title: Duplicate lexical declaration; cannot redefine let or const variables
body: <p>I am using VS 2015 Community for a Node application using <a href="https://github.com/Microsoft/nodejstools#readme" rel="nofollow noreferrer">nodejstools</a> tool.</p>
  
  <p>Using the following code I get an error in "Error List" palette. Despite this, the application runs fine.</p>
  
  <p>I am wondering why this error happens in my code or it is a bug related to VS IDE.</p>
  
  <pre><code>'use strict';
  
  const Q = require('q')
  const spawn = require('child_process').spawn;
  const exec = require('child_process').exec;
  const fs = require('fs');
  const del = require('del');
  const removeDirectories = require('remove-empty-directories');
  </code></pre>
  
  <p>Edit:</p>
  
  <p><a href="https://github.com/Microsoft/nodejstools/blob/master/Nodejs/Product/Analysis/JavaScript/activationobject.cs" rel="nofollow noreferrer">Source code for this exception</a>.</p>
  
  <p><a href="https://github.com/Microsoft/nodejstools/issues/862" rel="nofollow noreferrer">Bug report</a></p>