This is fantastic news! Any chance of this landing in Swift 4.x instead of 5?

R+

> On 17 Aug 2017, at 00:29, Chris Lattner via swift-evolution 
> <[email protected]> wrote:
> 
> Proposal Link: 
> https://github.com/apple/swift-evolution/blob/master/proposals/0185-synthesize-equatable-hashable.md
> 
> The review of SE-0185 “Synthesizing Equatable and Hashable conformance” ran 
> from August 9…15, 2017. Feedback for the feature was glowingly positive, and 
> the proposal is accepted.  The core team discussed the concerns raised in the 
> feedback thread for the proposal.  Here are some rough notes (not intended to 
> be exhaustive), but it is important to recognize that the proposal follows 
> the design of the auto-synthesized Codable proposal, and that many of these 
> same points were discussed when it came up:
> 
> - The core team feels that adding compiler magic for this case is reasonable 
> because it solves an important user need, and doesn’t preclude the 
> introduction of a more general feature (e.g. like a macro system, or Rust's 
> ‘deriving’ feature) in the future.  When/if that feature is designed and 
> built, the compiler magic can be replaced with standard library magic.
> 
> - The hash value of a type is not intended to be stable across rebuilds or 
> other changes to the code.  It is ok to change if fields are reordered, the 
> standard library changes the hash function, etc.  Tony pointed this out 
> on-thread, saying:  The stdlib documentation for hashValue states "Hash 
> values are not guaranteed to be equal across different executions of your 
> program. Do not save hash values to use during a future execution.”
> 
> - The code synthesized is meant to feel like a default implementation that 
> you’re getting for free from a (constrained) extension on the protocol.  This 
> is why conformance to the protocol itself is all that is required, not 
> something like “AutoEquatable”.  
> 
> Many thanks to Tony Allevato for driving forward this proposal.  The patch 
> just needs final code review now - I think we’re all looking forward to this 
> landing, congrats!
> 
> Chris Lattner 
> Review Manager
> 
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