Did you ever want to restrict access to some projects maintaining role names?.. I.e. not by creating special roles like ”<Project name> developer”?.. I did!
What I also wanted to do is to make some projects more restrictive for non-members… That’s the situation when the problem really occurs! You can’t assign a different role for non-members! As well as you can’t assign a different role to anonymous users… That’s Redmine limitation!