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 nested7;
extern(C) int printf(char*, ...);

void main()
{
    int i;
    i = 52;
    printf("i = %d\n", i);

    void func()
    {
        i++;

        void func2()
        {
            i++;

            void func3()
            {
                i++;
            }

            func3();
        }

        func2();
    }

    func();

    printf("i = %d\n", i);
    assert(i == 55);
}