Class cast exception with quoted match

[nicolasstucki]

minimized code

https://contributors.scala-lang.org/t/pre-sip-curried-varargs/3608/89?u=nicolasstucki

[nicolasstucki]

import scala.quoted._
import scala.quoted.matching._

trait Show[T] {
  def show(x: T): String
}

def showInterpolatorImpl(sc: Expr[StringContext], argsExpr: Expr[Seq[Any]])(using qctx: QuoteContext): Expr[String] =
  import qctx.tasty._
  val shownArgs: List[Expr[String]] = argsExpr.unseal.underlyingArgument match
    case Typed(Repeated(args, _), _) =>
      args.foreach {
        case '{ $arg: $t } =>
          summonExpr[Show[$t]] match
            case None =>
              qctx.error(s"No Show instance found for $arg", argsExpr)
              '{""}
            case Some(showImpl) =>
              '{$showImpl.show($arg)}
      }
      Nil
    case _ =>
      qctx.error("Expected statically known argument list", argsExpr)
      Nil

  '{ $sc.s(${Expr.ofList(shownArgs)}) }

inline def (sc: => StringContext) show (args: Any*): String = ${ showInterpolatorImpl('sc, 'args) }

def test = show"${1}"

[nicolasstucki]

Can be minimized to

import scala.quoted._
import scala.quoted.matching._

trait Show[T] {
  def show(x: T): String
}

def showInterpolatorImpl(sc: Expr[StringContext], argsExpr: Expr[Seq[Any]])(using qctx: QuoteContext): Expr[String] =
  argsExpr.unseal match
    case '{ $arg: $t } => 
  ???

inline def (sc: => StringContext) show (args: Any*): String = ${ showInterpolatorImpl('sc, 'args) }