compiler != runtime ultimately no code is free of side effects. this is a tool to mark code as safe and propagate that safety up the call stack to make your co

compiler != runtime ultimately no code is free of side effects. this is a tool to mark code as safe and propagate that safety up the call stack to make your code's safety something you can reason about. it's definitely true that if a piece of code is unsafe, you need to be more careful. (not a rust programmer, but have had to fight the compiler when i first looked at it)