Latex Alert + Array + Infer bug

You can't do the following in Latex:


\documentclass{beamer}
\usepackage{proof}

\begin{document}

\begin{frame}
  \begin{array}{c}
    \alert{\infer{A}{A}}
  \end{array}
\end{frame}

\end{document}

For some reason you can \alert an \infer outside of an \array, but not inside.  Weird bug.

Workaround:  Use tabular instea


\begin{frame}
  \[
  \begin{tabular}{c}
    \alert{\infer{A}{A}}
  \end{tabular}
  \]
\end{frame}