Fix nested references to 'ref' foreach variables. These "walk around" the array being iterated over, so they're a bit trickier than other variables to get right.

module mini.foreach6;

struct S
{
    long l;
    float f;
}

void main()
{
    S[4] arr = void;
    foreach(i,v;arr) {
        v = S(i, i*2.5);
    }
}