Goal:
    T : Type -> Type  M : Monad T  A : Type  P : A -> Type  Q : A -> Type
  ============================
   ((forall x : A, ∥ Q x ∥ -> T (∥ P x ∥)) ->
    list A -> forall (a : A) (l : list A), ∥ All Q (a :: l) ∥ -> ∥ Q a ∥)


DEBUG:Going to execute:
intro || (let H := fresh in
                     intro
                     H)
DEBUG LTAC Evaluated term: (list A ->
                            forall (a : A) (l : list A),
                            ∥ All Q (a :: l) ∥ -> ∥ Q a ∥)
DEBUG LTAC Evaluated term: Prop