The following comment accompanies the declaration of the SubSequence associated type in the Collection protocol:
/// A sequence that represents a contiguous subrange of the collection's
/// This associated type appears as a requirement in the `Sequence`
/// protocol, but it is restated here with stricter constraints. In a
/// collection, the subsequence should also conform to `Collection`.
associatedtype SubSequence : IndexableBase, Sequence = Slice<Self>
The comments clearly state that the subsequence should conform to Collection, however, it is not declared as such. Why is this?