--- /dev/null
+// ------------------------------------------------------------------------
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+// Copyright (C) 2005 - 2020 by the deal.II authors
+//
+// This file is part of the deal.II library.
+//
+// Part of the source code is dual licensed under Apache-2.0 WITH
+// LLVM-exception OR LGPL-2.1-or-later. Detailed license information
+// governing the source code and code contributions can be found in
+// LICENSE.md and CONTRIBUTING.md at the top level directory of deal.II.
+//
+// ------------------------------------------------------------------------
+
+// Test that an assertion is thrown if output argument of FullMatrix::mmult() is
+// also an input argument
+
+#include <deal.II/lac/full_matrix.h>
+
+#include "../tests.h"
+
+int
+main()
+{
+ initlog();
+
+ try
+ {
+ dealii::FullMatrix<double> A(2, 2);
+ dealii::FullMatrix<double> B(2, 2);
+
+ // This should trigger an assertion
+ A.mmult(A, B);
+ }
+ catch (const dealii::ExceptionBase &exc)
+ {
+ deallog << exc.get_exc_name() << std::endl;
+ }
+
+ return 0;
+}