[PATCH] __debug::list use C++11 direct initialization

[Jonathan Wakely]

On 09/10/18 07:11 +0200, François Dumont wrote:
>Here is the communication for my yesterday's patch which I thought svn 
>had failed to commit (I had to interrupt it).
>
>Similarly to what I've done for associative containers here is a 
>cleanup of the std::__debug::list implementation leveraging more on 
>C++11 direct initialization.
>
>I also made sure we use consistent comparison between 
>iterator/const_iterator in erase and emplace methods.
>
>2018-10-08  François Dumont <fdumont@gcc.gnu.org>
>
>Â Â Â  * include/debug/list (list<>::cbegin()): Use C++11 direct
>Â Â Â  initialization.
>Â Â Â  (list<>::cend()): Likewise.
>Â Â Â  (list<>::emplace<>(const_iterator, _Args&&...)): Likewise.
>Â Â Â  (list<>::insert(const_iterator, initializer_list<>)): Likewise.
>Â Â Â  (list<>::insert(const_iterator, size_type, const _Tp&)): Likewise.
>Â Â Â  (list<>::erase(const_iterator, const_iterator)): Ensure consistent
>Â Â Â  iterator comparisons.
>Â Â Â  (list<>::splice(const_iterator, list&&, const_iterator,
>Â Â Â  const_iterator)): Likewise.
>
>Tested under Linux x86_64 Debug mode and committed.
>
>François
>

>diff --git a/libstdc++-v3/include/debug/list b/libstdc++-v3/include/debug/list
>index 8add1d596e0..879e1177497 100644
>--- a/libstdc++-v3/include/debug/list
>+++ b/libstdc++-v3/include/debug/list
>@@ -244,11 +244,11 @@ namespace __debug
> #if __cplusplus >= 201103L
>       const_iterator
>       cbegin() const noexcept
>-      { return const_iterator(_Base::begin(), this); }
>+      { return { _Base::begin(), this }; }
> 
>       const_iterator
>       cend() const noexcept
>-      { return const_iterator(_Base::end(), this); }
>+      { return { _Base::end(), this }; }

For functions like emplace (which are C++11-only) and for forward_list
(also C++11-only) using this syntax makes it clearer.

But for these functions it just makes cbegin() and cend() look
different to the C++98 begin() and end() functions, for no obvious
benefit.

Simply using { return end(); } would have been another option.