PHP 7, Fatal error: Constant expression contains invalid operations
<p>I am building a login sequence for a website that I am designing for a school project with <strong>MySQL</strong> and <strong>PHP7</strong> (which I am relatively new to). I need some help understanding what this error means and how I can resolve the issue: </p>

<blockquote>
  <p>Fatal error: Constant expression contains invalid operations in
  C:\Abyss Web Server\htdocs\login_tools.php on line 19</p>
</blockquote>

<p>Here is the line of code for a function which ensures a login has succeeded and retrieves the associated user details:</p>

<pre><code>function validate($dbc, $email=",$pwd=")
</code></pre>