diff --git a/src/PhpGenerator/GlobalFunction.php b/src/PhpGenerator/GlobalFunction.php
index 3a6a5a3b..f25689a2 100644
--- a/src/PhpGenerator/GlobalFunction.php
+++ b/src/PhpGenerator/GlobalFunction.php
@@ -9,6 +9,8 @@
 
 namespace Nette\PhpGenerator;
 
+use Nette;
+
 
 /**
  * Global function.
@@ -20,9 +22,9 @@ final class GlobalFunction
 	use Traits\CommentAware;
 	use Traits\AttributeAware;
 
-	public static function from(string $function, bool $withBody = false): self
+	public static function from(string|\Closure $function, bool $withBody = false): self
 	{
-		return (new Factory)->fromFunctionReflection(new \ReflectionFunction($function), $withBody);
+		return (new Factory)->fromFunctionReflection(Nette\Utils\Callback::toReflection($function), $withBody);
 	}
 
 
diff --git a/src/PhpGenerator/Method.php b/src/PhpGenerator/Method.php
index 5c10fec4..b414f966 100644
--- a/src/PhpGenerator/Method.php
+++ b/src/PhpGenerator/Method.php
@@ -28,7 +28,7 @@ final class Method
 	private bool $abstract = false;
 
 
-	public static function from(string|array $method): static
+	public static function from(string|array|\Closure $method): static
 	{
 		return (new Factory)->fromMethodReflection(Nette\Utils\Callback::toReflection($method));
 	}
diff --git a/tests/PhpGenerator/GlobalFunction.from.81.phpt b/tests/PhpGenerator/GlobalFunction.from.81.phpt
new file mode 100644
index 00000000..10cab3ff
--- /dev/null
+++ b/tests/PhpGenerator/GlobalFunction.from.81.phpt
@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * @phpVersion 8.1
+ */
+
+declare(strict_types=1);
+
+use Nette\PhpGenerator\GlobalFunction;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+/** global */
+#[ExampleAttribute]
+function func(stdClass $a, $b = null)
+{
+	echo sprintf('hello, %s', 'world');
+	return 1;
+}
+
+
+$function = GlobalFunction::from(func(...));
+same(
+	<<<'XX'
+		/**
+		 * global
+		 */
+		#[ExampleAttribute]
+		function func(stdClass $a, $b = null)
+		{
+		}
+
+		XX,
+	(string) $function,
+);
diff --git a/tests/PhpGenerator/Method.from.81.phpt b/tests/PhpGenerator/Method.from.81.phpt
new file mode 100644
index 00000000..03c5ad02
--- /dev/null
+++ b/tests/PhpGenerator/Method.from.81.phpt
@@ -0,0 +1,30 @@
+<?php
+
+/**
+ * @phpVersion 8.1
+ */
+
+declare(strict_types=1);
+
+use Nette\PhpGenerator\Method;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+class Foo
+{
+	public static function bar(int $a, ...$b): void
+	{
+	}
+}
+
+$method = Method::from(Foo::bar(...));
+same(
+	<<<'XX'
+		public static function bar(int $a, ...$b): void
+		{
+		}
+
+		XX,
+	(string) $method,
+);