SI-6710 Clarify stub methods in primitive value classes

- Replaces the implementations of box/unbox in AnyVal companions by
  `???`, the methods are only stubs, and the impls did not correspond
  to the actual behavior. The doc comment already points to the actual
  implementation in BoxesRunTime.
- Replaces the body of `getClass` from `null` to `???` and clarifies in
  a comment why the overrides exist.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/library/scala/Double.scala b/src/library/scala/Double.scala
index a58fa3ed25..9b2cca2cbc 100644
--- a/src/library/scala/Double.scala
+++ b/src/library/scala/Double.scala
@@ -200,7 +200,8 @@ final abstract class Double private extends AnyVal {
   /** Returns the remainder of the division of this value by `x`. */
   def %(x: Double): Double
 
-  override def getClass(): Class[Double] = null
+  // Provide a more specific return type for Scaladoc
+  override def getClass(): Class[Double] = ???
 }
 
 object Double extends AnyValCompanion {
@@ -229,7 +230,7 @@ object Double extends AnyValCompanion {
    *  @param  x   the Double to be boxed
    *  @return     a java.lang.Double offering `x` as its underlying value.
    */
-  def box(x: Double): java.lang.Double = java.lang.Double.valueOf(x)
+  def box(x: Double): java.lang.Double = ???
 
   /** Transform a boxed type into a value type.  Note that this
    *  method is not typesafe: it accepts any Object, but will throw
@@ -241,7 +242,7 @@ object Double extends AnyValCompanion {
    *  @throws     ClassCastException  if the argument is not a java.lang.Double
    *  @return     the Double resulting from calling doubleValue() on `x`
    */
-  def unbox(x: java.lang.Object): Double = x.asInstanceOf[java.lang.Double].doubleValue()
+  def unbox(x: java.lang.Object): Double = ???
 
   /** The String representation of the scala.Double companion object. */
   override def toString = "object scala.Double"