-	 * @param  File $file
-	 * @return string
-	 */
-	protected function getChecksum(File $file)
+	protected function getChecksum(File $file): string
 	{
 		$content = @file_get_contents($file->path);
 		if ($content === false) {
@@ -118,11 +111,10 @@ protected function getChecksum(File $file)
 
 
 	/**
-	 * @param  string $dir
-	 * @return string[]
+	 * @return list<string>
 	 * @throws IOException
 	 */
-	protected function getFilesRecursive($dir)
+	protected function getFilesRecursive(string $dir): array
 	{
 		$items = $this->getItems($dir);
 		foreach ($items as $i => $item) {
@@ -144,10 +136,9 @@ protected function getFilesRecursive($dir)
 
 
 	/**
-	 * @param  string $dir
-	 * @return array
+	 * @return list<string>
 	 */
-	protected function getItems($dir)
+	protected function getItems(string $dir): array
 	{
 		return @scandir($dir) ?: []; // directory may not exist
 	}
diff --git a/src/Engine/OrderResolver.php b/src/Engine/OrderResolver.php
index 1a13768..0f77c18 100644
--- a/src/Engine/OrderResolver.php
+++ b/src/Engine/OrderResolver.php
@@ -18,14 +18,13 @@
 class OrderResolver
 {
 	/**
-	 * @param  Migration[] $migrations
-	 * @param  Group[]     $groups
-	 * @param  File[]      $files
-	 * @param  string      $mode
-	 * @return File[]
+	 * @param  list<Migration> $migrations
+	 * @param  list<Group>     $groups
+	 * @param  list<File>      $files
+	 * @return list<File>
 	 * @throws LogicException
 	 */
-	public function resolve(array $migrations, array $groups, array $files, $mode)
+	public function resolve(array $migrations, array $groups, array $files, string $mode): array
 	{
 		$groups = $this->getAssocGroups($groups);
 		$this->validateGroups($groups);
@@ -107,13 +106,13 @@ public function resolve(array $migrations, array $groups, array $files, $mode)
 
 
 	/**
-	 * @param  File[] $files
-	 * @param  array  $groups (name => Group)
-	 * @return File[] sorted
+	 * @param  list<File> $files
+	 * @param  array<string, Group>  $groups (name => Group)
+	 * @return list<File> sorted
 	 */
-	protected function sortFiles(array $files, array $groups)
+	protected function sortFiles(array $files, array $groups): array
 	{
-		usort($files, function (File $a, File $b) use ($groups) {
+		usort($files, function (File $a, File $b) use ($groups): int {
 			$cmp = strcmp($a->name, $b->name);
 			if ($cmp === 0 && $a !== $b) {
 				$cmpA = $this->isGroupDependentOn($groups, $a->group, $b->group);
@@ -144,16 +143,14 @@ protected function sortFiles(array $files, array $groups)
 	/**
 	 * Returns true if groupA depends on groupB.
 	 *
-	 * @param  array $groups (name => Group)
-	 * @param  Group $groupA
-	 * @param  Group $groupB
-	 * @return bool
+	 * @param  array<string, Group> $groups (name => Group)
 	 */
-	protected function isGroupDependentOn(array $groups, Group $groupA, Group $groupB)
+	protected function isGroupDependentOn(array $groups, Group $groupA, Group $groupB): bool
 	{
 		$visited = [];
 		$queue = $groupB->dependencies;
 		$queue[] = $groupB->name;
+
 		while ($node = array_shift($queue)) {
 			if (isset($visited[$node])) {
 				continue;
@@ -168,74 +165,100 @@ protected function isGroupDependentOn(array $groups, Group $groupA, Group $group
 				$queue[] = $dep;
 			}
 		}
+
 		return false;
 	}
 
 
-	protected function getAssocMigrations(array $migrations)
+    /**
+     * @param  list<Migration> $migrations
+     * @return array<string, array<string, Migration>> (group => (filename => Migration))
+     */
+	protected function getAssocMigrations(array $migrations): array
 	{
 		$assoc = [];
+
 		foreach ($migrations as $migration) {
 			$assoc[$migration->group][$migration->filename] = $migration;
 		}
+
 		return $assoc;
 	}
 
 
-	protected function getAssocGroups(array $groups)
+    /**
+     * @param  list<Group> $groups
+     * @return array<string, Group> (name => Group)
+     */
+	protected function getAssocGroups(array $groups): array
 	{
 		$assoc = [];
+
 		foreach ($groups as $group) {
 			$assoc[$group->name] = $group;
 		}
+
 		return $assoc;
 	}
 
 
-	protected function getAssocFiles(array $files)
+    /**
+     * @param  list<File> $files
+     * @return array<string, array<string, File>> (group => (filename => File))
+     */
+	protected function getAssocFiles(array $files): array
 	{
 		$assoc = [];
+
 		foreach ($files as $file) {
 			$assoc[$file->group->name][$file->name] = $file;
 		}
+
 		return $assoc;
 	}
 
 
-	protected function getFlatFiles(array $files)
+    /**
+     * @param  array<string, array<string, File>> $files
+     * @return list<File>
+     */
+	protected function getFlatFiles(array $files): array
 	{
 		$flat = [];
+
 		foreach ($files as $tmp) {
 			foreach ($tmp as $file) {
 				$flat[] = $file;
 			}
 		}
+
 		return $flat;
 	}
 
 
 	/**
-	 * @param  File[] $files
-	 * @return File[] first file for each group
+	 * @param  list<File> $files
+	 * @return array<string, File> (group => File)
 	 */
-	protected function getFirstFiles(array $files)
+	protected function getFirstFiles(array $files): array
 	{
 		$firstFiles = [];
+
 		foreach ($files as $file) {
 			if (!isset($firstFiles[$file->group->name])) {
 				$firstFiles[$file->group->name] = $file;
 			}
 		}
+
 		return $firstFiles;
 	}
 
