Decompiler produces a strange unneeded cast but it's `(<unknown>)`

[Kroppeb]

Source:

  public void test() {
    boolean vvv1 = true, vvv2 = false;
    try {
      if (vvv2) {
        throw new RuntimeException();
      }
      vvv2 = vvv1;
    } finally {
      char vvv31;
    }
    vvv1 = vvv2;
    Object vvv34 = null;
    while (vvv34 != null) {
      vvv2 = vvv1;
      System.out.println(vvv34);
      vvv1 = vvv2;
    }
  }

Result:

   public void test() {
      boolean vvv1 = true;
      boolean vvv2 = false;

      try {
         if (vvv2) {
            throw new RuntimeException();
         }

         vvv2 = vvv1;
      } finally {
         ;
      }

      boolean var8 = (<unknown>)vvv2; // what?

      for(Object vvv34 = null; vvv34 != null; var8 = var8) {
         System.out.println(vvv34);
      }

   }