if ($vars !== readable) do using $this;

rename_vars.php

<?php
/*
here source https://stackoverflow.com/questions/32393232/php-rename-all-variables-inside-code
*/
function clearvar($file, $out)
{
	$tokens = token_get_all(file_get_contents($file));
	$globals = array('$GLOBALS', '$_SERVER', '$_GET', '$_POST', '$_FILES', '$_COOKIE', '$_SESSION', '$_REQUEST', '$_ENV');
	$registry = get_defined_functions();
	$registry = $registry['internal'];
	foreach ($tokens as $key => $element) {
		if (!is_array($element)) {
			continue;
		}
		switch ($element[0]) {
			case T_VARIABLE:
				if (in_array($element[1], $globals)) {
					continue 2;
				}
				$prefix = '$';
				$index = $key;
				break;
			default:
				continue 2;
		}
		if (!isset($registry[$tokens[$index][1]])) {
			$word = preg_split("/\r\n|\n|\r/", file_get_contents("word.txt"));
			$x = 0;
			do {
				$replacement = $prefix . $word[$x];
				$x++;
			} while (in_array($replacement, $registry));
			$registry[$tokens[$index][1]] = $replacement;
		}
		$tokens[$index][1] = $registry[$tokens[$index][1]];
	}
	$rawdata = "";
	foreach ($tokens as $token) {
		$rawdata .= $token[1] ?? $token;
	}
	echo $rawdata;
	file_put_contents($out, $rawdata);
	echo " done !";
}
if (count($argv) < 2) {
	die("usage: php main.php <file/php> <out/php>");
} else {
	clearvar($argv[1], $argv[2]);
}
?>