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 mini.norun_debug8;

struct Str
{
    size_t len;
    void* ptr;
}

struct Foo
{
    long l;
    Bar bar;
}

struct Bar
{
    float x,y,z;
    Foo* foo;
}

void main()
{
    Str str;
    Foo foo;
    foo.l = 42;
    foo.bar.y = 3.1415;
    foo.bar.foo = &foo;

    int* fail = cast(int*) 1;
    *fail = 0;
}