Freemarker "has_content" builtin causing unexpected error
<p>I'm trying to use <code>has_content</code> to check whether a map property is non-empty before testing it as a boolean, because the data model (for reasons that are painful and tedious) can sometimes populate the field with an empty string instead of a Boolean.</p>

<p>However, when I try</p>

<pre><code>&lt;#if (mecflag?has_content &amp;&amp; mecflag)&gt;
</code></pre>

<p>(meaning, I think, "if the variable is not empty and if it's Boolean <code>true</code>), I get an error. The error says that Freemarker doesn't like the fact that <code>has_content</code> isn't a camel-case identifier. That seems really weird.</p>

<p>I'm using what I think is the current stable Freemarker, 2.3.25.</p>

<p>The error text:</p>

<blockquote>
  <p>Naming convention mismatch. Identifiers that are part of the template language (not the user specified ones) must consistently use the same naming convention within the same template. This template uses camel case naming convention (like: exampleName) estabilished by auto-detection at line 37, column 121 by token "upperCase", but the problematic token, "has_content", uses a different convention.</p>
</blockquote>