Goal:
    G : t  x : V.t  i : V.t  source_vertex0 : VSet.In (s G) (V G)
  ============================
   True


DEBUG:Going to execute:
<Coq.Init.Tauto.find_cut>
            ltac:(fun id0 id1 X2 =>
                    assert X2; [ exact (id0 id1) | clear id0 ])
Level 5: evaluation returns
<coq-core.plugins.tauto::is_disj@0>
where
tauto_flags := 
of type
tauto_flags
X1 := VSet.In (s G) (V G)
of type
constr of type tacvalue

Level 5: Backtrace:

Tactic failure.
Level 5: Backtrace:

Tactic failure.
Level 4: Backtrace:

Tactic failure.
Level 4: Backtrace:

Tactic failure.
Level 4: Backtrace:

Tactic failure.
Level 4: Backtrace:

Tactic failure.