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Date: Tue, 27 Nov 2018 15:16:05 -0600
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Subject: Re: [PHP-DEV] [RFC][Discuss] Covariant return- and contravariant parameter- types
From: larry@garfieldtech.com (Larry Garfield)

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On Tuesday, November 27, 2018 3:00:27 PM CST Levi Morrison wrote:
> On Tue, Nov 27, 2018 at 11:36 AM Larry Garfield <larry@garfieldtech.com> 
wrote:

> > Looks like fun!
> > 
> > Would this also include allowing a return type of `static`, which would be
> > useful for the "Return the object that was invoked" case or "return a new
> > instance of the same object" case?  Currently we're limited to `return
> > self`, which is, of course, not the same thing and less flexible.
> > 
> > --Larry Garfield
> 
> It does not. To be honest, I did not think of it until your question.

On Tuesday, November 27, 2018 3:04:30 PM CST Marcos Passos wrote:
> Supporting `static` return would come in handy to define interfaces for
> immutable objects.

Exactly the sort of use case I was thinking of.  Or for builder objects, where 
you mutate the object in place and then return it.  That's a common pattern, 
but return self and subclasses don't play that nicely there.

Levi, is that something that could be reasonably added to this RFC or is that 
Hard(tm), like scalar/callable/etc?

(I don't know that a static/self parameter declaration is even a thing, so it 
probably doesn't matter there; it does matter for returns, though.)

--Larry Garfield
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