diff --git a/src/Dibi/Connection.php b/src/Dibi/Connection.php
index 69f2cef2..785406ef 100644
--- a/src/Dibi/Connection.php
+++ b/src/Dibi/Connection.php
@@ -482,10 +482,9 @@ class Connection
 	/**
 	 * Executes SQL query and fetch result - shortcut for query() & fetch().
 	 * @param  mixed    one or more arguments
-	 * @return Row|NULL
 	 * @throws Exception
 	 */
-	public function fetch(...$args)
+	public function fetch(...$args): ?Row
 	{
 		return $this->query($args)->fetch();
 	}
diff --git a/src/Dibi/DataSource.php b/src/Dibi/DataSource.php
index 15365796..af013b57 100644
--- a/src/Dibi/DataSource.php
+++ b/src/Dibi/DataSource.php
@@ -155,9 +155,8 @@ class DataSource implements IDataSource
 
 	/**
 	 * Generates, executes SQL query and fetches the single row.
-	 * @return Row|NULL
 	 */
-	public function fetch()
+	public function fetch(): ?Row
 	{
 		return $this->getResult()->fetch();
 	}
diff --git a/src/Dibi/DateTime.php b/src/Dibi/DateTime.php
index 0347bee1..e71a3bf1 100644
--- a/src/Dibi/DateTime.php
+++ b/src/Dibi/DateTime.php
@@ -24,7 +24,7 @@ class DateTime extends \DateTime
 	{
 		if (is_numeric($time)) {
 			parent::__construct('@' . $time);
-			$this->setTimeZone($timezone ? $timezone : new \DateTimeZone(date_default_timezone_get()));
+			$this->setTimezone($timezone ? $timezone : new \DateTimeZone(date_default_timezone_get()));
 		} elseif ($timezone === null) {
 			parent::__construct($time);
 		} else {
@@ -44,7 +44,7 @@ class DateTime extends \DateTime
 	{
 		$zone = $this->getTimezone();
 		$this->__construct('@' . $timestamp);
-		return $this->setTimeZone($zone);
+		return $this->setTimezone($zone);
 	}
 
 
diff --git a/src/Dibi/Fluent.php b/src/Dibi/Fluent.php
index 21007604..f637159d 100644
--- a/src/Dibi/Fluent.php
+++ b/src/Dibi/Fluent.php
@@ -302,9 +302,8 @@ class Fluent implements IDataSource
 
 	/**
 	 * Generates, executes SQL query and fetches the single row.
-	 * @return Row|NULL
 	 */
-	public function fetch()
+	public function fetch(): ?Row
 	{
 		if ($this->command === 'SELECT' && !$this->clauses['LIMIT']) {
 			return $this->query($this->_export(null, ['%lmt', 1]))->fetch();
diff --git a/src/Dibi/Helpers.php b/src/Dibi/Helpers.php
index e13dcaef..d1b3d80f 100644
--- a/src/Dibi/Helpers.php
+++ b/src/Dibi/Helpers.php
@@ -289,7 +289,6 @@ class Helpers
 
 	/**
 	 * @internal
-	 * @return string|int
 	 */
 	public static function intVal($value): int
 	{
diff --git a/src/Dibi/Result.php b/src/Dibi/Result.php
index 11030dc5..5add1ee5 100644
--- a/src/Dibi/Result.php
+++ b/src/Dibi/Result.php
@@ -32,13 +32,13 @@ class Result implements IDataSource
 {
 	use Strict;
 
-	/** @var array  ResultDriver */
+	/** @var ResultDriver|null */
 	private $driver;
 
 	/** @var array  Translate table */
 	private $types = [];
 
-	/** @var Reflection\Result */
+	/** @var Reflection\Result|null */
 	private $meta;
 
 	/** @var bool  Already fetched? Used for allowance for first seek(0) */
@@ -162,7 +162,7 @@ class Result implements IDataSource
 	/**
 	 * Fetches the row at current position, process optional type conversion.
 	 * and moves the internal cursor to the next position
-	 * @return ?Row|array
+	 * @return Row|array|null
 	 */
 	final public function fetch()
 	{
diff --git a/src/Dibi/Row.php b/src/Dibi/Row.php
index 3ff38393..ef96dd33 100644
--- a/src/Dibi/Row.php
+++ b/src/Dibi/Row.php
@@ -31,8 +31,9 @@ class Row implements \ArrayAccess, \IteratorAggregate, \Countable
 
 	/**
 	 * Converts value to DateTime object.
+	 * @return \DateTime|string|null
 	 */
-	public function asDateTime(string $key, string $format = null): \DateTime
+	public function asDateTime(string $key, string $format = null)
 	{
 		$time = $this[$key];
 		if (!$time instanceof DateTime) {
diff --git a/src/Dibi/dibi.php b/src/Dibi/dibi.php
index f9cd61e1..27ef0347 100644
--- a/src/Dibi/dibi.php
+++ b/src/Dibi/dibi.php
@@ -170,10 +170,9 @@ class dibi
 	/**
 	 * Executes SQL query and fetch result - Monostate for Dibi\Connection::query() & fetch().
 	 * @param  mixed    one or more arguments
-	 * @return Dibi\Row|NULL
 	 * @throws Dibi\Exception
 	 */
-	public static function fetch(...$args)
+	public static function fetch(...$args): ?Dibi\Row
 	{
 		return self::getConnection()->query($args)->fetch();
 	}