Crying Wolf
// Copyright 2026 Google LLC
// SPDX-License-Identifier: Apache-2.0
pub unsafe fn copy(dest: &mut [u8], source: &[u8]) {
for (dest, src) in dest.iter_mut().zip(source) {
*dest = *src;
}
}
fn main() {
let a = &[114, 117, 115, 116];
let b = &mut [82, 85, 83, 84];
println!("{}", String::from_utf8_lossy(b));
unsafe { copy(b, a) };
println!("{}", String::from_utf8_lossy(b));
}
“It is also possible to create so-called crying wolf functions.
“These are functions which are tagged as unsafe, but which have no safety preconditions that programmers need to check.