--- /dev/null
+// { dg-options "-std=gnu++2a" }
+// { dg-do run { target c++2a } }
+
+// Copyright (C) 2020 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/>.
+
+#include <iterator>
+#include <sstream>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+ static_assert( std::sentinel_for<std::default_sentinel_t,
+ std::istreambuf_iterator<char>> );
+
+ std::istreambuf_iterator<char> i = std::default_sentinel;
+ VERIFY( i == std::default_sentinel );
+ VERIFY( std::default_sentinel == i );
+}
+
+void
+test02()
+{
+ std::istringstream in("abc");
+ std::istreambuf_iterator<char> iter(in);
+ VERIFY( iter != std::default_sentinel );
+ VERIFY( std::default_sentinel != iter );
+
+ std::next(iter, 3);
+ VERIFY( iter == std::default_sentinel );
+ VERIFY( std::default_sentinel == iter );
+}
+
+int main()
+{
+ test01();
+ test02();
+}