@vasily-kirichenko I wonder if the issue is with the implementation itself at https://github.com/Microsoft/visualfsharp/blob/b3f6501ead8997c2b7f2e34fce75219d657aed2c/src/fsharp/vs/service.fs#L1394 ?

Maybe it is at least worth putting a comment at the call site explaining the reason for Array.distinctBy fst, as well as a comment in the method itself mentioning duplicate spans being potentially returned.

I also completely fixes #2140

@smoothdeveloper other editors may want to get duplicated spans because I suspect (I've not checked, sorry) they are not strictly duplicated, but related to different symbols (for example, type itself and its primary ctor, I believe). I think it's absolutely necessary to distinct spans right on VS side because an assumption that FCS does not return duplicates is rather weak and fragile.