Handle usage of O$.this outside of object O

Author: liufengyun

compiler/src/dotty/tools/dotc/transform/init/Summarization.scala

@@ -253,13 +253,16 @@ object Summarization {
 
   def resolveThis(cls: ClassSymbol, pot: Potential, cur: ClassSymbol, source: Tree)(implicit env: Env): Summary =
   trace("resolve " + cls.show + ", pot = " + pot.show + ", cur = " + cur.show, init, s => Summary.show(s.asInstanceOf[Summary])) {
-    if (cls.is(Flags.Package)) (Potentials.empty, Effects.empty)
+    if (cls.is(Flags.Package)) Summary.empty
     else if (cls == cur) (pot.toPots, Effects.empty)
     else if (pot.size > 2) (Potentials.empty, Promote(pot)(source).toEffs)
     else {
-      val pot2 = Outer(pot, cur)(pot.source)
       val enclosing = cur.owner.lexicallyEnclosingClass.asClass
+      // Dotty uses O$.this outside of the object O
+      if (enclosing.is(Flags.Package) && cls.is(Flags.Module)) return Summary.empty
+
       assert(!enclosing.is(Flags.Package), "enclosing = " + enclosing.show + ", cls = " + cls.show + ", pot = " + pot.show + ", cur = " + cur.show)
+      val pot2 = Outer(pot, cur)(pot.source)
       resolveThis(cls, pot2, enclosing, source)
     }
   }