With this MWE :
\documentclass{beamer}
\usepackage[flushleft,alwaysadjust]{paralist}
\begin{document}
\begin{frame}
\begin{compactenum}
\item essai
\end{compactenum}
\end{frame}
\end{document}
I have the next error message :
(/usr/local/texlive/2018/texmf-dist/tex/latex/beamer/beamerpatchparalist.sty)
No file bob.nav.
! Undefined control sequence.
<argument> enumerate \beameritemnestingprefix
item
l.11 \end{frame}
enumitem
andparalist
are not compatible withbeamer
.beamer
is not evidence they actually did.