IdentityKeyPath+Bad.swift

func inPredicateBad<S: Sequence>(_ values: S) -> NSComparisonPredicate {
    let ex1 = NSExpression(forKeyPath: \S.Element.self)
    let ex2 = NSExpression(forConstantValue: values)
    return NSComparisonPredicate(leftExpression: ex1, rightExpression: ex2, modifier: .direct, type: .in)
}

func inPredicateOk<S: Sequence>(_ values: S) -> NSComparisonPredicate {
    let ex1 = NSExpression.expressionForEvaluatedObject()
    let ex2 = NSExpression(forConstantValue: values)
    return NSComparisonPredicate(leftExpression: ex1, rightExpression: ex2, modifier: .direct, type: .in)
}

func refetch<S: Sequence>(_ context: NSManagedObjectContext, _ sequence: S) throws -> [S.Element] where S.Element: NSManagedObject {
    let request = S.Element.fetchRequest() as! NSFetchRequest<S.Element>
    request.predicate = inPredicateBad(sequence)
    return try context.fetch(request)
}

let crashArray = try! refetch(currentBackgroundContext, arrayOfFaultedObjectsFromAnotherContext)

/* Crash log example:
CoreData: error: SQLCore dispatchRequest: exception handling request: <NSSQLFetchRequestContext: 0x600001797020> , unimplemented SQL generation for predicate : (#self IN {<DMStatusSendingPending: 0x600000d3a210> (entity: DMStatusSendingPending; id: 0x90de07f9ad97c6de <x-coredata://43CA7069-0B00-4104-A655-982F4A525339/DMStatusSendingPending/p44> ; data: <fault>)}) with userInfo of (null)
libc++abi.dylib: terminating with uncaught exception of type NSException
*/