Implement C++17 tuple bits. Including apply and make_from_tuple.

This patch upgrades <tuple> to be C++17 compliant by implementing:

* tuple_size_v: This was forgotten when implementing the other _v traits.
* std::apply: This was added via LFTS v1 in p0220r1.
* std::make_from_tuple: This was added in p0209r2.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@275745 91177308-0d34-0410-b5e6-96231b3b80d8

include/tuple

@@ -76,10 +76,18 @@ template <class... T> tuple<V...>  make_tuple(T&&...); // constexpr in C++14
 template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept; // constexpr in C++14
 template <class... T> tuple<T&...> tie(T&...) noexcept; // constexpr in C++14
 template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls); // constexpr in C++14
-  
+
+// [tuple.apply], calling a function with a tuple of arguments:
+template <class F, class Tuple>
+  constexpr decltype(auto) apply(F&& f, Tuple&& t); // C++17
+template <class T, class Tuple>
+  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<tuple<T...>>;
+template <class T>
+ constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
 template <size_t I, class T> class tuple_element; // undefined
 template <size_t I, class... T> class tuple_element<I, tuple<T...>>;
 template <size_t I, class T>
@@ -1361,6 +1369,50 @@ pair<_T1, _T2>::pair(piecewise_construct_t,
 
 #endif  // _LIBCPP_HAS_NO_VARIADICS
 
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
+
+#define _LIBCPP_NOEXCEPT_RETURN(...) noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
+
+template <class _Fn, class _Tuple, size_t ..._Id>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr decltype(auto) __apply_tuple_impl(_Fn && __f, _Tuple && __t,
+                                            __tuple_indices<_Id...>)
+_LIBCPP_NOEXCEPT_RETURN(
+    _VSTD::__invoke_constexpr(
+        _VSTD::forward<_Fn>(__f),
+        _VSTD::get<_Id>(_VSTD::forward<_Tuple>(__t))...)
+)
+
+template <class _Fn, class _Tuple>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr decltype(auto) apply(_Fn && __f, _Tuple && __t)
+_LIBCPP_NOEXCEPT_RETURN(
+    _VSTD::__apply_tuple_impl(
+        _VSTD::forward<_Fn>(__f), _VSTD::forward<_Tuple>(__t),
+        typename __make_tuple_indices<tuple_size_v<decay_t<_Tuple>>>::type{})
+)
+
+template <class _Tp, class _Tuple, size_t... _Idx>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
+_LIBCPP_NOEXCEPT_RETURN(
+    _Tp(_VSTD::get<_Idx>(_VSTD::forward<_Tuple>(__t))...)
+)
+
+template <class _Tp, class _Tuple>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _Tp make_from_tuple(_Tuple&& __t)
+_LIBCPP_NOEXCEPT_RETURN(
+    _VSTD::__make_from_tuple_impl<_Tp>(_VSTD::forward<_Tuple>(__t),
+        typename __make_tuple_indices<tuple_size_v<decay_t<_Tuple>>>::type{})
+)
+
+#undef _LIBCPP_NOEXCEPT_RETURN
+
+#endif // _LIBCPP_STD_VER > 14
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif  // _LIBCPP_TUPLE

