I have tons of an IDE errors, where the file is red - even there is "No problems found" in the files.
Update: I realised I had moved some files around just before upgrading. And as the right answer states it, the red files are unversioned under Git(see answer from artspb)
This happened after upgrading to Goland 2021.2 - MacOS Big Sur
I tried to "Invalidate caches..." under files.
Do you know how to solve this?
The red files are unversioned under Git, the green files are staged, and so on (see help).