Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:126869
Date: Thu, 20 Mar 2025 16:24:19 +0000
To: Larry Garfield <larry@garfieldtech.com>
Cc: php internals <internals@lists.php.net>
Subject: Re: [PHP-DEV] [RFC] [Discussion] Never parameters
Message-ID: <g4O0Q4GSjNBFDWMnxLBOnCT8A6vj8SoQ7AkdEHL7IUXV4ecEvc_HZVeHXMJOg_HzyJ1MTT-yo-_7_pbsjuB_7t79LGu1WRtlhVnnL-KPiac=@gpb.moe>
In-Reply-To: <3e35cd25-c851-4ecc-8a1b-102dadb226e5@app.fastmail.com>
References: <CALaXqqRWL8ygMGoA5xnMtt7w6rE-5WJJZ5P9oiO3vHgqvod=Fw@mail.gmail.com> <3e35cd25-c851-4ecc-8a1b-102dadb226e5@app.fastmail.com>
Feedback-ID: 96993444:user:proton
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
From: internals@gpb.moe ("Gina P. Banyard")

On Tuesday, 11 March 2025 at 21:45, Larry Garfield <larry@garfieldtech.com>=
 wrote:

> On Mon, Mar 10, 2025, at 2:05 PM, Daniel Scherzer wrote:
>=20
> > Hi internals,
> >=20
> > I'd like to start discussion on a new RFC about allowing `never` for
> > parameter types when declaring a method.
> >=20
> > * RFC: https://wiki.php.net/rfc/never-parameters-v2
> > * Implementation: https://github.com/php/php-src/pull/18016
> >=20
> > -Daniel
>=20
>=20
> I have a use case for this in Serde, so would be in favor.
>=20
> We should not block this kind of improvement on the hope of generics. Wor=
st case, we have this plus generics so you have options, how terrible.
>=20
> Rust-style associated types would probably work as well. I'd be fine with=
 that approach, too. One could argue they're more valuable as a sort of "ju=
nior generics," but absent anyone able and willing to implement them, again=
, worst-case we end up with options in the future.
>=20
> --Larry Garfield

As the person that had the initial discussion in R11 with Jordan [1] never =
as a parameter type for an interface actually is not the solution for "poor=
 man generics".
Matthew Fonda [2] already replied to the thread pointing out the remark Nik=
ita made in the discussion of the previous RFC.
But importantly, going from mixed parameter type to a generic parameter typ=
e is *allowed* and not a BC change,
however, going from a never parameter type to a generic parameter type is a=
 BC break.

Thus, I am not sure this really a good idea.
The argument from Alwin is more compelling but considering we don't have co=
nditional types, not sure if this makes sense either.

Best regards,

Gina P. Banyard

[1] https://chat.stackoverflow.com/transcript/11?m=3D52810456#52810456
[2] https://externals.io/message/126698#126791