Should synonyms work with filtering?

Description

We were looking at synonyms (specifically one-way synonyms) as a way to improve a client's search. The search uses filter_by in order to only return exact matches. But there's a special case of search where synonyms would be convenient.

Testing from the cli, I find that a one-way synonym works exactly as expected when using an ordinary search, but not at all when using filter_by for the search.

Am I seeing:

• the correct behaviour?
• a planned behaviour?
• a bug?

Steps to reproduce

Returns synonyms in results

http://typesense/collections/vehicles/documents/search
  ?q=volkswagen golf
  &query_by=vehicle
  &include_fields=make,model,year,price

Doesn't return any synonyms in results

http://typesense/collections/vehicles/documents/search
  ?q=*
  &query_by=vehicle
  &filter_by=vehicle:=[volkswagen golf]
  &include_fields=make,model,year,price

Expected Behavior

I don't know. I can't tell from the docs if what I'm trying is expected/unexpected/desired/undesired 😀

Actual Behavior

No synonyms in results when using a filter_by query.

Metadata

Typsense Version: 0.20.0

OS: any

Reproduce both documented search requests from the CLI, comparing the ordinary synonym search with the filter_by request against the reported Typesense version. Read the synonym and filter_by search paths to determine whether their interaction is supported; done should include a decided behavior, matching implementation or documentation, and coverage for the reproduced case.