diff --git a/libcxx/include/iterator b/libcxx/include/iterator
--- a/libcxx/include/iterator
+++ b/libcxx/include/iterator
@@ -767,16 +767,25 @@
 
 template <class _Container>
 class _LIBCPP_TEMPLATE_VIS back_insert_iterator
+#if _LIBCPP_STD_VER <= 17
     : public iterator<output_iterator_tag,
                       void,
                       void,
                       void,
                       void>
+#endif // _LIBCPP_STD_VER <= 17
 {
 protected:
     _Container* container;
 public:
     typedef _Container container_type;
+#if _LIBCPP_STD_VER > 17
+    typedef output_iterator_tag iterator_category;
+    typedef void value_type;
+    typedef ptrdiff_t difference_type;
+    typedef void pointer;
+    typedef void reference;
+#endif // _LIBCPP_STD_VER > 17
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit back_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 back_insert_iterator& operator=(const typename _Container::value_type& __value_)
@@ -800,16 +809,25 @@
 
 template <class _Container>
 class _LIBCPP_TEMPLATE_VIS front_insert_iterator
+#if _LIBCPP_STD_VER <= 17
     : public iterator<output_iterator_tag,
                       void,
                       void,
                       void,
                       void>
+#endif // _LIBCPP_STD_VER <= 17
 {
 protected:
     _Container* container;
 public:
     typedef _Container container_type;
+#if _LIBCPP_STD_VER > 17
+    typedef output_iterator_tag iterator_category;
+    typedef void value_type;
+    typedef ptrdiff_t difference_type;
+    typedef void pointer;
+    typedef void reference;
+#endif // _LIBCPP_STD_VER > 17
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit front_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator& operator=(const typename _Container::value_type& __value_)
@@ -833,17 +851,26 @@
 
 template <class _Container>
 class _LIBCPP_TEMPLATE_VIS insert_iterator
+#if _LIBCPP_STD_VER <= 17
     : public iterator<output_iterator_tag,
                       void,
                       void,
                       void,
                       void>
+#endif // _LIBCPP_STD_VER <= 17
 {
 protected:
     _Container* container;
     typename _Container::iterator iter;
 public:
     typedef _Container container_type;
+#if _LIBCPP_STD_VER > 17
+    typedef output_iterator_tag iterator_category;
+    typedef void value_type;
+    typedef ptrdiff_t difference_type;
+    typedef void pointer;
+    typedef void reference;
+#endif // _LIBCPP_STD_VER > 17
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 insert_iterator(_Container& __x, typename _Container::iterator __i)
         : container(_VSTD::addressof(__x)), iter(__i) {}
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/cxx20_iterator_traits.compile.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/cxx20_iterator_traits.compile.pass.cpp
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/cxx20_iterator_traits.compile.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/cxx20_iterator_traits.compile.pass.cpp
@@ -173,10 +173,10 @@
 static_assert(
     testStdlibIterator<std::reverse_iterator<std::vector<int>::iterator>, int, std::random_access_iterator_tag>());
 static_assert(
-    testStdlibIterator<std::back_insert_iterator<std::vector<int>::iterator>, void, std::output_iterator_tag>());
+    testStdlibIterator<std::back_insert_iterator<std::vector<int>::iterator>, void, std::output_iterator_tag, std::ptrdiff_t>());
 static_assert(
-    testStdlibIterator<std::front_insert_iterator<std::vector<int>::iterator>, void, std::output_iterator_tag>());
-static_assert(testStdlibIterator<std::insert_iterator<std::vector<int> >, void, std::output_iterator_tag>());
+    testStdlibIterator<std::front_insert_iterator<std::vector<int>::iterator>, void, std::output_iterator_tag, std::ptrdiff_t>());
+static_assert(testStdlibIterator<std::insert_iterator<std::vector<int> >, void, std::output_iterator_tag, std::ptrdiff_t>());
 static_assert(testStdlibIteratorConst<std::istream_iterator<int, char>, int, std::input_iterator_tag>());
 
 #if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp
@@ -48,7 +48,7 @@
     q.test();
     static_assert((std::is_same<typename R::container_type, C>::value), "");
     static_assert((std::is_same<typename R::value_type, void>::value), "");
-    static_assert((std::is_same<typename R::difference_type, void>::value), "");
+    static_assert((std::is_same<typename R::difference_type, std::ptrdiff_t>::value), "");
     static_assert((std::is_same<typename R::reference, void>::value), "");
     static_assert((std::is_same<typename R::pointer, void>::value), "");
     static_assert((std::is_same<typename R::iterator_category, std::output_iterator_tag>::value), "");
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp
@@ -49,7 +49,7 @@
     q.test();
     static_assert((std::is_same<typename R::container_type, C>::value), "");
     static_assert((std::is_same<typename R::value_type, void>::value), "");
-    static_assert((std::is_same<typename R::difference_type, void>::value), "");
+    static_assert((std::is_same<typename R::difference_type, std::ptrdiff_t>::value), "");
     static_assert((std::is_same<typename R::reference, void>::value), "");
     static_assert((std::is_same<typename R::pointer, void>::value), "");
     static_assert((std::is_same<typename R::iterator_category, std::output_iterator_tag>::value), "");
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp
@@ -52,7 +52,7 @@
     q.test();
     static_assert((std::is_same<typename R::container_type, C>::value), "");
     static_assert((std::is_same<typename R::value_type, void>::value), "");
-    static_assert((std::is_same<typename R::difference_type, void>::value), "");
+    static_assert((std::is_same<typename R::difference_type, std::ptrdiff_t>::value), "");
     static_assert((std::is_same<typename R::reference, void>::value), "");
     static_assert((std::is_same<typename R::pointer, void>::value), "");
     static_assert((std::is_same<typename R::iterator_category, std::output_iterator_tag>::value), "");