In your example, when `Foo` is a class, then `A` does not see a mutation since the storage is out-of-line. When `Foo` is a struct, it is stored in-line and a mutation does mutate `A`.
In other words, when what’s stored in `A` is a reference, the reference itself does not get mutated when you mutate your `Foo`. If you change the statement in your loop to `a.foo = Foo()`, you’ll see that the `didSet` gets invoked again. Cheers, Guillaume Lessard _______________________________________________ swift-users mailing list swift-users@swift.org https://lists.swift.org/mailman/listinfo/swift-users
