In the beginning, I was trying to use Rust like C (which I think lot of people do) and was struggling with the borrow checker. I had a light bulb in my head one

In the beginning, I was trying to use Rust like C (which I think lot of people do) and was struggling with the borrow checker. I had a light bulb in my head one day to read the function signature and see if its '&self' or '&mut self'. If any one API of a struct/enum has '&mut self' then its instance cannot be shared across threads without using a mutex (which brings its own friend along i.e Arc). This led me to structure the code in my mind much in advance to prevent borrow checker issues. Another use of this is while embedding an object in a struct. When I realized that '&mut self' infects everything up the call chain it was a big learning moment. That is the embedding struct also needs a mutable borrow as well.