In general in Rust, “length” refers to “count”. If you view strings as being sequences of Unicode scalar values, then it might seem odd that `str::len` counts bytes, but if you view strings as being a subset of byte slices it makes perfect sense that it gives the number of UTF-8 code units (and it is analoguous to, say, how Javascript uses `.length` to return the number of UTF-16 code units). So I think it depends on perspective.