Conflict between colortbl and \hrulefill

Question

I define a new environment \CCG that takes two arguments (i.e. above and below texts) and an optional suffix. I use \hrulefill to make sure that horizontal line fills the space before a suffix.

This solution seems to be messed up by colortbl package (e.g. when I use coloring a cell, for example).

How I can use colortbl and still have the structure similar to CCG? Manually encoding \hrule size is not a solution as CCG structures can be nested and length of texts can also vary.

MWE2 with nested structures:

\documentclass[10pt,a4paper]{article}

\usepackage{colortbl}

\newcommand{\CCG}[3][]{
\begin{tabular}[t]{@{\hspace{-3pt}}c@{\hspace{-3pt}}}
#2\\[-7pt]
\hrulefill\raisebox{-2.5pt}{\footnotesize{#1}}\\
    \begin{tabular}[t]{@{}c@{}}
        #3
    \end{tabular}
\end{tabular}
}  

\begin{document}

\CCG[suffix]{\cellcolor{green}above text}{below text}
%\hspace{2cm}
%\CCG[suffix]{above text}{below text}
\vspace{5mm}

\CCG[$<$]{
    \CCG[$>$]{%
        \CCG{some}{$NP/N$}
        \CCG{man}{$N$}}
    {$NP$} 
    \CCG{run}{$S\backslash NP$}}
    {$S$}

\end{document}

Answer 1

The comments in colortbl.dtx suggest that the author of the package, David Carlisle, deliberately changed first-order infinite glue (fil) around cells with second-order one (fill), in order “to dissuade people from putting stretch glue in table entries”. You can easily see this glue with \showlists.

A possible, but horrible, workaround could be the following:

\documentclass[10pt,a4paper]{article}

\usepackage{colortbl}

\newcommand{\CCG}[3][]{
\begin{tabular}[t]{@{\hspace{-3pt}}c@{\hspace{-3pt}}}
#2\\[-7pt]
\leavevmode \leaders \hrule \hskip 0pt plus 1filll \kern 0pt % <<< change
    \raisebox{-2.5pt}{\footnotesize{#1}}\\
    \begin{tabular}[t]{@{}c@{}}
        #3
    \end{tabular}
\end{tabular}
}  

\begin{document}

\CCG[suffix]{\cellcolor{green}above text}{below text}
\hspace{2cm}
\CCG[suffix]{above text}{below text}
% \showboxbreadth = 1000
% \showboxdepth = 10
% \showlists
\vspace{5mm}

\CCG[$<$]{
    \CCG[$>$]{%
        \CCG{some}{$NP/N$}
        \CCG{man}{$N$}}
    {$NP$} 
    \CCG{run}{$S\backslash NP$}}
    {$S$}

\end{document}

but I cannot accept any responsibility for anything this could break down inside the colortbl package! ;-)

Edit

Btw, here is the output:

Answer 2

I did the new environment with calc package for calculating widths of texts and then setting a size of \rule according to them.

Though the lines are nicely drawn (what I needed), cell coloring is bit messed. But it works well outside the new environment.

It would be helpful to know why the colors go outside the boundaries in the new environment.

\documentclass[10pt,a4paper]{article}

\usepackage{colortbl}
\usepackage{calc}

\newcommand{\newccg}[3][]{%
\begin{tabular}[t]{@{\kern-1pt}c@{\kern-1pt}}
#2
\\[-1mm]
\rule[2.3pt]{\maxof{\widthof{#2}}{\widthof{#3}}-\widthof{#1}}{1pt}#1
\\[-1mm]
#3
\end{tabular}
}

\begin{document}

\newccg[$>>>$]{AA}{BBBBB}
~
\newccg[$<$]{CCCCCCCC}{DD}
~
\newccg[$<$]{
    \newccg[$>$]{%
        \newccg{\cellcolor{green}some}{$NP/N$}
        \newccg{man}{$N$}}
    {$NP$}
    \newccg{run}{\cellcolor{red}$S\backslash NP$}}
    {$S$}

\begin{tabular}{c | c}\hline
A & \cellcolor{red}A\\\hline
 \cellcolor{green}C & D\\\hline
\end{tabular}

\end{document}