Collective extension syntax cannot be used inside function

[SrTobi]

minimized code

object Main {
  def main(args: Array[String]): Unit = {
    extension on (a: AnyRef) {
      def putout(): Unit = println(a)
    }
    
    "blub".putout()
  }
}

(usign 0.22.0-bin-20200202-c2478a3-NIGHTLY)

Compilation output

[error] -- [E006] Unbound Identifier Error: /home/tobi/workspace/playground/dotty-test/src/main/scala/Main.scala:4:4 
[error] 4 |    extension on (a: AnyRef) {
[error]   |    ^^^^^^^^^
[error]   |    Not found: extension
[error] -- [E008] Member Not Found Error: /home/tobi/workspace/playground/dotty-test/src/main/scala/Main.scala:8:11 
[error] 8 |    "blub".putout()
[error]   |    ^^^^^^^^^^^^^
[error]   |    value putout is not a member of String
[error] two errors found
[

expectation

Compiles

Note

Putting the extension clause outside it works:

object Main {
  extension on (a: AnyRef) {
    def putout(): Unit = println(a)
  }

  def main(args: Array[String]): Unit =
    "blub".putout()
}

and the desugared version (described here https://dotty.epfl.ch/docs/reference/contextual/extension-methods-new.html) also works:

object Main {
  def main(args: Array[String]): Unit = {
    given extension_ops: AnyRef {
      def (a: AnyRef).putout(): Unit = println(a)
    }

    "blub".putout()
  }
}

so this seems to be either a bug or an unnecessary restriction.