Goal:
  
  A : Type
  B : Type
  f : A → B
  H : ∀ l : list A, nth_error (map f l) 0 = option_map f (nth_error l 0)
  l : list A
  ============================
   (option_map f (nth_error l 1) = nth_error (map f l) 1)


DEBUG:Going to execute:
<coq-core.plugins.ltac::trivial@0> $1 $2