Unreachable code error when matching on Scala 3 sealed trait

[jadenPete]

Reproduction steps

Scala 2 version: 2.13.16
Scala 3 version: 3.6.3

1. Compile the following code with Scala 3:

sealed trait Pet

case class Dog(name: String) extends Pet
case class Cat(name: String) extends Pet

2. Compile the following code with Scala 2:

class PetPrinter {
  def printPet(pet: Pet): Unit = println(
    pet match {
      case Dog(_) => "I'm a dog."
      case Cat(_) => "I'm a cat."
    },
  )
}

3. Observe the following compiler error:

[Error] .../Scala2.scala:5:22: unreachable code
[Error] Applicable -Wconf / @nowarn filters for this fatal warning: msg=<part of the message>, cat=other-match-analysis, site=PetPrinter.printPet
[Error]       case Cat(_) => "I'm a cat."
[Error] 

Problem

The Scala 2 code should've compiled successfully.

[lrytz]

I tried but could not reproduce this; I'm not getting the "unreachable code" warning. Can you share step by step instructions, or a small project that shows the issue?

[lrytz]

Please reopen if appropriate.

[som-snytt]

Me neither, using scala-cli.

//> using scala 2.13.16
//> using options -Ytasty-reader -Xsource:3-cross -Xlint
//> using dep org.scala-lang:scala3-library_3:3.7.1

other-match-analysis is Scala 2; does [Error] mean sbt?