anchor.diff:  cc_single_write({RL, WL, Vers}, _WriteFilter, _Val) ->
       Checks = [ { [] =:= RL,    readlock_is_set },
                  { false =:= WL, writelock_is_set } ],
  -    cc_return_val(cc_single_write, Checks, _UI_if_ok = Vers, _Log = true).
  +    cc_return_val(cc_single_write, Checks, _UI_if_ok = Vers, ?LOG_CC_FAILS).
   
   -spec wf_set_vers_val(db_entry() | prbr_bottom, version(),
                         client_value()) -> db_entry().
  
positive.code:           { false =:= WL
              orelse TxId =:= WL, {txid_mismatch, WL, TxId} },
            { [] =:= RL,          {readlock_not_empty, RL} } ],
      cc_return_val(cc_set_wl, Checks, _UI_if_ok = none, _Log = true).
  
  -spec wf_set_wl
         (prbr_bottom, UI :: none, {txid_on_cseq:txid(), -1}) -> db_entry();
  
negative.code: cc_set_rl({WL, Vers}, _WF, _Val = {_TxId, TLogVers}) ->
      Checks = [ { TLogVers =:= Vers, {version_mismatch, TLogVers, Vers} },
                 { false =:= WL,      writelock_is_set } ],
      cc_return_val(cc_set_rl, Checks, _UI_if_ok = none, ?LOG_CC_FAILS).
  
  -spec wf_set_rl(db_entry(), UI :: {writelock(), version()} | no_value_yet,
                  {txid_on_cseq:txid(), version()}) -> db_entry().
  