title: ReSharper is not detecting use of some ES6 features when configured for ES5
body: <p>I work at a company where we use ReSharper 2016 extensively to inspect and refactor our C# code, and we would now like to use those same tools to ensure the quality of our javascript.</p>
  
  <p>We're supporting IE, so ES6 features are out, however when the inspection language is set to ES5 in ReSharper's options and warnings are set for unsupported language features (as in the image below) only <em>some</em> ES6 features are being flagged up.</p>
  
  <p><a href="https://i.stack.imgur.com/vlve3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vlve3.png" alt="Inspections settings"></a></p>
  
  <p><a href="https://i.stack.imgur.com/YV20i.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/YV20i.png" alt="Inspection severity settings"></a></p>
  
  <p>So, for example, <code>let</code> and <code>const</code> are highlighted with an error, however lambda functions are not. Default parameters are highlighted, but <code>Array.find()</code> is not, and so on. It seems fairly arbitrary what is and what isn't detected.</p>
  
  <p><a href="https://i.stack.imgur.com/c8aBf.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/c8aBf.png" alt="Highlighting of ES6 features"></a></p>
  
  <p>Is there some additional configuration needed, or am I perhaps misunderstanding something about the ES6 feature set? <strong>How can I ensure all ES6 features result in errors?</strong></p>