VerifyError on super call, trait extends class

[som-snytt]

Compiler version

3.2.1

Minimized code

case class Ball(value: Int) {
  def number = value
  def isMagic = number == 8
}

trait Magicify extends Ball {
  override def number: Int = super[Ball].number + 1
}

object m extends Ball(1) with Magicify

@main def test() = println(m)

Output

Exception in thread "main" java.lang.VerifyError: Bad invokespecial instruction: current class isn't assignable to reference class.

Expectation

2.13.10 says

restricted.scala:8: error: Implementation restriction: traits may not select fields or methods from super[C] where C is a class

same ballpark:
#9341
#1501