--- /dev/null
+// { dg-do run { xfail *-*-* } }
+// { dg-options "-std=gnu++17 -O0" }
+// { dg-require-debug-mode "" }
+
+// Copyright (C) 2013-2018 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 <string_view>
+
+// libstdc++/21674
+// NB: Should work without any inlining or optimizations (ie. -O0).
+int
+main()
+{
+ typedef std::wstring_view string_view_type;
+ string_view_type s;
+ s[0]; // abort
+}