ClassCastException running staged code that uses typeOf

[tellurion]

minimized code

import scala.quoted._
import scala.quoted.staging.{run, withQuoteContext, Toolbox}

object Main {
  given Toolbox = Toolbox.make(getClass.getClassLoader)

  def main(args: Array[String]): Unit = {
    println(staged[Int])
  }

  def staged[T] = run { (given qctx: QuoteContext) =>
    import qctx.tasty.{_, given}
    given typeT: quoted.Type[T]
    val tTypeTree = typeT.unseal // class cast exception
    val tt = typeOf[T] // also class cast exception

    '{ "in staged" }
  }
}

Execution output

[info] Running Main
[error] (run-main-a) java.lang.ClassCastException: Main$typeT$1$ cannot be cast to dotty.tools.dotc.tastyreflect.TreeType
[error] java.lang.ClassCastException: Main$typeT$1$ cannot be cast to dotty.tools.dotc.tastyreflect.TreeType
[error] 	at dotty.tools.dotc.core.quoted.PickledQuotes$.quotedTypeToTree(PickledQuotes.scala:48)
[error] 	at dotty.tools.dotc.tastyreflect.ReflectionCompilerInterface.QuotedType_unseal(ReflectionCompilerInterface.scala:1777)
[error] 	at dotty.tools.dotc.tastyreflect.ReflectionCompilerInterface.QuotedType_unseal(ReflectionCompilerInterface.scala:1776)
[error] 	at scala.tasty.reflect.QuotedOps$QuotedTypeAPI.unseal(QuotedOps.scala:19)
[error] 	at Main$.staged$$anonfun$1(Main.scala:14)
[error] 	at scala.quoted.staging.package$.run$$anonfun$1(staging.scala:19)
[error] 	at scala.quoted.staging.QuoteCompiler$QuotedFrontend.runOn$$anonfun$1(QuoteCompiler.scala:71)
[error] 	at scala.collection.immutable.List.flatMap(List.scala:265)
[error] 	at scala.quoted.staging.QuoteCompiler$QuotedFrontend.runOn(QuoteCompiler.scala:84)
[error] 	at dotty.tools.dotc.Run.runPhases$4$$anonfun$4(Run.scala:161)
[error] 	at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:15)
[error] 	at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:10)
[error] 	at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
[error] 	at dotty.tools.dotc.Run.runPhases$5(Run.scala:171)
[error] 	at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:179)
[error] 	at dotty.runtime.function.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
[error] 	at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:65)
[error] 	at dotty.tools.dotc.Run.compileUnits(Run.scala:186)
[error] 	at dotty.tools.dotc.Run.compileUnits(Run.scala:128)
[error] 	at scala.quoted.staging.QuoteCompiler$ExprRun.compileExpr(QuoteCompiler.scala:104)
[error] 	at scala.quoted.staging.QuoteDriver.run(QuoteDriver.scala:37)
[error] 	at scala.quoted.staging.Toolbox$$anon$1.run(Toolbox.scala:36)
[error] 	at scala.quoted.staging.package$.run(staging.scala:19)
[error] 	at Main$.staged(Main.scala:18)
[error] 	at Main$.main(Main.scala:8)
[error] 	at Main.main(Main.scala)
[error] 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[error] 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
[error] 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[error] 	at java.lang.reflect.Method.invoke(Method.java:498)
[error] Nonzero exit code: 1
[error] (Compile / run) Nonzero exit code: 1

The code compiles without error and throws exception when run.
Expectation is that it should either not compile if unsupported, or run without error.

[nicolasstucki]

given typeT: quoted.Type[T] creates a new subclass of quoted.Type that the compiler does not know. This should be an error.