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


DEBUG:Going to execute:
setoid_rewrite skipn_nil; cbn
Level 0: Backtrace:

No matching clauses for match.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.
Level 1: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.