Fix to elidable prefix.

The previous condition was too weak. The fix revealed a problem where
an "undefined symbol" error was thrown when reading an alias annotation
in the unpickler. The exception is now suppressed, the comment explains why.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/dotty/tools/dotc/core/Denotations.scala b/src/dotty/tools/dotc/core/Denotations.scala
index 376e63c41..c56d2b882 100644
--- a/src/dotty/tools/dotc/core/Denotations.scala
+++ b/src/dotty/tools/dotc/core/Denotations.scala
@@ -576,7 +576,7 @@ object Denotations {
             //println(s"searching: $cur at $currentPeriod, valid for ${cur.validFor}")
             cur = cur.nextInRun
             cnt += 1
-            assert(cnt <= MaxPossiblePhaseId, demandOutsideDefinedMsg)
+            if (cnt > MaxPossiblePhaseId) throw new NotDefinedHere(demandOutsideDefinedMsg)
           }
           cur
         }
@@ -890,5 +890,10 @@ object Denotations {
     util.Stats.record("stale symbol")
     override def getMessage() = msg
   }
+
+  class NotDefinedHere(msg: => String) extends Exception {
+    util.Stats.record("not defined here")
+    override def getMessage() = msg
+  }
 }