title: r dplyr filter error - Column has unsupported type
body: <p><strong>Situation</strong></p>
  
  <p>I have a data frame <code>df</code> with two variables, <code>ReportYear</code> and <code>Salary</code>.</p>
  
  <pre><code>dput(df)
  
  structure(list(ReportYear = structure(c(2012, 2012, 2012, 2012, 
  2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 
  2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 
  2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 2012, 
  2012, 2012, 2012, 2012, 2012), class = c("summaryDefault", "table"
  )), Salary = structure(c(198000, 495500, 745000, 1417000, 1662000, 
  5483000, 260100, 460000, 697000, 1595000, 2160000, 5778000, 331000, 
  790000, 1260000, 1736000, 1670000, 9310000, 270000, 459500, 602000, 
  1355000, 984200, 6191000, 290000, 463200, 564500, 1420000, 779500, 
  6779000, 650300, 1448000, 2076000, 2907000, 3894000, 6938000, 
  157000, 404800, 481000, 1074000, 1199000, 4603000), class = c("summaryDefault", 
  "table"))), row.names = c(NA, -42L), class = "data.frame", .Names = c("ReportYear", 
  "Salary"))
  </code></pre>
  
  <p>I'm trying to <code>filter</code> the data, but get an error:</p>
  
  <pre><code>library(dplyr)
  df &lt;- filter(df, Salary &gt; 10)
  Error: column 'ReportYear' has unsupported type
  </code></pre>
  
  <p><strong>Question</strong></p>
  
  <p>Does anyone know why my <code>ReportYear</code> is the wrong type? Is it to do with the "list" structure, and if so how do I resolve it so that I can <code>filter</code> the data?</p>
  
  <p><strong>Other Notes</strong></p>
  
  <pre><code>&gt; str(df)
  'data.frame':   42 obs. of  2 variables:
   $ ReportYear:Classes 'summaryDefault', 'table'  num [1:42] 2012 2012 2012 2012 2012 ...
   $ Salary    :Classes 'summaryDefault', 'table'  num [1:42] 198000 495500 745000 1417000 1662000     ... 
  &gt; 
  </code></pre>
  
  <p>The data was generated by <code>summary</code>.</p>