I think the poster understands that, it's just in Swift if you assign a Swift Array (not an NSArray) using let it is immutable both in reference and in whether

I think the poster understands that, it's just in Swift if you assign a Swift Array (not an NSArray) using let it is immutable both in reference and in whether or not items can be added or removed from it. That said, it's a quirk of the interop and I don't think Apple should spend time fixing it - rather developers should avoid NSArray within Swift.