Serialization Error

cell1.scala

val rdd = sc.parallelize(Stream.from(1).take(1000).toList,4)

class NotSerializable()

val bar = new NotSerializable()

val simpleVariable = Set(1, 2, 3, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19)

// here's the problem, this code runs forever:
 rdd
   .filter(x => simpleVariable(x)) // translates to this.simpleVariable
   .collect()

// btw, and this works, fine because of parameter capture:
rdd
  .filter(simpleVariable)
  .collect()

/* =========== here's a workaround: =============================
object Foo1 {
val simpleVariable = Set(1, 2, 3, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19)
}
import Foo1._
rdd
  .filter(x => simpleVariable(x)) 
  .collect()
*/

// But for a newbie scala user it would be quite difficult to figure out this solution!!!!
// so my question is - why not we wrap each line in an object automatically, as in a workaround?
// If the answer is positive I will create a new ticket and will try to fix this and submit PR.

cell2.scala

rdd
  .filter(x => simpleVariable(x)) // translates to $line11.$read$$iw.......$iw.simpleVariable,  works fine
  .collect()

yeah, I already see a problem with defining companion objects for example, and out of order definitions, maybe we'll need a special cell type for them, which will complicate things, but I hope that we will avoid a greater evil