[xpressive] regression test failures in VC10 Beta 2

[rwebb <richard.webb@…>]

Quite a few on the xpressive regression tests fail on VC10 Beta 2, seemingly because of more problems related to singular (default constructed) iterators.

For example, the misc1 and test6u tests get an error from line 54 of boost\xpressive\detail\core\matcher\mark_end_matcher.hpp :

     br.first = old_first;

where old_first is empty.

The test_actions test gets an error from line 655 of boost\xpressive\match_results.hpp

    std::swap(this->base_, that.base_);

Where that.base_ is empty.

I haven't looked into any other failures yet.

[Eric Niebler]

Patches welcome. I don't have VC10.

[Eric Niebler]

(In [57592]) do NOT copy singular iterators, fixes #3538