Fix for SerialVersionUID instability.

Can hardly believe this has been broken for a decade or so, but
there it is - see test case. Four classes attempt to set their
SerialVersionUID to 13. One succeeds. No warnings or errors. The
output before this patch (for me anyway - your random numbers may
differ) was:

  860336111422349646
  13
  8409527228024057943
  -7852527872932878365

There was already code in place for rejecting annotations
with non-constant args when constant args are required, but
that check is only performed on ClassfileAnnotations, and
SerialVersionUID was a StaticAnnotation. Maybe people don't
reach for ClassfileAnnotation because of this giant warning
which I see no way to suppress:

  warning: Implementation restriction: subclassing Classfile does
  not make your annotation visible at runtime. If that is what you
  want, you must write the annotation class in Java.

Why did I change the name of the field from uid to value?
If you don't use the name 'value', you have to name the argument
every time you use it, even if it's the only parameter. I didn't
relish breaking every usage of scala's @SerialVersionUID in the
known universe.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/library/scala/SerialVersionUID.scala b/src/library/scala/SerialVersionUID.scala
index 1f7d047060..77094f0bbf 100644
--- a/src/library/scala/SerialVersionUID.scala
+++ b/src/library/scala/SerialVersionUID.scala
@@ -12,4 +12,4 @@ package scala
  * Annotation for specifying the `static SerialVersionUID` field
  * of a serializable class.
  */
-class SerialVersionUID(uid: Long) extends scala.annotation.StaticAnnotation
+class SerialVersionUID(value: Long) extends scala.annotation.ClassfileAnnotation