Goal:
  
  A : Type
  p : A → bool
  x : A
  l : list A
  IHl : forallb p (List.rev l) = forallb p l
  ============================
   (forallb p (List.rev (l ++ [x])) = forallb p (l ++ [x]))


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