Goal:
  
  b : Byte.byte
  xs : t
  b0 : Byte.byte
  ys : t
  IHxs : forall ys : t,
         eqb xs ys = match compare xs ys with
                     | Eq => true
                     | _ => false
                     end
  ============================
   (eqb xs ys = match compare xs ys with
                | Eq => true
                | _ => false
                end)


DEBUG:Going to execute:
trivial; hnf; intros; (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 ])