PHP parse error with no explanation

PHP is giving me a parse error here.

if ($detalleReserva->isGratis() || $detalleReserva->isPasajeroSinCosto()){
    $cantPaxGratis++;
}

Parse error: parse error in /Library/WebServer/Documents/versioned/software/tur/liquidacionHead.php on line 58

The if line is line 58. I’ve tried changing de ||¬†with OR but the same. If I change the second part (after || ) for a ‘1’ or a ‘0’ it works fine.

Extra information:

function isPasajeroSinCosto() {
     return ($this->tipo == 4);
}

PHP version:

PHP 7.1.0 (cli) (built: Dec 2 2016 03:30:24) ( NTS )


Source: stackoverflow-php