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.const1;

void* g = cast(void*)&foobar;

int foobar()
{
    return 42;
}

void main()
{
    auto fn = cast(int function())g;
    int i = fn();
    assert(i == 42);
}