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. >
