diff --git a/composer.json b/composer.json
index 9f79b3be..fc193a79 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
 	},
 	"require-dev": {
 		"nette/tester": "^2.4",
-		"nikic/php-parser": "^4.14",
+		"nikic/php-parser": "^4.15",
 		"tracy/tracy": "^2.8",
 		"phpstan/phpstan": "^1.0"
 	},
diff --git a/src/PhpGenerator/Helpers.php b/src/PhpGenerator/Helpers.php
index 71e7de6f..e49db879 100644
--- a/src/PhpGenerator/Helpers.php
+++ b/src/PhpGenerator/Helpers.php
@@ -174,10 +174,14 @@ public static function validateType(?string $type, bool &$nullable): ?string
 			return null;
 		}
 
-		if (!preg_match('#(?:
-			\?[\w\\\\]+|
-			[\w\\\\]+ (?: (&[\w\\\\]+)* | (\|[\w\\\\]+)* )
-		)()$#xAD', $type)) {
+		if (!preg_match(<<<'XX'
+			~(?n)
+			(
+				\?? (?<type> [\w\\]+)|
+				(?<intersection> (?&type) (& (?&type))+  )|
+				(?<upart> (?&type) | \( (?&intersection) \) )  (\| (?&upart) )+
+			)$~xAD
+			XX, $type)) {
 			throw new Nette\InvalidArgumentException("Value '$type' is not valid type.");
 		}
 
diff --git a/tests/PhpGenerator/ClassType.phpt b/tests/PhpGenerator/ClassType.phpt
index cc6c2a4f..86fc78ef 100644
--- a/tests/PhpGenerator/ClassType.phpt
+++ b/tests/PhpGenerator/ClassType.phpt
@@ -131,8 +131,8 @@ $method->addParameter('res', null)
 		->setType(Type::union(Type::Array, 'null'));
 
 $method->addParameter('bar', null)
-		->setType('stdClass|string')
-		->setNullable(true);
+		->setNullable(true)
+		->setType('stdClass|string');
 
 $class->addTrait('foo');
 $class->removeTrait('foo');
diff --git a/tests/PhpGenerator/Helpers.validateType.phpt b/tests/PhpGenerator/Helpers.validateType.phpt
new file mode 100644
index 00000000..1277ca8f
--- /dev/null
+++ b/tests/PhpGenerator/Helpers.validateType.phpt
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+use Nette\PhpGenerator\Helpers;
+use Tester\Assert;
+
+
+require __DIR__ . '/../bootstrap.php';
+
+
+$foo = false;
+Assert::null(Helpers::validateType('', $foo));
+Assert::null(Helpers::validateType(null, $foo));
+Assert::same('Foo', Helpers::validateType('Foo', $foo));
+Assert::same('Foo\Bar', Helpers::validateType('Foo\Bar', $foo));
+Assert::same('\Foo\Bar', Helpers::validateType('\Foo\Bar', $foo));
+Assert::same('Foo', Helpers::validateType('?Foo', $foo));
+Assert::true($foo);
+Assert::same('Foo|Bar', Helpers::validateType('Foo|Bar', $foo));
+Assert::same('Foo&Bar\X', Helpers::validateType('Foo&Bar\X', $foo));
+Assert::same('(Foo&Bar\X)|Baz', Helpers::validateType('(Foo&Bar\X)|Baz', $foo));
+Assert::same('Abc\C|(Abc\X&Abc\D)|null', Helpers::validateType('Abc\C|(Abc\X&Abc\D)|null', $foo));
+
+Assert::exception(
+	fn() => Helpers::validateType('-', $foo),
+	Nette\InvalidArgumentException::class,
+);
+
+Assert::exception(
+	fn() => Helpers::validateType('?Foo|Bar', $foo),
+	Nette\InvalidArgumentException::class,
+);
+
+Assert::exception(
+	fn() => Helpers::validateType('(Foo)', $foo),
+	Nette\InvalidArgumentException::class,
+);
+
+Assert::exception(
+	fn() => Helpers::validateType('(Foo&Bar)', $foo),
+	Nette\InvalidArgumentException::class,
+);
diff --git a/tests/PhpGenerator/expected/ClassType.from.82.expect b/tests/PhpGenerator/expected/ClassType.from.82.expect
index 4c03d053..6ea6378a 100644
--- a/tests/PhpGenerator/expected/ClassType.from.82.expect
+++ b/tests/PhpGenerator/expected/ClassType.from.82.expect
@@ -1,5 +1,8 @@
 readonly class Class13
 {
+	public function func(C|(X&D)|null $foo): (A&B)|null
+	{
+	}
 }
 
 trait Trait13
diff --git a/tests/PhpGenerator/expected/Extractor.classes.82.expect b/tests/PhpGenerator/expected/Extractor.classes.82.expect
index c7de3d7e..54f5c525 100644
--- a/tests/PhpGenerator/expected/Extractor.classes.82.expect
+++ b/tests/PhpGenerator/expected/Extractor.classes.82.expect
@@ -6,6 +6,9 @@ namespace Abc;
 
 readonly class Class13
 {
+	public function func(C|(X&D)|null $foo): (A&B)|null
+	{
+	}
 }
 
 trait Trait13
diff --git a/tests/PhpGenerator/fixtures/classes.82.php b/tests/PhpGenerator/fixtures/classes.82.php
index 95e594ff..ae22c11e 100644
--- a/tests/PhpGenerator/fixtures/classes.82.php
+++ b/tests/PhpGenerator/fixtures/classes.82.php
@@ -6,6 +6,9 @@
 
 readonly class Class13
 {
+	public function func(C|(X&D)|null $foo): (A&B)|null
+	{
+	}
 }