Unreachable case false-positive for type-parametered boolean extractors

[ivan-klass]

Compiler version

3.5.1

Minimized code

import scala.reflect.ClassTag

opaque type EntryName = String

object EntryName:
  def apply[T](using cls: ClassTag[T]): EntryName =
    cls.runtimeClass.getSimpleName.replaceAll("([a-z])([A-Z]+)", "$1 $2")

  def unapply[T](s: EntryName)(using ct: ClassTag[T]): Boolean = s == apply[T]


sealed abstract class Shape

case class Square(side: Int) extends Shape
case class Circle(radius: Int) extends Shape
case class Rectangle(xSide: Int, ySide: Int) extends Shape

// make groups by EntryName while ordering
given Ordering[(EntryName, Int)] = Ordering.by { case (n, size) => n match 
  case EntryName[Circle]() => (0, size)
  case EntryName[Square]() => (1, size) // reachable!
  case EntryName[Rectangle]() => (2, size)  // reachable!
}

println(
  Vector(
  EntryName[Circle] -> 4,
  EntryName[Rectangle] -> 8,
  EntryName[Square] -> 12,
  EntryName[Circle] -> 1
).sorted == Vector(
    EntryName[Circle] -> 1,
    EntryName[Circle] -> 4,
    EntryName[Square] -> 12,
    EntryName[Rectangle] -> 8,
  )
)

Output

[E030]  Match case Unreachable Warning:
  case EntryName[Square]() => (1, size)

[E030]  Match case Unreachable Warning:
  case EntryName[Rectangle]() => (2, size)

Expectation

No warnings issued

Note: also reproducible without opaque type