 
 	/**
-	 * @param  Group[] $groups
-	 * @return void
+	 * @param  array<Group> $groups
 	 * @throws LogicException
 	 */
-	private function validateGroups(array $groups)
+	private function validateGroups(array $groups): void
 	{
 		foreach ($groups as $group) {
 			foreach ($group->dependencies as $dependency) {
diff --git a/src/Engine/Runner.php b/src/Engine/Runner.php
index 1101870..5e49e31 100644
--- a/src/Engine/Runner.php
+++ b/src/Engine/Runner.php
@@ -33,10 +33,10 @@ class Runner
 	/** @var IPrinter */
 	private $printer;
 
-	/** @var array (extension => IExtensionHandler) */
+	/** @var array<string, IExtensionHandler> (extension => IExtensionHandler) */
 	private $extensionsHandlers = [];
 
-	/** @var Group[] */
+	/** @var list<Group> */
 	private $groups = [];
 
 	/** @var IDriver */
@@ -58,19 +58,14 @@ public function __construct(IDriver $driver, IPrinter $printer)
 	}
 
 
-	public function addGroup(Group $group)
+	public function addGroup(Group $group): self
 	{
 		$this->groups[] = $group;
 		return $this;
 	}
 
 
-	/**
-	 * @param  string            $extension
-	 * @param  IExtensionHandler $handler
-	 * @return self
-	 */
-	public function addExtensionHandler($extension, IExtensionHandler $handler)
+	public function addExtensionHandler(string $extension, IExtensionHandler $handler): self
 	{
 		if (isset($this->extensionsHandlers[$extension])) {
 			throw new LogicException("Extension '$extension' has already been defined.");
@@ -82,11 +77,9 @@ public function addExtensionHandler($extension, IExtensionHandler $handler)
 
 
 	/**
-	 * @param  string         $mode self::MODE_CONTINUE|self::MODE_RESET|self::MODE_INIT
-	 * @param  IConfiguration $config
-	 * @return void
+	 * @param  self::MODE_*   $mode
 	 */
-	public function run($mode = self::MODE_CONTINUE, IConfiguration $config = null)
+	public function run(string $mode = self::MODE_CONTINUE, ?IConfiguration $config = null): void
 	{
 		if ($config) {
 			foreach ($config->getGroups() as $group) {
@@ -142,24 +135,20 @@ public function run($mode = self::MODE_CONTINUE, IConfiguration $config = null)
 	}
 
 
-	/**
-	 * @param  string $name
-	 * @return IExtensionHandler
-	 */
-	public function getExtension($name)
+	public function getExtension(string $name): IExtensionHandler
 	{
 		if (!isset($this->extensionsHandlers[$name])) {
 			throw new LogicException("Extension '$name' not found.");
 		}
+
 		return $this->extensionsHandlers[$name];
 	}
 
 
 	/**
-	 * @param  File $file
 	 * @return int  number of executed queries
 	 */
-	protected function execute(File $file)
+	protected function execute(File $file): int
 	{
 		$this->driver->beginTransaction();
 
@@ -173,6 +162,7 @@ protected function execute(File $file)
 
 		try {
 			$queriesCount = $this->getExtension($file->extension)->execute($file);
+
 		} catch (\Exception $e) {
 			$this->driver->rollbackTransaction();
 			throw new ExecutionException(sprintf('Executing migration "%s" has failed.', $file->path), 0, $e);
diff --git a/src/Entities/Group.php b/src/Entities/Group.php
index 00fc2e4..146db30 100644
--- a/src/Entities/Group.php
+++ b/src/Entities/Group.php
@@ -26,7 +26,7 @@ class Group
 	/** @var string absolute path do directory */
 	public $directory;
 
-	/** @var string[] */
+	/** @var list<string> */
 	public $dependencies;
 
 	/** @var IDiffGenerator|null */
diff --git a/src/Extensions/PhpHandler.php b/src/Extensions/PhpHandler.php
index 2f77a6c..08ab3a7 100644
--- a/src/Extensions/PhpHandler.php
+++ b/src/Extensions/PhpHandler.php
@@ -20,12 +20,12 @@
  */
 class PhpHandler implements IExtensionHandler
 {
-	/** @var array name => value */
+	/** @var array<string, mixed> name => value */
 	private $params;
 
 
 	/**
-	 * @param  array $params name => value
+	 * @param  array<string, mixed> $params (name => value)
 	 */
 	public function __construct(array $params = [])
 	{
@@ -34,11 +34,9 @@ public function __construct(array $params = [])
 
 
 	/**
-	 * @param  string $name
 	 * @param  mixed  $value
-	 * @return self
 	 */
-	public function addParameter($name, $value)
+	public function addParameter(string $name, $value): self
 	{
 		$this->params[$name] = $value;
 		return $this;
@@ -46,25 +44,23 @@ public function addParameter($name, $value)
 
 
 	/**
-	 * @return array (name => value)
+	 * @return array<string, mixed> (name => value)
 	 */
-	public function getParameters()
+	public function getParameters(): array
 	{
 		return $this->params;
 	}
 
 
-	/**
-	 * @param  File $file
-	 * @return int number of queries
-	 */
-	public function execute(File $file)
+	public function execute(File $file): int
 	{
 		extract($this->params, EXTR_SKIP);
 		$count = @include $file->path;
+
 		if ($count === false) {
 			throw new IOException("Cannot include file '{$file->path}'.");
 		}
+
 		return $count;
 	}
 }
diff --git a/src/Extensions/SqlHandler.php b/src/Extensions/SqlHandler.php
index 6996ea2..7eb61ab 100644
--- a/src/Extensions/SqlHandler.php
+++ b/src/Extensions/SqlHandler.php
@@ -24,25 +24,20 @@ class SqlHandler implements IExtensionHandler
 	private $driver;
 
 
-	/**
-	 * @param  IDriver $driver
-	 */
 	public function __construct(IDriver $driver)
 	{
 		$this->driver = $driver;
 	}
 
 
-	/**
-	 * @param  File $file
-	 * @return int number of queries
-	 */
-	public function execute(File $file)
+	public function execute(File $file): int
 	{
 		$count = $this->driver->loadFile($file->path);
+
 		if ($count === 0) {
 			throw new LogicException("{$file->path} is empty");
 		}
+
 		return $count;
 	}
 }
diff --git a/src/IConfiguration.php b/src/IConfiguration.php
index c354ea4..436367d 100644
--- a/src/IConfiguration.php
+++ b/src/IConfiguration.php
@@ -18,13 +18,13 @@
 interface IConfiguration
 {
 	/**
-	 * @return Group[]
+	 * @return list<Group>
 	 */
-	public function getGroups();
+	public function getGroups(): array;
 
