Goal:
    x : V.t  y : V.t  p : VSet.t  H : x = y -> False  a : V.t  H0 : y = a
  ============================
   (False ->
    (x = a \/ VSet.In a p /\ y <> a -> (x = a \/ VSet.In a p) /\ y <> a) /\
    ((x = a \/ VSet.In a p) /\ y <> a -> x = a \/ VSet.In a p /\ y <> a))


DEBUG:Going to execute:
intro; clear id
Level 3: evaluation returns
<coq-core.plugins.ltac::cut@0>
where
$1 := False
of type
constr of type tacvalue