title: R ggplot: stat = "identity" is not working for some reason
body: <p>I have a datafile which looks something like this...</p>
  
  <pre><code>Rate &lt;- runif(14, 0, 20)
  Day &lt;- c("Sunday", "Monday", "Tuesday", 
           "Wednesday", "Thursday", "Friday", "Saturday", 
           "Sunday", "Monday", "Tuesday", 
           "Wednesday", "Thursday", "Friday", "Saturday")
  Grouper &lt;- c(rep(1, 7), rep(2, 7))
  df &lt;- data.frame(Rate, Day, Grouper)
  </code></pre>
  
  <p>...and I want to make a bar chart with two bars for each day: one bar for <code>Grouper = 1</code> and one bar for <code>Grouper = 2</code>. The y-value is not a count, it's the <code>Rate</code> variable, so I need to use <code>stat = "identity"</code> to make it work...</p>
  
  <pre><code># Set max chart height
  maxlimit = max(df$Rate) * 1.1
  # Actual plot code 
  ggplot(df, aes(Day, Rate)) +
    geom_bar(stat = "identity") +
    geom_bar(aes(fill = Grouper), position = "dodge") + 
    scale_y_continuous(limits = c(0, maxlimit)) + 
    theme_classic()
  </code></pre>
  
  <p>...but I am still getting the error <code>stat_count() must not be used with a y aesthetic.</code> Can someone explain to me why I am getting this error and what I can do to fix it?</p>