While sure, more things could be baked as results, most of the time when you see a panic that's not the case. It's a violation of the callee's invariants that t

While sure, more things could be baked as results, most of the time when you see a panic that's not the case. It's a violation of the callee's invariants that the caller fucked up. Essentially an error means that the caller failed in a way that's expected. A panic means the caller broke some contract that wasn't expressed in the arguments. A good example of this is array indexing. If you're using it you're saying that the caller (whoever is indexing into the array) has already agreed not to access out of bounds. But we still have to double check if that's the case. And if you were to say that hey, that implies that the checks and branches should just be elided - you can! But not in safe rust, because safe code can't invoke undefined behavior.