Is there a way to convert any generic Numeric into a Double?

Question

So I have a method that has 3 different types of arguments that could come in:

Int32, Int and Double. So the idea was to use

Answer 1

Just for purposes of syntactical illustration, here's an example of making this a generic and arriving at a Double for all three types:

func f(_ i: T) {
    var d = 0.0
    switch i {
    case let ii as Int:
        d = Double(ii)
    case let ii as Int32:
        d = Double(ii)
    case let ii as Double:
        d = ii
    default:
        fatalError("oops")
    }
    print(d)
}

But whether this is better than overloading is a matter of opinion. In my view, overloading is far better, because with the generic we are letting a bunch of unwanted types in the door. The Numeric contract is a lie. A triple set of overloads for Double, Int, and Int32 would turn the compiler into a source of truth.