I've also taken a look at Golang's slices, which have rather confusing ownership semantics. One can take a subslice of a slice, and its elements will track those of the original, but appending to that subslice will copy the values into an entirely new array. In fact, appending to the original slice past its capacity causes a reallocation, which can invalidate any preexisting subslices. This also occurs with C++ vectors and spans, if I am not mistaken. This is an area where I think Rust's borrow checker really shines; it prevents you from resizing a vector if there are any active slices, encouraging you to instead store a pair of indices or some other self-contained representation.