Goal:
    x : V.t  y : V.t  p : VSet.t  a : V.t
  ============================
   ((x = a \/ y = a \/ VSet.In a p -> y = a \/ x = a \/ VSet.In a p) /\
    (y = a \/ x = a \/ VSet.In a p -> x = a \/ y = a \/ VSet.In a p))


DEBUG:Going to execute:
Ltac.split
Level 3: evaluation returns
<coq-core.plugins.tauto::is_conj@0>
where
tauto_flags := 
of type
tauto_flags
X1 := (x = a \/ y = a \/ VSet.In a p -> y = a \/ x = a \/ VSet.In a p) /\
      (y = a \/ x = a \/ VSet.In a p -> x = a \/ y = a \/ VSet.In a p)
of type
constr of type tacvalue