SI-9702 Fix backend crash with classOf[T] annotation argument

This commit fixes various issues with classOf literals and Java
annotations.

  - Ensure that a Type within a ConstantType (i.e., a classOf literal)
    is erased, so `classOf[List[Int]]` becomes `classOf[List]`.
  - Ensure that no non-erased types are passed to `typeToBType` in the
    backend. This happens for Java annotations: the annotation type and
    `classOf` annotation arguments are not erased, the annotationInfos
    of a symbol are not touched in the compiler pipeline.
  - If T is an alias to a value class, ensure that `classOf[T]` erases
    to the value class by calling `dealiasWiden` in erasure.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/Erasure.scala b/src/compiler/scala/tools/nsc/transform/Erasure.scala
index 41f22e5669..ba15b01446 100644
--- a/src/compiler/scala/tools/nsc/transform/Erasure.scala
+++ b/src/compiler/scala/tools/nsc/transform/Erasure.scala
@@ -1112,7 +1112,7 @@ abstract class Erasure extends AddInterfaces
 
         case Literal(ct) if ct.tag == ClazzTag
                          && ct.typeValue.typeSymbol != definitions.UnitClass =>
-          val erased = ct.typeValue match {
+          val erased = ct.typeValue.dealiasWiden match {
             case tr @ TypeRef(_, clazz, _) if clazz.isDerivedValueClass => scalaErasure.eraseNormalClassRef(tr)
             case tpe => specialScalaErasure(tpe)
           }