 
 	/**
-	 * @return array (extension => IExtensionHandler)
+	 * @return array<string, IExtensionHandler> (extension => IExtensionHandler)
 	 */
-	public function getExtensionHandlers();
+	public function getExtensionHandlers(): array;
 }
diff --git a/src/IDbal.php b/src/IDbal.php
index b020e53..2c5a4e4 100644
--- a/src/IDbal.php
+++ b/src/IDbal.php
@@ -9,7 +9,7 @@
 
 namespace Nextras\Migrations;
 
-use DateTime;
+use DateTimeInterface;
 
 
 /**
@@ -18,51 +18,28 @@
 interface IDbal
 {
 	/**
-	 * @param  string $sql
-	 * @return array list of rows represented by assoc. arrays
+	 * @return array<int, array<string, mixed>> list of rows represented by assoc. arrays
 	 */
-	function query($sql);
+	public function query(string $sql): array;
 
 
 	/**
-	 * @param  string $sql
 	 * @return int number of affected rows
 	 */
-	function exec($sql);
+	public function exec(string $sql): int;
 
 
-	/**
-	 * @param  string $value
-	 * @return string escaped string wrapped in quotes
-	 */
-	function escapeString($value);
+	public function escapeString(string $value): string;
 
 
-	/**
-	 * @param  int $value
-	 * @return string
-	 */
-	function escapeInt($value);
+	public function escapeInt(int $value): string;
 
 
-	/**
-	 * @param  bool $value
-	 * @return string
-	 */
-	function escapeBool($value);
+	public function escapeBool(bool $value): string;
 
 
-	/**
-	 * @param  DateTime $value
-	 * @return string
-	 */
-	function escapeDateTime(DateTime $value);
-
+	public function escapeDateTime(DateTimeInterface $value): string;
 
-	/**
-	 * @param  string $value
-	 * @return string
-	 */
-	function escapeIdentifier($value);
 
+	public function escapeIdentifier(string $value): string;
 }
diff --git a/src/IDiffGenerator.php b/src/IDiffGenerator.php
index 605a1d6..2ecb2f4 100644
--- a/src/IDiffGenerator.php
+++ b/src/IDiffGenerator.php
@@ -12,15 +12,14 @@
 
 interface IDiffGenerator
 {
-
 	/**
-	 * @return string
+	 * @return string file extension
 	 */
-	function getExtension();
+	public function getExtension(): string;
 
 
 	/**
 	 * @return string SQL (semicolon-separated queries)
 	 */
-	function generateContent();
+	public function generateContent(): string;
 }
diff --git a/src/IDriver.php b/src/IDriver.php
index 0c96b81..67740e0 100644
--- a/src/IDriver.php
+++ b/src/IDriver.php
@@ -18,112 +18,98 @@
  */
 interface IDriver
 {
-	/** @const shared lock identifier */
-	const LOCK_NAME = 'Nextras.Migrations';
-
-
 	/**
 	 * Setups the connection, such as encoding, default schema, etc.
 	 */
-	function setupConnection();
+	public function setupConnection(): void;
 
 
 	/**
-	 * Drops the database / schema. Should removes all db objects (tables, views, procedures, sequences, ...)
-	 *
-	 * @return mixed
+	 * Drops the database / schema. Should remove all db objects (tables, views, procedures, sequences, ...)
 	 */
-	function emptyDatabase();
+	public function emptyDatabase(): void;
 
 
 	/**
 	 * Loads and executes SQL queries from given file.
 	 *
-	 * @param  string $path
 	 * @return int number of executed queries
 	 */
-	function loadFile($path);
+	public function loadFile(string $path): int;
 
 
 	/**
 	 * Starts transaction.
 	 */
-	function beginTransaction();
+	public function beginTransaction(): void;
 
 
 	/**
 	 * Commit transaction.
 	 */
-	function commitTransaction();
+	public function commitTransaction(): void;
 
 
 	/**
 	 * Rollback transaction.
 	 */
-	function rollbackTransaction();
+	public function rollbackTransaction(): void;
 
 
 	/**
 	 * Locks database for running migrations.
 	 */
-	function lock();
+	public function lock(): void;
 
 
 	/**
 	 * Unlocks database.
 	 */
-	function unlock();
+	public function unlock(): void;
 
 
 	/**
 	 * Creates migration table.
 	 */
-	function createTable();
+	public function createTable(): void;
 
 
 	/**
 	 * Drop migration table.
 	 */
-	function dropTable();
+	public function dropTable(): void;
 
 
 	/**
 	 * Inserts migration info into migration table.
-	 *
-	 * @param  Migration $migration
 	 */
-	function insertMigration(Migration $migration);
+	public function insertMigration(Migration $migration): void;
 
 
 	/**
 	 * Updated migration as executed.
-	 *
-	 * @param  Migration $migration
 	 */
-	function markMigrationAsReady(Migration $migration);
+	public function markMigrationAsReady(Migration $migration): void;
 
 
 	/**
 	 * Returns all migrations stored in migration table sorted by time.
 	 *
-	 * @return Migration[]
+	 * @return list<Migration>
 	 */
-	function getAllMigrations();
+	public function getAllMigrations(): array;
 
 
 	/**
 	 * Returns source code for migration table initialization.
-	 *
-	 * @return string
 	 */
-	function getInitTableSource();
+	public function getInitTableSource(): string;
 
