Added proper "need 'this' to access member foo" errors instead of "variable foo not resolved" for some cases, added FIXME for the old error! Added a bit more information to the runtime's cyclic dependency detection exception.

module bug25;
extern(C) int printf(char*, ...);

void main()
{
    int i = 2;
    delegate {
        i = i*i;
        i += i*i;
    }();
    printf("%d\n", i);
    assert(i == 20);
}