Issue with types in multi field search for a document index

[kunal-singh]

Description
When performing a search on multiple fields in a document index, where each field needs to be queried with a different phrase, the search function is not correctly typed. Though the returned results are just fine. I am using v0.7.43.

Code to Reproduce
I've reproduced it here

Additional Questions
Also I was wondering if there is a way to use the bool param properly here. As you can see in the example the bool "and" is not working as expected. For now I am manually doing an intersection of the results arrays but would like to know if there is a proper way of doing the same.