------- Comment #1 from pinskia at gcc dot gnu dot org 2007-03-17 16:58 ------- Lets look at the IR: ;; Function __gnu_debug::_Safe_iterator<_Iterator, _Sequence>::_Safe_iterator() [with _Iterator = __gnu_cxx::__normal_iterator<int*, __gnu_norm::vector<int, std::allocator<int> > >, _Sequence = __gnu_debug_def::vector<int, std::allocator<int> >] (_ZN11__gnu_debug14_Safe_iteratorIN9__gnu_cxx17__normal_iteratorIPiN10__gnu_norm6vectorIiSaIiEEEEEN15__gnu_debug_def6vectorIiS6_EEEC4Ev *INTERNAL* ) ;; enabled by -tree-original
{ <<cleanup_point <<< Unknown tree: expr_stmt __base_ctor (&((struct _Safe_iterator<__gnu_cxx::__normal_iterator<int*, __gnu_norm::vector<int, std::allocator<int> > >,__gnu_debug_def::vector<int, std::allocator<int> > > *) this)->D.12082) >>> >>; try { <<cleanup_point <<< Unknown tree: expr_stmt __comp_ctor (&((struct _Safe_iterator<__gnu_cxx::__normal_iterator<int*, __gnu_norm::vector<int, std::allocator<int> > >,__gnu_debug_def::vector<int, std::allocator<int> > > *) this)->_M_current) >>> >>; } catch { __base_dtor ((struct _Safe_iterator_base *) this); } } and the constructor for ->M_current: __gnu_debug::_Safe_iterator<__gnu_cxx::__normal_iterator<int*, __gnu_norm::vector<int, std::allocator<int> > >, __gnu_debug_def::vector<int, std::allocator<int> > >::~_Safe_iterator() (this, __in_chrg) { struct _Safe_iterator_base * this.102; [/usr/include/c++/4.0.0/debug/safe_iterator.h : 65] { [/usr/include/c++/4.0.0/debug/safe_iterator.h : 65] try { } finally { [/usr/include/c++/4.0.0/debug/safe_iterator.h : 65] this.102 = (struct _Safe_iterator_base *) this; [/usr/include/c++/4.0.0/debug/safe_iterator.h : 65] __base_dtor (this.102); } } [/usr/include/c++/4.0.0/debug/safe_iterator.h : 65] <D12095>:; } So the constructor for that cannot throw so the catch part is removed in both cases. The warning is not strange and is correct in that the __base_dtor cannot be called ever. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31246