sangria-graphql/sangria

Regarding the above mentioned bug involving Argument()

I'm think that this is a Sangria-related issue, as opposed to simply a Scala issue.
When I get rid of all the Sangria code (instead just constructing a list containing some case class), the null disappears.

import org.scalatest.funsuite.AnyFunSuite
import sangria.schema.{Argument, EnumType, EnumValue, OptionInputType}

object SchemaInitTest {
  sealed trait Episode
  object Episode {
    final case object EPISODE_1 extends Episode
  }

  case class Test(string: String)

  val EpisodeEnum = EnumType(
    "Episode",
    Some("One of the films in the Star Wars Trilogy"),
    List(EnumValue("NEWHOPE", value = Episode.EPISODE_1, description = Some("Released in 1977.")))
  )

  object EpisodeArgs {
//    val arg = Test("test") // test passes when we don't use Sangria code at all!
    val arg = Argument("activityRef", OptionInputType(EpisodeEnum)) // but this fails!
  }

  val episodeArgs = EpisodeArgs.arg :: Nil
}

class SchemaInitTest extends AnyFunSuite {

  import SchemaInitTest._

  test("A list of args should be the same, regardless of where it is initialised") {
//    assert(episodeArgs == EpisodeArgs.arg :: Nil) // this passes for some reason!
    assert(EpisodeArgs.arg :: Nil == episodeArgs) // but this fails!
  }
}

Another thing I noticed is that changing the order we compare for equality in the assert also makes the problem go away.