Intersection types

> On Sat, May 30, 2020, at 3:02 AM, Gert de Pagter wrote: > > Hi Internals, > > > > With recent additions of the type system like union types [1], id like > > to propose adding intersection types as well. > > > > Looking through past RFCs I found one from 2016 [2] which never left > > the discussion phase and is currently marked as inactive. > > Before continuing with an RFC I'd like to know if there are any > > particular reasons why the original RFC never got into a voting phase, > > so that this one may be more successful. > > > > P.S. I’d also like to get RFC karma so I could create a proposal. > > > > Thanks in advance! > > > > > > [1] https://wiki.php.net/rfc/union_types_v2 > > <https://wiki.php.net/rfc/union_types_v2> > > [2] https://wiki.php.net/rfc/intersection_types > > <https://wiki.php.net/rfc/intersection_types> > > To my recollection, the original RFC was met with a general "meh, sounds > complicated, and why would you want to do that?" which is why it never went > as far as a vote. I don't know if there was an implementation. Note that > it was proposed seemingly in conjunction with union types v1, and a lot of > the discussion really confused the two. > > 4 years later, Nikita tried union types a second time and they sailed > through. I couldn't say why, but I speculate that it was a combination of > 4 years of the community maturing, different people being around, and just > union types without intersection types being an easier thing to swallow. > > I'd say go for it. I'd love to see intersection types, as it would be > very helpful to certain use cases with FIG PSRs. (Eg, "I want an object > that is a Response and also has the Link extensions from PSR-13 on it" is > currently impossible to specify. Intersection types would solve that > perfectly.) > > --Larry Garfield > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php