Goal:
    P : E.t -> Prop  P_Proper : Proper (E.eq ==> impl) P  s : t
  ============================
   (Forall P nil -> forall x : elt, InA E.eq x nil -> P x)


DEBUG:Going to execute:
inversion 2
Level 0: Backtrace:

Not an inductive definition.
Level 0: Backtrace:

Not an inductive definition.