<?php
class Foo implements NonExistentInterface {
    public static function bar() { var_dump(__METHOD__); }
}

<?php
require __DIR__.'/vendor/autoload.php';
$resource = new \Symfony\Component\Config\Resource\ClassExistenceResource('Foo', false);

// The following line autoloads the Foo class,
// even though it implements a non-existent interface
$resource->isFresh(1);

// The following lines would normally result in a ClassNotFoundException for the missing interface.
var_dump((new \ReflectionClass('Foo'))->getInterfaces());
// array(0) {}
Foo::bar();
// string(8) "Foo::bar"