auto on multi-dimension array fails in for loop

[nshaheed]

The following code:

[[ 1, 2], [3, 4, 5], [6], [7, 8]] @=> int grid[][];


for (auto arr: grid) {
    for (auto val: arr) {
        <<< val >>>;
    }
}

(webchuck link)
Gives the compiler error

untitled:4:6: error: for( X : ARRAY ) X [int] must have one less array dimension than ARRAY [int[][]]
[4] for (auto arr: grid) {

However, if I explicitly set the type it works:

[[ 1, 2], [3, 4, 5], [6], [7, 8]] @=> int grid[][];


for (int arr[]: grid) {
    for (auto val: arr) {
        <<< val >>>;
    }
}