Goal:
  
  b : Byte.byte
  x : string
  IHx : forall y z : t,
        compare x y = Lt -> compare y z = Lt -> compare x z = Lt
  y : string
  b1 : Byte.byte
  H : ByteCompare.compare b b1 = Lt
  z : string
  ============================
   (compare y z = Lt -> Lt = Lt)


DEBUG:Going to execute:
let rec do_ccl :=
            try do_atom; repeat (do_intro; try do_atom); (solve
             [ Ltac.split; do_ccl ])
           in
           (solve [ do_atom | use_hyps; do_ccl ]) ||
             fail "Cannot solve this goal"