Bug report

Since PHPstan 2.1.34, it declares that one of @param-out union type is never assigned, so it can be removed, but it is a possible return type. If I remove the type that's apparently never assigned, I get the opposite error that the @param-out type is too narrow.

 /**
 *
 * @param array{
 *   key1: int
 * } $item
 *
 * @param-out array{
 *   key1: int
 * }|array{
 *   key2: float
 * } $item
 *
 */
function example(array &$item): void
{
	if (!empty($item["key1"])) {
		$item['key2'] = 1.00;
		unset($item["key1"]);
	}
}

Error:

Function example() never assigns array{key1: int} to &$item so it can be removed from the @param-out type.

Code snippet that reproduces the problem

https://phpstan.org/r/12b15a19-d9c7-4dae-b7b7-029b2b8cc4cc

Expected output

If the if condition is false, then key1 key will still be set, and so the @param-out type is correct

https://3v4l.org/rhfM6#vnull

Did PHPStan help you today? Did it make you happy in any way?

Great work as always!