As an idea. If \--gc:arc works out well and Nim compiler itself is ported to arc then it opens up the way for a multithreaded Nim compiler. Nim compiler historically keeps good module level separation, so we can implement a module level multithreading when a thread from the threadpool gets a module to compile. It is a lot of work no doubts, possibly we will need more sophisticated locks and guards to make it happen and lent and sink and borrowing will be needed to. But it can potentially deliver 10x-30x performance improvement to nim compiler. Possibly it will work workout better than incrementalization of compiler.
As an Idea: multithreaded arc nim compiler vs incrementalized compiler roadmap discussion
