False-positive unreachable case warning

[arainko]

Compiler version

3.3.1, 3.4.0-RC1-bin-20231223-938d405-NIGHTLY

Minimized code

//> using scala 3.3.1

sealed trait Plan[+E <: Plan.Error, +F[+e <: E] <: Plan.Fallible[e]]

object Plan {
  case class Upcast() extends Plan[Nothing, Nothing]
  case class BetweenProducts[+E <: Plan.Error, +F[+e <: E] <: Plan.Fallible[e]](fields: List[Plan[E, F]]) extends Plan[E, F]
  case class Error() extends Plan[Plan.Error, Nothing]
  case class Fallible[+E <: Plan.Error]() extends Plan[E, Plan.Fallible]
}

@main def main = {
  val erroneousNotFallible: Plan[Plan.Error, Nothing] = Plan.BetweenProducts(Nil)
  
  erroneousNotFallible match
    case Plan.Upcast() => println("not boom")
    case Plan.BetweenProducts(fields) => println("reachable after all")
    case Plan.Error() => println("not boom")
}

Output

Compiling project (Scala 3.3.1, JVM (11))
[warn] ./Repro.scala:17:10
[warn] Unreachable case
[warn]     case Plan.BetweenProducts(fields) => println("reachable after all")
[warn]          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Compiled project (Scala 3.3.1, JVM (11))
reachable after all

Expectation

No unreachable case warning.