Goal:
  
  A : Type
  P : nat → A → Type
  p : nat → A → bool
  n : nat
  Hp : ∀ (i : nat) (x : A), reflectT (P i x) (p i x)
  ============================
   (alli p n [] → Alli P n [])


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