Referencing assembly does not seem to work

Hi everyone,

I am unsure if the following is a bug or if I misunderstood something, since I only recently started to learn how to use assembly definitions in Unity.

I have a Unity 6.3 project with two subfolders in my Scripts folder, each of which has its own assembly definition.

I installed the Unity OSC package: https://github.com/Unity-Technologies/UnityOSCProtocolSupport

Now when I edit some of my code and enter something like protected OscSender sender;, Rider correctly suggests to reference the assembly (although it weirdly shows version 0.0.0.0) and import the type OscSender. This seems to work, until I activate the Unity window and hence trigger a recompile, at which point Unity notices that it does not indeed know the Unity.Media.Osc namespace.

I solve this by manually adding a reference to the assembly to my own assembly definition. So I guess Rider does not recognize my assembly definition and therefore does not edit it. I just wonder what Rider actually does the moment I click the “reference assembly” suggestion?

If this sounds like a bug, I can open a ticket and supply the usual logs there.