\def\cals@issue@rowsep@alone{}
\def\cals@issue@rowsep{}
\def\cals@issue@row{}
%
% Check that there are no unneeded whitespace in output
%
\setbox0=\vbox{
\begin{calstable}
\colwidths{{100pt}{200pt}}
\brow{}
\cell{aaaaa} \nullcell{ltb} \nullcell{rtb} \spancontent{bbbbb} \cell{bbbb} \erow{} % ok
\end{calstable}
}
\showbox0