tuple was accidentally lacking a valid copy assignment operator. It went undetected because I had failed to test assigning from a const lvalue. This fixes http://llvm.org/bugs/show_bug.cgi?id=11921

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@150613 91177308-0d34-0410-b5e6-96231b3b80d8

include/tuple

@@ -500,6 +500,14 @@ struct __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
             return *this;
         }
 
+        _LIBCPP_INLINE_VISIBILITY
+        __tuple_impl&
+        operator=(const __tuple_impl& __t)
+        {
+            __swallow(__tuple_leaf<_Indx, _Tp>::operator=(static_cast<const __tuple_leaf<_Indx, _Tp>&>(__t).get())...);
+            return *this;
+        }
+
     _LIBCPP_INLINE_VISIBILITY
     void swap(__tuple_impl& __t)
         _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)

test/utilities/tuple/tuple.tuple/tuple.assign/copy.pass.cpp

@@ -42,7 +42,7 @@ int main()
     }
     {
         typedef std::tuple<int, char, std::string> T;
-        T t0(2, 'a', "some text");
+        const T t0(2, 'a', "some text");
         T t;
         t = t0;
         assert(std::get<0>(t) == 2);

test/utilities/tuple/tuple.tuple/tuple.cnstr/copy.pass.cpp

@@ -39,7 +39,7 @@ int main()
     }
     {
         typedef std::tuple<int, char, std::string> T;
-        T t0(2, 'a', "some text");
+        const T t0(2, 'a', "some text");
         T t = t0;
         assert(std::get<0>(t) == 2);
         assert(std::get<1>(t) == 'a');