I assert that the problem is that the bounds checking in MSVC is wrong - it should only be checking for the de-referencing of invalid iterators not their creation.
It is not valid according to the standard. The operational equivalent for v.begin() + n, in Table 76 (random access iterator requirements) is:
vector::iterator tmp(v.begin()); tmp += n;
The operational semantics for tmp += n, same table, is:
iterator_traits<vector::iterator>::difference_type m(n); if (m >= 0) while (m--) ++tmp; else while (m++) --tmp;
Finally, the precondition for ++tmp, from Table 74 (forward iterator requirements), and for --tmp, from Table 75 (bidirectional iterator requirements), requires that tmp be dereferenceable.
Presumably the above requirement for the random access iterator is a result of it being an extension of a forward iterator?
Once n >= v.size(), the resulting iterator is no longer dereferenceable and the MSVC checking is valid.
Fair enough. It is what it is. As long as I know what to believe I'm happy. -ed ------------------------------------------------ "No more boom and bust." -- Dr. J. G. Brown, 1997