Goal:
  
  G : t
  s0 : VSet.t
  s' : VSet.t
  x : V.t
  y : V.t
  z : V.t
  p : SPath s0 x y
  t0 : VSet.t
  t1 : V.t
  hin : Disjoint t0 s'
  q : SPath s' t1 z
  ============================
   (VSet.Subset s' (VSet.union t0 s'))


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