Address review comments

Author: odersky

compiler/src/dotty/tools/dotc/printing/Formatting.scala

@@ -28,7 +28,7 @@ object Formatting {
       case arg: Showable =>
         try arg.show
         catch {
-          case ex: CyclicReference => "..."
+          case ex: CyclicReference => "... (caught cyclic reference) ..."
           case NonFatal(ex)
           if !ctx.mode.is(Mode.PrintShowExceptions) &&
              !ctx.settings.YshowPrintErrors.value =>

library/src-bootstrapped/scala/StagedTuple.scala

@@ -122,11 +122,11 @@ object StagedTuple {
   }
 
   def applyStaged[Tup <: NonEmptyTuple : Type, N <: Int : Type](tup: Expr[Tup], size: Option[Int], n: Expr[N], nValue: Option[Int]): Expr[Elem[Tup, N]] = {
-    if (!specialize) '{dynamicApply($tup, $n)}.asInstanceOf // TODO: check that variance is OK here
+    if (!specialize) '{dynamicApply($tup, $n)}
     else {
       def fallbackApply(): Expr[Elem[Tup, N]] = nValue match {
         case Some(n) => quoted.QuoteError("index out of bounds: " + n)
-        case None => '{dynamicApply($tup, $n)}.asInstanceOf // TODO: check that variance is OK here
+        case None => '{dynamicApply($tup, $n)}
       }
       val res = size match {
         case Some(1) =>

library/src-bootstrapped/scala/Tuple.scala

@@ -374,7 +374,7 @@ sealed trait NonEmptyTuple extends Tuple {
   inline def fallbackApply(n: Int) =
     inline constValueOpt[n.type] match {
       case Some(n: Int) => error("index out of bounds: ", n)
-      case None => dynamicApply[this.type](this, n)
+      case None => dynamicApply[this.type, n.type](this, n)
     }
 
   inline def apply[This >: this.type <: NonEmptyTuple](n: Int): Elem[This, n.type] =
@@ -462,8 +462,8 @@ object NonEmptyTuple {
     res.asInstanceOf[Result]
   }
 
-  def dynamicApply[This <: NonEmptyTuple] (self: This, n: Int): Elem[This, n.type] = {
-    type Result = Elem[This, n.type]
+  def dynamicApply[This <: NonEmptyTuple, N <: Int] (self: This, n: N): Elem[This, N] = {
+    type Result = Elem[This, N]
     val res = (self: Any) match {
       case self: TupleXXL => self.elems(n)
       case self: Product => self.productElement(n)