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Date: Fri, 19 Mar 2021 11:48:58 -0400
Message-ID: <CAKuGYLSn4Vr7=mXTEnUffq-KSxykca4fv=r0HYAZS9gZZ-+iNA@mail.gmail.com>
To: Nikita Popov <nikita.ppv@gmail.com>
Cc: Marco Pivetta <ocramius@gmail.com>, Internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] noreturn type
From: matthewmatthew@gmail.com (Matthew Brown)

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On Fri, 19 Mar 2021 at 10:53, Nikita Popov <nikita.ppv@gmail.com> wrote:

> On Fri, Mar 19, 2021 at 3:45 PM Marco Pivetta <ocramius@gmail.com> wrote:
>
>> Hey Nikita,
>>
>> On Fri, Mar 19, 2021, 14:35 Nikita Popov <nikita.ppv@gmail.com> wrote:
>>
>>>
>>> Is it allowed to declare a noreturn function that returns by reference?
>>>
>>> function &foo(): noreturn {}
>>>
>>
>> Given that `noreturn` means it should throw, loop forever or exit, how
>> would a by-ref usage be applied/useful?
>>
>> Or is it a hint at a missing test?
>>
>
> Mainly a hint for missing spec ;)
>
> Context is that we're considering to deprecate by-ref void return (
> https://wiki.php.net/rfc/deprecations_php_8_1#return_by_reference_with_vo=
id_type),
> so it would make sense to me to prohibit this for noreturn from the start=
.
>
> However, I could also see an argument for why allowing it may be useful
> due to variance considerations. It would allow you to write something lik=
e
> this:
>
> <?php
> class A {
>     public function &test(): int { ... }
> }
> class B extends A {
>     public function &test(): noreturn { throw new Exception; }
> }
>
> While dropping the by-ref return on B::test() would be forbidden by
> variance (and I don't think we'd want to add more special rules here, lik=
e
> ignoring ref-return variance for noreturn functions).
>
> Regards,
> Nikita
>

I think it should be allowed due to the variance considerations =E2=80=93 I=
've
updated the RFC to include your example.

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