Goal:
  
  A : Type
  H : ReflectEq A
  l : list A
  _x_ : list A
  a : A
  l0 : list A
  p : [] = (a :: l0) ++ _x_
  ============================
   (a :: l0 = [])


DEBUG:Going to execute:
solve
[ do
![ solve
 [ trivial | apply : eq_sym ; trivial ]
 | discriminate
 | contradiction
 | Ltac.split ]
| case not_locked_false_eq_true; Ltac.assumption
| match goal with
  | H:¬ _ |- _ => solve [ case H; trivial ]
  end ]