From de589f2f8f9498f8006dc954e177a195ef6eb136 Mon Sep 17 00:00:00 2001
From: Howard Hinnant <hhinnant@apple.com>
Date: Sat, 21 Sep 2013 21:13:54 +0000
Subject: [PATCH] Peter Collingbourne: If a pointer is passed as the third
 argument of the (iterator, iterator, allocator) constructor with the
 intention of it being implicitly converted to the allocator type, it is
 possible for overload resolution to favour the (iterator, iterator,
 enable_if) constructor. Eliminate this possibility by moving the enable_if to
 one of the existing arguments and removing the third argument.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@191145 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/vector                                | 20 +++++++++++--------
 .../construct_iter_iter_alloc.pass.cpp        | 16 +++++++++++++--
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/include/vector b/include/vector
index 258a950d..619faaa5 100644
--- a/include/vector
+++ b/include/vector
@@ -524,12 +524,13 @@ public:
     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 &&
@@ -538,11 +539,12 @@ public:
                                     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 &&
@@ -1072,12 +1074,13 @@ vector<_Tp, _Allocator>::vector(size_type __n, const_reference __x, const alloca
 
 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);
@@ -1105,11 +1108,12 @@ vector<_Tp, _Allocator>::vector(_InputIterator __first, _InputIterator __last, c
 
 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);
diff --git a/test/containers/sequences/vector/vector.cons/construct_iter_iter_alloc.pass.cpp b/test/containers/sequences/vector/vector.cons/construct_iter_iter_alloc.pass.cpp
index e386297c..afc8ea5d 100644
--- a/test/containers/sequences/vector/vector.cons/construct_iter_iter_alloc.pass.cpp
+++ b/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 +30,17 @@ test(Iterator first, Iterator last, const typename C::allocator_type& a)
         assert(*i == *first);
 }
 
+#if __cplusplus >= 201103L
+
+template <class T>
+struct implicit_conv_allocator : min_allocator<T>
+{
+    implicit_conv_allocator(void* p) {}
+    implicit_conv_allocator(const implicit_conv_allocator&) = default;
+};
+
+#endif
+
 int main()
 {
     {
@@ -52,6 +63,7 @@ int main()
     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
 }