Scala: compilation error when declaring continuation of type Any => Nothing

Question

This code gives compilation error:

import scala.util.continuations._

object CTest {
    def loop: Nothing = reset {
        shift {c: (Unit => Nothing) => c()}
        loop
    }

   def main(argv: Array[String]) {loop}
}

Error message:

    error: type mismatch;
 found   : ((Unit) => Nothing) => (Unit) => Nothing
 required: ((Unit) => B) => (Unit) => Nothing

But this code works as expected:

import scala.util.continuations._

object CTest {
    def loop: Nothing = reset {
        shift {c: (Unit => Any) => c.asInstanceOf[Unit => Nothing]()}
        loop
    }

   def main(argv: Array[String]) {loop}
}

The question is: why Scala compiler hates me continuations of type Any => Nothing?

Answer 1

It compiles if I specify the type arguments:

shift[Unit, Nothing, Nothing] {c: (Unit => Nothing) => c()}

It looks to me like the compiler should infer that B is Nothing, but it doesn't.