Why does this use of SequenceType cause a compiler error? https://github.com/ReactiveCocoa/ReactiveCocoa/pull/1518

fail.swift

public static func fromSequence<S: SequenceType where S.Generator.Element == T>(sequence: S) -> Producer<T> {
	return Producer { consumer in
		for value in sequence { // error: cannot convert the expression's type 'S' to type 'S'
			consumer.put(.Next(Box(value)))
		}

		consumer.put(.Completed)
	}
}

success.swift

public static func fromSequence(sequence: SequenceOf<T>) -> Producer<T> {
	return Producer { consumer in
		for value in sequence {
			consumer.put(.Next(Box(value)))
		}

		consumer.put(.Completed)
	}
}

Was fighting this in Set just last night 😕