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Date: Fri, 17 Nov 2023 16:02:29 +0100
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To: Rowan Tommins <rowan.collins@gmail.com>
Subject: Re: [PHP-DEV] [RFC][Discussion] Harmonise "untyped" and "typed"
 properties
From: claude.pache@gmail.com (Claude Pache)



> Le 17 nov. 2023 =C3=A0 14:53, Rowan Tommins <rowan.collins@gmail.com> =
a =C3=A9crit :
>=20
> On 17 November 2023 13:30:42 GMT, Claude Pache =
<claude.pache@gmail.com> wrote:
>>=20
>> Yes, except that an untyped (respectively `mixed`) property cannot be =
redeclared as `mixed` (resp. untyped) in a subclass. A small step in the =
right direction is to allow that.
>=20
> Huh, I didn't know that. I'll add it to the RFC, at least to consider.
>=20
> The RFC to add "mixed" gives an example of removing the type as =
invariance, but doesn't seem to justify why "untyped" and "mixed" should =
be considered different, from a type system point of view. =
https://wiki.php.net/rfc/mixed_type_v2

Note that untyped is different from `mixed` in the case of return values =
of functions: in that context, untyped is equivalent to `mixed|void`. In =
all other contexts, untyped and `mixed` are effectively equivalent, =
because `void` is void of sense.

=E2=80=94Claude