About: https://github.com/lampepfl/dotty/issues/6996

StringLiteralType.scala

object StringLiteralType {
  def isAType(arg: String): Unit = arg match {    
    case _ : "a" => println("This is `a` type")
    case _ => println("not `a`")
  }

  def a1 = isAType("a")
  def a2 = isAType(new String("a"))
  def a3 = new String("a").isInstanceOf["a"]


  def main(args: Array[String]): Unit = {
    println(a1)
    println(a2)
    println(a3)
  }
}