Goal:
    x : VSet.elt  y : VSet.elt  p : VSet.t  H : x <> y
  ============================
   (VSet.Equal (VSet.add x (VSet.remove y p)) (VSet.remove y (VSet.add x p)))


DEBUG:Going to execute:
match goal with
           | H':context [ H ] |- _ => clear dependent H'
           end
DEBUG LTAC Evaluated term: (x <> y)
DEBUG LTAC Evaluated term: Prop
Level 3: type of P
 has value 
Prop