PHP - Anonymous Object Methods

I've always had an issue needing to write and maintain script to validate both client side and sever side so a while back I wrote a validation class whose primary purpose was:

I recently looked at the code and it is a train wreck.  I used a single class and had a bunch of protected functions where some would validate per a given rule and return the message upon error and others would sanitize.  For non-typical rules required by the specific application, I would extend the class and add them.  Some of these added rules required other resources such as an entities primary key, a PDO connection, etc.

While inheritance worked fine to add simple rules, it did not do so for the rules which needed other resources.  Also, even though I used "final" on my base class methods, I never liked this single class of many methods as I couldn't use the same name for a given rule and sanitize method (i.e. would rather use digit and digit instead of digit and int).

I am thinking of changing it to something like the following.  While this is definitely better, I question whether I should be using traditional classes to define my standard and custom rules.  Any recommendations?  Thanks

class Validator
{
    protected $options,
    $rules=[
        "digit"=>function($value, $prop, $name){
            return /*validate and return error string or null*/;
        },
        "minlength"=>"ect, etc"    
    ];

    public function __construct(string $json, \Closure ...$customRules=[]) {
        $this->options=json_decode($json);
        $this->rules=array_merge($this->rules, $customRules);
    }
}

class Application
{
    public function someMethod() {
        $pdo=$this->pdo;
        $applicationCustomRules=[
            'someCustomRule'=>function($value, $prop, $name) use ($pdo) {
                return /*validate and return error string or null*/;
            }
        ];
        $validator=new Validator($json, ...$applicationCustomRules);

        //Which can be used such as:
        $jQueryOptions=$validator->getJQueryOptions();
        $validator->validate($data);
        $validator->validateProperty('account', $account);
    }
}

When using the phpDoc PHAR to parse the following file, it returns Parse Error: Syntax error, unexpected '(' on line 16  No summary was found for this file, and doesn't include the file.  The specific script which triggers the error is ($this->prototype)().

I am using the PHAR listed on https://www.phpdoc.org/ which appears to be the same as https://github.com/phpDocumentor/phpDocumentor2/releases/download/v2.9.0/phpDocumentor.phar, and am running PHP 7.1.26.

Any guess why I am getting this error?  Recommended workarounds?  As a hack, I am thinking of adding an ignored function or class who's only missing is to invoke the anonymous function.

I've also tried using the PHAR at https://github.com/phpDocumentor/phpDocumentor2/releases/tag/v3.0.0-alpha.3, and while I don't get this error, I don't get any output.  I first tried it without downloading the public key but got ssl errors.  Is there more to in than just locating the two files in the same directory?

Thanks

<?php
/**
* My Summary.
*
* My Description.
*/
class Foo
{
    private $prototype;

    public function __construct() {
        $this->prototype=function(){ return 'prototype';};
    }

    public function getPrototype() {
        $prototype=($this->prototype)();
        return $prototype;
    }

}

[michael@devserver test]$ php /usr/share/phar/phpDocumentor.phar -d ./phpDocDir -t ./phpDocTarget
Collecting files .. OK
Initializing parser .. OK
Parsing files
Parsing /var/www/public/test/phpDocDir/testphpdocs.php
Parse Error: Syntax error, unexpected '(' on line 16  No summary was found for this file
Storing cache in "/var/www/public/test/phpDocTarget" .. OK
Load cache                                                         ..    0.001s
Preparing template "clean"                                         ..    0.011s
Preparing 17 transformations                                       ..    0.000s
Build "elements" index                                             ..    0.000s
Replace textual FQCNs with object aliases                          ..    0.000s
Resolve @link and @see tags in descriptions                        ..    0.000s
Enriches inline example tags with their sources                    ..    0.000s
Build "packages" index                                             ..    0.000s
Build "namespaces" index and add namespaces to "elements"          ..    0.000s
Collect all markers embedded in tags                               ..    0.000s
Transform analyzed project into artifacts                          ..
Applying 17 transformations
  Initialize writer "phpDocumentor\Plugin\Core\Transformer\Writer\FileIo"
  Initialize writer "phpDocumentor\Plugin\Twig\Writer\Twig"
  Initialize writer "phpDocumentor\Plugin\Graphs\Writer\Graph"
  Execute transformation using writer "FileIo"
  Execute transformation using writer "FileIo"
  Execute transformation using writer "FileIo"
  Execute transformation using writer "FileIo"
  Execute transformation using writer "FileIo"
  Execute transformation using writer "twig"
  Execute transformation using writer "twig"
  Execute transformation using writer "twig"
  Execute transformation using writer "twig"
  Execute transformation using writer "twig"
  Execute transformation using writer "twig"
  Execute transformation using writer "twig"
  Execute transformation using writer "twig"
  Execute transformation using writer "twig"
  Execute transformation using writer "twig"
  Execute transformation using writer "twig"
  Execute transformation using writer "Graph"
   0.073s
Analyze results and write report to log                            ..    0.000s
[michael@devserver test]$