Goal:
  
  A : Type
  P : A → Type
  Q : A → Type
  x : A
  l : list A
  p : P x
  Hl : All P l
  Hl' : All Q (x :: l)
  ============================
   ((All Q l → All (λ x : A, P x × Q x) l)
    → let H := CoreTactics.block in All (λ x : A, P x × Q x) (x :: l))


DEBUG:Going to execute:
CoreTactics.block_goal
Level 9: evaluation returns
idtac of type tacvalue

Level 7: evaluation returns
idtac of type tacvalue

Level 6: evaluation returns
idtac of type tacvalue

Level 4: evaluation returns
idtac of type tacvalue

Level 2: evaluation returns
idtac of type tacvalue

Level 1: evaluation returns
idtac of type tacvalue