Goal:
    A : Type  p : nat → A → bool  n : nat  l : list A  i : nat  x : A
  ============================
   (false → False)


DEBUG:Going to execute:
contradiction
Level 1: Backtrace:

Cannot find a relation to rewrite.
Level 0: Backtrace:

Cannot find a relation to rewrite.
Level 0: Backtrace:

Cannot find a relation to rewrite.