Error Identifier: nullsafe.byRef
Every error reported by PHPStan has an error identifier. Here’s a list of all error identifiers. In PHPStan Pro you can see the error identifier next to each error and filter errors by their identifiers.
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;
+ }
}
Non-ignorable error #
This error cannot be ignored using @phpstan-ignore or the ignoreErrors configuration. Non-ignorable errors indicate code that would cause a crash or a fatal error at runtime, or a fundamental problem in the analysed code that must be addressed.