Goal:
  
  G : t
  fuel : nat
  s : VSet.t
  x : V.t
  z : V.t
  IHfuel : forall (s : VSet.t) (x z : V.t),
           lsp00_fast fuel s x z = lsp00 fuel s x z
  acc : Nbar.t
  src : V.t
  w : Z
  tgt : V.t
  ============================
   (max acc (Some w + lsp00_fast fuel (VSet.remove x s) tgt z) =
    max acc (Some w + lsp00 fuel (VSet.remove x s) tgt z))


DEBUG:Going to execute:
solve
[ do
![ solve
 [ trivial | apply : eq_sym ; trivial ]
 | discriminate
 | contradiction
 | Ltac.split ]
| case not_locked_false_eq_true; Ltac.assumption
| match goal with
  | H:~ _ |- _ => solve [ case H; trivial ]
  end ]