Goal:
    A : Type  n : nat  a : A  IHn : List.rev (repeat a n) = repeat a n
  ============================
   (List.rev (repeat a (S n)) = repeat a (S n))


DEBUG:Going to execute:
<coq-core.plugins.ltac::replace@0> $1 $2 $3 $4
DEBUG LTAC Evaluated term: (n + 1)