int[] a = { 0, 1, 2, 3 };

​

// this at least gives a warning 

a = a; // <- [CS1717]

​

// but this doesn't... which makes sense...

a = a[..];

​

// but this doesn't...

a = a  [..][..];

​

// or this...

a = a[..][0..];

a = a[..][..^0];

a = a[..][0..^0];

a = a[..][..(a.Length)];

​

// or this...

a[0] = a[..][0];

a[0] = a[0..^0][0];

​

// or this...

int[][] b = { a, a, a, };

b = b[..][..]; // <- not even a full clone

b[1][1] = b[..][1][1];

b[2][2] = b[2][..][2];