Multiple colliding roles

role tree{
 method bark(){...}
}

role dog{
  method bark(){...}
}

class dog_tree does tree does dog{
  method dog::bark(){ say "woof" }
  method tree::bark(){ say "rough" }
}

sub pet_dog( my dog $dog ){
  $dog.bark;
  # actually calls
  # $dog.meta.does(dog).bark
  # $dog.dog::bark
  # or something similar
}