Index: include/vector
===================================================================
--- include/vector
+++ include/vector
@@ -519,12 +519,13 @@
     vector(size_type __n, const_reference __x);
     vector(size_type __n, const_reference __x, const allocator_type& __a);
     template <class _InputIterator>
-        vector(_InputIterator __first, _InputIterator __last,
+        vector(_InputIterator __first,
                typename enable_if<__is_input_iterator  <_InputIterator>::value &&
                                  !__is_forward_iterator<_InputIterator>::value &&
                                  is_constructible<
                                     value_type,
-                                    typename iterator_traits<_InputIterator>::reference>::value>::type* = 0);
+                                    typename iterator_traits<_InputIterator>::reference>::value,
+                                 _InputIterator>::type __last);
     template <class _InputIterator>
         vector(_InputIterator __first, _InputIterator __last, const allocator_type& __a,
                typename enable_if<__is_input_iterator  <_InputIterator>::value &&
@@ -533,11 +534,12 @@
                                     value_type,
                                     typename iterator_traits<_InputIterator>::reference>::value>::type* = 0);
     template <class _ForwardIterator>
-        vector(_ForwardIterator __first, _ForwardIterator __last,
+        vector(_ForwardIterator __first,
                typename enable_if<__is_forward_iterator<_ForwardIterator>::value &&
                                  is_constructible<
                                     value_type,
-                                    typename iterator_traits<_ForwardIterator>::reference>::value>::type* = 0);
+                                    typename iterator_traits<_ForwardIterator>::reference>::value,
+                                 _ForwardIterator>::type __last);
     template <class _ForwardIterator>
         vector(_ForwardIterator __first, _ForwardIterator __last, const allocator_type& __a,
                typename enable_if<__is_forward_iterator<_ForwardIterator>::value &&
@@ -1051,12 +1053,13 @@
 
 template <class _Tp, class _Allocator>
 template <class _InputIterator>
-vector<_Tp, _Allocator>::vector(_InputIterator __first, _InputIterator __last,
+vector<_Tp, _Allocator>::vector(_InputIterator __first,
        typename enable_if<__is_input_iterator  <_InputIterator>::value &&
                          !__is_forward_iterator<_InputIterator>::value &&
                          is_constructible<
                             value_type,
-                            typename iterator_traits<_InputIterator>::reference>::value>::type*)
+                            typename iterator_traits<_InputIterator>::reference>::value,
+                          _InputIterator>::type __last)
 {
 #if _LIBCPP_DEBUG_LEVEL >= 2
     __get_db()->__insert_c(this);
@@ -1084,11 +1087,12 @@
 
 template <class _Tp, class _Allocator>
 template <class _ForwardIterator>
-vector<_Tp, _Allocator>::vector(_ForwardIterator __first, _ForwardIterator __last,
+vector<_Tp, _Allocator>::vector(_ForwardIterator __first,
                                 typename enable_if<__is_forward_iterator<_ForwardIterator>::value &&
                                 is_constructible<
                                    value_type,
-                                   typename iterator_traits<_ForwardIterator>::reference>::value>::type*)
+                                   typename iterator_traits<_ForwardIterator>::reference>::value,
+                                                   _ForwardIterator>::type __last)
 {
 #if _LIBCPP_DEBUG_LEVEL >= 2
     __get_db()->__insert_c(this);
Index: test/containers/sequences/vector/vector.cons/construct_iter_iter_alloc.pass.cpp
===================================================================
--- test/containers/sequences/vector/vector.cons/construct_iter_iter_alloc.pass.cpp
+++ test/containers/sequences/vector/vector.cons/construct_iter_iter_alloc.pass.cpp
@@ -19,9 +19,9 @@
 #include "../../../stack_allocator.h"
 #include "../../../min_allocator.h"
 
-template <class C, class Iterator>
+template <class C, class Iterator, class A>
 void
-test(Iterator first, Iterator last, const typename C::allocator_type& a)
+test(Iterator first, Iterator last, const A& a)
 {
     C c(first, last, a);
     assert(c.__invariants());
@@ -30,6 +30,13 @@
         assert(*i == *first);
 }
 
+template <class T>
+struct implicit_conv_allocator : min_allocator<T>
+{
+    implicit_conv_allocator(void* p) {}
+    implicit_conv_allocator(const implicit_conv_allocator&) = default;
+};
+
 int main()
 {
     {
@@ -52,6 +59,7 @@
     test<std::vector<int, min_allocator<int>> >(bidirectional_iterator<const int*>(a), bidirectional_iterator<const int*>(an), alloc);
     test<std::vector<int, min_allocator<int>> >(random_access_iterator<const int*>(a), random_access_iterator<const int*>(an), alloc);
     test<std::vector<int, min_allocator<int>> >(a, an, alloc);
+    test<std::vector<int, implicit_conv_allocator<int>> >(a, an, nullptr);
     }
 #endif
 }