Fix of computeDenot.

Since we demand that after erasure all TermRefs are SymDenotations we need to
assure this when computing the denotations of term refs in new phases.

1 files changed, 10 insertions, 4 deletions

diff --git a/src/dotty/tools/dotc/core/Types.scala b/src/dotty/tools/dotc/core/Types.scala
index d0ddfdd28..6dce5581d 100644
--- a/src/dotty/tools/dotc/core/Types.scala
+++ b/src/dotty/tools/dotc/core/Types.scala
@@ -1173,8 +1173,12 @@ object Types {
               if (newd.exists) newd else d.staleSymbolError
             }
           case d =>
-            if (d.validFor.runId == ctx.period.runId) d.current
-            else loadDenot
+            if (d.validFor.runId != ctx.period.runId)
+              loadDenot
+            else if (ctx.erasedTypes && lastSymbol != null)
+              denotOfSym(lastSymbol) // avoid keeping non-sym denotations after erasure; they violate the assertErased contract
+            else
+              d.current
         }
         if (ctx.typerState.ephemeral) record("ephemeral cache miss: loadDenot")
         else if (d.exists) {
@@ -1623,8 +1627,10 @@ object Types {
   final class CachedSuperType(thistpe: Type, supertpe: Type) extends SuperType(thistpe, supertpe)
 
   object SuperType {
-    def apply(thistpe: Type, supertpe: Type)(implicit ctx: Context): Type =
+    def apply(thistpe: Type, supertpe: Type)(implicit ctx: Context): Type = {
+      assert(thistpe != NoPrefix)
       unique(new CachedSuperType(thistpe, supertpe))
+    }
   }
 
   /** A constant type with  single `value`. */
@@ -1817,7 +1823,7 @@ object Types {
     }
     catch {
       case ex: AssertionError =>
-        println(i"failure while taking result signture of $resultType")
+        println(i"failure while taking result signture of $this: $resultType")
         throw ex
     }