Example (Apple Official): pub1’s failure type is Never while pub2’s failure type is Error, which are inconsistent. So we need use setFailureType to make them consistent and we can use combineLatest later.
let pub1 = [0, 1, 2, 3, 4, 5].publisher
let pub2 = CurrentValueSubject<Int, Error>(0)
let cancellable = pub1
.setFailureType(to: Error.self)
.combineLatest(pub2)
.sink(
receiveCompletion: { print ("completed: \($0)") },
receiveValue: { print ("value: \($0)")}
)