private func liftToEnumerated<A1, A2, B>(_ f: @escaping (A1, A2) -> B) -> ((Int, A1), (Int, A2)) -> B {
    return { enumerated1, enumerated2 in f(enumerated1.1, enumerated2.1) }
}

private func liftAllToEnumerated<A1, A2, B>(_ fs: [(A1, A2) -> B]) -> [((Int, A1), (Int, A2)) -> B] {
    return fs.map(liftToEnumerated)
}

extension Sequence {
    func sorted(byMultiple predicates: [(Element, Element) -> Bool]) -> [Self.Element] {
        let combinedPredicate = { (e1: Element, e2: Element) -> Bool in
            return predicates.reduce(false) { areInIncreasingOrder, predicate in
                return areInIncreasingOrder || predicate(e1, e2)
            }
        }

        return sorted(by: combinedPredicate)
    }
}

let ps: [(Int, Int) -> Bool] = [{_, _ in true}]
// this is fine:
[1,2,3].sorted(byMultiple: ps)
// this crashes:
[1,2,3].enumerated().sorted(byMultiple: liftAllToEnumerated(ps))

Could not cast value of type '((Swift.Int, Swift.Int), (Swift.Int, Swift.Int)) -> Swift.Bool' (0x1013d29b8) to '((offset: Swift.Int, element: Swift.Int), (offset: Swift.Int, element: Swift.Int)) -> Swift.Bool' (0x1013d2cc0).
2019-02-27 16:42:18.871464+0100 repl_swift[65408:923280] Could not cast value of type '((Swift.Int, Swift.Int), (Swift.Int, Swift.Int)) -> Swift.Bool' (0x1013d29b8) to '((offset: Swift.Int, element: Swift.Int), (offset: Swift.Int, element: Swift.Int)) -> Swift.Bool' (0x1013d2cc0).
Execution interrupted. Enter code to recover and continue.
Enter LLDB commands to investigate (type :help for assistance.)
Process 65408 stopped
* thread #​1, queue = 'com.apple.main-thread', stop reason = signal SIGABRT
    frame #​0: 0x00007fff7879623e libsystem_kernel.dylib`__pthread_kill + 10
libsystem_kernel.dylib`__pthread_kill:
->  0x7fff7879623e <+10>: jae    0x7fff78796248            ; <+20>
    0x7fff78796240 <+12>: movq   %rax, %rdi
    0x7fff78796243 <+15>: jmp    0x7fff787903b7            ; cerror_nocancel
    0x7fff78796248 <+20>: retq
Target 0: (repl_swift) stopped.