Index: test/std/utilities/allocator.adaptor/types.pass.cpp
===================================================================
--- test/std/utilities/allocator.adaptor/types.pass.cpp
+++ test/std/utilities/allocator.adaptor/types.pass.cpp
@@ -27,6 +27,7 @@
 
 #include <scoped_allocator>
 #include <type_traits>
+#include <cstddef>
 
 #include "allocators.h"
 
@@ -76,11 +77,11 @@
 
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A2<int>, A1<int>>::size_type,
-        unsigned>::value), "");
+        std::size_t>::value), "");
 
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A2<int>, A1<int>>::difference_type,
-        int>::value), "");
+        std::ptrdiff_t>::value), "");
 
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A2<int>, A1<int>>::pointer,
Index: test/support/allocators.h
===================================================================
--- test/support/allocators.h
+++ test/support/allocators.h
@@ -12,6 +12,7 @@
 
 #include <type_traits>
 #include <utility>
+#include <cstddef>
 
 #include "test_macros.h"
 
@@ -85,8 +86,8 @@
 
     typedef T value_type;
 
-    typedef unsigned size_type;
-    typedef int difference_type;
+    typedef std::size_t size_type;
+    typedef std::ptrdiff_t difference_type;
 
     typedef std::true_type propagate_on_container_move_assignment;
 
Index: test/support/test_allocator.h
===================================================================
--- test/support/test_allocator.h
+++ test/support/test_allocator.h
@@ -51,8 +51,8 @@
     template <class U> friend class test_allocator;
 public:
 
-    typedef unsigned                                                   size_type;
-    typedef int                                                        difference_type;
+    typedef std::size_t                                                size_type;
+    typedef std::ptrdiff_t                                             difference_type;
     typedef T                                                          value_type;
     typedef value_type*                                                pointer;
     typedef const value_type*                                          const_pointer;
@@ -112,8 +112,8 @@
     template <class U> friend class non_default_test_allocator;
 public:
 
-    typedef unsigned                                                   size_type;
-    typedef int                                                        difference_type;
+    typedef std::size_t                                                size_type;
+    typedef std::ptrdiff_t                                             difference_type;
     typedef T                                                          value_type;
     typedef value_type*                                                pointer;
     typedef const value_type*                                          const_pointer;
@@ -173,8 +173,8 @@
     template <class U> friend class test_allocator;
 public:
 
-    typedef unsigned                                                   size_type;
-    typedef int                                                        difference_type;
+    typedef std::size_t                                                size_type;
+    typedef std::ptrdiff_t                                             difference_type;
     typedef void                                                       value_type;
     typedef value_type*                                                pointer;
     typedef const value_type*                                          const_pointer;