Immutable value as inout argument

Evolution Discussion
3

Yes, ideally this is done by Swift itself behind the scenes, just imagine doesntMutate takes several pointer parameters:

withUnsafePointer(to: a) { a in
    withUnsafePointer(to: b) { b in
        withUnsafePointer(to: c) { c in
            doesntMutate(a, b, c)
        }
    }
}

Found this old thread.