Packages are never fully completed

The previous commit made packages always fully completed.
This is wrong - since new members can be added to packages
at any time, packages are never fully completed.

Author: odersky

src/dotty/tools/dotc/core/SymDenotations.scala

@@ -1211,18 +1211,19 @@ object SymDenotations {
 
     /** The denotation is fully completed: all attributes are fully defined.
      *  ClassDenotations compiled from source are first completed, then fully completed.
+     *  Packages are never fully completed since members can be added at any time.
      *  @see Namer#ClassCompleter
      */
     private def isFullyCompleted(implicit ctx: Context): Boolean = {
       def isFullyCompletedRef(tp: TypeRef) = tp.denot match {
         case d: ClassDenotation => d.isFullyCompleted
         case _ => false
       }
-      def isLocallyFullyCompleted =
-        if (classParents.isEmpty) is(Package) || symbol.eq(defn.AnyClass)
+      def testFullyCompleted =
+        if (classParents.isEmpty) !is(Package) && symbol.eq(defn.AnyClass)
         else classParents.forall(isFullyCompletedRef)
       flagsUNSAFE.is(FullyCompleted) ||
-        isCompleted && isLocallyFullyCompleted && { setFlag(FullyCompleted); true }
+        isCompleted && testFullyCompleted && { setFlag(FullyCompleted); true }
     }
 
     // ------ syncing inheritance-related info -----------------------------