Upload proper source maps files for GWT project

I have a GWT project and want to send client error stacktraces to Sentry . I’ve tried to upload to Sentry sourceMap0.json (renamed to project-name.js.map) and HASH_cache.js (renamed to project-name.js ) from GWT project build artifacts.

But it doesn’t work - events created with deobfuscated stacktrace which looks exactly as on the client’s side. Event log excerpt:

Error: io.reactivex.exceptions.OnErrorNotImplementedException: The exception was not handled due to missing onError handler in the subscribe() method call. Further reading: https://github.com/ReactiveX/RxJava/wiki/Error-Handling | com.google.gwt.core.client.JavaScriptException: (TypeError) : a._m is not a function
    at T1i.Zp [as Kb] (dispatch-0.js:8296:4606)
    at T1i.cq [as Ob] (dispatch-0.js:8296:4909)
    at T1i.Yp (dispatch-0.js:4937:60)
    at T1i.iq (dispatch-0.js:2954:21)
    at T1i.mq (dispatch-0.js:2953:21)
    at new T1i (dispatch-0.js:7331:20)

In build artifacts I have also permutation-0.js and HASH.symbolMap files, maybe I could use it but how I don’t know.

I would appreciate for any help or advise