Goal:
    A : Type  v : A
  ============================
   (((∃ n : nat, hd_error (skipn n []) = Some v) → False)
    ∧ (False → ∃ n : nat, hd_error (skipn n []) = Some v))


DEBUG:Going to execute:
match goal with
           | H:¬ _ |- _ => solve [ case H; trivial ]
           end
Level 1: Backtrace:

No such assumption.
Level 0: Backtrace:

No such assumption.
Level 0: Backtrace:

No such assumption.
Level 0: Backtrace:

No such assumption.