Re: [RFC][Discuss] Covariant return- and contravariant parameter- types

On 11.12.2018 at 21:34, Levi Morrison wrote: > On Mon, Nov 26, 2018 at 2:25 PM Levi Morrison <levim@php.net> wrote: > >> I am happy to announce my latest RFC, [Covariant Returns and >> Contravariant Parameters][1], is open for discussion. If you do not >> recognize those terms then hopefully the introduction coupled with the >> [examples][2] will help. […] >> >> [1]: >> https://wiki.php.net/rfc/covariant-returns-and-contravariant-parameters >> [2]: >> https://wiki.php.net/rfc/covariant-returns-and-contravariant-parameters#examples > > It has been two weeks now. If you want to provide any feedback, or > follow-up on anything from the discussion, please do so soon. I hope > to put this to vote before the end of the year. Thanks for working on this, Levi. Highly appreciated! I may have missed this, but otherwise I'd be quite surprised that nobody had commented on: | Therefore, by-reference parameters are still contravariant, […] Call-by-reference is not seldom used to provide out-parameters, but these should not be contravariant according to LSP. Therefore, it might be best to keep by-reference parameters invariant. -- Christoph M. Becker