[gcc(refs/users/guojiufu/heads/guojiufu-branch)] libstdc++: Remove converting constructors from views (LWG 3280)

[Jiu Fu Guo]

https://gcc.gnu.org/g:4cc3b275d310dbf5982544cb88c11630349f414c

commit 4cc3b275d310dbf5982544cb88c11630349f414c
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Feb 19 12:26:19 2020 +0000

    libstdc++: Remove converting constructors from views (LWG 3280)
    
            * include/std/ranges (filter_view, transform_view, take_view)
            (join_view, split_view, reverse_view): Remove commented-out converting
            constructors (LWG 3280).

Diff:
---
 libstdc++-v3/ChangeLog          |  4 +++
 libstdc++-v3/include/std/ranges | 68 +++--------------------------------------
 2 files changed, 8 insertions(+), 64 deletions(-)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 5408a89c7fb..9ccba4345d5 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,9 @@
 2020-02-19  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/std/ranges (filter_view, transform_view, take_view)
+	(join_view, split_view, reverse_view): Remove commented-out converting
+	constructors (LWG 3280).
+
 	* include/std/memory (uninitialized_construct_using_allocator): Use
 	std::construct_at (LWG 3321).
 
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 4bfda88c319..cf4c19ffaab 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -1470,17 +1470,6 @@ namespace views
 	: _M_base(std::move(__base)), _M_pred(std::move(__pred))
       { }
 
-      /* XXX: P3280 removes this constructor
-      template<input_range _Range>
-	requires viewable_range<_Range>
-	  && constructible_from<_Vp, all_view<_Range>>
-	constexpr
-	filter_view(_Range&& __r, _Pred __pred)
-	  : _M_base(views::all(std::forward<_Range>(__r))),
-	    _M_pred(std::move(__pred))
-	{ }
-      */
-
       constexpr _Vp
       base() const& requires copy_constructible<_Vp>
       { return _M_base; }
@@ -1799,17 +1788,6 @@ namespace views
 	: _M_base(std::move(__base)), _M_fun(std::move(__fun))
       { }
 
-      /* XXX: P3280 removes this constructor
-      template<input_range _Range>
-	requires viewable_range<_Range>
-	  && constructible_from<_Vp, all_view<_Range>>
-	constexpr
-	transform_view(_Range&& __r, _Fp __fun)
-	  : _M_base(views::all(std::forward<_Range>(__r)))
-	{
-	}
-	*/
-
       constexpr _Vp
       base() const& requires copy_constructible<_Vp>
       { return _M_base ; }
@@ -1915,15 +1893,6 @@ namespace views
 	: _M_base(std::move(base)), _M_count(std::move(__count))
       { }
 
-      /* XXX: P3280 removes this constructor
-      template<viewable_range _Range>
-	requires constructible_from<_Vp, all_view<_Range>>
-      constexpr
-      take_view(_Range&& __r, range_difference_t<_Vp> __count)
-	: _M_base(views::all(std::forward<_Range>(__r))), _M_count(__count)
-      { }
-      */
-
       constexpr _Vp
       base() const& requires copy_constructible<_Vp>
       { return _M_base; }
@@ -2491,16 +2460,6 @@ namespace views
 	: _M_base(std::move(__base))
       { }
 
-      /* XXX: P3280 removes this constructor
-      template<input_range _Range>
-	requires viewable_range<_Range>
-	  && constructible_from<_Vp, all_view<_Range>>
-      constexpr explicit
-      join_view(_Range&& __r)
-	: _M_base(views::all(std::forward<_Range>(__r)))
-      { }
-      */
-
       constexpr _Vp
       base() const& requires copy_constructible<_Vp>
       { return _M_base; }
@@ -2878,17 +2837,6 @@ namespace views
 	: _M_base(std::move(__base)), _M_pattern(std::move(__pattern))
       { }
 
-      /* XXX: P3280 removes this constructor
-      template<input_range _Range, forward_range _Pred>
-	requires constructible_from<_Vp, all_view<_Range>>
-	  && constructible_from<_Pattern, all_view<_Pred>>
-	constexpr
-	split_view(_Range&& __r, _Pred&& __p)
-	  : _M_base(views::all(std::forward<_Range>(__r))),
-	    _M_pattern(views::all(std::forward<_Pred>(__p)))
-      { }
-      */
-
       template<input_range _Range>
 	requires constructible_from<_Vp, all_view<_Range>>
 	  && constructible_from<_Pattern, single_view<range_value_t<_Range>>>
@@ -2994,14 +2942,15 @@ namespace views
 	: _M_base(std::move(__r))
       { }
 
-      /* XXX: P3280 doesn't remove this constructor, but I think it should?
+      /* XXX: LWG 3280 didn't remove this constructor, but I think it should?
       template<viewable_range _Range>
-	requires (!common_range<_Range>) && constructible_from<_Vp, all_view<_Range>>
+	requires (!common_range<_Range>)
+	  && constructible_from<_Vp, all_view<_Range>>
 	constexpr explicit
 	common_view(_Range&& __r)
 	  : _M_base(views::all(std::forward<_Range>(__r)))
 	{ }
-	*/
+      */
 
       constexpr _Vp
       base() const& requires copy_constructible<_Vp>
@@ -3092,15 +3041,6 @@ namespace views
 	: _M_base(std::move(__r))
 	{ }
 
-      /* XXX: P3280 removes this constructor
-      template<viewable_range _Range>
-	requires bidirectional_range<_Range> && constructible_from<_Vp, all_view<_Range>>
-	constexpr explicit
-	reverse_view(_Range&& __r)
-	  : _M_base(views::all(std::forward<_Range>(__r)))
-	{ }
-	*/
-
       constexpr _Vp
       base() const& requires copy_constructible<_Vp>
       { return _M_base; }