ShapeError when trying "into_shape" for reversed slice

[kleino]

So first of all, I'm quite new to Rust, so my apologies if this is a stupid thing to do.

I'm trying append multiple ArrayView1-rows to an Array2. In order to do that, I have to transform the ArrayView1-slices to ArrayView2. However, this works only if the slice is not reversed, see following code snippet:

let mut result: Array2<i32> = Array::zeros((0, 4));
let arr: Array1<i32> = Array::from(vec![1,2,3,4]);
let slice: ArrayView1<i32> = arr.slice(s![..;1]);
// This works
let slice: ArrayView2<i32> = slice.into_shape((1, 4)).unwrap();
result.append(Axis(0), slice);

let slice_rev: ArrayView1<i32> = arr.slice(s![..;-1]);
// This fails with ShapeError/IncompatibleLayout: incompatible memory layout
let slice_rev: ArrayView2<i32> = slice_rev.into_shape((1, 4)).unwrap();
result.append(Axis(0), slice_rev);

So could someone point out to me, why this is failing? What am I doing wrong here?

Thanks and best regards