PR libstdc++/90239 use uses_allocator_construction_args in <scoped_allocator>

PR libstdc++/90239
	* doc/xml/manual/status_cxx2020.xml: Amend P0591R4 status.
	* include/std/scoped_allocator [__cplusplus > 201703L]
	(scoped_allocator_adaptor::construct): Define in terms of
	uses_allocator_construction_args, as per P0591R4.
	* testsuite/20_util/scoped_allocator/construct_pair_c++2a.cc: New test.
	* testsuite/util/testsuite_allocator.h: Remove name of unused
	parameter.

From-SVN: r270588

libstdc++-v3/ChangeLog

@@ -1,3 +1,14 @@
+2019-04-25  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/90239
+	* doc/xml/manual/status_cxx2020.xml: Amend P0591R4 status.
+	* include/std/scoped_allocator [__cplusplus > 201703L]
+	(scoped_allocator_adaptor::construct): Define in terms of
+	uses_allocator_construction_args, as per P0591R4.
+	* testsuite/20_util/scoped_allocator/construct_pair_c++2a.cc: New test.
+	* testsuite/util/testsuite_allocator.h: Remove name of unused
+	parameter.
+
 2019-04-24  Jonathan Wakely  <jwakely@redhat.com>
 
 	* doc/xml/manual/status_cxx2017.xml: Document P0024R2 status.

libstdc++-v3/doc/xml/manual/status_cxx2020.xml

@@ -674,7 +674,9 @@ Feature-testing recommendations for C++</link>.
 	</link>
       </entry>
       <entry align="center"> 9.1 </entry>
-      <entry />
+      <entry>
+        <code>std::scoped_allocator_adaptor</code> changes missing in 9.1.0
+      </entry>
     </row>
 
     <row>

libstdc++-v3/include/std/scoped_allocator

@@ -35,6 +35,7 @@
 # include <bits/c++0x_warning.h>
 #else
 
+#include <memory>
 #include <utility>
 #include <tuple>
 #include <bits/alloc_traits.h>
@@ -187,6 +188,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	using __outermost_alloc_traits
 	  = allocator_traits<typename __outermost_type<_Alloc>::type>;
 
+#if __cplusplus <= 201703
       template<typename _Tp, typename... _Args>
         void
         _M_construct(__uses_alloc0, _Tp* __p, _Args&&... __args)
@@ -218,6 +220,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 			       std::forward<_Args>(__args)...,
 			       inner_allocator());
         }
+#endif // C++17
 
       template<typename _Alloc>
         static _Alloc
@@ -355,6 +358,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       size_type max_size() const
       { return __traits::max_size(outer_allocator()); }
 
+#if __cplusplus <= 201703
       template<typename _Tp, typename... _Args>
 	typename __not_pair<_Tp>::type
 	construct(_Tp* __p, _Args&&... __args)
@@ -417,6 +421,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 		    std::forward_as_tuple(std::forward<_Up>(__x.first)),
 		    std::forward_as_tuple(std::forward<_Vp>(__x.second)));
 	}
+#else // C++2a
+      template<typename _Tp, typename... _Args>
+	__attribute__((__nonnull__))
+	void
+	construct(_Tp* __p, _Args&&... __args)
+	{
+	  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
+	  std::apply([__p, this](auto&&... __newargs) {
+	      _O_traits::construct(__outermost(*this), __p,
+		  std::forward<decltype(__newargs)>(__newargs)...);
+	  },
+	  uses_allocator_construction_args<_Tp>(inner_allocator(),
+	    std::forward<_Args>(__args)...));
+	}
+#endif // C++2a
 
       template<typename _Tp>
         void destroy(_Tp* __p)
@@ -439,6 +458,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
                  const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept;
 
     private:
+#if __cplusplus <= 201703L
       template<typename _Ind, typename... _Args>
 	tuple<_Args&&...>
 	_M_construct_p(__uses_alloc0, _Ind, tuple<_Args...>& __t)
@@ -461,6 +481,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	{
 	  return { std::get<_Ind>(std::move(__t))..., inner_allocator() };
 	}
+#endif // C++17
     };
 
   template <typename _OutA1, typename _OutA2, typename... _InA>

libstdc++-v3/testsuite/20_util/scoped_allocator/construct_pair_c++2a.cc

@@ -0,0 +1,97 @@
+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do run { target c++2a } }
+
+#include <scoped_allocator>
+#include <vector>
+#include <testsuite_hooks.h>
+#include <testsuite_allocator.h>
+
+struct X
+{
+  using allocator_type = __gnu_test::uneq_allocator<int>;
+
+  X(int personality) : a(personality) { }
+  X(std::allocator_arg_t, allocator_type a) : a(a) { }
+  X(std::allocator_arg_t, allocator_type a, const X&) : a(a) { }
+
+  allocator_type a;
+};
+
+void
+test01()
+{
+  using value_type = std::pair<std::pair<X, int>, std::pair<int, X>>;
+  using scoped_alloc
+    = std::scoped_allocator_adaptor<__gnu_test::uneq_allocator<value_type>>;
+
+  const scoped_alloc a(10);
+  std::vector<value_type, scoped_alloc> v(a);
+  VERIFY( v.get_allocator().get_personality() == a.get_personality() );
+
+  value_type val( { X(1), 2 }, { 3, X(4) } );
+  v.push_back(val);
+  X& x1 = v.back().first.first;
+  VERIFY( x1.a.get_personality() != val.first.first.a.get_personality() );
+  VERIFY( x1.a.get_personality() == a.get_personality() );
+
+  X& x2 = v.back().second.second;
+  VERIFY( x2.a.get_personality() != val.second.second.a.get_personality() );
+  VERIFY( x2.a.get_personality() == a.get_personality() );
+
+  // Check other members of the pairs are correctly initialized too:
+  VERIFY( v.back().first.second == val.first.second );
+  VERIFY( v.back().second.first == val.second.first );
+}
+
+void
+test02()
+{
+  using value_type = std::pair<std::pair<X, int>, std::pair<int, X>>;
+  using scoped_alloc
+    = std::scoped_allocator_adaptor<__gnu_test::uneq_allocator<value_type>,
+				    X::allocator_type>;
+
+  const scoped_alloc a(10, 20);
+  std::vector<value_type, scoped_alloc> v(a);
+  VERIFY( v.get_allocator().get_personality() == a.get_personality() );
+
+  value_type val( { X(1), 2 }, { 3, X(4) } );
+  v.push_back(val);
+  X& x1 = v.back().first.first;
+  VERIFY( x1.a.get_personality() != val.first.first.a.get_personality() );
+  VERIFY( x1.a.get_personality() != a.get_personality() );
+  VERIFY( x1.a.get_personality() == a.inner_allocator().get_personality() );
+
+  X& x2 = v.back().second.second;
+  VERIFY( x2.a.get_personality() != val.second.second.a.get_personality() );
+  VERIFY( x2.a.get_personality() != a.get_personality() );
+  VERIFY( x2.a.get_personality() == a.inner_allocator().get_personality() );
+
+  // Check other members of the pairs are correctly initialized too:
+  VERIFY( v.back().first.second == val.first.second );
+  VERIFY( v.back().second.first == val.second.first );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}

libstdc++-v3/testsuite/util/testsuite_allocator.h

@@ -334,7 +334,7 @@ namespace __gnu_test
       int get_personality() const { return personality; }
 
       pointer
-      allocate(size_type n, const void* hint = 0)
+      allocate(size_type n, const void* = 0)
       {
 	pointer p = AllocTraits::allocate(*this, n);