libstdc++: Apply proposed resolutions for LWG 3428, 3447

libstdc++-v3/ChangeLog:

	* include/std/ranges (single_view::single_view): Mark the
	in place constructor explicit as per LWG 3428.
	(take_view): Remove the constraint on the deduction guide's
	template parameter as per LWG 3447.

(cherry picked from commit 50106208ff65fe8076329169cd97460a03e27388)

diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 23f7d9e32b1fedf7da99fe5eb9268294b5fac171..fa58c16511064232e55a53f8abecab02b19fa0e8 100644 (file)
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -538,9 +538,11 @@ namespace ranges
       : _M_value(std::move(__t))
       { }
 
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3428. single_view's in place constructor should be explicit
       template<typename... _Args>
        requires constructible_from<_Tp, _Args...>
-       constexpr
+       constexpr explicit
        single_view(in_place_t, _Args&&... __args)
        : _M_value{in_place, std::forward<_Args>(__args)...}
        { }
@@ -2121,7 +2123,10 @@ namespace views
       }
     };
 
-  template<range _Range>
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 3447. Deduction guides for take_view and drop_view have different
+  // constraints
+  template<typename _Range>
     take_view(_Range&&, range_difference_t<_Range>)
       -> take_view<views::all_t<_Range>>;