\begin{Schunk}
\begin{Sinput}
 library(codetools)
 rm(x)
 checkUsage(myf)
\end{Sinput}
\begin{Soutput}
<anonymous>: no visible binding for global variable 'x' (functions-2.Rnw:435)
\end{Soutput}
\end{Schunk}
