fn box_clone_from_ptr_stability() {
    for size in (0..8).map(|i| 2usize.pow(i)) {
        let control = vec![Dummy { _data: 42 }; size].into_boxed_slice();
        let mut copy = vec![Dummy { _data: 84 }; size].into_boxed_slice();
        let copy_raw = copy.as_ptr() as usize;
        copy.clone_from(&control);
        assert_eq!(copy.as_ptr() as usize, copy_raw);
    }
}
Creates a [`Vec`] containing the arguments.

`vec!` allows `Vec`s to be defined with the same syntax as array expressions.
There are two forms of this macro:

- Create a [`Vec`] containing a given list of elements:

```
let v = vec![1, 2, 3];
assert_eq!(v[0], 1);
assert_eq!(v[1], 2);
assert_eq!(v[2], 3);
```

- Create a [`Vec`] from a given element and size:

```
let v = vec![1; 3];
assert_eq!(v, [1, 1, 1]);
```

Note that unlike array expressions this syntax supports all elements
which implement [`Clone`] and the number of elements doesn't have to be
a constant.

This will use `clone` to duplicate an expression, so one should be careful
using this with types having a nonstand
benchmarks/haystacks/code/rust-library.rs