Cannot create impure partial functions with scala2-library-cc

[natsukagami]

Compiler version

Latest main

Minimized code

//> using scala 3.7.2-RC1-bin-SNAPSHOT
//> using dep org.scala-lang::scala2-library-cc-tasty-experimental::3.7.2-RC1-bin-SNAPSHOT
import language.experimental.captureChecking
import scala.caps.Capability

class A

def run(f: PartialFunction[A, A]^): A = f(A())

class File extends Capability:
  def read() = ()

def main() =
  val file = File()

  run:
    case a =>
      file.read()
      a

Output

[error] ./partial-function.scala:17:5
[error] illegal inheritance: self type 
[error]   scala.runtime.AbstractPartialFunction[Option[partialfunctions.A],
[error]     partialfunctions.A]
[error]  with Serializable {...}^{file} of anonymous class
[error]   
[error]     scala.runtime.AbstractPartialFunction[Option[partialfunctions.A],
[error]       partialfunctions.A]
[error]    with 
[error] Serializable {...} does not conform to self type scala.runtime.AbstractPartialFunction[Option[partialfunctions.A],
[error]   partialfunctions.A]
[error] of parent class AbstractPartialFunction

This is due to AbstractPartialFunction being declared with a self =>, which assumes a pure self type:

abstract class AbstractPartialFunction[@specialized(Specializable.Arg) -T1, @specialized(Specializable.Return) +R] extends Function1[T1, R] with PartialFunction[T1, R] { self =>
  // ...
}

Since AbstractPartialFunction is specialized, not sure if we can override this in scala2-library-cc Tasty.

Expectation

Should compile.