Swift slices computes hashes based on their contents.

slice-hash.swift

do {
    let a = "ABCABC"
    let i = a.index(a.startIndex, offsetBy: 3)
    let b = a[a.startIndex..<i]
    let c = a[i...]
    var s = Set<Substring>()
    s.insert(b)
    s.insert(c)
    print(b.hashValue)
    print(c.hashValue)
    print(s)
    // Prints same hash with `["ABC"]`.
    // Hash is based on content and works well.
}

do {
    let a = [111,222,333,111,222,333]
    let i = a.index(a.startIndex, offsetBy: 3)
    let b = a[a.startIndex..<i]
    let c = a[i...]
    var s = Set<ArraySlice<Int>>()
    s.insert(b)
    s.insert(c)
    print(b.hashValue)
    print(c.hashValue)
    print(s)
    // Prints same hash with `[ArraySlice([111, 222, 333])]`.
    // Hash is based on content and works well.
}