http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53477
--- Comment #6 from asmwarrior <asmwarrior at gmail dot com> --- Hi, all, I create a simple c++ program to reproduce this bug: #include <set> #include <map> typedef std::set<int> IntSet; typedef std::map<int, IntSet> IntToSetMap; int main() { IntToSetMap m; IntSet s; s.insert(5); m[3] = s; IntSet& refSet = m[3]; refSet.insert(6); return 0; } Now, you can set a BP in the line "refSet.insert(6);", and run the command "p refSet", you will get the error message. Python Exception <type 'exceptions.IndexError'> list index out of range: $1 = std::set with 1 elements If you run "n", and then type "p refSet" again, you get: Python Exception <type 'exceptions.IndexError'> list index out of range: $2 = std::set with 2 elements It looks like the elements number(from 1 to 2) is correct. Thanks Yuanhui Zhang