Visual studio 2019 go to definition and Intellisense not working

Question

I have noticed a weird issue with Visual Studio 2019 v16.0.1 the IntelliSense about \"Using directive is unnecessary\" normally grey is missing and type reference suggestion

Answer 1

For anyone who are searching for another suggestion, I just go throught this issue, as OP said, I've deleted .vs folder, I've update vs to last version, I've uninstalled and reinstalled vs to the last version, I've reset settings, delete all obj folders, I've installed Microsoft.Net.Compilers but nothing worked, at the end I just remembered that sometimes the projects required WindowsBase library, until now I don't know why, but after adding that dll Intellisense started to function again.