Goal:
  
  A : Type
  P : A -> Type
  p : A -> bool
  Hp : forall x : A, reflectT (P x) (p x)
  ============================
   (reflectT unit true)


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