Example of the perils of binding rvalues to const ref

[IgorStepanov via Digitalmars-d]

BTW. About r-values:

void fun(S s)
{
     fun2(s); //pass s by value.
}

Now, compiler inserts postblit call before func2 call and dtor 
before end of fun. However, it is able to doesn't it, because 
after fun2 call, s isn't used.
Thus, we can implement last postblit optimization:
If compiler want to insert postblit, and object is't used after 
this postblit, compiler is able to doesn't generate postblit and 
last dtor calls.
Is there limitation of this optimization?
It may 90 percent to solve a r-value ref task.