 
 	/**
 	 * Returns source code for migration table data initialization.
 	 *
-	 * @param  File[] $files
-	 * @return string
+	 * @param  list<File> $files
 	 */
-	function getInitMigrationsSource(array $files);
+	public function getInitMigrationsSource(array $files): string;
 }
diff --git a/src/IExtensionHandler.php b/src/IExtensionHandler.php
index ea631af..12c5551 100644
--- a/src/IExtensionHandler.php
+++ b/src/IExtensionHandler.php
@@ -19,8 +19,7 @@
 interface IExtensionHandler
 {
 	/**
-	 * @param  File $file
 	 * @return int number of queries
 	 */
-	function execute(File $file);
+	public function execute(File $file): int;
 }
diff --git a/src/IPrinter.php b/src/IPrinter.php
index 1a83aae..71a11fe 100644
--- a/src/IPrinter.php
+++ b/src/IPrinter.php
@@ -18,51 +18,42 @@
 interface IPrinter
 {
 	/**
-	 * Print general info about mode.
-	 * - reset = Database has been wiped.
-	 * - continue = Running new migrations.
-	 *
-	 * @param  string $mode
+	 * Prints general info about mode.
 	 */
-	function printIntro($mode);
+	public function printIntro(string $mode): void;
 
 
 	/**
 	 * List of migrations which should be executed has been completed.
 	 *
-	 * @param  File[] $toExecute
+	 * @param  list<File> $toExecute
 	 */
-	function printToExecute(array $toExecute);
+	public function printToExecute(array $toExecute): void;
 
 
 	/**
 	 * A migration has been successfully executed.
 	 *
-	 * @param  File  $file
 	 * @param  int   $count number of executed queries
-	 * @param  float $time  elapsed time in milliseconds
+	 * @param  float $time  elapsed time in seconds
 	 */
-	function printExecute(File $file, $count, $time);
+	public function printExecute(File $file, int $count, float $time): void;
 
 
 	/**
 	 * All migrations have been successfully executed.
 	 */
-	function printDone();
+	public function printDone(): void;
 
 
 	/**
 	 * An error has occurred during execution of a migration.
-	 *
-	 * @param  Exception $e
 	 */
-	function printError(Exception $e);
+	public function printError(Exception $e): void;
 
 
 	/**
 	 * Prints init source code.
-	 *
-	 * @param  string $code
 	 */
-	function printSource($code);
+	public function printSource(string $code): void;
 }
diff --git a/src/Printers/Console.php b/src/Printers/Console.php
index 4d42c72..6b52c3b 100644
--- a/src/Printers/Console.php
+++ b/src/Printers/Console.php
@@ -36,14 +36,14 @@ public function __construct()
 	}
 
 
-	public function printIntro($mode)
+	public function printIntro(string $mode): void
 	{
 		$this->output('Nextras Migrations');
 		$this->output(strtoupper($mode), self::COLOR_INTRO);
 	}
 
 
-	public function printToExecute(array $toExecute)
+	public function printToExecute(array $toExecute): void
 	{
 		if ($toExecute) {
 			$count = count($toExecute);
@@ -54,30 +54,30 @@ public function printToExecute(array $toExecute)
 	}
 
 
-	public function printExecute(File $file, $count, $time)
+	public function printExecute(File $file, int $count, float $time): void
 	{
 		$this->output(
 			'- ' . $file->group->name . '/' . $file->name . '; '
-			. $this->color($count, self::COLOR_INFO) . ' queries; '
-			. $this->color(sprintf('%0.3f', $time), self::COLOR_INFO) . ' s'
+			. $this->colorize((string) $count, self::COLOR_INFO) . ' queries; '
+			. $this->colorize(sprintf('%0.3f', $time), self::COLOR_INFO) . ' s'
 		);
 	}
 
 
-	public function printDone()
+	public function printDone(): void
 	{
 		$this->output('OK', self::COLOR_SUCCESS);
 	}
 
 
-	public function printError(Exception $e)
+	public function printError(Exception $e): void
 	{
 		$this->output('ERROR: ' . $e->getMessage(), self::COLOR_ERROR);
 		throw $e;
 	}
 
 
-	public function printSource($code)
+	public function printSource(string $code): void
 	{
 		$this->output($code);
 	}
@@ -86,41 +86,27 @@ public function printSource($code)
 	/**
 	 * Prints text to a console, optionally in a specific color.
 	 *
-	 * @param  string      $s
-	 * @param  string|NULL $color self::COLOR_*
+	 * @param  string|null $color self::COLOR_*
 	 */
-	protected function output($s, $color = null)
+	protected function output(string $s, ?string $color = null): void
 	{
-		if ($color === null || !$this->useColors) {
-			echo "$s\n";
-		} else {
-			echo $this->color($s, $color) . "\n";
-		}
+		echo $this->colorize($s, $color) . "\n";
 	}
 
 
-	/**
-	 * @param  string $s
-	 * @param  string $color
-	 * @return string
-	 */
-	protected function color($s, $color)
+	protected function colorize(string $s, ?string $color): string
 	{
-		if (!$this->useColors) {
-			return $s;
-		}
-		return "\033[{$color}m$s\033[22;39m";
+		return $this->useColors && $color !== null ? "\033[{$color}m$s\033[22;39m" : $s;
 	}
 
 
 	/**
-	 * @return  bool TRUE if terminal support colors, FALSE otherwise
-	 * @license New BSD License
-	 * @author  David Grudl
+	 * @return  bool true if terminal support colors, false otherwise
 	 */
-	protected function detectColorSupport()
+	protected function detectColorSupport(): bool
 	{
-		return (getenv('ConEmuANSI') === 'ON' || getenv('ANSICON') !== false
-			|| (defined('STDOUT') && function_exists('posix_isatty') && posix_isatty(STDOUT)));
+		return (function_exists('posix_isatty') && posix_isatty(STDOUT))
+			|| (function_exists('stream_isatty') && stream_isatty(STDOUT))
+			|| (function_exists('sapi_windows_vt100_support') && sapi_windows_vt100_support(STDOUT));
 	}
 }
diff --git a/src/Printers/DevNull.php b/src/Printers/DevNull.php
index 36a88c6..7479e97 100644
--- a/src/Printers/DevNull.php
+++ b/src/Printers/DevNull.php
@@ -21,32 +21,32 @@
  */
 class DevNull implements IPrinter
 {
-	public function printIntro($mode)
+	public function printIntro(string $mode): void
 	{
 	}
 
 
-	public function printToExecute(array $toExecute)
+	public function printToExecute(array $toExecute): void
 	{
 	}
 
 
-	public function printExecute(File $file, $count, $time)
+	public function printExecute(File $file, int $count, float $time): void
 	{
 	}
 
