From 113e5d824fbd3a859ea7f0723433bce344b9b4d5 Mon Sep 17 00:00:00 2001
From: David Wells <wellsd2@rpi.edu>
Date: Sat, 28 Oct 2017 14:16:21 -0400
Subject: [PATCH] Correctly implement
 FullMatrix<T>::const_iterator::operator++(int).

This operator had the wrong return type and was previously unimplemented.
---
 include/deal.II/lac/full_matrix.h            | 14 +++++++++++++-
 tests/full_matrix/full_matrix_iterator_01.cc | 10 ++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/include/deal.II/lac/full_matrix.h b/include/deal.II/lac/full_matrix.h
index 351e2dd6c1..9b3e315a59 100644
--- a/include/deal.II/lac/full_matrix.h
+++ b/include/deal.II/lac/full_matrix.h
@@ -165,7 +165,7 @@ public:
     /**
      * Postfix increment.
      */
-    const_iterator &operator++ (int);
+    const_iterator operator++ (int);
 
     /**
      * Dereferencing operator.
@@ -1379,6 +1379,18 @@ FullMatrix<number>::const_iterator::operator++ ()
 }
 
 
+template <typename number>
+inline
+typename FullMatrix<number>::const_iterator
+FullMatrix<number>::const_iterator::operator++ (int)
+{
+  const typename FullMatrix<number>::const_iterator current = *this;
+  ++(*this);
+
+  return current;
+}
+
+
 template <typename number>
 inline
 const typename FullMatrix<number>::Accessor &
diff --git a/tests/full_matrix/full_matrix_iterator_01.cc b/tests/full_matrix/full_matrix_iterator_01.cc
index 19123c6f3c..63160feba6 100644
--- a/tests/full_matrix/full_matrix_iterator_01.cc
+++ b/tests/full_matrix/full_matrix_iterator_01.cc
@@ -25,6 +25,7 @@ void test ()
 {
   FullMatrix<double> A(3,3);
 
+  // test prefix operator
   const FullMatrix<double>::const_iterator k = A.begin(),
                                            j = ++A.begin();
 
@@ -40,6 +41,15 @@ void test ()
   AssertThrow (k == k, ExcInternalError());
   AssertThrow (!(k != k), ExcInternalError());
 
+  // test postfix operator
+  FullMatrix<double>::const_iterator l = A.begin();
+  FullMatrix<double>::const_iterator m = l++;
+
+  AssertThrow(m == k, ExcInternalError());
+  AssertThrow(l > m, ExcInternalError());
+  AssertThrow(l->column() == k->column() + 1, ExcInternalError());
+
+
   deallog << "OK" << std::endl;
 }
 
-- 
2.39.5