PR libstdc++/92124 fix incorrect container move assignment

The container requirements say that for move assignment "All existing
elements of [the target] are either move assigned or destroyed". Some of
our containers currently use __make_move_if_noexcept which makes the
move depend on whether the element type is nothrow move constructible.
This is incorrect, because the standard says we must move assign, not
move or copy depending on the move constructor.

Use make_move_iterator instead so that we move unconditionally. This
ensures existing elements won't be copy assigned.

	PR libstdc++/92124
	* include/bits/forward_list.h
	(_M_move_assign(forward_list&&, false_type)): Do not use
	__make_move_if_noexcept, instead move unconditionally.
	* include/bits/stl_deque.h (_M_move_assign2(deque&&, false_type)):
	Likewise.
	* include/bits/stl_list.h (_M_move_assign(list&&, false_type)):
	Likewise.
	* include/bits/stl_vector.h (_M_move_assign(vector&&, false_type)):
	Likewise.
	* testsuite/23_containers/vector/92124.cc: New test.

From-SVN: r277113

libstdc++-v3/ChangeLog

+2019-10-17  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/92124
+	* include/bits/forward_list.h
+	(_M_move_assign(forward_list&&, false_type)): Do not use
+	__make_move_if_noexcept, instead move unconditionally.
+	* include/bits/stl_deque.h (_M_move_assign2(deque&&, false_type)):
+	Likewise.
+	* include/bits/stl_list.h (_M_move_assign(list&&, false_type)):
+	Likewise.
+	* include/bits/stl_vector.h (_M_move_assign(vector&&, false_type)):
+	Likewise.
+	* testsuite/23_containers/vector/92124.cc: New test.
+
 2019-10-16  Jonathan Wakely  <jwakely@redhat.com>
 
 	* include/bits/c++config (_GLIBCXX_BUILTIN_IS_SAME_AS): Define to

libstdc++-v3/include/bits/forward_list.h

@@ -1336,8 +1336,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 	else
 	  // The rvalue's allocator cannot be moved, or is not equal,
 	  // so we need to individually move each element.
-	  this->assign(std::__make_move_if_noexcept_iterator(__list.begin()),
-		       std::__make_move_if_noexcept_iterator(__list.end()));
+	  this->assign(std::make_move_iterator(__list.begin()),
+		       std::make_move_iterator(__list.end()));
       }
 
       // Called by assign(_InputIterator, _InputIterator) if _Tp is

libstdc++-v3/include/bits/stl_deque.h

@@ -2256,8 +2256,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 	  {
 	    // The rvalue's allocator cannot be moved and is not equal,
 	    // so we need to individually move each element.
-	    _M_assign_aux(std::__make_move_if_noexcept_iterator(__x.begin()),
-			  std::__make_move_if_noexcept_iterator(__x.end()),
+	    _M_assign_aux(std::make_move_iterator(__x.begin()),
+			  std::make_move_iterator(__x.end()),
 			  std::random_access_iterator_tag());
 	    __x.clear();
 	  }

libstdc++-v3/include/bits/stl_list.h

@@ -1957,8 +1957,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
 	else
 	  // The rvalue's allocator cannot be moved, or is not equal,
 	  // so we need to individually move each element.
-	  _M_assign_dispatch(std::__make_move_if_noexcept_iterator(__x.begin()),
-			     std::__make_move_if_noexcept_iterator(__x.end()),
+	  _M_assign_dispatch(std::make_move_iterator(__x.begin()),
+			     std::make_move_iterator(__x.end()),
 			     __false_type{});
       }
 #endif

libstdc++-v3/include/bits/stl_vector.h

@@ -1828,8 +1828,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 	  {
 	    // The rvalue's allocator cannot be moved and is not equal,
 	    // so we need to individually move each element.
-	    this->assign(std::__make_move_if_noexcept_iterator(__x.begin()),
-			 std::__make_move_if_noexcept_iterator(__x.end()));
+	    this->_M_assign_aux(std::make_move_iterator(__x.begin()),
+			        std::make_move_iterator(__x.end()),
+				std::random_access_iterator_tag());
 	    __x.clear();
 	  }
       }

libstdc++-v3/testsuite/23_containers/deque/92124.cc

+// 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-do run { target c++11 } }
+
+#include <deque>
+#include <testsuite_allocator.h>
+
+struct X {
+    X() = default;
+    X(const X&) = default;
+
+    // Move constructor might throw
+    X(X&&) noexcept(false) {}
+
+    // Tracking calls to assignment functions
+    X& operator=(const X&) { throw 1; }
+
+    X& operator=(X&&) noexcept(true) { return *this; }
+};
+
+void
+test01()
+{
+  using A = __gnu_test::propagating_allocator<X, false>;
+  A a1(1), a2(2);
+  std::deque<X, A> v1(1, a1), v2(1, a2);
+  v1 = std::move(v2);
+}
+
+int
+main()
+{
+  test01();
+}

libstdc++-v3/testsuite/23_containers/forward_list/92124.cc

+// 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-do run { target c++11 } }
+
+#include <forward_list>
+#include <testsuite_allocator.h>
+
+struct X {
+    X() = default;
+    X(const X&) = default;
+
+    // Move constructor might throw
+    X(X&&) noexcept(false) {}
+
+    // Tracking calls to assignment functions
+    X& operator=(const X&) { throw 1; }
+
+    X& operator=(X&&) noexcept(true) { return *this; }
+};
+
+void
+test01()
+{
+  using A = __gnu_test::propagating_allocator<X, false>;
+  A a1(1), a2(2);
+  std::forward_list<X, A> v1(1, a1), v2(1, a2);
+  v1 = std::move(v2);
+}
+
+int
+main()
+{
+  test01();
+}

libstdc++-v3/testsuite/23_containers/list/92124.cc

+// 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-do run { target c++11 } }
+
+#include <list>
+#include <testsuite_allocator.h>
+
+struct X {
+    X() = default;
+    X(const X&) = default;
+
+    // Move constructor might throw
+    X(X&&) noexcept(false) {}
+
+    // Tracking calls to assignment functions
+    X& operator=(const X&) { throw 1; }
+
+    X& operator=(X&&) noexcept(true) { return *this; }
+};
+
+void
+test01()
+{
+  using A = __gnu_test::propagating_allocator<X, false>;
+  A a1(1), a2(2);
+  std::list<X, A> v1(1, a1), v2(1, a2);
+  v1 = std::move(v2);
+}
+
+int
+main()
+{
+  test01();
+}

libstdc++-v3/testsuite/23_containers/vector/92124.cc

+// 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-do run { target c++11 } }
+
+#include <vector>
+#include <testsuite_allocator.h>
+
+struct X {
+    X() = default;
+    X(const X&) = default;
+
+    // Move constructor might throw
+    X(X&&) noexcept(false) {}
+
+    // Tracking calls to assignment functions
+    X& operator=(const X&) { throw 1; }
+
+    X& operator=(X&&) noexcept(true) { return *this; }
+};
+
+void
+test01()
+{
+  using A = __gnu_test::propagating_allocator<X, false>;
+  A a1(1), a2(2);
+  std::vector<X, A> v1(1, a1), v2(1, a2);
+  v1 = std::move(v2);
+}
+
+int
+main()
+{
+  test01();
+}