Type bound lost in pattern matching

[Krever]

Compiler version

3.3.3, 3.4.0, 3.4.1-RC2

Minimized code

sealed trait Foo[A]
final case class Bar[A, B <: A]() extends Foo[A]

/*
def getB[A](f: Foo[A]): Unit = f match {
  case bar: Bar[A, b] =>
    println(summon[b <:< A])
}
*/

def getB[A](f: Foo[A]): Unit = f match {
  case bar1: Bar[A, ? <: A] => bar1 match {
    case bar2: Bar[A, b] =>
      println(summon[b <:< A])
  }
}

Output

If we uncomment faulty implementation, the compiler outputs:

Cannot prove that b <:< A.

Expectation

I believe the both variants are equivalent and should work.