diff --git a/composer.json b/composer.json
index ec1f858..31af6b9 100644
--- a/composer.json
+++ b/composer.json
@@ -25,7 +25,7 @@
 		"nette/neon": "~3.0",
 		"nextras/multi-query-parser": "1.0.0",
 		"phpstan/extension-installer": "1.4.3",
-		"phpstan/phpstan": "1.10.66",
+		"phpstan/phpstan": "1.12.6",
 		"phpstan/phpstan-deprecation-rules": "1.1.4",
 		"phpstan/phpstan-strict-rules": "1.5.2",
 		"symfony/config": "~4.4 || ~5.0",
diff --git a/src/Drivers/Mysqli/MysqliResultAdapter.php b/src/Drivers/Mysqli/MysqliResultAdapter.php
index 24037b1..b50df9e 100644
--- a/src/Drivers/Mysqli/MysqliResultAdapter.php
+++ b/src/Drivers/Mysqli/MysqliResultAdapter.php
@@ -57,7 +57,9 @@ public function seek(int $index): void
 
 	public function fetch(): ?array
 	{
-		return $this->result->fetch_assoc();
+		$fetched = $this->result->fetch_assoc();
+		if ($fetched === false) throw new InvalidStateException();
+		return $fetched;
 	}
 
 
diff --git a/src/Drivers/Mysqli/MysqliResultNormalizerFactory.php b/src/Drivers/Mysqli/MysqliResultNormalizerFactory.php
index b5df9ff..1de9f19 100644
--- a/src/Drivers/Mysqli/MysqliResultNormalizerFactory.php
+++ b/src/Drivers/Mysqli/MysqliResultNormalizerFactory.php
@@ -6,6 +6,7 @@
 use Closure;
 use DateInterval;
 use DateTimeZone;
+use Nextras\Dbal\Exception\InvalidArgumentException;
 use Nextras\Dbal\Utils\DateTimeImmutable;
 use Nextras\Dbal\Utils\StrictObjectTrait;
 use function date_default_timezone_get;
@@ -42,7 +43,10 @@ public function __construct(MysqliDriver $driver)
 
 		$this->timeNormalizer = static function($value): ?DateInterval {
 			if ($value === null) return null;
-			preg_match('#^(-?)(\d+):(\d+):(\d+)#', $value, $m);
+			$matched = preg_match('#^(-?)(\d+):(\d+):(\d+)#', $value, $m);
+			if ($matched !== 1) {
+				throw new InvalidArgumentException("Unsupported value format for TIME column: $value. Unable to parse to DateInterval");
+			}
 			$value = new DateInterval("PT{$m[2]}H{$m[3]}M{$m[4]}S");
 			$value->invert = $m[1] === '-' ? 1 : 0;
 			return $value;
diff --git a/src/Drivers/PdoMysql/PdoMysqlResultNormalizerFactory.php b/src/Drivers/PdoMysql/PdoMysqlResultNormalizerFactory.php
index b4a20d5..8e81c24 100644
--- a/src/Drivers/PdoMysql/PdoMysqlResultNormalizerFactory.php
+++ b/src/Drivers/PdoMysql/PdoMysqlResultNormalizerFactory.php
@@ -6,6 +6,7 @@
 use Closure;
 use DateInterval;
 use DateTimeZone;
+use Nextras\Dbal\Exception\InvalidArgumentException;
 use Nextras\Dbal\Utils\DateTimeImmutable;
 use Nextras\Dbal\Utils\StrictObjectTrait;
 use function date_default_timezone_get;
@@ -43,7 +44,10 @@ public function __construct(PdoMysqlDriver $driver)
 
 		$this->timeNormalizer = static function ($value): ?DateInterval {
 			if ($value === null) return null;
-			preg_match('#^(-?)(\d+):(\d+):(\d+)#', $value, $m);
+			$matched = preg_match('#^(-?)(\d+):(\d+):(\d+)#', $value, $m);
+			if ($matched !== 1) {
+				throw new InvalidArgumentException("Unsupported value format for TIME column: $value. Unable to parse to DateInterval");
+			}
 			$value = new DateInterval("PT{$m[2]}H{$m[3]}M{$m[4]}S");
 			$value->invert = $m[1] === '-' ? 1 : 0;
 			return $value;