diff --git a/include/iosfwd b/include/iosfwd
index eccfd349a..e4149ef22 100644
--- a/include/iosfwd
+++ b/include/iosfwd
@@ -194,6 +194,11 @@ template <class _CharT,             // for <stdexcept>
 typedef basic_string<char, char_traits<char>, allocator<char> > string;
 typedef basic_string<wchar_t, char_traits<wchar_t>, allocator<wchar_t> > wstring;
 
+
+// Include other forward declarations here
+template <class _Tp, class _Alloc = allocator<_Tp> >
+class _LIBCPP_TYPE_VIS_ONLY vector;
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif  // _LIBCPP_IOSFWD
diff --git a/include/iterator b/include/iterator
index 8d9b31101..e5bb49318 100644
--- a/include/iterator
+++ b/include/iterator
@@ -340,10 +340,10 @@ template <class E> constexpr const E* data(initializer_list<E> il) noexcept;
 */
 
 #include <__config>
+#include <iosfwd> // for forward declarations of vector and string.
 #include <__functional_base>
 #include <type_traits>
 #include <cstddef>
-#include <iosfwd>
 #include <initializer_list>
 #ifdef __APPLE__
 #include <Availability.h>
diff --git a/include/vector b/include/vector
index dbc0dd321..0e413350d 100644
--- a/include/vector
+++ b/include/vector
@@ -262,6 +262,7 @@ void swap(vector<T,Allocator>& x, vector<T,Allocator>& y)
 */
 
 #include <__config>
+#include <iosfwd> // for forward declaration of vector
 #include <__bit_reference>
 #include <type_traits>
 #include <climits>
@@ -453,7 +454,7 @@ __vector_base<_Tp, _Allocator>::~__vector_base()
     }
 }
 
-template <class _Tp, class _Allocator = allocator<_Tp> >
+template <class _Tp, class _Allocator /* = allocator<_Tp> */>
 class _LIBCPP_TYPE_VIS_ONLY vector
     : private __vector_base<_Tp, _Allocator>
 {