Package denotations are never transformed

Packages should always have a single denotation, which is invariant for all transformations.
Package members should always be entered in the first phase, and should never be entered
after a given phase.

This reflects the fact that package members correspond to classfiles. Once you create a classfile, it
stays around and is available from the start of the next run. Also, we need to prevent multiple
denotation versions of packages from hanging on to stale symbols. It would not be enough to replace
a package member by a newly compiled one; if packages had multiple denotations we'd have to do this
for all of them.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/dotty/tools/dotc/core/Denotations.scala b/src/dotty/tools/dotc/core/Denotations.scala
index dceec47a2..fa2292c60 100644
--- a/src/dotty/tools/dotc/core/Denotations.scala
+++ b/src/dotty/tools/dotc/core/Denotations.scala
@@ -553,7 +553,9 @@ object Denotations {
                 startPid = cur.validFor.firstPhaseId
               else {
                 next match {
-                  case next: ClassDenotation => next.resetFlag(Frozen)
+                  case next: ClassDenotation =>
+                    assert(!next.is(Package), s"illegal transfomation of package denotation by transformer ${ctx.withPhase(transformer).phase}")
+                    next.resetFlag(Frozen)
                   case _ =>
                 }
                 next.nextInRun = cur.nextInRun