Implement LWG 2770 - Make tuple_size<T> defined for all T
llvm-svn: 286779
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 237158926663f31f2fcdb02cfedc0da19d6437f6
diff --git a/include/__tuple b/include/__tuple
index caa427a..775d734 100644
--- a/include/__tuple
+++ b/include/__tuple
@@ -22,7 +22,7 @@
_LIBCPP_BEGIN_NAMESPACE_STD
-template <class _Tp> class _LIBCPP_TYPE_VIS_ONLY tuple_size;
+template <class _Tp> class _LIBCPP_TYPE_VIS_ONLY tuple_size {};
template <class _Tp>
class _LIBCPP_TYPE_VIS_ONLY tuple_size<const _Tp>
diff --git a/include/tuple b/include/tuple
index 9f6661f..251443e 100644
--- a/include/tuple
+++ b/include/tuple
@@ -84,7 +84,7 @@
constexpr T make_from_tuple(Tuple&& t); // C++17
// 20.4.1.4, tuple helper classes:
-template <class T> class tuple_size; // undefined
+template <class T> class tuple_size;
template <class... T> class tuple_size<tuple<T...>>;
template <class T>
constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
diff --git a/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp b/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp
index 3f132e4..50c6f17 100644
--- a/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp
+++ b/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp
@@ -21,7 +21,7 @@
int main()
{
- (void)std::tuple_size<std::tuple<> &>::value; // expected-error {{implicit instantiation of undefined template}}
- (void)std::tuple_size<int>::value; // expected-error {{implicit instantiation of undefined template}}
- (void)std::tuple_size<std::tuple<>*>::value; // expected-error {{implicit instantiation of undefined template}}
+ (void)std::tuple_size<std::tuple<> &>::value; // expected-error {{no member named 'value'}}
+ (void)std::tuple_size<int>::value; // expected-error {{no member named 'value'}}
+ (void)std::tuple_size<std::tuple<>*>::value; // expected-error {{no member named 'value'}}
}
diff --git a/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp b/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp
index 49b4215..40214f6 100644
--- a/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp
+++ b/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp
@@ -18,19 +18,36 @@
// UNSUPPORTED: c++98, c++03
#include <tuple>
+#include <utility>
+#include <array>
#include <type_traits>
+template <class T, class = decltype(std::tuple_size<T>::value)>
+constexpr bool has_value(int) { return true; }
+template <class> constexpr bool has_value(long) { return false; }
+template <class T> constexpr bool has_value() { return has_value<T>(0); }
+
+
template <class T, std::size_t N>
void test()
{
+ static_assert(has_value<T>(), "");
static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
std::tuple_size<T> >::value), "");
+ static_assert(has_value<const T>(), "");
static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
std::tuple_size<const T> >::value), "");
+ static_assert(has_value<volatile T>(), "");
static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
std::tuple_size<volatile T> >::value), "");
+
+ static_assert(has_value<const volatile T>(), "");
static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
std::tuple_size<const volatile T> >::value), "");
+ {
+ static_assert(!has_value<T &>(), "");
+ static_assert(!has_value<T *>(), "");
+ }
}
int main()
@@ -39,4 +56,13 @@
test<std::tuple<int>, 1>();
test<std::tuple<char, int>, 2>();
test<std::tuple<char, char*, int>, 3>();
+ test<std::pair<int, void*>, 2>();
+ test<std::array<int, 42>, 42>();
+ {
+ static_assert(!has_value<void>(), "");
+ static_assert(!has_value<void*>(), "");
+ static_assert(!has_value<int>(), "");
+ static_assert(!has_value<std::pair<int, int>*>(), "");
+ static_assert(!has_value<std::array<int, 42>&>(), "");
+ }
}
diff --git a/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp b/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp
index 957a683..700dd95 100644
--- a/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp
+++ b/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp
@@ -22,5 +22,5 @@
(void)std::tuple_size_v<std::tuple<> &>; // expected-note {{requested here}}
(void)std::tuple_size_v<int>; // expected-note {{requested here}}
(void)std::tuple_size_v<std::tuple<>*>; // expected-note {{requested here}}
- // expected-error@tuple:* 3 {{implicit instantiation of undefined template}}
+ // expected-error@tuple:* 3 {{no member named 'value'}}
}