cannot use std containers... sometimes?
This is getting ridiculous.
I recalled that I've used std::vector in some class. So I opened it to verify and indeed it was OK. When I returned to previous file both unordered_map and string were without errors and I could ctrl-click at them and go into source code. The build was successful with zero errors.
Then I run "clean" and "rebuild" on the project, at which point errors came back.
It looks like indexer goes crazy on these classes for no apparent reason.