Goal:
    A : Type  P : A → Type  a : A  X : All P [a]
  ============================
   (P a)


DEBUG:Going to execute:
DepElim.do_intros H; DepElim.generalize_by_eqs H
Level 1: evaluation returns
DepElim.do_intros H; DepElim.generalize_by_eqs H; tac H
where
tac := fun hyp => DepElim.do_case hyp
       where
       id := X
       of type
       constr
of type
tacvalue
H := X
of type
constr of type tacvalue