Refinement creates raw type in Java generic signature

[bishabosha]

Compiler version

If you're not sure what version you're using, run print scalaVersion from sbt
(if you're running scalac manually, use scalac -version instead).

Minimized code

package dottyErasure

trait B
trait Cov[+T]

class Z {
  def cov_125(x: Cov[B]): Unit = {}
  def cov_126(x: Cov[B] { type X }): Unit = {}
}

Output

// javap dottyErasure.Z
public class dottyErasure.Z {
  public dottyErasure.Z();
  public void cov_125(dottyErasure.Cov<tastytest.dottyErasure.B>);
  public void cov_126(dottyErasure.Cov);
}

Expectation

both signatures to be the same, unless this is expected as they are not the same type?