[swift-evolution] Universal Equatability, Hashability, and Comparability

[Jan E. Schotsman]

On May 24, 2016, at 6:50 PM, Tony Allevato wrote:

> On the one hand, getting the conformance implicitly matches how
> RawRepresentable is already treated, and makes getting the  
> conformance zero
> effort. On the other hand, it makes error handling trickier: if you  
> add a
> non-Equatable/non-Hashable field or associated value to a struct/ 
> enum, all
> of your call sites break. (I guess they would even if you declared the
> conformance, but at least there you'd also get the "Type does not  
> conform
> to Equatable/Hashable" error at the struct/enum itself, and the  
> compiler
> could even potentially flag the offending field/associated value  
> that's
> causing the conformance to fail.) Thoughts?

I would like to have the option to override the compiler-provided  
equality etc.
For example, exclude one field from the definition of equality.
It would be nice if the default implementation would be available  
inside the definition of a custom implementation so you can base your  
custom implementation on that.

Jan E.

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