I just switched to the 5/17 swift 4.0 tool chain on Linux, and I am getting
the following complaint when using swap on array elements. Is this warning
legitimate because of a copy on write issue? If so, is there some new swap
function for array elements? I realize I can turn 1 line into 3 and do the
swapping myself, it's just verbose.
*warning: simultaneous accesses to var 'dims', but modification requires
exclusive access; consider copying to a local variable*
* swap(&dims[lastIndex], &dims[lastIndex-1])*