Evaluating values in a Scala macro

Macro.scala

import scala.reflect.macros.blackbox

object Macro {
  
  def filterRanges(ranges: List[(Char, Char)])(f: Char => Boolean): List[(Char, Char)] =
    macro filterRangesImpl
  
  def filterRangesImpl(
      c: blackbox.Context
    )(
      ranges: c.Expr[List[(Char, Char)]]
    )(
      f: c.Expr[Char => Boolean]
    ): c.Expr[List[(Char, Char)]] = {
    val r: List[(Char, Char)] = evalUntyped(c)(ranges)
    val p: Char => Boolean    = evalUntyped(c)(f)
    ???
  }

  private def evalUntyped[A](c: blackbox.Context)(a: c.Expr[A]): A =
    c.eval(cloneUntyped(c)(a))

  @SuppressWarnings(Array("org.wartremover.warts.NonUnitStatements"))
  private def cloneUntyped[A](c: blackbox.Context)(a: c.Expr[A]): c.Expr[A] =
    c.Expr[A](c.untypecheck(a.tree.duplicate))

}