Is there a rule to convert implicitly nullable types to explict ones?

[mfn]

Question

I learned about this via sebastianbergmann/phpunit#5719 which references https://wiki.php.net/rfc/deprecate-implicitly-nullable-types , and I was wondering if per chance there is already a rule covering this?

I went through all of them but couldn't find one where I had the feeling it was the correct one; but maybe I searched for the wrong keywords (nullable, implicitly).

Thanks

[samsonasik]

That seems php 8.4 rfc, so I think we can wait until that got merged to master branch of php-src so we can add to PhpVersionFeature, also need to verify if that cause signature bc break.

[sebastianbergmann]

also need to verify if that cause signature bc break

It does not:

<?php declare(strict_types=1);
interface I
{
    public function m(?string $a = null): void;
}

class C implements I
{
    public function m(string $a = null): void
    {
    }
}

As you can see here, the above does not trigger a signature incompatibility error. This is because both ?string $a = null and string $a = null declare a nullable parameter, the former explicitly, the latter implicitly.

[samsonasik]

@sebastianbergmann thank you for verify 👍

[mfn]

RFC was accepted https://externals.io/message/122534#122632

[samsonasik]

I created PR:

• [Php84] Add ExplicitNullableParamTypeRector rector-src#5724

for it.

[staabm]

fwiw, I think this is already possible with PHP CS-Fixer and maybe ECS. not sure we need it also in rector.

[samsonasik]

@staabm let make it possible with rector as well 👍

[mfn]

Nice, thank you 🙇🏼