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Date: Sun, 8 Nov 2020 18:47:01 +0200
Message-ID: <CAM0Ccxh+nDoBOUJbM2TEmUN6mjbSzTB_WP7kNBtFUdLAYFX=yQ@mail.gmail.com>
To: Marco Pivetta <ocramius@gmail.com>
Cc: PHP Internals <internals@lists.php.net>, levim@php.net
Content-Type: multipart/alternative; boundary="00000000000096fa0905b39b320e"
Subject: Re: [PHP-DEV] Union `&` operator
From: zsidelnik@gmail.com (Eugene Sidelnyk)

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> As for when to allow them: as others have suggested in this thread, keep
it simple for now, and only allow intersection of class/interface
references.

Yes, I think that single intersection type should support just one class
and any/or any number of interfaces with the condition that they don't
collide with one another.

> If you want to raise an RFC, special care has to be taken for the
variance in inheritance semantics.

I don't think neither that I am able to consider all possible impacts to
write the RFC nor implement this, but Levi Morrison (levim@php.net) can.

On Sun, Nov 8, 2020 at 4:53 PM Marco Pivetta <ocramius@gmail.com> wrote:

> Hey Eugene,
>
> On Sat, Nov 7, 2020 at 4:13 PM Eugene Sidelnyk <zsidelnik@gmail.com>
> wrote:
>
>> ```php
>> function foo(A & B & E $object) {
>>   // some work
>>
>>   var_dump($object);
>> }
>> ```
>>
>
> Fully support this for parameter, property and return types: already
> making good use of intersection types since a few years.
>
> As for when to allow them: as others have suggested in this thread, keep
> it simple for now, and only allow intersection of class/interface
> references.
>
> If you want to raise an RFC, special care has to be taken for the variance
> in inheritance semantics.
>
> Greets,
>
> Marco Pivetta
>
> http://twitter.com/Ocramius
>
> http://ocramius.github.com/
>

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