I don't understand the need for this.

The following variation of this test passes without this.

```

import tools.partest.DirectTest

// verify that all languageFeature names are accepted by -language
object Test extends DirectTest {
  override def code = ""

  override def extraSettings = s"-usejavacp -d ${testOutput.path}"

  override def show() = {
    val global = newCompiler("")
    new global.Run()
    import global._, global.definitions._

    exitingTyper {
      def isFeature(s: Symbol) = s hasAnnotation LanguageFeatureAnnot
      val langf  = languageFeatureModule.typeSignature
      val feats  = langf.declarations filter (s => isFeature(s)) map (_.name.decoded)
      val xmen   = langf.member(TermName("experimental")).typeSignature.declarations filter (s =>
         isFeature(s)) map (s => s"experimental.${s.name.decoded}"
      )
      val all    = (feats ++ xmen) mkString ","

      assert(feats.nonEmpty, "Test must find feature flags.")

      //dynamics,postfixOps,reflectiveCalls,implicitConversions,higherKinds,existentials,experimental.macros
      compile(s"-language:$all")
    }
  }
}
```