Using the same variable name for a function's argument and  its return value*
<p>In</p>

<pre><code>  public function bind($query, $input_param, $btypes)
    {   
    // $input_param = $this-&gt;ref_arr($input_param);  // this self assignment gives an error!
    $input_ref = $this-&gt;ref_arr($input_param);       // this works 
    }
</code></pre>

<p>I learned this by trial and error...but I'm tryng to figure out why?</p>

<p>I haven't had a chance to form more test cases but if I use $input_param as in input to the function I can not return the result back to $input_param.  Once I change the name to something else, in this case $input_ref it works.</p>
