cannot resize a dynamic array of int[int]

[Ran]

It should be a stupid question. But I still hope for any response. Could anyone tell me pls why the following code doesn't work ?

uint numberOfSubsets(uint n) {
	return (1 << n) - 1;
}

void main(char[][] args) {
	int[int] a[];
	a.length = numberOfSubsets(3);
}
The generated program runs endlessly. I'm using D2.
Ran