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 scope2;
extern(C) int printf(char*, ...);
void main()
{
    scope(exit) printf("exit\n");
    scope(failure) printf("failure\n");
    scope(success) printf("success\n");
}