 
-	public function printDone()
+	public function printDone(): void
 	{
 	}
 
 
-	public function printError(Exception $e)
+	public function printError(Exception $e): void
 	{
 	}
 
 
-	public function printSource($code)
+	public function printSource(string $code): void
 	{
 	}
 }
diff --git a/src/Printers/HtmlDump.php b/src/Printers/HtmlDump.php
index 8c6b6f0..5d35d7e 100644
--- a/src/Printers/HtmlDump.php
+++ b/src/Printers/HtmlDump.php
@@ -27,7 +27,7 @@ class HtmlDump implements IPrinter
 	private $index;
 
 
-	public function printIntro($mode)
+	public function printIntro(string $mode): void
 	{
 		if ($mode === Runner::MODE_RESET) {
 			$this->output('     RESET: All tables, views and data has been destroyed!');
@@ -37,7 +37,7 @@ public function printIntro($mode)
 	}
 
 
-	public function printToExecute(array $toExecute)
+	public function printToExecute(array $toExecute): void
 	{
 		if ($toExecute) {
 			$this->output('     ' . count($toExecute) . ' migrations need to be executed.');
@@ -50,9 +50,9 @@ public function printToExecute(array $toExecute)
 	}
 
 
-	public function printExecute(File $file, $count, $time)
+	public function printExecute(File $file, int $count, float $time): void
 	{
-		$format = '%0' . strlen($this->count) . 'd';
+		$format = '%0' . strlen((string) $this->count) . 'd';
 		$name = htmlspecialchars($file->group->name . '/' . $file->name);
 		$this->output(sprintf(
 			$format . '/' . $format . ': <strong>%s</strong> (%d %s, %0.3f s)',
@@ -61,31 +61,26 @@ public function printExecute(File $file, $count, $time)
 	}
 
 
-	public function printDone()
+	public function printDone(): void
 	{
 		$this->output('OK', 'success');
 	}
 
 
-	public function printError(Exception $e)
+	public function printError(Exception $e): void
 	{
 		$this->output('ERROR: ' . htmlspecialchars($e->getMessage()), 'error');
 		throw $e;
 	}
 
 
-	public function printSource($code)
+	public function printSource(string $code): void
 	{
 		$this->output($code);
 	}
 
 
-	/**
-	 * @param  string $s HTML string
-	 * @param  string $class
-	 * @return void
-	 */
-	protected function output($s, $class = 'info')
+	protected function output(string $s, string $class = 'info'): void
 	{
 		echo "<div class=\"$class\">$s</div>\n";
 	}
diff --git a/src/exceptions.php b/src/exceptions.php
index 903bbe7..3fa3034 100644
--- a/src/exceptions.php
+++ b/src/exceptions.php
@@ -9,11 +9,13 @@
 
 namespace Nextras\Migrations;
 
+use Throwable;
+
 
 /**
  * Marker interface.
  */
-interface Exception
+interface Exception extends Throwable
 {
 }
 
diff --git a/tests/cases/integration/dbal/Runner.EmptyRun.phpt b/tests/cases/integration/dbal/Runner.EmptyRun.phpt
index 5bc1c7e..255182c 100644
--- a/tests/cases/integration/dbal/Runner.EmptyRun.phpt
+++ b/tests/cases/integration/dbal/Runner.EmptyRun.phpt
@@ -15,7 +15,7 @@ require __DIR__ . '/../../../bootstrap.php';
 
 class EmptyRunTest extends IntegrationTestCase
 {
-	public function testReset()
+	public function testReset(): void
 	{
 		$this->runner->run(Runner::MODE_RESET);
 		Assert::same([
@@ -29,7 +29,7 @@ class EmptyRunTest extends IntegrationTestCase
 	}
 
 
-	protected function getGroups($dir)
+	protected function getGroups(string $dir): array
 	{
 		return [];
 	}
diff --git a/tests/cases/integration/dbal/Runner.FirstRun.phpt b/tests/cases/integration/dbal/Runner.FirstRun.phpt
index 2051f11..dc54197 100644
--- a/tests/cases/integration/dbal/Runner.FirstRun.phpt
+++ b/tests/cases/integration/dbal/Runner.FirstRun.phpt
@@ -16,7 +16,7 @@ require __DIR__ . '/../../../bootstrap.php';
 
 class FirstRunTest extends IntegrationTestCase
 {
-	public function testReset()
+	public function testReset(): void
 	{
 		$this->runner->run(Runner::MODE_RESET);
 		Assert::same([
@@ -54,7 +54,7 @@ class FirstRunTest extends IntegrationTestCase
 	}
 
 
-	public function testContinue()
+	public function testContinue(): void
 	{
 		$this->runner->run(Runner::MODE_CONTINUE);
 		Assert::same([
@@ -92,7 +92,7 @@ class FirstRunTest extends IntegrationTestCase
 	}
 
 
-	public function testInit()
+	public function testInit(): void
 	{
 		$options = Tester\Environment::loadData();
 		$this->runner->run(Runner::MODE_INIT);
diff --git a/tests/cases/integration/dbal/Runner.SecondRun.phpt b/tests/cases/integration/dbal/Runner.SecondRun.phpt
index 0756b62..c0c5947 100644
--- a/tests/cases/integration/dbal/Runner.SecondRun.phpt
+++ b/tests/cases/integration/dbal/Runner.SecondRun.phpt
@@ -17,7 +17,7 @@ require __DIR__ . '/../../../bootstrap.php';
 
 class SecondRunTest extends IntegrationTestCase
 {
-	public function testReset()
+	public function testReset(): void
 	{
 		$this->driver->loadFile($this->fixtureDir . '/3ok.sql');
 		Assert::count(3, $this->driver->getAllMigrations());
@@ -39,7 +39,7 @@ class SecondRunTest extends IntegrationTestCase
 	}
 
 
-	public function testContinueOk()
+	public function testContinueOk(): void
 	{
 		$this->driver->loadFile($this->fixtureDir . '/3ok.sql');
 		Assert::count(3, $this->driver->getAllMigrations());
@@ -58,7 +58,7 @@ class SecondRunTest extends IntegrationTestCase
 	}
 
