[PATCH] libstdc++: Implement LWG 3546 changes to common_iterator

[PATCH] libstdc++: Implement LWG 3546 changes to common_iterator

[Patrick Palka]

libstdc++-v3/ChangeLog:

	* include/bits/stl_iterator.h
	(__detail::__common_iter_use_postfix_proxy): Add
	move_constructible constraint as LWG 3546.
	(common_iterator::__postfix_proxy): Adjust initializer of
	_M_keep as per LWG 3546.
---
 libstdc++-v3/include/bits/stl_iterator.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h
index 6ec046b597b..7fe727d8093 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -1672,7 +1672,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     template<typename _It>
       concept __common_iter_use_postfix_proxy
 	= (!requires (_It& __i) { { *__i++ } -> __can_reference; })
-	  && constructible_from<iter_value_t<_It>, iter_reference_t<_It>>;
+	  && constructible_from<iter_value_t<_It>, iter_reference_t<_It>>
+	  && move_constructible<iter_value_t<_It>>;
   } // namespace __detail
 
   /// An iterator/sentinel adaptor for representing a non-common range.
@@ -1715,7 +1716,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       iter_value_t<_It> _M_keep;
 
       __postfix_proxy(iter_reference_t<_It>&& __x)
-      : _M_keep(std::move(__x)) { }
+      : _M_keep(std::forward<iter_reference_t<_It>>(__x)) { }
 
       friend class common_iterator;
 
-- 
2.32.0.93.g670b81a890

Re: [PATCH] libstdc++: Implement LWG 3546 changes to common_iterator

[Jonathan Wakely]

On Fri, 18 Jun 2021 at 04:59, Patrick Palka via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> libstdc++-v3/ChangeLog:
>
>         * include/bits/stl_iterator.h
>         (__detail::__common_iter_use_postfix_proxy): Add
>         move_constructible constraint as LWG 3546.
>         (common_iterator::__postfix_proxy): Adjust initializer of
>         _M_keep as per LWG 3546.

OK, thanks


> ---
>  libstdc++-v3/include/bits/stl_iterator.h | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h
> index 6ec046b597b..7fe727d8093 100644
> --- a/libstdc++-v3/include/bits/stl_iterator.h
> +++ b/libstdc++-v3/include/bits/stl_iterator.h
> @@ -1672,7 +1672,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>      template<typename _It>
>        concept __common_iter_use_postfix_proxy
>         = (!requires (_It& __i) { { *__i++ } -> __can_reference; })
> -         && constructible_from<iter_value_t<_It>, iter_reference_t<_It>>;
> +         && constructible_from<iter_value_t<_It>, iter_reference_t<_It>>
> +         && move_constructible<iter_value_t<_It>>;
>    } // namespace __detail
>
>    /// An iterator/sentinel adaptor for representing a non-common range.
> @@ -1715,7 +1716,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        iter_value_t<_It> _M_keep;
>
>        __postfix_proxy(iter_reference_t<_It>&& __x)
> -      : _M_keep(std::move(__x)) { }
> +      : _M_keep(std::forward<iter_reference_t<_It>>(__x)) { }
>
>        friend class common_iterator;
>
> --
> 2.32.0.93.g670b81a890
>