How to add nullable return type declaration?

[brandonkelly]

I need to configure an AddReturnTypeDeclarationRector rule similar to this example, except the return type must be nullable. For example:

 class SomeClass
 {
-    public function getData()
+    public function getData(): ?array
     {
     }
 }

How exactly can that be expressed as a PHPStan\Type\Type object for AddReturnTypeDeclarationRector?

[samsonasik]

You possibly can do with:

use PHPStan\Type\UnionType;
use PHPStan\Type\ArrayType;
use PHPStan\Type\NullType;
use PHPStan\Type\MixedType;

new UnionType([new ArrayType(new MixedType(), new MixedType()), new NullType()])