QuickHashableDemo.swift

struct A<T: Hashable>: Hashable {
    static func == (lhs: A<T>, rhs: A<T>) -> Bool { lhs.tVar == rhs.tVar }
    
    let tVar: T
    
    init(_ inVat: T) {
        tVar = inVat
    }
}

let arVal = [A<Int>](arrayLiteral: A(0), A(1), A(2))

arVal.forEach { print($0.tVar) }

let arDict: [A<Int>: Int] = [
    arVal[0]: arVal[0].tVar,
    arVal[1]: arVal[1].tVar,
    arVal[2]: arVal[2].tVar
]

arDict.forEach { print("\($0.key): \($0.value)") }

// Prints:
// 0
// 1
// 2
// A<Int>(tVar: 2): 2
// A<Int>(tVar: 0): 0
// A<Int>(tVar: 1): 1