[swift-users] is this a defect in equatable for swift tuples?

[Jens Persson]

(Also, note that your implementation of == uses lhs === rhs thus will only
return true when lhs and rhs are the same instance of SomeClass.)
/Jens

On Sun, Jul 9, 2017 at 5:24 PM, Jens Persson <jens at bitcycle.com> wrote:

> Making SomeClass conform to Equatable should fix it:
>
> class SomeClass : Equatable {
>
>     static public func ==(_ lhs:SomeClass, _ rhs:SomeClass) -> Bool {
>
>         return lhs === rhs
>
>     }
>
> }
>
> /Jens
>
>
> On Sun, Jul 9, 2017 at 5:11 PM, David Baraff via swift-users <
> swift-users at swift.org> wrote:
>
>> Given 2-tuples of type (T1, T2), you should be able to invoke the ==
>> operator if you could on both types T1 and T2, right?  i.e.
>>
>> (“abc”, 3) == (“abc”, 4) // legal
>>
>> but:
>>
>> class SomeClass {
>>     static public func ==(_ lhs:SomeClass, _ rhs:SomeClass) -> Bool {
>>         return lhs === rhs
>>     }
>> }
>>
>> let c1 = SomeClass()
>> let c2 = SomeClass()
>>
>> let t1 = ("abc", c1)
>> let t2 = ("abc", c2)
>>
>> c1 == c2 // legal
>> t1 == t2 // illegal
>>
>>
>>
>>
>> Why is t1 == t2 not legal given that c1 == c2 IS legal?
>>
>>
>>
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>>
>>
>
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