从拟引用调用带隐式参数的函数

Question

由于某种原因，每次我尝试调用带有准引号的隐式参数的函数时，它都会失败Can't unquote x.universe.Tree, consider providing an implicit instance of Liftable[x.universe.Tree]

那有什么不对吗?我不能这么做吗?我找不到任何地方说我不能做

import scala.language.experimental.macros
import scala.reflect.macros.whitebox
object Foo {
  def foo: Unit = macro fooImpl
  def fooImpl(c: whitebox.Context): c.Expr[Unit] = {
    import c.universe._
    implicit val x = c      
    val res = q"$sysoutFQN"
    c.Expr(res)
  }
  def sysoutFQN(implicit c: whitebox.Context): c.universe.Tree = {
    import c.universe._
    q"java.lang.System.out.println()"
  }
}

Answer 1

因为路径依赖所以c.universe.Tree != x.universe.Tree

所以你需要写x type

implicit val x: c.type = c