Symfony version(s) affected

7.0

Description

According to docs, we can use null-coalescing operator to provide fallback to potentially empty or even nonexistent variables. However I can't make it work, even in a simple file with nothing but Expression Language.

How to reproduce

$lang = new ExpressionLanguage();

$data = [
    'exists' => true,
];

$expression1 = 'notexists ?? "nope,"';
$expression2 = '(notexists ?? "nope,")';
$expression3 = '(notexists ?? false) ? "yes" : "no"';

foreach ([$expression1, $expression2, $expression3] as $exp) {
    try {
        var_dump($lang->evaluate($exp, $data));
    } catch (\Throwable $th) {
        echo('!');
    }
}
// expected: nope,nope,no
// actual: !!!

(In the reproduction I have suppressed the throws, but every evaluate fails with Fatal error: Uncaught Symfony\Component\ExpressionLanguage\SyntaxError: Variable "notexists" is not valid around position …

Possible Solution

No response

Additional Context

No response