# Extending soul underline up to the right side of tabular

I found the \longunderline command at Extending underline up to the right side.

However it does not work as expected in an tabular:

\documentclass{article}
\usepackage{tabularx}
\usepackage{soul}
\usepackage{linegoal}
\newcommand{\raisedrule}[1]{\rule[#1]{\linegoal}{0.1ex}}
\newcommand{\longunderline}[1]{\ul{#1}\raisedrule{-.75ex}}
\begin{document}
\begin{tabular}{p{4em}p{18em}}
row 1 &
\longunderline{Some long text. Some long text. Some long text. Some long text. Some long text. Some long text.}
\end{tabular}
\end{document}


The underline is extended, but not to the right side exactly.

p.s. I'd like to comment and @user11232 under the original post, but I have not enough reputation.