Fix return type of std::tuple_cat.
When the arguments to tuple cat were const, the const was incorrectly
propagated into the type of the resulting tuple. For example:
const std::tuple<int> t(42);
auto r = std::tuple_cat(t, t);
// Incorrect! should be std::tuple<int, int>.
static_assert(is_same_v<decltype(r), std::tuple<const int, const int>>);
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@359255 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/tuple b/include/tuple
index 335e59e..7437d5c 100644
--- a/include/tuple
+++ b/include/tuple
@@ -1211,7 +1211,7 @@
struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0>
{
typedef typename __tuple_cat_type<tuple<_Types...>,
- typename __make_tuple_types<typename remove_reference<_Tuple0>::type>::type>::type
+ typename __make_tuple_types<typename __uncvref<_Tuple0>::type>::type>::type
type;
};
@@ -1220,7 +1220,7 @@
: public __tuple_cat_return_1<
typename __tuple_cat_type<
tuple<_Types...>,
- typename __make_tuple_types<typename remove_reference<_Tuple0>::type>::type
+ typename __make_tuple_types<typename __uncvref<_Tuple0>::type>::type
>::type,
__tuple_like<typename remove_reference<_Tuple1>::type>::value,
_Tuple1, _Tuples...>
diff --git a/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp b/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp
index 40efbd1..5d5927d 100644
--- a/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp
+++ b/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp
@@ -238,6 +238,21 @@
);
assert(t2 == std::make_tuple(std::make_tuple(1), std::make_tuple(2)));
}
+ {
+ int x = 101;
+ std::tuple<int, int&, const int&, int&&> t(42, x, x, std::move(x));
+ const auto& ct = t;
+ std::tuple<int, int&, const int&> t2(42, x, x);
+ const auto& ct2 = t2;
+ auto r = std::tuple_cat(std::move(t), std::move(ct), t2, ct2);
+
+ ASSERT_SAME_TYPE(decltype(r), std::tuple<
+ int, int&, const int&, int&&,
+ int, int&, const int&, int&&,
+ int, int&, const int&,
+ int, int&, const int&>);
+ ((void)r);
+ }
return 0;
}