diff --git a/libcxx/include/__iterator/insert_iterator.h b/libcxx/include/__iterator/insert_iterator.h
--- a/libcxx/include/__iterator/insert_iterator.h
+++ b/libcxx/include/__iterator/insert_iterator.h
@@ -14,6 +14,7 @@
 #include <__iterator/iterator.h>
 #include <__iterator/iterator_traits.h>
 #include <__memory/addressof.h>
+#include <__ranges/access.h>
 #include <__utility/move.h>
 #include <cstddef>
 
@@ -36,8 +37,12 @@
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 protected:
     _Container* container;
-    typename _Container::iterator iter; // FIXME: `ranges::iterator_t<Container>` in C++20 mode
-public:
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+    ranges::iterator_t<_Container> iter;
+#else
+    typename _Container::iterator iter;
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+  public:
     typedef output_iterator_tag iterator_category;
     typedef void value_type;
 #if _LIBCPP_STD_VER > 17
@@ -49,7 +54,7 @@
     typedef void reference;
     typedef _Container container_type;
 
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 insert_iterator(_Container& __x, typename _Container::iterator __i)
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 insert_iterator(_Container& __x, decltype(iter) __i)
         : container(_VSTD::addressof(__x)), iter(__i) {}
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 insert_iterator& operator=(const typename _Container::value_type& __value_)
         {iter = container->insert(iter, __value_); ++iter; return *this;}
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
@@ -28,6 +28,7 @@
 //   typedef void                   pointer;
 // };
 
+#include <__ranges/access.h>
 #include <iterator>
 #include <type_traits>
 #include <vector>
@@ -74,5 +75,27 @@
 {
     test<std::vector<int> >();
 
-  return 0;
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+    struct WithoutIteratorTypeAlias {
+    private:
+      using Container = std::vector<int>;
+
+    public:
+      WithoutIteratorTypeAlias() = default;
+      WithoutIteratorTypeAlias(const WithoutIteratorTypeAlias&) = default;
+
+      using value_type = Container;
+
+      std::ranges::iterator_t<Container> iter{};
+
+      auto begin() { return iter; }
+
+      std::insert_iterator<value_type> insert(Container& container, decltype(iter) i) {
+        return std::insert_iterator<Container>(container, i);
+      }
+    };
+    test<WithoutIteratorTypeAlias>();
+#endif
+
+    return 0;
 }