#0  ~basic_string (this=0x7fffc259adc0, __in_chrg=<optimized out>) at /usr/include/c++/4.7/bits/basic_string.h:536
No locals.
#1  pkgProblemResolver::DoUpgrade (this=0x7fffc259adf0, Pkg=<incomplete type>) at algorithms.cc:730
        P = <incomplete type>
        Start = {<pkgCache::Iterator<pkgCache::Dependency, pkgCache::DepIterator>> = {<std::iterator<std::forward_iterator_tag, pkgCache::Dependency, long, pkgCache::Dependency*, pkgCache::Dependency&>> = {<No data fields>}, _vptr.Iterator = 0x2cc, S = 0x4, Owner = 0x7fffc259ae5f}, Type = (unknown: 3260657720)}
        End = {<pkgCache::Iterator<pkgCache::Dependency, pkgCache::DepIterator>> = {<std::iterator<std::forward_iterator_tag, pkgCache::Dependency, long, pkgCache::Dependency*, pkgCache::Dependency&>> = {<No data fields>}, _vptr.Iterator = 0x61030d0e00, S = 0xfa2a08, Owner = 0x6b1d58}, Type = (unknown: 13735072)}
        D = {<pkgCache::Iterator<pkgCache::Dependency, pkgCache::DepIterator>> = {<std::iterator<std::forward_iterator_tag, pkgCache::Dependency, long, pkgCache::Dependency*, pkgCache::Dependency&>> = {<No data fields>}, _vptr.Iterator = 0x1583770, S = 0x163d1e0, Owner = 0xe75370}, Type = (unknown: 4466924)}
        group = {cache = @0x110d770, released = 112}
        WasKept = false
        Fail = <optimized out>
#2  0x0000000000000000 in ?? ()
No symbol table info available.