How can I check if an object will be successfully instantiated with the given argument, without actually creating the instance?

Actually I'm only checking (didn't tested this code, but should work fine...) the number of required parameters, ignoring types:

// Filter definition and arguments as per configuration
$filter = $container->getDefinition($serviceId);
$args   = $activeFilters[$filterName];

// Check number of required arguments vs arguments in config
$constructor = $reflector->getConstructor();

$numRequired  = $constructor->getNumberOfRequiredParameters();
$numSpecified = is_array($args) ? count($args) : 1;

if($numRequired < $numSpecified) {
    throw new InvalidFilterDefinitionException(
        $serviceId,
        $numRequired,
        $numSpecified
    );
}