[Boost-bugs] [Boost C++ Libraries] #3746: list_iterator::operator == fails to accept a non-const var to the left and a const one to the right

Subject: [Boost-bugs] [Boost C++ Libraries] #3746: list_iterator::operator == fails to accept a non-const var to the left and a const one to the right
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-12-10 12:02:54

#3746: list_iterator::operator == fails to accept a non-const var to the left and
a const one to the right
--------------------------+-------------------------------------------------
 Reporter:  gvlad@…       |       Owner:  igaztanaga
     Type:  Bugs          |      Status:  new       
Milestone:  Boost 1.42.0  |   Component:  intrusive 
  Version:  Boost 1.41.0  |    Severity:  Problem   
 Keywords:                |  
--------------------------+-------------------------------------------------
 The following code fails to compile (msvc 9):

 using namespace boost::intrusive;
 struct my_struct : list_base_hook<> {};
 typedef list<my_struct> my_list;
 my_list l;
 my_list::const_iterator it = l.begin();
 if (l.end() == it) {} // fails
 if (it == l.end()) {} // succeeds

 If to use std::list there is no such problem because std::list::iterator
 is derived from std::list::const_iterator.
 My suggesion is to use template "operator ==" for list_iterator that
 accepts both const and non-const interator. For example:

 ("list_node.hpp")
 template <bool IsOtherConst>
 bool operator== (const list_iterator<Container, IsOtherConst>& i) const
    {  return members_.nodeptr_ == i.pointed_node();   }

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3746>
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