Local scope in included files

bar.php

<?php
$foo = require __DIR__ . '/foo.php';
var_dump($foo);
var_dump(isset($innerVar));

foo.php

<?php
return (function() {
    $innerVar = 'This var is invisible';
    return 'This is what gets returned';
})();

result

[f3ath@proton playground]$ php bar.php 
/home/f3ath/project/playground/bar.php:3:
string(26) "This is what gets returned"
/home/f3ath/project/playground/bar.php:4:
bool(false)
[f3ath@proton playground]$