Using in modularity

Scala Improvement Process
1

How to rewrite context parameters to the new modularity syntax?

//some type class
trait TC[X]:
  def doSth(sth: X): X

given [T]: TC[List[T]] with
  def doSth(sth: List[T]): List[T] = sth

//can be rewritten to:
  
given [T] => TC[List[T]]:
  def doSth(sth: List[T]): List[T] = sth
  
// but what if we have
given [T](using DummyImplicit): TC[List[T]] with
  def doSth(sth: List[T]): List[T] = sth

//???

It can be hacked via

type Dummy[X] = DummyImplicit

given [T: Dummy] => TC[List[T]]:
  def doSth(sth: List[T]): List[T] = sth
2 
given [T] => DummyImplicit => TC[List[T]]:
  def doSth(sth: List[T]): List[T] = sth

is

    given class given_TC_List[T >: Nothing <: Any](using x$1: DummyImplicit)
       extends Object(), TC[List[given_TC_List.this.T]] {
      T
      protected given val x$1: DummyImplicit
      def doSth(sth: List[given_TC_List.this.T]): List[given_TC_List.this.T] =
        sth
    }
    final given def given_TC_List[T >: Nothing <: Any](using x$1: DummyImplicit)
      : given_TC_List[T] = new given_TC_List[T](using x$1)()
3

Omg, I tried with ?=> Thank you!