Missing transformers

[stevanradovanovic]

Description

During the implementation of LiformBundle in my project (Symfony 4), I noticed that some transformers are missing. In particular, the transformers for hidden and submit inputs are missing and I got error about that.

This is how my form type looks:

$builder
            ->setMethod('GET')
            ->add('param1', TextType::class)
            ->add('param2', HiddenType::class)
            ->add('search', SubmitType::class);

Creating new transformers has solved the problem so I wonder if we can do the same in Liform library...or maybe there is some other solution?

Thanks!