Address review

Author: liufengyun

compiler/src/dotty/tools/dotc/typer/Checking.scala

@@ -785,10 +785,9 @@ trait Checking {
                    |its constructor cannot be called again""", call.sourcePos)
 
       if (caller.is(Module)) {
-        val objRef = caller.sourceModule.termRef
         val traverser = new TreeTraverser {
           def traverse(tree: Tree)(implicit ctx: Context) = tree match {
-            case tree: RefTree if tree.isTerm && tree.tpe <:< objRef =>
+            case tree: RefTree if tree.isTerm && (tree.tpe.widen.classSymbol eq caller) =>
               ctx.error("super constructor cannot be passed a self reference", tree.sourcePos)
             case _ =>
               traverseChildren(tree)

tests/run/i4659b.scala

@@ -1,5 +1,6 @@
 case class SourcePosition(outer: SourcePosition = (NoSourcePosition: SourcePosition))
 
+// The code should not compile -- currently out of reach
 object NoSourcePosition extends SourcePosition()
 
 object Test extends App {