[致命的]Amountでのイレイジャ

TestAmountEraser.groovy

@GrabResolver(name='jsciencerepos', root='http://maven.obiba.org/maven2/')
@Grab('org.jscience:jscience:4.3.1')

import javax.measure.quantity.*
import org.jscience.physics.amount.Amount

a = Amount.valueOf("1 m")
b = Amount.valueOf("1 m")
Amount<Mass> c = (a + b).to(Length.UNIT) // 正しくは Amount<Length>

TestAmountEraser.scala

scala> import javax.measure.quantity._
import javax.measure.quantity._

scala> import org.jscience.physics.amount.Amount
import org.jscience.physics.amount.Amount

scala> val a = Amount.valueOf("1 m")
a: org.jscience.physics.amount.Amount[_] = 1 m

scala> val b = Amount.valueOf("1 m")
b: org.jscience.physics.amount.Amount[_] = 1 m

scala> val c: Amount[Mass] = (a plus b) to Length.UNIT
<console>:11: error: type mismatch;
 found   : javax.measure.unit.Unit[javax.measure.quantity.Length]
 required: javax.measure.unit.Unit[javax.measure.quantity.Mass]
       val c: Amount[Mass] = (a plus b) to Length.UNIT
                                                  ^