[Bug c++/22591] New: std::swap() followed by list::erase() produces incorrect list::begin()

[Simon dot Finn at reify dot co dot uk]

Save the following as foo.C, then

g++ foo.C -o foo

Running foo blows the assertion.

g++ -v produces:

Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ../gcc-4.0.1/configure
Thread model: posix
gcc version 4.0.1

Uncommenting the print statements shows that my_list.begin()
has not been updated by the call to my_list.erase(), even
though the first (only) element of this list has just been deleted.


//----------------------------------------------------------------------------

#include <list>
#include <iostream>
#include <cassert>

using namespace std;

main()
{
        list<int> my_list;
        my_list.push_front(1);

        list<int> my_other_list;
        my_other_list.push_front(2);

//cerr << "Lists built \n";
//cerr << "my_list.end() = " << ((void *) (&*my_list.end())) << "\n";
//cerr << "my_list.begin() = " << ((void *) (&*my_list.begin())) << "\n";
//cerr << "my_other_list.end() = " << ((void *) (&*my_other_list.end())) << 
"\n";
//cerr << "my_other_list.begin() = " << ((void *) (&*my_other_list.begin())) <<
"\n";

        swap(my_list,my_other_list);

//cerr << "After swap \n";
//cerr << "my_list.end() = " << ((void *) (&*my_list.end())) << "\n";
//cerr << "my_list.begin() = " << ((void *) (&*my_list.begin())) << "\n";
//cerr << "my_other_list.end() = " << ((void *) (&*my_other_list.end())) << 
"\n";
//cerr << "my_other_list.begin() = " << ((void *) (&*my_other_list.begin())) <<
"\n";

        list<int>::iterator it = my_list.begin();
        while (it != my_list.end())
        {
//cerr << "erasing: " << ((void *)(&*it)) << "\n";
                it = my_list.erase(it);
//cerr << "my_list.end() = " << ((void *) (&*my_list.end())) << "\n";
//cerr << "my_list.begin() = " << ((void *) (&*my_list.begin())) << "\n";
        }

//cerr << "At end \n";
//cerr << "my_list.end() = " << ((void *) (&*my_list.end())) << "\n";
//cerr << "my_list.begin() = " << ((void *) (&*my_list.begin())) << "\n";
//cerr << "my_other_list.end() = " << ((void *) (&*my_other_list.end())) << 
"\n";
//cerr << "my_other_list.begin() = " << ((void *) (&*my_other_list.begin())) <<
"\n";

        assert(my_list.begin() == my_list.end());
}

-- 
           Summary: std::swap() followed by list::erase() produces incorrect
                    list::begin()
           Product: gcc
           Version: 4.0.1
            Status: UNCONFIRMED
          Severity: critical
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: Simon dot Finn at reify dot co dot uk
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22591