> If the attribute makes any substantive change to S (e.g., changes its > size, alignment, etc.) then bad things happen. For example, the member > functions of "S" have expectations about the layout of "S" that are not > satisfied if they are called with a "T". Depending on the attribute and > circumstances, we do all manner of bad things, including ICE, generate > wrong code, etc. > > For a while now, I've been promising to propose semantics for these > constructs.
You might want to take a look at the Ada concept of "freeze point". That's one approach to a similar problem.
