Matthias\SymfonyServiceDefinitionValidator\ServiceDefinitionValidator::validateClass PHP Method

    private function validateClass(Definition $definition)
    {
        $class = $definition->getClass();
        if ($class) {
            $class = $this->containerBuilder->getParameterBag()->resolveValue($class);
            // TODO only services created using a factory can have an interface
            if (!class_exists($class) && !interface_exists($class)) {
                throw new ClassNotFoundException($class);
            }
        } elseif ($this->shouldDefinitionHaveAClass($definition)) {
            throw new DefinitionHasNoClassException();
        }
    }