Smithy's NeighborProvider and unit shapes

demo.scala

//> using lib "software.amazon.smithy:smithy-model:1.26.4"
//> using scala "2.13.10"
import software.amazon.smithy.model.Model
import software.amazon.smithy.model.neighbor.NeighborProvider
import software.amazon.smithy.model.shapes.ShapeId

import scala.jdk.CollectionConverters._

object demo extends App {

  val model = Model
    .assembler()
    .addUnparsedModel(
      "test.smithy",
      """$version: "2"
        |namespace test
        |
        |operation Hello { output: Unit, input: Unit
        |}
        |""".stripMargin,
    )
    .assemble()
    .unwrap()

  println(
    NeighborProvider
      .of(model)
      .getNeighbors(model.expectShape(ShapeId.from("test#Hello")))
      .asScala
      .toList
  )

}