[swift-users] Type "T?" does not conform to protocol 'Equatable'

[Chris McIntyre]

Int? is not Equatable, b. You would have to use a non-optional. 

Under the hood, Optionals are actually an Enum with two cases, None, and Some<T>. func ==(lhs: Int?, rhs: Int?) must be designed essentially as a switch statement to handle each possibility. 
--
Chris McIntyre




> On Feb 29, 2016, at 9:24 AM, Rudolf Adamkovič via swift-users <swift-users at swift.org> wrote:
> 
> Hi everyone!
> 
> I have a generic class similar to this one:
> 
> class C<T: Equatable> {
>     let t: T
>     init(t: T) { self.t = t }
> }
> 
> When try to wrap ‘Int?' inside, I get the following error:
> 
> let a = C<Int?>(t: nil) // ERROR: Type "Int?" does not conform to protocol 'Equatable'
> 
> Yet when I try to compare two ‘Int?’ values, everything works:
> 
> let a: Int? = 5
> let b: Int? = 6
> 
> let c = a == b // NO ERROR
> 
> So, is ‘Int?' equatable or not?
> 
> Thanks!
> 
> R+
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