SI-9534 Use BoxedUnit in all cases for creating Array[Unit]

Calling `wrap` or one of the higher-dimension Array factory methods on
the `Manifest` for `Unit` led to an exception because it tried to use
`void` as a primitive type. Unlike all other primitive Scala types,
`Unit` needs to be boxed. The basic `newArray` method was not affected
by this bug because it was already special-cased. The fix is to also
special-case `arrayClass`.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/library/scala/reflect/Manifest.scala b/src/library/scala/reflect/Manifest.scala
index 4ff49c44d0..e099853463 100644
--- a/src/library/scala/reflect/Manifest.scala
+++ b/src/library/scala/reflect/Manifest.scala
@@ -157,6 +157,9 @@ object ManifestFactory {
     override def newArray(len: Int): Array[Unit] = new Array[Unit](len)
     override def newWrappedArray(len: Int): WrappedArray[Unit] = new WrappedArray.ofUnit(new Array[Unit](len))
     override def newArrayBuilder(): ArrayBuilder[Unit] = new ArrayBuilder.ofUnit()
+    override protected def arrayClass[T](tp: Class[_]): Class[Array[T]] =
+      if (tp eq runtimeClass) classOf[Array[scala.runtime.BoxedUnit]].asInstanceOf[Class[Array[T]]]
+      else super.arrayClass(tp)
     private def readResolve(): Any = Manifest.Unit
   }