Re: [PHP-DEV] [Discussion] Revisiting typed closures

There was also this: https://wiki.php.net/rfc/functional-interfaces

A re-reading of the very brief thread, shows Dmitry thought it an inelegant
use/abuse of the type system, and more generally there was a feeling that
anon classes could be used in their place.

Cheers
Joe

On Wed, 1 Jul 2026, 16:44 Matheus Martins, <[email protected]> wrote:

> Hello internals,
>
> I would like to revisit the idea of giving closures a typed call signature.
>
> e.g. Closure(int, string): array -- enforced at the point a value crosses a
> type boundary (an argument, a return, a property), the same places any
> other
> type is checked.
>
> Today a closure can only be typed as Closure or callable, neither of which
> says anything about its parameters or return, even though that information
> is
> right there.
>
> I know this is not new ground: Callable Prototypes was declined in 2016,
> and
> Garfield and Grekas shared two further RFCs in 2023 -- Structural Typing
> for
> Closures, and Allow Closures to Declare Interfaces they Implement -- both
> still
> in draft.
>
> Before taking it further, I would like to know whether closure typing
> is still considered worth pursuing -- or whether the topic is now regarded
> as
> settled.
>
> References:
>
> - https://wiki.php.net/rfc/callable-types
> - https://wiki.php.net/rfc/structural-typing-for-closures
> -
> https://wiki.php.net/rfc/allow-closures-to-declare-interfaces-they-implement
>
> Thanks.
>