title: Importing S3 generics from another package
body: <p>I am writing a package which builds on the <code>autoplot()</code> generic from the ggplot2 package. Currently, I have a function named <code>breg()</code> which acts as a constructor for the class <code>breg</code>; the output of which can be plotted using <code>autoplot.breg()</code>. Within my <code>breg()</code> function, my Roxygen commands are as such:</p>
  
  <pre><code>#' @export breg
  </code></pre>
  
  <p>Then within <code>autoplot.breg()</code> I have</p>
  
  <pre><code>#' @import ggplot2
  #' @importFrom ggplot2 autoplot
  #'
  #' @method autoplot breg
  #' @export
  </code></pre>
  
  <p>I wasn't convinced I needed <code>@importFrom ggplot2 autoplot</code> if I was importing the whole of <code>ggplot2</code>. However I digress, in my <code>NAMESPACE</code> file I have</p>
  
  <pre><code>S3method(autoplot,breg)
  export(breg)
  import(ggplot2)
  importFrom(ggplot2,autoplot)
  </code></pre>
  
  <p>My question is, why do I still have the following warning message:</p>
  
  <pre><code>Warning message:
  In setup_ns_exports(pkg, export_all) :
    Objects listed as exports, but not present in namespace: autoplot
  </code></pre>