checks if number overflows using ?=

gistfile1.txt

func ?= <T:IntNumberConvertible, U:NumberConvertible>(var lhs: T, rhs: U) -> T{
    print("INTNUMBER")
    
    let max  :Double = T.max.convert()
    let test :Double = rhs.convert()
    
    if test > max{
        assert(false, "Conversion Loss")
    }
    
    lhs = rhs.convert()
    let x:T = rhs.convert()
    return x;
}

//Test Cases
let res555:Int = 0
res555 ?= Int(100000) * Int64(100000) //success
res555 ?= Int(1000000000000000000) * Int64(1000000000000000000) //overflow


public protocol IntNumberConvertible : NumberConvertible {
    static var max: Self { get }
}


extension CGFloat : NumberConvertible {}
extension Double  : NumberConvertible {}
extension Int     : IntNumberConvertible {}
extension Float   : NumberConvertible {}
extension UInt8   : IntNumberConvertible {}
extension Int8    : IntNumberConvertible {}
extension UInt16  : IntNumberConvertible {}
extension Int16   : IntNumberConvertible {}
extension UInt32  : IntNumberConvertible {}
extension Int32   : IntNumberConvertible {}
extension UInt64  : IntNumberConvertible {}
extension Int64   : IntNumberConvertible {}
extension UInt    : IntNumberConvertible {}