Drop Module flag from lifted symbols.

Reason: A lifted module is no longer a module (i.e. singleton object) in the scope
to which it is lifted.

Fixes #689.

Author: odersky

src/dotty/tools/dotc/transform/LambdaLift.scala

@@ -309,7 +309,8 @@ class LambdaLift extends MiniPhase with IdentityDenotTransformer { thisTransform
         local.copySymDenotation(
           owner = newOwner,
           name = newName(local),
-          initFlags = local.flags &~ InSuperCall | Private | maybeStatic,
+          initFlags = local.flags &~ (InSuperCall | Module) | Private | maybeStatic,
+            // drop Module because class is no longer a singleton in the lifted context.
           info = liftedInfo(local)).installAfter(thisTransform)
         if (local.isClass)
           for (member <- local.asClass.info.decls)

tests/run/i689.scala

@@ -0,0 +1,10 @@
+object Test {
+  def main(args: Array[String]): Unit = {
+    object A {
+      def a = new A
+      def y = 0
+    }
+    class A { A.y }
+    A.a
+  }
+}