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Date: Wed, 23 Apr 2025 18:20:56 +0100
To: internals@lists.php.net
Subject: Re: [PHP-DEV][Pre-RFC] Associated Types
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From: imsop.php@rwec.co.uk ("Rowan Tommins [IMSoP]")



On 22 April 2025 14:37:48 BST, "Gina P=2E Banyard" <internals@gpb=2Emoe> w=
rote:
>Having talked with Arnaud off-list, it seems that using the "usual" gener=
ic syntax of (assuming our parser can cope with it):
>```
>interface I<T : int|string> {
>    public function foo(T $param): T;
>}
>class CS implements I<string> {
>    public function foo(string $param): string {
>        return $param =2E '!';
>    }
>}
>```
>is possible and would not conflict with any future proposal for generics=
=2E

I think if this works, it would be a really great step towards generics, w=
here some use cases would be possible, and some would have easier work arou=
nds than today=2E Possibly we could slowly add places the syntax is allowed=
, where we can make it make sense without tackling the tricky parts like va=
riance/inheritance and type inference=2E

Rowan Tommins
[IMSoP]