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Date: Thu, 18 Feb 2016 04:35:00 -0600
Subject: Re: [PHP-DEV] Re: [RFC] Traits with interfaces
From: larry@garfieldtech.com (Larry Garfield)

On Wed, Feb 17, 2016, at 01:05 PM, Kevin Gessner wrote:
> On Wed, Feb 17, 2016 at 9:25 AM, Kevin Gessner <kgessner@etsy.com> wrote:
> 
> > Hello internals team!  I'd like to propose an RFC to allow traits to
> > implement interfaces.
> >
> 
> I've created a proper RFC wiki page here with the draft:
> https://wiki.php.net/rfc/traits-with-interfaces
> 
> It includes more detail and several example code snippets.  Thanks all
> for
> your feedback so far.

Thanks, Kevin.

At the risk of a "me too" post, I would also be in favor of allowing
traits to declare an interface but NOT in favor of a use-ing class
implicitly implementing the interface as a result.  I'd rather the class
still need to self-declare the interface; that it uses a trait to
fulfill that contract is irrelevant to the outside world.  

At that point, the benefit becomes two-fold:

1) Communicate to users of the trait what the intent of the trait is: To
provide the boilerplate for some interface, or portion thereof.  This
could be covered by PHPDoc, potentially, and I've suggested the same for
PSR-5 before.

2) Ask the engine to do a syntax check on the class to make sure I did
not forget something or screwed up in some way.  That is, not fulfilling
the interface on the trait would cause a parse error (or an error in my
IDE), forcing me to fix my bug before I even try running it.  PHPDoc
would NOT have this benefit.

Thus I feel this addition does have value that a PHPDoc alternative
would not.

--Larry Garfield