Use a delegate for FlagSet extension methods

Author: odersky

compiler/src/dotty/tools/dotc/core/Flags.scala

@@ -19,7 +19,7 @@ object Flags {
   type FlagSet = opaques.FlagSet
   def FlagSet(bits: Long): FlagSet = opaques.FlagSet(bits)
 
-  implicit object FlagOps {
+  delegate FlagOps {
 
     def (xs: FlagSet) bits: Long = opaques.toBits(xs)
 

compiler/src/dotty/tools/dotc/tastyreflect/KernelImpl.scala

@@ -17,6 +17,8 @@ import dotty.tools.dotc.util.SourceFile
 
 import scala.tasty.reflect.Kernel
 
+import delegate Flags.FlagOps // DOTTY problem: this should not be needed as we should include prefixes of aliases in implicit scopes
+
 class KernelImpl(val rootContext: core.Contexts.Context, val rootPosition: util.SourcePosition) extends Kernel {
 
   private implicit def ctx: core.Contexts.Context = rootContext

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

@@ -3,6 +3,7 @@ package typer
 
 import core._
 import Types._, Contexts._, Flags._, Symbols._, Annotations._
+import delegate Flags.FlagOps // DOTTY problem: this should not be needed as we should include prefixes of aliases in implicit scopes
 
 object Variances {