Errors using context bounded poly functions in Scala 3

polyMap.scala

package polyMap

type Id[T] = T

trait Negation[A]:
  def neg(a: A): A

object Negation:
  def apply[A](using ev: Negation[A]): Negation[A] = ev

  given Negation[Int]     = (a: Int) => -a
  given Negation[String]  = (x: String) => s"no-$x"
  given Negation[Boolean] = (x: Boolean) => !x
 
@main def PolyMapApp(): Unit =
  val t = (10, "foo", true)
  
  // 0. context bound -> syntax not allowed
  //val r = t.map[Id]([T: Negation] => (x: T) => Negation[T].neg(x))
  // error: ']' expected, but ':' found

  // 1. anonymous context parameter -> syntax error!
  //val r = t.map[Id]([T] => (x: T) => (using Negation[T]) => Negation[T].neg(x))
  // error: ')' expected, but '[' found 
  
  // 2. named context parameter -> compilation error!
  //val r = t.map[Id]([T] => (x: T) => (using negation: Negation[T]) => negation.neg(x))
  //Found:    Object with PolyFunction {...}
  //Required: PolyFunction{apply: [t](x$1: t): polyMap.Id[t]}
  
  // 3. context function type -> no compilation error but tuple of lambdas as result.
  //    It seems the compiler is not providing the context parameter implicitly
  type Negate[A] = Negation[A] ?=> A
  val r = t.map[Negate]([T] => (x: T) => (using negation: Negation[T]) => negation.neg(x))
  println(r)
  // (Lambda$10139/824777939@371ca907,Lambda$10139/824777939@1cb498e1,Lambda$10139/824777939@51362999)