複数の条件付きプロトコル適合

gistfile1.swift

struct Hoge<T> {
    let t: T

    init(t: T) {
        self.t = t
    }
}

protocol FooProtocol {
}
class Foo: FooProtocol {}


protocol BarProtocol {
}
class Bar: BarProtocol {}

let hogeFoo1 = Hoge<FooProtocol>(t: Foo())
let hogeFoo2 = Hoge<FooProtocol>(t: Foo())

let hogeBar1 = Hoge<BarProtocol>(t: Bar())
let hogeBar2 = Hoge<BarProtocol>(t: Bar())

extension Hoge: Equatable where T == FooProtocol {
    static func == (lhs: Hoge<T>, rhs: Hoge<T>) -> Bool {
        return true // 本当は条件を書く
    }
}

extension Hoge: Equatable where T == BarProtocol { // Error: Redundant conformance of 'Hoge<T>' to protocol 'Equatable'
    static func == (lhs: Hoge<T>, rhs: Hoge<T>) -> Bool {
        return true // 本当は条件を書く
    }
}


print(hogeFoo1 == hogeFoo2)
print(hogeBar1 == hogeBar2)