Fixing validity checking of denotations.

To get this to work, we need to store the name of a scope netry irectly in the entry. This is arguably the right model anyway. A symbol can have different denotations with different names, and it might exist under different names in different scopes. In the previous model once a symbol's name changed in some phase, all scopes referring to that symbol from previous phases would become invalid. Now, the symbol is still visible under its original name.

1 files changed, 4 insertions, 5 deletions

diff --git a/src/dotty/tools/dotc/core/Denotations.scala b/src/dotty/tools/dotc/core/Denotations.scala
index 8b5dcc5dc..e551c8af2 100644
--- a/src/dotty/tools/dotc/core/Denotations.scala
+++ b/src/dotty/tools/dotc/core/Denotations.scala
@@ -454,11 +454,10 @@ object Denotations {
     def current(implicit ctx: Context): SingleDenotation = {
       val currentPeriod = ctx.period
       val valid = myValidFor
-      def stillValid(denot: SymDenotation) =
-        !denot.exists || {
-          val top = denot.topLevelSym
-          top.owner.info.decl(top.name).symbol eq top
-        }
+      def stillValid(denot: SymDenotation): Boolean =
+        if (!denot.exists || (denot.flags is PackageClass)) true
+        else if (denot.owner is PackageClass) denot.owner.decls.lookup(denot.name) eq symbol
+        else stillValid(denot.owner)
       def bringForward(): SingleDenotation = this match {
         case denot: SymDenotation if stillValid(denot) =>
           var d: SingleDenotation = denot