> aren't they just annotations? "Just" annotations... that are automatically added (in the vast majority of cases) and enforced by the compiler. > proper use

> aren't they just annotations? "Just" annotations... that are automatically added (in the vast majority of cases) and enforced by the compiler. > proper use of mutexes and lock ordering aren't that hard, they just require a little bit of discipline and consistency. Yes, like how avoiding type confusion/OOB/use-after-free/etc. "just require[s] a little bit of discipline and consistency"? The point of offloading these kinds of things onto the compiler/language is precisely so that you have something watching your back if/when your discipline and consistency slips, especially when dealing with larger/more complex systems/teams. Most of us are only human, after all. > how well does it all hold up when you have teamwork and everything isn't strictly adherent to one specific philosophy. Again, part of the point is that Send/Sync are virtually always handled by the compiler, so teamwork and philosophy generally aren't in the picture in the first place. Consider it an extension of your "regular" strong static type system checks (e.g., can't pass object of type A to a function that expects an unrelated object of type B) to cross-thread concerns.