それとHashableのやつは https://github.com/apple/swift-evolution/pull/808 で後付でSE-0143に含まれたのでもちろん4.1のタイミングではまだで（当初のスコープ外）、でも https://github.com/apple/swift/pull/15382 がマージされたので4.2に間に合ったと思います（masterからswift-4.2-branchへのリブランチはまだある）。 (edited)

[SE-0143] Amend to explicitly allow conditional conformances to Ha...

Following discussions on this forum thread, amend SE-0143 to explicitly include the adoption of conditional conformances for Hashable by the following types: Optional Array ArraySlice ContiguousAr...

[SE-0143][stdlib] Conditionally conform stdlib types to Hashable b...

As a followup to SE-0143, this adds conditional conformance to Hashable to the following types in the standard library: Optional Array, ContiguousArray, ArraySlice Dictionary Range, ClosedRange T...