[swift-evolution] [Proposal] Explicit Synthetic Behaviour

[Ben Rimmington]

> On 14 Sep 2017, at 15:31, Haravikk wrote:
> 
>> On 14 Sep 2017, at 02:12, Xiaodi Wu wrote:
>> 
>>> On Wed, Sep 13, 2017 at 09:13 Haravikk wrote:
>>> 
>>> I mean because not once have you summarised what these alleged "considerations" were; if they exist then you should be able do so, yet all I am hearing is "it was considered", which frankly is not an argument at all as it is entirely without substance.
>> 
>> Of course it is not an argument at all. It is a factual statement. The objections which you mentioned were also mentioned prior to a decision about SE-0185. The community and the core team had an opportunity to view those objections. After that time, a decision was made, having considered all the stated pros and cons which included the ones that you are now repeating. What "considerations" are you looking for?
> 
> Ones with proof that they were ever made! Once again you are stating that these issues were "considered", yet you show not a single shred of proof that that was the case. You're asking me to take you at your word but I have no reason to trust that the problem has been as carefully considered as you claim.
> I was involved in one such discussion and the response from the core team was frankly pitiful; they did not provide any justification whatsoever.

Chris Lattner already said that the core team discussed your concerns:

<https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170814/038854.html>

<https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170814/038883.html>

The original idea was for most types to be *implicitly* equatable and hashable:

<https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160307/012099.html>

The accepted proposal, with *explicit* declaration of conformance, is a good compromise.

Instead of discussing hypothetical issues with SE-0185, we can wait for Swift 4.1 beta.

-- Ben