Why is the property observer called if no assignment takes place?

PropertyObserver.swift

var value : String = "Test" {
    didSet {
        print("Changed Item Value")
    }
}
let newValue = "Test"

private func changeIfNew<T: Comparable>(inout current: T, new: T) {
    // This evaluates to false (as current == new) and the loop is skipped yet the property observer is still triggered
    if current != new {
        print("current \(current) - new: \(new)")
        current = new
    }
}

// If this is not called the observer is not triggered
changeIfNew(&value, new: newValue)