anchor.diff:                      (lhs:flex_t) (bs_lhs:binders) (t_res_lhs:term)
                       (rhs:term)
           : solution =
  -        //if Env.debug env <| Options.Other "RelCheck"
  +        //if Env.debug env <| Options.Other "Rel"
           //then printfn "imitate_app 1:\n\tlhs=%s\n\tbs_lhs=%s\n\tt_res_lhs=%s\n\trhs=%s\n"
           //    (flex_t_to_string lhs)
           //    (Print.binders_to_string ", " bs_lhs)
  
positive.code: 
        | Failed (p, msg) ->
           UF.rollback tx;
           if Env.debug env <| Options.Other "RelCheck"
           then BU.print1 "meet/join attempted and failed to solve problems:\n%s\n"
                          (List.map (prob_to_string env) (TProb eq_prob::sub_probs) |> String.concat "\n");
           (match rank, base_and_refinement env bound_typ with
  
negative.code:                     (t, [p], wl)
                in
                let t1, ps, wl = combine t1 t2 wl in
                if Env.debug env <| Options.Other "Rel"
                then BU.print1 "pairwise fallback2 succeeded: %s"
                              (Print.term_to_string t1);
                t1, ps, wl
  