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 typeinfo13;

void main()
{
    float[long] aa;
    auto ti = typeid(typeof(aa));
    assert(ti.toString() == "float[long]");
    assert(ti.next() is typeid(float));
    assert(ti.tsize() == size_t.sizeof);
    auto aati = cast(TypeInfo_AssociativeArray)ti;
    assert(aati.value is typeid(float));
    assert(aati.key is typeid(long));
}