Goal:
    x : VSet.elt  y : VSet.elt  p : VSet.t
  ============================
   (VSet.Equal (VSet.add x (VSet.add y p)) (VSet.add y (VSet.add x p)))


DEBUG:Going to execute:
match goal with
           | H:?P
             |- _ =>
                 match type of P with
                 | Prop =>
                     match goal with
                     | H':context [ H ] |- _ => clear dependent H'
                     end
                 | _ => fail
                 end; VSetDecide.MSetDecideAuxiliary.no_logical_interdep
           | _ => idtac
           end