diff --git a/examples/using-substitutions.php b/examples/using-substitutions.php
index d10d85a1..058ed47b 100644
--- a/examples/using-substitutions.php
+++ b/examples/using-substitutions.php
@@ -45,7 +45,7 @@ function substFallBack($expr)
 
 
 // define callback
-$dibi->getSubstitutes()->setCallback('substFallBack');
+$dibi->getSubstitutes()->setCallback(substFallBack(...));
 
 // define substitutes as constants
 define('SUBST_ACCOUNT', 'eshop_');
diff --git a/src/Dibi/Bridges/Tracy/Panel.php b/src/Dibi/Bridges/Tracy/Panel.php
index d5695e84..f53e5002 100644
--- a/src/Dibi/Bridges/Tracy/Panel.php
+++ b/src/Dibi/Bridges/Tracy/Panel.php
@@ -36,8 +36,8 @@ class Panel implements Tracy\IBarPanel
 	public function register(Dibi\Connection $connection): void
 	{
 		Tracy\Debugger::getBar()->addPanel($this);
-		Tracy\Debugger::getBlueScreen()->addPanel([self::class, 'renderException']);
-		$connection->onEvent[] = [$this, 'logEvent'];
+		Tracy\Debugger::getBlueScreen()->addPanel(self::renderException(...));
+		$connection->onEvent[] = $this->logEvent(...);
 	}
 
 
diff --git a/src/Dibi/Drivers/PostgreDriver.php b/src/Dibi/Drivers/PostgreDriver.php
index ea5d080a..40b76b3d 100644
--- a/src/Dibi/Drivers/PostgreDriver.php
+++ b/src/Dibi/Drivers/PostgreDriver.php
@@ -24,13 +24,12 @@ use function in_array, is_array, is_resource, strlen;
  *   - schema => the schema search path
  *   - charset => character encoding to set (default is utf8)
  *   - persistent (bool) => try to find a persistent link?
- *   - resource (resource) => existing connection resource
+ *   - resource (PgSql\Connection) => existing connection resource
  *   - connect_type (int) => see pg_connect()
  */
 class PostgreDriver implements Dibi\Driver
 {
-	/** @var resource|PgSql\Connection */
-	private $connection;
+	private PgSql\Connection $connection;
 	private ?int $affectedRows;
 
 
@@ -73,7 +72,7 @@ class PostgreDriver implements Dibi\Driver
 			restore_error_handler();
 		}
 
-		if (!is_resource($this->connection) && !$this->connection instanceof PgSql\Connection) {
+		if (!$this->connection instanceof PgSql\Connection) {
 			throw new Dibi\DriverException($error ?: 'Connecting error.');
 		}
 
@@ -119,7 +118,7 @@ class PostgreDriver implements Dibi\Driver
 		if ($res === false) {
 			throw static::createException(pg_last_error($this->connection), null, $sql);
 
-		} elseif (is_resource($res) || $res instanceof PgSql\Result) {
+		} elseif ($res instanceof PgSql\Result) {
 			$this->affectedRows = Helpers::false2Null(pg_affected_rows($res));
 			if (pg_num_fields($res)) {
 				return $this->createResultDriver($res);
@@ -223,13 +222,10 @@ class PostgreDriver implements Dibi\Driver
 
 	/**
 	 * Returns the connection resource.
-	 * @return resource|null
 	 */
-	public function getResource(): mixed
+	public function getResource(): PgSql\Connection
 	{
-		return is_resource($this->connection) || $this->connection instanceof PgSql\Connection
-			? $this->connection
-			: null;
+		return $this->connection;
 	}
 
 
@@ -244,9 +240,8 @@ class PostgreDriver implements Dibi\Driver
 
 	/**
 	 * Result set driver factory.
-	 * @param  resource  $resource
 	 */
-	public function createResultDriver($resource): PostgreResult
+	public function createResultDriver(PgSql\Result $resource): PostgreResult
 	{
 		return new PostgreResult($resource);
 	}
diff --git a/src/Dibi/Drivers/PostgreResult.php b/src/Dibi/Drivers/PostgreResult.php
index 25f0011f..d2e9cf49 100644
--- a/src/Dibi/Drivers/PostgreResult.php
+++ b/src/Dibi/Drivers/PostgreResult.php
@@ -21,8 +21,7 @@ use function is_resource;
 class PostgreResult implements Dibi\ResultDriver
 {
 	public function __construct(
-		/** @var resource|PgSql\Result */
-		private $resultSet,
+		private PgSql\Result $resultSet,
 	) {
 	}
 
@@ -89,13 +88,10 @@ class PostgreResult implements Dibi\ResultDriver
 
 	/**
 	 * Returns the result set resource.
-	 * @return resource|PgSql\Result|null
 	 */
-	public function getResultResource(): mixed
+	public function getResultResource(): PgSql\Result
 	{
-		return is_resource($this->resultSet) || $this->resultSet instanceof PgSql\Result
-			? $this->resultSet
-			: null;
+		return $this->resultSet;
 	}
 
 
diff --git a/src/Dibi/Fluent.php b/src/Dibi/Fluent.php
index 4519bff8..0f72cbfa 100644
--- a/src/Dibi/Fluent.php
+++ b/src/Dibi/Fluent.php
@@ -115,7 +115,7 @@ class Fluent implements IDataSource
 		$this->connection = $connection;
 
 		if (!isset(self::$normalizer)) {
-			self::$normalizer = new HashMap([self::class, '_formatClause']);
+			self::$normalizer = new HashMap(self::_formatClause(...));
 		}
 	}
 
diff --git a/src/Dibi/Helpers.php b/src/Dibi/Helpers.php
index 7224fd60..6db7b167 100644
--- a/src/Dibi/Helpers.php
+++ b/src/Dibi/Helpers.php
@@ -211,7 +211,7 @@ class Helpers
 	public static function getTypeCache(): HashMap
 	{
 		if (!isset(self::$types)) {
-			self::$types = new HashMap([self::class, 'detectType']);
+			self::$types = new HashMap(self::detectType(...));
 		}
 
 		return self::$types;
diff --git a/src/Dibi/Translator.php b/src/Dibi/Translator.php
index b8df335a..cb9a80db 100644
--- a/src/Dibi/Translator.php
+++ b/src/Dibi/Translator.php
@@ -36,7 +36,7 @@ final class Translator
 	{
 		$this->connection = $connection;
 		$this->driver = $connection->getDriver();
-		$this->identifiers = new HashMap([$this, 'delimite']);
+		$this->identifiers = new HashMap($this->delimite(...));
 	}
 
 
@@ -90,7 +90,7 @@ final class Translator
 									(\?)                            ## 11) placeholder
 								)/xs
 								XX,
-							[$this, 'cb'],
+							$this->cb(...),
 							substr($arg, $toSkip),
 						);
 					if (preg_last_error()) {
@@ -436,7 +436,7 @@ final class Translator
 										:(\S*?:)([a-zA-Z0-9._]?)
 									)/sx
 									XX,
-								[$this, 'cb'],
+								$this->cb(...),
 								substr($value, $toSkip),
 							);
 						if (preg_last_error()) {