nullsafe.byRef

Code example

<?php declare(strict_types = 1);

class Foo
{
	public string $value = 'hello';
}

function doFoo(?Foo $foo): void
{
	$ref =& $foo?->value;
}

Why is it reported?

The nullsafe operator (?->) cannot be used in a context that requires a reference. The nullsafe operator may return null when the left side is null, and null is not a variable that can be referenced. This applies to assignment by reference (=&), return by reference, and arrow function return by reference.

How to fix it

Check for null explicitly instead of using the nullsafe operator:

 <?php declare(strict_types = 1);

 function doFoo(?Foo $foo): void
 {
-	$ref =& $foo?->value;
+	if ($foo !== null) {
+		$ref =& $foo->value;
+	}
 }