Script for finding variable-variable usages potentially affected by uniform variable syntax

varVar.php

<?php

use PhpParser\Node;
use PhpParser\Node\Expr;

error_reporting(E_ALL);

ini_set('memory_limit', -1);

//$dir = __DIR__ . '/../../Symfony_2.3';
$dir = __DIR__ . '/../../ZendFramework-2.0.2';

require_once __DIR__ . '/../lib/bootstrap.php';

class AnalyzingVisitor extends PhpParser\NodeVisitorAbstract {
    private $file;
    private $code;

    public function setFile($file, $code) {
        $this->file = realpath($file);
        $this->code = $code;
    }

    public function printNodeContext(Node $node) {
        $lineNo = $node->getLine();
        $lineCode = explode("\n", $this->code)[$lineNo-1];
        echo "$this->file @ $lineNo:\n$lineCode\n";
    }
}

class VarVarVisitor extends AnalyzingVisitor {
    public function enterNode(Node $node) {
        if (!$node instanceof Expr\Variable
            && !$node instanceof Expr\PropertyFetch && !$node instanceof Expr\StaticPropertyFetch
            && !$node instanceof Expr\MethodCall && !$node instanceof Expr\StaticCall
        ) {
            return;
        }

        if ($node->name instanceof Expr\ArrayDimFetch) {
            $this->printNodeContext($node);
        }
    }
}

$parser = new PhpParser\Parser(new PhpParser\Lexer);
$visitor = new VarVarVisitor;
$traverser = new PhpParser\NodeTraverser;
$traverser->addVisitor($visitor);

foreach (new RecursiveIteratorIterator(
             new RecursiveDirectoryIterator($dir),
             RecursiveIteratorIterator::LEAVES_ONLY)
         as $file
) {
    if (!preg_match('/\.php$/', $file)) continue;

    $code = file_get_contents($file);
    $visitor->setFile($file, $code);

    try {
        $traverser->traverse($parser->parse(file_get_contents($file)));
    } catch (PhpParser\Error $e) {
        echo $file, "\n", $e->getMessage(), "\n";
    }
}