Reach capabilities get dropped in cv

[Linyxus]

Compiler version

main

Minimized code

import language.experimental.captureChecking
trait File:
  def write(x: String): Unit
def usingFile[R](op: File^ => R): R = ???
case class Box[+T](get: T)

def main(): Unit =
  val trick: Box[File^] -> Unit = (x: Box[File^]) =>
    val x1: Box[File^{x*}] = x
    val x2: File^{x*} = x.get
    x2.write("Hello")
  val bad: () -> Unit = usingFile[() -> Unit]: f =>
    val boxed: Box[File^] = Box(f)
    () => trick(boxed)
  bad()  // boom

Output

It compiles.

Expectation

It should not.

I am working on a fix.

[Linyxus]

Has been resolved.