Pitch: Defining custom number types integers with bound ranges

[Sajjon]

It would be great to be able to work with (brand new shiny big) binary integers and using these to define bounded number types. Number bounded by range, e.g. a BigInt bound from -273 to infinity, representing Kelvin.

I've given an attempt to do this in my SPM Package "DelTal".

/// `BUNCInt` is short _B_ound _U_nsigned _N_amed _C_ategorized _Int_eger
public typealias Kelvin = BUNCInt<NoBound<BigUInt>, KelvinName, Temperatur>

public struct KelvinName: IntegerName {
    public static let nameOfInteger = "Kelvin"
}

public struct Temperatur: IntegerCategory {
    public static let nameOfCategory = "Temperature"
}

public extension Kelvin {
    enum Water {}
}

/* Verbose (needed) syntax for: `extension Kelvin.Water` */
public extension BUNCInt.Water where Name == KelvinName, Category == Temperatur {
    static var meltsAt: Kelvin { .init(magnitude: 273) }
    static var boilsAt: Kelvin { meltsAt + 100 }
}

It allows for expressive and safe wrapping of primitives according to Object-Calisthenics rule #3, and fits perfectly with Swift philosophy of safety.

It would really be amazing if developers were able to get compile-time errors inline, just like, defining this overflowing UInt8 yields a compile-time

let uint8: UInt8 = 1337

Integer literal '1337' overflows when stored into 'UInt8'

Being able to get that for custom defined integer types (or typealiases) would be... awesome!