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 throw1;

extern(C) int rand();

class C
{
}

void func(bool b)
{
    if (b)
        throw new C;
}

int main()
{
    bool b = true;
    try
    {
        func(b);
    }
    catch(Object)
    {
        return 0;
    }
    return 1;
}