additional class tags for reflection API

Introduces a test that iterates all abstract types in reflection API
and makes sure that every one of them has an associated class tag.

After being introduced, the test has immediately failed exposing
the lack of tags for TreeCopier, Mirror and RuntimeClass, which has been
subsequently fixed in this commit.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index 1617db7517..1098766a07 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -15,6 +15,7 @@ import scala.collection.{ mutable, immutable }
 import io.{ SourceReader, AbstractFile, Path }
 import reporters.{ Reporter, ConsoleReporter }
 import util.{ ClassPath, MergedClassPath, StatisticsInfo, returning, stackTraceString }
+import scala.reflect.ClassTag
 import scala.reflect.internal.util.{ OffsetPosition, SourceFile, NoSourceFile, BatchSourceFile, ScriptSourceFile }
 import scala.reflect.internal.pickling.{ PickleBuffer, PickleFormat }
 import scala.reflect.io.VirtualFile
@@ -49,11 +50,15 @@ class Global(var currentSettings: Settings, var reporter: Reporter)
   override def isCompilerUniverse = true
   override val useOffsetPositions = !currentSettings.Yrangepos
 
+  type RuntimeClass = java.lang.Class[_]
+  implicit val RuntimeClassTag: ClassTag[RuntimeClass] = ClassTag[RuntimeClass](classOf[RuntimeClass])
+
   class GlobalMirror extends Roots(NoSymbol) {
     val universe: self.type = self
     def rootLoader: LazyType = new loaders.PackageLoader(classPath)
     override def toString = "compiler mirror"
   }
+  implicit val MirrorTag: ClassTag[Mirror] = ClassTag[Mirror](classOf[GlobalMirror])
 
   lazy val rootMirror: Mirror = {
     val rm = new GlobalMirror