title: Rstudio Support for S4 Method Auto-completion
body: <p>I'm attempting to see if it is possible for Rstudio to autocomplete S4 method parameters for a generic I own.  An <a href="https://support.rstudio.com/hc/en-us/articles/205273297-Code-Completion" rel="nofollow noreferrer">Rstudio blogpost</a> suggests this might be possible, but trying it on methods in my <a href="https://github.com/brodieG/diffobj" rel="nofollow noreferrer">diffobj</a> package does not appear to work, e.g.:</p>
  <pre><code>library(diffobj)
  diffPrint('hello', 'world', for...
  </code></pre>
  <p>where <code>for...</code> denotes me starting to type one of the parameters for the <code>c('ANY', 'ANY')</code> method to the generic (i.e. the default one) only gives me the generic parameters.  The generic only has three parameters: <code>target</code>, <code>current</code>, and <code>...</code>.  The methods have lots of parameters that are matched to the <code>...</code> in the generic.</p>
  <p>So, should I expect this to work?  Are there known working S4 examples I could look at to figure out what's different for them, or even better, specific instructions of how to get this to work?</p>
  <p><strong>UPDATE</strong>: This is now reported as an <a href="https://github.com/rstudio/rstudio/issues/7851" rel="nofollow noreferrer">Rstudio bug</a></p>