Erasure elimination in scala : non-variable type argument is unchecked since it is eliminated by erasure

Question

I\'ve got a sequence Seq[Any] that has a variety of objects in it (like String, Integer, List[String], etc). I\'m trying to sift through the list and break it up into separa

Answer 1

val v = 1 ::"abc" :: true :: Nil
v : List[Any] = List(1,abc,true) 

type parameter of List type has been unified to the greatest common super type of the elements in the List which is Any.

Shapeless is to the rescue.

import shapeless._
import HList._

val s = 1 :: "abc" :: true: HNil
s : shapeless.::[Int,shapeless.::[String,shapelsss.::[Boolean,shapeless.HNil]]]
= 1 :: abc :: true :: HNil

With Shapeless HList you can get compile time safety for a heterogeneous list. you can now filter in a typesafe manner. e.g.

s.filter[String]