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I was merily experimenting with the new trailing return types, where I hit a problem with this (simplified) code #include <list> class MyContainer{ std::list<int> ints; auto begin( ) -> decltype(ints.begin()) { return ints.begin(); } auto begin( ) const -> decltype(ints.begin()) { return ints.begin(); } }; Ignore the fact of how pointless this code is. The important part is the compiler error generated when using GCC 4.6.1 (with -std=c++0x flag): In member function 'std::list<int>::iterator MyContainer::begin() const': error: could not convert '((const MyContainer*)this)->MyContainer::ints.std::list<_Tp, _Alloc>::begin [with _Tp = int, _Alloc = std::allocator<int>, std::list<_Tp, _Alloc>::const_iterator = std::_List_const_iterator<int>]()' from 'std::list<int>::const_iterator {aka std::_List_const_iterator<int>}' to 'std::list<int>::iterator {aka std::_List_iterator<int>}' In case you're not of fan of error involving templates, the short story is that in the body of the const version of MyContainer::begin , the expression ints.begin() returns a value of type std::list<int>::const_iterator (since ints is const in such a context). However, decltype(ints.begin()) produces the type std::list<int>::iterator , i.e. decltype ignores the const qualifier of the begin method when deciding the type of the expression. Unsurprisingly, a conflict in types is the result. This seems to me to be a bug in the GCC compiler. It would only make sense for decltype to honor the const qualifier and produce the const_iterator type. Can anyone confirm or deny (maybe even explain) this? Maybe I am overlooki

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