Template limits in D2

[bearophile]

I am trying to create a non-dynamic array at compile time, so I have written 
this test code:

int sumSqrt(int n) {
    int result = 0;
    while (n) {
        int digit = n % 10;
        n /= 10;
        result += digit * digit;
    }
    return result;
}
template GenSquares(int n) {
    static if (n < 0)
        const int[] GenSquares = [];
    else
        const int[] GenSquares = GenSquares!(n-1) ~ [sumSqrt(n)];
}
void main() {
    const int CHUNK = 1000;
    static const auto squares = cast(int[CHUNK])GenSquares!(CHUNK-1);
}

That code works with D1. But with D2 it gives:
templates_test.d(15): Error: template instance templates_test.GenSquares!(499) 
recursive expansion
Do you know why D2 allows less templates?


The second problem is that compile-time functions are nicer, so I'd like to not 
use templates when possible. But the following code doesn't work at compile 
time, can you tell me why? (I have had to use a not nice temporary struct to 
return the static array)

struct S(int N) { int[N] a; }

S!(N) genSquares(int N)() {
    S!(N) s;
    for (int i = 0; i < N; i++) {
        int n = i;
        int m = 0;
        while (n) {
            int digit = n % 10;
            n /= 10;
            m += digit * digit;
        }
        s.a[i] = m;
    }

    return s;
}
void main() {
    const int CHUNK = 1000;
    static const auto squares = genSquares!(CHUNK)().a;
}

Bye and thank you,
bearophile