Tree attachments are not preserved by typer transform of {stats, expr.f}(args) to {stats, expr.f(args)}

[retronym]

Reproduction steps

class C {
  def test(a: Any, b: Any)(byname: => Any)(d: AnyRef) = 0

  val x = test(b = "", a = "")(null)(null)
}

Problem

The block introduced by NamesDefaults bears a NamedApplyInfo tree attachment. This is not attached to the corresponding block post typer. This discards some useful information that could be used by downstream third party compiler plugins.