Slight fix for r351820

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351821 91177308-0d34-0410-b5e6-96231b3b80d8

Author: serge-sans-paille-qb

include/llvm/Support/type_traits.h

@@ -124,15 +124,15 @@ struct is_trivially_move_constructible<T &&> : std::true_type {};
 template <typename T>
 struct is_copy_assignable {
   template<class F>
-    static auto get(F*) -> decltype(std::declval<T &>() = std::declval<const T &>(), std::true_type{});
+    static auto get(F*) -> decltype(std::declval<F &>() = std::declval<const F &>(), std::true_type{});
     static std::false_type get(...);
     static constexpr bool value = decltype(get((T*)nullptr))::value;
 };
 
 template <typename T>
 struct is_move_assignable {
   template<class F>
-    static auto get(F*) -> decltype(std::declval<T &>() = std::declval<T &&>(), std::true_type{});
+    static auto get(F*) -> decltype(std::declval<F &>() = std::declval<F &&>(), std::true_type{});
     static std::false_type get(...);
     static constexpr bool value = decltype(get((T*)nullptr))::value;
 };