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Date: Sat, 17 Jul 2021 13:47:37 +0200
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Subject: Re: [PHP-DEV] Readonly properties - immutability by default
From: a.leathley@gmx.net (Andreas Leathley)

On 16.07.21 09:06, Nikita Popov wrote:
> We cannot make properties readonly by default, because that would be a
> major backwards compatibility break.
>
> If you're going for brevity, something you can do is omit the visibility
> specifier, as it is public by default. "readonly int $prop" works.

Would it be possible to adapt constructor property promotion to support
this (as far as I tell, it currently does not)? Namely:

class A {
 =C2=A0=C2=A0=C2=A0 public function __construct(
 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 readonly int $id,
 =C2=A0=C2=A0=C2=A0 ) {
 =C2=A0=C2=A0=C2=A0 }
}

According to the constructor property promotion RFC, the promotion only
happens when public, private and protected is used for an constructor
parameter. With the readonly RFC accepted, it would make sense to also
do constructor property promotion when readonly is used, to avoid the
explicit public, because readonly would also clearly define the
parameter as not-only-a-parameter.