 
-	public function testContinueError()
+	public function testContinueError(): void
 	{
 		$this->driver->loadFile($this->fixtureDir . '/2ok, 1ko.sql');
 		Assert::count(3, $this->driver->getAllMigrations());
@@ -77,7 +77,7 @@ class SecondRunTest extends IntegrationTestCase
 	}
 
 
-	public function testInit()
+	public function testInit(): void
 	{
 		$options = Tester\Environment::loadData();
 		$this->driver->loadFile($this->fixtureDir . '/3ok.sql');
diff --git a/tests/cases/integration/nette-di/MigrationsExtension.phpt b/tests/cases/integration/nette-di/MigrationsExtension.phpt
index 0167527..80cb5d1 100644
--- a/tests/cases/integration/nette-di/MigrationsExtension.phpt
+++ b/tests/cases/integration/nette-di/MigrationsExtension.phpt
@@ -21,7 +21,7 @@ class MigrationsExtensionTest extends TestCase
 	/**
 	 * @dataProvider provideCommandsData
 	 */
-	public function testCommands($config)
+	public function testCommands(string $config): void
 	{
 		$dic = $this->createContainer($config);
 
@@ -31,7 +31,7 @@ class MigrationsExtensionTest extends TestCase
 	}
 
 
-	public function provideCommandsData()
+	public function provideCommandsData(): array
 	{
 		return [
 			['configA'],
@@ -47,7 +47,7 @@ class MigrationsExtensionTest extends TestCase
 	/**
 	 * @dataProvider provideDiffGeneratorData
 	 */
-	public function testDoctrineDiffGenerator($config)
+	public function testDoctrineDiffGenerator(string $config): void
 	{
 		$dic = $this->createContainer($config);
 
@@ -62,7 +62,7 @@ class MigrationsExtensionTest extends TestCase
 	}
 
 
-	public function provideDiffGeneratorData()
+	public function provideDiffGeneratorData(): array
 	{
 		return [
 			['diffGenerator.configA'],
@@ -71,7 +71,7 @@ class MigrationsExtensionTest extends TestCase
 	}
 
 
-	public function testDynamicContainerParameters()
+	public function testDynamicContainerParameters(): void
 	{
 		if (!method_exists(Nette\DI\Compiler::class, 'setDynamicParameterNames')) {
 			Environment::skip('Required Nette >= 2.4.7');
@@ -89,7 +89,7 @@ class MigrationsExtensionTest extends TestCase
 	}
 
 
-	public function testOptionsAsService()
+	public function testOptionsAsService(): void
 	{
 		$container = $this->createContainer('optionsAsService');
 
@@ -100,7 +100,7 @@ class MigrationsExtensionTest extends TestCase
 	}
 
 
-	public function testMultipleRegistrations()
+	public function testMultipleRegistrations(): void
 	{
 		$container = $this->createContainer('multipleRegistrations');
 
@@ -113,11 +113,7 @@ class MigrationsExtensionTest extends TestCase
 	}
 
 
-	/**
-	 * @param  string $config
-	 * @return Nette\DI\Container
-	 */
-	protected function createContainer($config, array $dynamicParameters = null)
+	protected function createContainer(string $config, array $dynamicParameters = null): Nette\DI\Container
 	{
 		$options = parse_ini_file(__DIR__ . '/../../../drivers.ini', true)['mysql'];
 
diff --git a/tests/cases/integration/symfony-bundle/SymfonyBundleTest.phpt b/tests/cases/integration/symfony-bundle/SymfonyBundleTest.phpt
index 15621af..2af253b 100644
--- a/tests/cases/integration/symfony-bundle/SymfonyBundleTest.phpt
+++ b/tests/cases/integration/symfony-bundle/SymfonyBundleTest.phpt
@@ -24,7 +24,7 @@ class SymfonyBundleTest extends TestCase
 	private $symfonyKernel;
 
 
-	protected function setUp()
+	protected function setUp(): void
 	{
 		parent::setUp();
 
@@ -48,7 +48,7 @@ class SymfonyBundleTest extends TestCase
 	}
 
 
-	public function testMigrationsReset()
+	public function testMigrationsReset(): void
 	{
 		$application = new Application($this->symfonyKernel);
 
@@ -58,7 +58,7 @@ class SymfonyBundleTest extends TestCase
 	}
 
 
-	public function testMigrationsContinue()
+	public function testMigrationsContinue(): void
 	{
 		$application = new Application($this->symfonyKernel);
 
diff --git a/tests/cases/unit/BaseDriverTest.phpt b/tests/cases/unit/BaseDriverTest.phpt
index 3ebfa19..1623d5f 100644
--- a/tests/cases/unit/BaseDriverTest.phpt
+++ b/tests/cases/unit/BaseDriverTest.phpt
@@ -19,7 +19,7 @@ class BaseDriverTest extends Tester\TestCase
 	/**
 	 * @dataProvider provideLoadFileData
 	 */
-	public function testLoadFile($content, array $expectedQueries)
+	public function testLoadFile(string $content, array $expectedQueries): void
 	{
 		$dbal = Mockery::mock(Nextras\Migrations\IDbal::class);
 		$dbal->shouldReceive('escapeIdentifier')->with('migrations')->andReturn('migrations');
@@ -38,7 +38,7 @@ class BaseDriverTest extends Tester\TestCase
 	}
 
 
-	protected function provideLoadFileData()
+	protected function provideLoadFileData(): array
 	{
 		return [
 			[
diff --git a/tests/cases/unit/CreateCommandTest.phpt b/tests/cases/unit/CreateCommandTest.phpt
index cb3da98..70065d3 100644
--- a/tests/cases/unit/CreateCommandTest.phpt
+++ b/tests/cases/unit/CreateCommandTest.phpt
@@ -18,7 +18,7 @@ require __DIR__ . '/../../bootstrap.php';
 
 class CreateCommandTest extends Tester\TestCase
 {
-	public function testTypeArgDescription()
+	public function testTypeArgDescription(): void
 	{
 		$driver = Mockery::mock(Nextras\Migrations\IDriver::class);
 		$config = new DefaultConfiguration('migrations', $driver);
diff --git a/tests/cases/unit/Finder.logicalName.phpt b/tests/cases/unit/Finder.logicalName.phpt
index fcf1c9d..7b125c6 100644
--- a/tests/cases/unit/Finder.logicalName.phpt
+++ b/tests/cases/unit/Finder.logicalName.phpt
@@ -22,11 +22,11 @@ class FinderLogicalNameTest extends Tester\TestCase
 	/** @var Finder|Mockery\MockInterface */
 	private $finder;
 
