Add assertions to extract(const_iterator) functions

	* include/bits/stl_map.h (map::extract(const_iterator)): Assert that
	iterator is not past-the-end.
	* include/bits/stl_multimap.h (multimap::extract(const_iterator)):
	Likewise.
	* include/bits/stl_multiset.h (multiset::extract(const_iterator)):
	Likewise.
	* include/bits/stl_set.h (set::extract(const_iterator)): Likewise.
	* include/bits/unordered_map.h (unordered_map::extract(const_iterator))
	(unordered_multimap::extract(const_iterator)): Likewise.
	* include/bits/unordered_set.h (unordered_set::extract(const_iterator))
	(unordered_multiset::extract(const_iterator)): Likewise.

From-SVN: r240487

libstdc++-v3/ChangeLog

+2016-09-26  Jonathan Wakely  <jwakely@redhat.com>
+
+	* include/bits/stl_map.h (map::extract(const_iterator)): Assert that
+	iterator is not past-the-end.
+	* include/bits/stl_multimap.h (multimap::extract(const_iterator)):
+	Likewise.
+	* include/bits/stl_multiset.h (multiset::extract(const_iterator)):
+	Likewise.
+	* include/bits/stl_set.h (set::extract(const_iterator)): Likewise.
+	* include/bits/unordered_map.h (unordered_map::extract(const_iterator))
+	(unordered_multimap::extract(const_iterator)): Likewise.
+	* include/bits/unordered_set.h (unordered_set::extract(const_iterator))
+	(unordered_multiset::extract(const_iterator)): Likewise.
+
 2016-09-26  Ville Voutilainen  <ville.voutilainen@gmail.com>
 
 	PR libstdc++/77717

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

@@ -605,7 +605,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       /// Extract a node.
       node_type
       extract(const_iterator __pos)
-      { return _M_t.extract(__pos); }
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_t.extract(__pos);
+      }
 
       /// Extract a node.
       node_type

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

@@ -606,7 +606,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       /// Extract a node.
       node_type
       extract(const_iterator __pos)
-      { return _M_t.extract(__pos); }
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_t.extract(__pos);
+      }
 
       /// Extract a node.
       node_type

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

@@ -549,7 +549,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       /// Extract a node.
       node_type
       extract(const_iterator __pos)
-      { return _M_t.extract(__pos); }
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_t.extract(__pos);
+      }
 
       /// Extract a node.
       node_type

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

@@ -565,7 +565,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       /// Extract a node.
       node_type
       extract(const_iterator __pos)
-      { return _M_t.extract(__pos); }
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_t.extract(__pos);
+      }
 
       /// Extract a node.
       node_type

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

@@ -421,7 +421,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       /// Extract a node.
       node_type
       extract(const_iterator __pos)
-      { return _M_h.extract(__pos); }
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_h.extract(__pos);
+      }
 
       /// Extract a node.
       node_type
@@ -1534,7 +1537,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       /// Extract a node.
       node_type
       extract(const_iterator __pos)
-      { return _M_h.extract(__pos); }
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_h.extract(__pos);
+      }
 
       /// Extract a node.
       node_type

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

@@ -482,7 +482,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       /// Extract a node.
       node_type
       extract(const_iterator __pos)
-      { return _M_h.extract(__pos); }
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_h.extract(__pos);
+      }
 
       /// Extract a node.
       node_type
@@ -1190,7 +1193,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       /// Extract a node.
       node_type
       extract(const_iterator __pos)
-      { return _M_h.extract(__pos); }
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_h.extract(__pos);
+      }
 
       /// Extract a node.
       node_type