title: When/why would I want to use Groovy's @CompileStatic?
body: <p>I've read this:  <a href="http://docs.groovy-lang.org/latest/html/gapi/groovy/transform/CompileStatic.html" rel="noreferrer">http://docs.groovy-lang.org/latest/html/gapi/groovy/transform/CompileStatic.html</a>, and this:  <a href="https://stackoverflow.com/questions/14762094/should-i-use-groovys-compilestatic-if-im-also-using-java-7">Should I use Groovy&#39;s @CompileStatic if I&#39;m also using Java 7</a>, and understand there are certainly performance improvements to be had but is that it?  I don't understand exactly what <code>@CompileStatic</code> does.</p>
  
  <p>Are there certain classes on which adding <code>@CompileStatic</code> is a no-brainer?  Where would I not want it?</p>