-	/** @var Group[] */
+	/** @var list<Group> */
 	private $groups;
 
 
-	protected function setUp()
+	protected function setUp(): void
 	{
 		parent::setUp();
 		$this->finder = Mockery::mock(Nextras\Migrations\Engine\Finder::class)
@@ -44,7 +44,7 @@ class FinderLogicalNameTest extends Tester\TestCase
 	}
 
 
-	public function testSimple()
+	public function testSimple(): void
 	{
 		$this->finder->shouldReceive('getItems')
 			->with('./baseDir/structures')
@@ -62,7 +62,7 @@ class FinderLogicalNameTest extends Tester\TestCase
 	}
 
 
-	public function testComplex()
+	public function testComplex(): void
 	{
 		$this->finder->shouldReceive('getItems')
 			->with('./baseDir/structures')
diff --git a/tests/cases/unit/OrderResolverTest.phpt b/tests/cases/unit/OrderResolverTest.phpt
index 619b6b4..44af898 100644
--- a/tests/cases/unit/OrderResolverTest.phpt
+++ b/tests/cases/unit/OrderResolverTest.phpt
@@ -21,7 +21,7 @@ require __DIR__ . '/../../bootstrap.php';
 
 class OrderResolverTest extends Tester\TestCase
 {
-	public function testFirstRun()
+	public function testFirstRun(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -39,7 +39,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testFirstRunTwoGroups()
+	public function testFirstRunTwoGroups(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -59,7 +59,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testSecondRunContinue()
+	public function testSecondRunContinue(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -78,7 +78,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testSecondRunContinueNothingToDo()
+	public function testSecondRunContinueNothingToDo(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -98,7 +98,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testSecondRunContinueTwoGroups()
+	public function testSecondRunContinueTwoGroups(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -123,7 +123,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testSecondRunContinueDisabledGroup()
+	public function testSecondRunContinueDisabledGroup(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -146,7 +146,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testSecondRunReset()
+	public function testSecondRunReset(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -164,7 +164,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testRunWithDisabledGroups()
+	public function testRunWithDisabledGroups(): void
 	{
 		$groupA = $this->createGroup('structures');
 		$groupB = $this->createGroup('data', false, ['structures']);
@@ -181,7 +181,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testTopologicalOrder()
+	public function testTopologicalOrder(): void
 	{
 		$resolver = new OrderResolver();
 
@@ -200,7 +200,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testIndependentGroupsOrder1()
+	public function testIndependentGroupsOrder1(): void
 	{
 		$resolver = new OrderResolver();
 
@@ -222,7 +222,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testIndependentGroupsOrder2()
+	public function testIndependentGroupsOrder2(): void
 	{
 		$resolver = new OrderResolver();
 
@@ -247,7 +247,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorRemovedFile()
+	public function testErrorRemovedFile(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -267,7 +267,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorChangedChecksum()
+	public function testErrorChangedChecksum(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -288,7 +288,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorIncompleteMigration()
+	public function testErrorIncompleteMigration(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -309,7 +309,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorNewMigrationInTheMiddleOfExistingOnes()
+	public function testErrorNewMigrationInTheMiddleOfExistingOnes(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -332,7 +332,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorNewMigrationInTheMiddleOfExistingOnes2()
+	public function testErrorNewMigrationInTheMiddleOfExistingOnes2(): void
 	{
 		$resolver = new OrderResolver();
 
@@ -359,7 +359,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorNewMigrationInTheMiddleOfExistingOnes3()
+	public function testErrorNewMigrationInTheMiddleOfExistingOnes3(): void
 	{
 		$resolver = new OrderResolver();
 
@@ -385,7 +385,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorMigrationDependingOnUnknownGroup()
+	public function testErrorMigrationDependingOnUnknownGroup(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -402,7 +402,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorGroupDependingOnUnknownGroup()
+	public function testErrorGroupDependingOnUnknownGroup(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -419,7 +419,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorDisablingRequiredGroup()
+	public function testErrorDisablingRequiredGroup(): void
 	{
 		$resolver = new OrderResolver;
 
@@ -437,7 +437,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorAmbiguousLogicalName()
+	public function testErrorAmbiguousLogicalName(): void
 	{
 		$resolver = new OrderResolver();
 
@@ -458,7 +458,7 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	public function testErrorAmbiguousLogicalNameCyclic()
+	public function testErrorAmbiguousLogicalNameCyclic(): void
 	{
 		$resolver = new OrderResolver();
 
@@ -479,28 +479,31 @@ class OrderResolverTest extends Tester\TestCase
 	}
 
 
-	private function createMigration($groupName, $fileName, $checksum = null, $completed = true)
+	private function createMigration(string $groupName, string $fileName, ?string $checksum = null, bool $completed = true): Migration
 	{
 		$migration = new Migration;
 		$migration->group = $groupName;
 		$migration->filename = $fileName;
-		$migration->checksum = $checksum ?: "$fileName.md5";
+		$migration->checksum = $checksum ?? "$fileName.md5";
 		$migration->completed = $completed;
 		return $migration;
 	}
 
 
-	private function createFile($name, $group, $checksum = null)
+	private function createFile(string $name, Group $group, ?string $checksum = null): File
 	{
 		$file = new File;
 		$file->name = $name;
 		$file->group = $group;
-		$file->checksum = $checksum ?: "$name.md5";
+		$file->checksum = $checksum ?? "$name.md5";
 		return $file;
 	}
 
 
-	private function createGroup($name, $enabled = true, $deps = [])
+	/**
+	 * @param  list<string> $deps
+	 */
+	private function createGroup(string $name, bool $enabled = true, array $deps = []): Group
 	{
 		$group = new Group;
 		$group->name = $name;
diff --git a/tests/inc/IntegrationTestCase.php b/tests/inc/IntegrationTestCase.php
index 5d2e420..f68e152 100644
--- a/tests/inc/IntegrationTestCase.php
+++ b/tests/inc/IntegrationTestCase.php
@@ -40,7 +40,7 @@ abstract class IntegrationTestCase extends TestCase
 	protected $fixtureDir;
 
