Why don't associated types for protocols use generic type syntax in Swift?

Question

I'm confused about the difference between the syntax used for associated types for protocols, on the one hand, and generic types on the other.

In Swift, for example, one can defines a generic type using something like

struct Stack<T> {
    var items = [T]()
    mutating func push(item: T) {
        items.append(item)
    }
    mutating func pop() -> T {
        return items.removeLast()
    }
}

while one defines a protocol with associated types using something like

protocol Container {
    typealias T
    mutating func append(item: T)
    var count: Int { get }
    subscript(i: Int) -> T { get }
}

Why isn't the latter just:

protocol Container<T> {
    mutating func append(item: T)
    var count: Int { get }
    subscript(i: Int) -> T { get }
}

Is there some deep (or perhaps just obvious and lost on me) reason that the language hasn't adopted the latter syntax?