title: PropertyExpression is missing
body: <p>I try to write a simple example using Expressions, but have a strange bug: I can't use <code>PropertyExpression</code> at compile time. When I write it I get an error and it doesn't compile 
  <img src="https://i.stack.imgur.com/AqvG8.png" alt="enter image description here">
  But in runtime at breakpoint I can write </p>
  
  <pre><code>var runtimeBody = (System.Linq.Expressions.PropertyExpression)body2;
  </code></pre>
  
  <p>and it works, and casts as expected. Framework 4.5.1 is selected as target. </p>