def foo(field a, field b) -> field[2] {
    field c = a + b;
    field d = a * b;
    return [c, d];
}

def main(field a, field b) -> field[2] {
    field[2] mut c = [0; 2];
    asm {
        c <-- foo(a, b);
        a + b === c[0];
        a * b === c[1];
    }
    return c;
}