Make == for associative arrays test for equality, not identity. _aaEq was added to runtime/internal/aaA.d which forwards to TypeInfo_AssociativeArray.equals in genobj.d. On the codegen side, DtoAAEquals was added to gen/aa.cpp and is called from EqualExp::toElem in gen/toir.cpp. I assume that the frontend will produce an error if == is used on associative arrays of different type. This fixes DMD bug 1429.

module bug3;

struct S
{
    int[] arr;
    char[5] ch;
}

class C
{
    int[] arr;
    char[4] crs;
}

void main()
{
    S s;
    s.arr = new int[5];
    s.arr[1] = 32;
    int i;
    i = s.arr[0];
    //assert(s.arr[0] == 0);
    //assert(s.arr[1] == 32);
}