diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index bf0af28ad56..55ad108aca8 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,8 @@
 2019-10-23  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/ext/throw_allocator.h (throw_allocator_base): Qualify
+	size_t and ptrdiff_t.
+
 	* include/ext/pb_ds/detail/bin_search_tree_/bin_search_tree_.hpp:
 	Use detail::rebind_traits.
 	* include/ext/pb_ds/detail/bin_search_tree_/node_iterators.hpp:
diff --git a/libstdc++-v3/include/ext/throw_allocator.h b/libstdc++-v3/include/ext/throw_allocator.h
index f5da751eb69..a4b9fbc0176 100644
--- a/libstdc++-v3/include/ext/throw_allocator.h
+++ b/libstdc++-v3/include/ext/throw_allocator.h
@@ -796,8 +796,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     : public annotate_base, public _Cond
     {
     public:
-      typedef size_t 				size_type;
-      typedef ptrdiff_t 			difference_type;
+      typedef std::size_t 			size_type;
+      typedef std::ptrdiff_t 			difference_type;
       typedef _Tp 				value_type;
       typedef value_type* 			pointer;
       typedef const value_type* 		const_pointer;