[libc++] Fix PR22922 - Allocator support for std::function does not know how to rebind.

[EricWF]

Summary

This patch changes std::function to use allocator_traits to rebind the allocator instead of allocator itself.

It also changes most of the tests to use bare_allocator where possible instead of test_allocator.

[EricWF]

No longer use min_allocator. Only bare_allocator.

[mclow.lists]

This looks fine to me. Are there any other places in libc++ where we need to replace allocator rebind with traits rebind?

[EricWF]

Doesn't seem like it. I removed rebind from the test allocators and the only failures I saw were related to this bug.

include/functional

 __base<_Rp(_ArgTypes...)>*
 __func<_Fp, _Alloc, _Rp(_ArgTypes...)>::__clone() const
 {
-    typedef typename _Alloc::template rebind<__func>::other _Ap;
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __alloc_traits::template
+#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+            rebind_alloc<__func>
+#else
+            rebind_alloc<__func>::other
+#endif
+            _Ap;
     _Ap __a(__f_.second());
     typedef __allocator_destructor<_Ap> _Dp;
     unique_ptr<__func, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));

 void
 __func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy_deallocate() _NOEXCEPT
 {
-    typedef typename _Alloc::template rebind<__func>::other _Ap;
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __alloc_traits::template
+#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+            rebind_alloc<__func>
+#else
+            rebind_alloc<__func>::other
+#endif
+            _Ap;
     _Ap __a(__f_.second());
     __f_.~__compressed_pair<_Fp, _Alloc>();
     __a.deallocate(this, 1);

test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.pass.cpp

 #include <functional>
 #include <cassert>
 
-#include "test_allocator.h"
+#include "min_allocator.h"
 
 int main()
 {
-    std::function<int(int)> f(std::allocator_arg, test_allocator<int>());
+    {
+    std::function<int(int)> f(std::allocator_arg, bare_allocator<int>());
     assert(!f);
+    }
 }

test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.pass.cpp

 #include <functional>
 #include <cassert>
 
-#include "test_allocator.h"
+#include "min_allocator.h"
 
 class A
 {

 int main()
 {
     {
-    std::function<int(int)> f(std::allocator_arg, test_allocator<A>(), A());
+    std::function<int(int)> f(std::allocator_arg, bare_allocator<A>(), A());
     assert(A::count == 1);
     assert(f.target<A>());
     assert(f.target<int(*)(int)>() == 0);
     }
     assert(A::count == 0);
     {
-    std::function<int(int)> f(std::allocator_arg, test_allocator<int(*)(int)>(), g);
+    std::function<int(int)> f(std::allocator_arg, bare_allocator<int(*)(int)>(), g);
     assert(f.target<int(*)(int)>());
     assert(f.target<A>() == 0);
     }
     {
-    std::function<int(int)> f(std::allocator_arg, test_allocator<int(*)(int)>(),
+    std::function<int(int)> f(std::allocator_arg, bare_allocator<int(*)(int)>(),
                               (int (*)(int))0);
     assert(!f);
     assert(f.target<int(*)(int)>() == 0);

     }
     {
     std::function<int(const A*, int)> f(std::allocator_arg,
-                                        test_allocator<int(A::*)(int)const>(),
+                                        bare_allocator<int(A::*)(int)const>(),
                                         &A::foo);
     assert(f);
     assert(f.target<int (A::*)(int) const>() != 0);

 #endif
     {
     std::function<void(int)> fun(std::allocator_arg,
-                                 test_allocator<int(*)(int)>(),
+                                 bare_allocator<int(*)(int)>(),
                                  &g);
     assert(fun);
     assert(fun.target<int(*)(int)>() != 0);

test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.pass.cpp

 #include <functional>
 #include <cassert>
 
+#include "min_allocator.h"
 #include "test_allocator.h"
 #include "count_new.hpp"
 

     assert(globalMemCounter.checkOutstandingNewEq(1));
     assert(f.target<A>());
     assert(f.target<int(*)(int)>() == 0);
-    std::function<int(int)> f2(std::allocator_arg, test_allocator<A>(), f);
+    std::function<int(int)> f2(std::allocator_arg, bare_allocator<A>(), f);
     assert(A::count == 2);
     assert(globalMemCounter.checkOutstandingNewEq(2));
     assert(f2.target<A>());

     assert(globalMemCounter.checkOutstandingNewEq(0));
     assert(f.target<int(*)(int)>());
     assert(f.target<A>() == 0);
-    std::function<int(int)> f2(std::allocator_arg, test_allocator<int(*)(int)>(), f);
+    std::function<int(int)> f2(std::allocator_arg, bare_allocator<int(*)(int)>(), f);
     assert(globalMemCounter.checkOutstandingNewEq(0));
     assert(f2.target<int(*)(int)>());
     assert(f2.target<A>() == 0);

     assert(globalMemCounter.checkOutstandingNewEq(0));
     assert(f.target<int(*)(int)>() == 0);
     assert(f.target<A>() == 0);
-    std::function<int(int)> f2(std::allocator_arg, test_allocator<int>(), f);
+    std::function<int(int)> f2(std::allocator_arg, bare_allocator<int>(), f);
     assert(globalMemCounter.checkOutstandingNewEq(0));
     assert(f2.target<int(*)(int)>() == 0);
     assert(f2.target<A>() == 0);

test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.pass.cpp

 #include <functional>
 #include <cassert>
 
-#include "test_allocator.h"
+#include "min_allocator.h"
 
 int main()
 {
-    std::function<int(int)> f(std::allocator_arg, test_allocator<int>(), nullptr);
+    std::function<int(int)> f(std::allocator_arg, bare_allocator<int>(), nullptr);
     assert(!f);
 }

test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.pass.cpp

 #include <functional>
 #include <cassert>
 
-#include "test_allocator.h"
+#include "min_allocator.h"
 #include "count_new.hpp"
 
 class A

     assert(globalMemCounter.checkOutstandingNewEq(1));
     assert(f.target<A>());
     assert(f.target<int(*)(int)>() == 0);
-    std::function<int(int)> f2(std::allocator_arg, test_allocator<A>(), std::move(f));
+    std::function<int(int)> f2(std::allocator_arg, bare_allocator<A>(), std::move(f));
     assert(A::count == 1);
     assert(globalMemCounter.checkOutstandingNewEq(1));
     assert(f2.target<A>());