> Backwards from what? A reference can't be null, but it can still be invalid, which is a more common problem than forgetting to check for null-ness. no, a ref

> Backwards from what? A reference can't be null, but it can still be invalid, which is a more common problem than forgetting to check for null-ness. no, a reference cannot be invalid. If you are given an invalid reference (such as referring to an object after its lifetime ended, or referring to something that is not an object of the reference's type), then the fault lies on the caller. The callee cannot check the reference's validity, nor it is its responsibility to do so. This is *very* different from the case of a pointer, where the caller is not at fault, typesystem wise, for giving a nullptr to a function accepting a pointer. Increasing the probability of runtime errors to gain a little bit of readability at the caller's site is not a good tradeoff.