Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:126367
Precedence: bulk
MIME-Version: 1.0
Date: Mon, 10 Feb 2025 22:03:53 +0500
Message-ID: <CAJWOiuP6RZOKUqhq3Bw9rCBBJQz9BnQ3=Pub4D8DzTCLpjJ4Eg@mail.gmail.com>
Subject: [PHP-DEV] Override static in return types with self in final classes
To: PHP internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="00000000000039860f062dccb22b"
From: 91liahim@gmail.com (Mihail Liahimov)

--00000000000039860f062dccb22b
Content-Type: text/plain; charset="UTF-8"

After implementing static types in return methods, I noticed one thing that
was illogical, in my opinion.

We have the following code:

interface A
{
    public function method1(): static;
}

final class Foo extends B implements A
{
    public function method1(): static
    {
        return $this;
    }
}

It seems to me that in final classes, redefining return types in methods
from static to self will not be a violation of covariance, because the
final class will never have children. But now it triggers an error Fatal
error: Declaration of Foo::method1(): Foo must be compatible with
B::method1(): static. What do you think about this?

I think using static inside classes always implies that the class can have
children. And when static occurs in the final class, it's a bit confusing.
So I'd like to see the language provide the ability to replace static with
self, because again, it's not a violation of covariance.

In addition, the same PHPStorm suggests replacing static types with self
types in final classes (if this type is not specified in the prototype).

You can read some conversation and thoughts in github issue (PR is already
attached): https://github.com/php/php-src/issues/17725

--00000000000039860f062dccb22b
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">After implementing static types in return methods, I notic=
ed one thing that was illogical, in my opinion.<br><br>We have the followin=
g code:<br><br>interface A<br>{<br>=C2=A0 =C2=A0 public function method1():=
 static;<br>}<br><br>final class Foo extends B implements A<br>{<br>=C2=A0 =
=C2=A0 public function method1(): static<br>=C2=A0 =C2=A0 {<br>=C2=A0 =C2=
=A0 =C2=A0 =C2=A0 return $this;<br>=C2=A0 =C2=A0 }<br>}<br><br>It seems to =
me that in final classes, redefining return types in methods from static to=
 self will not be a violation of covariance, because the final class will n=
ever have children. But now it triggers an error Fatal error: Declaration o=
f Foo::method1(): Foo must be compatible with B::method1(): static. What do=
 you think about this?<br><br>I think using static inside classes always im=
plies that the class can have children. And when static occurs in the final=
 class, it&#39;s a bit confusing. So I&#39;d like to see the language provi=
de the ability to replace static with self, because again, it&#39;s not a v=
iolation of covariance.<br><br>In addition, the same PHPStorm suggests repl=
acing static types with self types in final classes (if this type is not sp=
ecified in the prototype).<br><br>You can read some conversation and though=
ts in github issue (PR is already attached): <a href=3D"https://github.com/=
php/php-src/issues/17725">https://github.com/php/php-src/issues/17725</a><b=
r><br><br></div>

--00000000000039860f062dccb22b--