Re: [PHP-DEV] [RFC] Primary Constructors

On Mon, Jun 29, 2026, at 5:52 AM, Rob Landers wrote:
> On Mon, Jun 29, 2026, at 12:27, Lynn wrote:
>> 
>> 
>> On Mon, Jun 29, 2026 at 2:20 AM Rob Landers <[email protected]> wrote:
>>> __
>>> Hello internals,
>>> 
>>> I'd like to put forward Primary Constructors <https://wiki.php.net/rfc/primary-constructors> for comment.
>>> 
>>> An implementation PR will be opened later today (UTC), and the RFC updated with this discussion thread.
>>> 
>>> — Rob
>> 
>> I don't see any mention of anonymous classes, I assume they aren't compatible syntax wise? 
>
> Hi Lynn,
>
> That's a good observation! Originally, I had a whole section and 
> decided to strip it, then forgot to add it back as non-supported and 
> future scope. FWIW, I was originally going to support them with 
> something like:
>
> $arg = 'foo';
> $class = new class(public int $x = $arg) {}
>
> Which desugars to:
>
> $arg = 'foo';
> $class = new class($arg) {
>   public function __construct(public int $x) {}
> }
>
> There are a lot of caveats, which is why I dropped it for future scope:
>  1. it would require types on the input parameters to disambiguate 
> between arguments and properties
>  2. it gets weird if you don't specify a default value for the property 
> and makes it ambiguous as a constructor
>  3. which begs the question of always having a default
> In essence, it deserves its own RFC because there is a lot of subtlety 
> and only makes sense in the context that primary constructors exist in 
> the first place.
>
> I'll address it in the RFC, thanks!
>
> — Rob

For anon classes, I would think the best approach is to have a compact, non-redundant syntax for "take this value from current scope and assign it to a property in this class."  Basically combining promotion and closure.  Doing that right now is horribly ugly.

That may well be out of scope for this RFC, and that's fine, but I wanted to put that out there.

--Larry Garfield