Goal:
    x : V.t  s : VSet.t
  ============================
   (~ VSet.In x (VSet.remove x s))


DEBUG:Going to execute:
match goal with
           | H:?T
             |- _ =>
                 progress change T with V.t in H;
                  repeat
                   match goal with
                   | J:_ |- _ => progress change T with V.t in J
                   | |- _ => progress change T with V.t
                   end
           | H:forall x : ?T, _
             |- _ =>
                 progress change T with V.t in H;
                  repeat
                   match goal with
                   | J:_ |- _ => progress change T with V.t in J
                   | |- _ => progress change T with V.t
                   end
           end
DEBUG LTAC Evaluated term: V.t
DEBUG LTAC Evaluated term: V.t
Level 1: Backtrace:

Failed to progress.
Level 1: Backtrace:

Failed to progress.
Level 1: Backtrace:

Failed to progress.
Level 0: Backtrace:

No matching clauses for match.