 
-	protected function setUp()
+	protected function setUp(): void
 	{
 		parent::setUp();
 
@@ -72,7 +72,7 @@ protected function setUp()
 	}
 
 
-	protected function tearDown()
+	protected function tearDown(): void
 	{
 		parent::tearDown();
 		$cleanupDb = require $this->fixtureDir . '/cleanup.php';
@@ -81,7 +81,10 @@ protected function tearDown()
 	}
 
 
-	protected function getGroups($dir)
+	/**
+	 * @return list<Group>
+	 */
+	protected function getGroups(string $dir): array
 	{
 		$structures = new Group();
 		$structures->enabled = true;
@@ -106,9 +109,9 @@ protected function getGroups($dir)
 
 
 	/**
-	 * @return array (extension => IExtensionHandler)
+	 * @return array<string, Nextras\Migrations\IExtensionHandler> (extension => IExtensionHandler)
 	 */
-	protected function getExtensionHandlers()
+	protected function getExtensionHandlers(): array
 	{
 		return [
 			'sql' => new Nextras\Migrations\Extensions\SqlHandler($this->driver),
@@ -117,11 +120,9 @@ protected function getExtensionHandlers()
 
 
 	/**
-	 * @param  array $options
-	 * @return IDbal
 	 * @throws \Exception
 	 */
-	protected function createDbal($options)
+	protected function createDbal(array $options): IDbal
 	{
 		switch ($options['dbal']) {
 			case 'dibi':
@@ -178,12 +179,7 @@ protected function createDbal($options)
 	}
 
 
-	/**
-	 * @param  array $name
-	 * @param  IDbal $dbal
-	 * @return IDriver
-	 */
-	protected function createDriver($name, IDbal $dbal)
+	protected function createDriver(string $name, IDbal $dbal): IDriver
 	{
 		switch ($name) {
 			case 'mysql':
@@ -191,14 +187,14 @@ protected function createDriver($name, IDbal $dbal)
 
 			case 'pgsql':
 				return new Nextras\Migrations\Drivers\PgSqlDriver($dbal, 'm', $this->dbName);
+
+			default:
+				throw new \Exception("Unknown driver '$name'.");
 		}
 	}
 
 
-	/**
-	 * @return IPrinter
-	 */
-	protected function createPrinter()
+	protected function createPrinter(): IPrinter
 	{
 		return new TestPrinter();
 	}
diff --git a/tests/inc/TestPrinter.php b/tests/inc/TestPrinter.php
index cdcf405..a1abf8e 100644
--- a/tests/inc/TestPrinter.php
+++ b/tests/inc/TestPrinter.php
@@ -7,7 +7,7 @@
 
 class TestPrinter extends Console
 {
-	/** @var string[] output lines */
+	/** @var list<string> output lines */
 	public $lines = [];
 
 	/** @var string whole output */
@@ -21,7 +21,7 @@ public function __construct()
 	}
 
 
-	protected function output($s, $color = NULL)
+	protected function output(string $s, string $color = null): void
 	{
 		$this->lines[] = preg_replace('#; \d+\.\d+ s#', '; XX s', $s);
 		$this->out .= "$s\n";
diff --git a/tests/inc/TestSymfonyKernel.php b/tests/inc/TestSymfonyKernel.php
index 9d93629..7a92c11 100644
--- a/tests/inc/TestSymfonyKernel.php
+++ b/tests/inc/TestSymfonyKernel.php
@@ -20,11 +20,7 @@ class TestSymfonyKernel extends Kernel
 	private $parameters;
 
 
-	/**
-	 * @param string $configPath
-	 * @param array  $parameters
-	 */
-	public function __construct($configPath, array $parameters)
+	public function __construct(string $configPath, array $parameters)
 	{
 		parent::__construct('dev', true);
 
@@ -33,13 +29,13 @@ public function __construct($configPath, array $parameters)
 	}
 
 
-	public function getRootDir()
+	public function getRootDir(): string
 	{
 		return TEMP_DIR . '/symfony-bundle';
 	}
 
 
-	public function registerBundles()
+	public function registerBundles(): array
 	{
 		return [
 			new FrameworkBundle(),
@@ -49,9 +45,9 @@ public function registerBundles()
 	}
 
 
-	public function registerContainerConfiguration(LoaderInterface $loader)
+	public function registerContainerConfiguration(LoaderInterface $loader): void
 	{
-		$loader->load(function (ContainerBuilder $container) {
+		$loader->load(function (ContainerBuilder $container): void {
 			$container->addResource(new ContainerParametersResource($this->parameters));
 			foreach ($this->parameters as $key => $value) {
 				$container->setParameter($key, $value);
diff --git a/tests/inc/TestSymfonyKernel6.php b/tests/inc/TestSymfonyKernel6.php
index 3e78f82..f95a6c3 100644
--- a/tests/inc/TestSymfonyKernel6.php
+++ b/tests/inc/TestSymfonyKernel6.php
@@ -21,10 +21,9 @@ class TestSymfonyKernel6 extends Kernel
 
 
 	/**
-	 * @param string $configPath
 	 * @param array  $parameters
 	 */
-	public function __construct($configPath, array $parameters)
+	public function __construct(string $configPath, array $parameters)
 	{
 		parent::__construct('dev', true);
 
@@ -33,7 +32,7 @@ public function __construct($configPath, array $parameters)
 	}
 
 
-	public function getRootDir()
+	public function getRootDir(): string
 	{
 		return TEMP_DIR . '/symfony-bundle';
 	}
@@ -49,9 +48,9 @@ public function registerBundles(): iterable
 	}
 
 
-	public function registerContainerConfiguration(LoaderInterface $loader)
+	public function registerContainerConfiguration(LoaderInterface $loader): void
 	{
-		$loader->load(function (ContainerBuilder $container) {
+		$loader->load(function (ContainerBuilder $container): void {
 			$container->addResource(new ContainerParametersResource($this->parameters));
 			foreach ($this->parameters as $key => $value) {
 				$container->setParameter($key, $value);