>>382
こんな感じでいいんじゃね？
知らんけど

func test<T>(num: Any) -> T {
switch (num) {
case is Int:
let ret: Int = num as! Int;
return(ret * 2 as! T);
case is Double:
let ret: Double = num as! Double;
return(ret * 2.0 as! T);
default:
return(type(of: num) as! T);
};
};