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.

3 files changed, 24 insertions, 0 deletions

diff --git a/test/files/run/reflection-tags.check b/test/files/run/reflection-tags.check
new file mode 100644
index 0000000000..375518e921
--- /dev/null
+++ b/test/files/run/reflection-tags.check
@@ -0,0 +1 @@
+List()
diff --git a/test/files/run/reflection-tags.scala b/test/files/run/reflection-tags.scala
new file mode 100644
index 0000000000..fba90f61e9
--- /dev/null
+++ b/test/files/run/reflection-tags.scala
@@ -0,0 +1,17 @@
+import scala.reflect.runtime.universe._
+import scala.reflect.ClassTag
+
+object Test extends App {
+  var typeMembers = typeOf[scala.reflect.api.Universe].members.filter(sym => sym.isType && !sym.isClass).toList
+  typeMembers = typeMembers.filter(_.name != TypeName("ModifiersCreator")) // type ModifiersCreator = ModifiersExtractor
+  val tags = typeOf[scala.reflect.api.Universe].members.filter(sym => sym.isImplicit).toList
+
+  typeMembers.foreach(_.typeSignature)
+  tags.foreach(_.typeSignature)
+
+  val outliers = typeMembers.filter(tm => !tags.exists(tag => tag.typeSignature match {
+    case NullaryMethodType(TypeRef(_, sym, targ :: Nil)) => sym == typeOf[ClassTag[_]].typeSymbol && targ.typeSymbol == tm
+    case _ => false
+  }))
+  println(outliers)
+}
\ No newline at end of file
diff --git a/test/junit/scala/tools/nsc/symtab/SymbolTableForUnitTesting.scala b/test/junit/scala/tools/nsc/symtab/SymbolTableForUnitTesting.scala
index b42e9a07cb..25d8c4667f 100644
--- a/test/junit/scala/tools/nsc/symtab/SymbolTableForUnitTesting.scala
+++ b/test/junit/scala/tools/nsc/symtab/SymbolTableForUnitTesting.scala
@@ -1,6 +1,7 @@
 package scala.tools.nsc
 package symtab
 
+import scala.reflect.ClassTag
 import scala.reflect.internal.{Phase, NoPhase, SomePhase}
 import scala.tools.util.PathResolver
 import util.ClassPath
@@ -89,4 +90,9 @@ class SymbolTableForUnitTesting extends SymbolTable {
   val currentFreshNameCreator = new reflect.internal.util.FreshNameCreator
 
   phase = SomePhase
+
+  type RuntimeClass = java.lang.Class[_]
+  implicit val RuntimeClassTag: ClassTag[RuntimeClass] = ClassTag[RuntimeClass](classOf[RuntimeClass])
+  implicit val MirrorTag: ClassTag[Mirror] = ClassTag[Mirror](classOf[GlobalMirror])
+  implicit val TreeCopierTag: ClassTag[TreeCopier] = ClassTag[TreeCopier](classOf[TreeCopier])
 }