How to make IntelliSense understand temp tables, linked servers and synonyms?

I'm using SSMS 17.6 which is the latest version at the time of posting. It is supposed to have the latest official IntelliSense version. However, it underlines my scripts with red squiggles where I'm using temp tables, linked server tables and synonyms. It's difficult to edit queries because I don't get correct error detection. Everything is filled with "errors", but queries run, and the results are what I want, as expected. I've tried a few third-party addons like SQL Complete and SSMSBoost, but they don't seem to improve IntelliSense, but rather extend the SSMS in other ways like tooltips and popups. Or maybe I just haven't figured out how to use them for improving IntelliSense. What can I do to make IntelliSense correctly handle these things? If there is no first-party way, then what third-party extensions exist and how to configure them to improve error highlighting?