Goal:
    A : Type  n : nat  P : A → bool  d : A
  ============================
   (true → S n < 0 → ∃ x : A, d = x ∧ P x)


DEBUG:Going to execute:
match goal with
           | H:_ ∧ _ |- _ => exact H || (destruct_hyp H; use_hyps)
           | H:_ * _ |- _ => exact H || (destruct_hyp H; use_hyps)
           | H:_ |- _ => solve [ inversion H ]
           | _ => idtac
           end