&gt; An external tool that isn&#x27;t a text based editor but does have in depth knowledge of the code?<p>It&#x27;s called a &quot;compiler&quot; ;)<p>Jokes aside, here&#x27;s a few tools that might give you an idea what&#x27;s out there:<p><pre><code>  - Racer for rust
  - Go fmt 
  - Youcompleteme
  - ghc-mod</code></pre>