gistfile1.swift

struct Foo {
    var bar: String = ""
}

class Something {
    var foo: Foo = Foo() {
        didSet {
            println("didSet called")
        }
    }
}

var s = Something()
s.foo.bar = "?????"
s.foo.bar = "?????"

// stdout:
// didSet called
// didSet called

If that's the expected behavior because a new copy of the struct is created then my question is: shouldn't one be able to modify a struct that is set as "var" on a class without replacing it?

Furthermore, I think that the fact the struct is copied, in this case, is an implementation detail that I don't think it should be carried to the didSet/willSet mechanism.

Thoughts?