If you take a look on the equal operator for tuples, you will see that both elements of the tuple must conform to Equatable.
public func ==<A, B>(lhs: (A, B), rhs: (A, B)) -> Bool where A : Equatable, B : Equatable Your SomeClass doesn’t conforme to Equatable so it doesn’t work. If you just add the conformance it’ll work. class SomeClass { } extension SomeClass: Equatable { static func ==(_ lhs: SomeClass, _ rhs: SomeClass) -> Bool { return lhs === rhs } } let c1 = SomeClass() let t1 = ("abc", c1) let t2 = ("abc", c1) t1 == t2 // legal // true Regards, Henrique Valcanaia Co-founder | iOS Engineer @ Darkshine.io <http://darkshine.io/> Computer Engineering undergraduate student @ Inf UFRGS http://bit.ly/valcanaia <http://bit.ly/valcanaia> > On 9 Jul 2017, at 12:11, David Baraff via swift-users <swift-users@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? > > > _______________________________________________ > swift-users mailing list > swift-users@swift.org > https://lists.swift.org/mailman/listinfo/swift-users
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