class ValueClass(val x: Int) extends AnyVal

object Test extends App {
  new ValueClass(1).getClass
}

java.lang.ClassCastException: ValueClass cannot be cast to scala.AnyVal
        at Test$delayedInit$body.apply(Test.scala:4)
        at scala.Function0$class.apply$mcV$sp(Function0.scala:40)
        at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
        at scala.App$$anonfun$main$1.apply(App.scala:61)
        at scala.App$$anonfun$main$1.apply(App.scala:61)
        at scala.collection.immutable.List.foreach(List.scala:309)
        at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:32)
        at scala.collection.mutable.ListBuffer.foreach(ListBuffer.scala:45)
        at scala.App$class.main(App.scala:61)
        at Test$.main(Test.scala:3)
        at Test.main(Test.scala)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at scala.tools.nsc.util.ScalaClassLoader$$anonfun$run$1.apply(ScalaClassLoader.scala:71)
        at scala.tools.nsc.util.ScalaClassLoader$class.asContext(ScalaClassLoader.scala:31)
        at scala.tools.nsc.util.ScalaClassLoader$URLClassLoader.asContext(ScalaClassLoader.scala:139)
        at scala.tools.nsc.util.ScalaClassLoader$class.run(ScalaClassLoader.scala:71)
        at scala.tools.nsc.util.ScalaClassLoader$URLClassLoader.run(ScalaClassLoader.scala:139)
        at scala.tools.nsc.CommonRunner$class.run(ObjectRunner.scala:28)
        at scala.tools.nsc.ObjectRunner$.run(ObjectRunner.scala:45)
        at scala.tools.nsc.CommonRunner$class.runAndCatch(ObjectRunner.scala:35)
        at scala.tools.nsc.ObjectRunner$.runAndCatch(ObjectRunner.scala:45)
        at scala.tools.nsc.MainGenericRunner.runTarget$1(MainGenericRunner.scala:74)
        at scala.tools.nsc.MainGenericRunner.process(MainGenericRunner.scala:96)
        at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:105)
        at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)

C:\Projects\Kepler\sandbox @ ticket/6318>scalac Test.scala -Xprint:erasure
[[syntax trees at end of                   erasure]] // Test.scala
package <empty> {
  final class ValueClass extends Object {
    <paramaccessor> private[this] val x: Int = _;
    <stable> <accessor> <paramaccessor> def x(): Int = ValueClass.this.x;
    def <init>(x: Int): ValueClass = {
      ValueClass.super.<init>();
      ()
    };
    override <synthetic> def hashCode(): Int = ValueClass.extension#Code(ValueClass.this.x().$asInstanceOf[ErasedValueType(ValueClass)]());
    override <synthetic> def equals(x$1: Object): Boolean = ValueClass.extension=uals(ValueClass.this.x().$asInstanceOf[ErasedValueType(ValueClass)](), x$1)
  };
  <synthetic> object ValueClass extends Object {
    def <init>(): ValueClass.type = {
      ValueClass.super.<init>();
      ()
    };
    final <synthetic> def extension#Code($this: ErasedValueType(ValueClass)): Int = scala.Int.box(new ValueClass($this.$asInstanceOf[Int]()).x()).hashCode();
    final <synthetic> def extension=uals($this: ErasedValueType(ValueClass), x$1: Object): Boolean = x$1.$isInstanceOf[ValueClass]().&&({
      <synthetic> val ValueClass$1: ErasedValueType(ValueClass) = x$1.$asInstanceOf[ValueClass]().x().$asInstanceOf[ErasedValueType(ValueClass)]();
      new ValueClass($this.$asInstanceOf[Int]()).x().==(new ValueClass(ValueClass$1.$asInstanceOf[Int]()).x())
    })
  };
  object Test extends Object with App {
    def <init>(): Test.type = {
      Test.super.<init>();
      Test.this.$asInstanceOf[App$class]()./*App$class*/$init$();
      ()
    };
    new ValueClass(1.$asInstanceOf[Int]()).$asInstanceOf[AnyVal]().getClass()
  }
}