title: Dapper not throwing an exception when select query does not contain expected column
body: <p>When using Dapper as follows:</p>
  
  <pre><code>connection.Query("select a from Foo").Select(x =&gt; new Foo(x.a, x.b));
  </code></pre>
  
  <p>My preference is that an exception is thrown when trying to access x.b, rather than it just returning null.</p>
  
  <p>I understand that just returning null may be by design (e.g. for performance reasons), and ideally tests would exist that flag up the missing data, but if I could have both, this seems like an additional layer of safety that may be worth having.</p>
  
  <p>Alternatively, is there another way to instantiate an object using a constructor in a way that will throw an exception when a needed column is missing?</p>