Remove an incorrect attribute: `noalias` doesn't apply to struct types, even if we prefer to think of that type as an array :(.

module complex3;

void main()
{
    cfloat c1 = 1f + 0i;
    cfloat c2 = 0f + 0i;
    c2 += 1f + 0i;
    assert(c1 == c2);
}