scala - Scala宏生成具有抽象字段的特征依赖注入的新类实例

Question

更新：修改代码以使用宏注释，但仍然缺少一些东西

以下代码有效（下面的问题）：

object MyTypes {

  trait RealType

  class Container[RT <: RealType] {
    this: RT =>
  }

  trait SomeRealType extends RealType

  trait PartialRealType extends RealType {
    val needed: Int
  }
}

import MyTypes._

object Container {
  import scala.reflect.macros.blackbox.Context
  import scala.language.experimental.macros

  def helper[RT <: RealType : c.WeakTypeTag](c : Context) : c.Expr[RT] = {
    import c.universe._
    val weakRT = weakTypeOf[RT]
    val genTree = q"new Container[$weakRT] with $weakRT {}"
    c.Expr(genTree)
  }
  def apply[RT <: RealType] : Container[RT] with RT = macro helper[RT]
}

val ok = new Container[SomeRealType] with SomeRealType
val ok_quasi = Container[SomeRealType]

---

我希望能够运行以下内容：

val partial = Container[PartialRealType]{val needed: Int = 0}

我试过这样做：

object Container {
  import scala.reflect.macros.blackbox.Context
  import scala.language.experimental.macros

  def helper[RT <: RealType : c.WeakTypeTag](c : Context)(body: c.Expr[Unit]) : c.Expr[RT] = {
    import c.universe._
    val weakRT = weakTypeOf[RT]
    val genTree = q"new Container[$weakRT] with $weakRT { $body }"
    c.Expr(genTree)
  }
  def apply[RT <: RealType](body: Unit) : Container[RT] with RT = macro helper[RT]
}

但是，这不起作用。