test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp

@@ -0,0 +1,275 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <tuple>
+
+// template <class F, class T> constexpr decltype(auto) apply(F &&, T &&)
+
+// Test with different ref/ptr/cv qualified argument types.
+
+#include <tuple>
+#include <array>
+#include <utility>
+#include <cassert>
+
+#include "test_macros.h"
+#include "type_id.h"
+
+// std::array is explicitly allowed to be initialized with A a = { init-list };.
+// Disable the missing braces warning for this reason.
+#include "disable_missing_braces_warning.h"
+
+
+constexpr int constexpr_sum_fn() { return 0; }
+
+template <class ...Ints>
+constexpr int constexpr_sum_fn(int x1, Ints... rest) { return x1 + constexpr_sum_fn(rest...); }
+
+struct ConstexprSumT {
+  constexpr ConstexprSumT() = default;
+  template <class ...Ints>
+  constexpr int operator()(Ints... values) const {
+      return constexpr_sum_fn(values...);
+  }
+};
+
+
+void test_constexpr_evaluation()
+{
+    constexpr ConstexprSumT sum_obj{};
+    {
+        using Tup = std::tuple<>;
+        using Fn = int(&)();
+        constexpr Tup t;
+        static_assert(std::apply(static_cast<Fn>(constexpr_sum_fn), t) == 0, "");
+        static_assert(std::apply(sum_obj, t) == 0, "");
+    }
+    {
+        using Tup = std::tuple<int>;
+        using Fn = int(&)(int);
+        constexpr Tup t(42);
+        static_assert(std::apply(static_cast<Fn>(constexpr_sum_fn), t) == 42, "");
+        static_assert(std::apply(sum_obj, t) == 42, "");
+    }
+    {
+        using Tup = std::tuple<int, long>;
+        using Fn = int(&)(int, int);
+        constexpr Tup t(42, 101);
+        static_assert(std::apply(static_cast<Fn>(constexpr_sum_fn), t) == 143, "");
+        static_assert(std::apply(sum_obj, t) == 143, "");
+    }
+    {
+        using Tup = std::pair<int, long>;
+        using Fn = int(&)(int, int);
+        constexpr Tup t(42, 101);
+        static_assert(std::apply(static_cast<Fn>(constexpr_sum_fn), t) == 143, "");
+        static_assert(std::apply(sum_obj, t) == 143, "");
+    }
+    {
+        using Tup = std::tuple<int, long, int>;
+        using Fn = int(&)(int, int, int);
+        constexpr Tup t(42, 101, -1);
+        static_assert(std::apply(static_cast<Fn>(constexpr_sum_fn), t) == 142, "");
+        static_assert(std::apply(sum_obj, t) == 142, "");
+    }
+    {
+        using Tup = std::array<int, 3>;
+        using Fn = int(&)(int, int, int);
+        constexpr Tup t = {42, 101, -1};
+        static_assert(std::apply(static_cast<Fn>(constexpr_sum_fn), t) == 142, "");
+        static_assert(std::apply(sum_obj, t) == 142, "");
+    }
+}
+
+
+enum CallQuals {
+  CQ_None,
+  CQ_LValue,
+  CQ_ConstLValue,
+  CQ_RValue,
+  CQ_ConstRValue
+};
+
+template <class Tuple>
+struct CallInfo {
+  CallQuals quals;
+  TypeID const* arg_types;
+  Tuple args;
+
+  template <class ...Args>
+  CallInfo(CallQuals q, Args&&... xargs)
+      : quals(q), arg_types(&makeArgumentID<Args&&...>()), args(std::forward<Args>(xargs)...)
+  {}
+};
+
+template <class ...Args>
+inline CallInfo<decltype(std::forward_as_tuple(std::declval<Args>()...))>
+makeCallInfo(CallQuals quals, Args&&... args) {
+    return {quals, std::forward<Args>(args)...};
+}
+
+struct TrackedCallable {
+
+  TrackedCallable() = default;
+
+  template <class ...Args> auto operator()(Args&&... xargs) &
+  { return makeCallInfo(CQ_LValue, std::forward<Args>(xargs)...); }
+
+  template <class ...Args> auto operator()(Args&&... xargs) const&
+  { return makeCallInfo(CQ_ConstLValue, std::forward<Args>(xargs)...); }
+
+  template <class ...Args> auto operator()(Args&&... xargs) &&
+  { return makeCallInfo(CQ_RValue, std::forward<Args>(xargs)...); }
+
+  template <class ...Args> auto operator()(Args&&... xargs) const&&
+  { return makeCallInfo(CQ_ConstRValue, std::forward<Args>(xargs)...); }
+};
+
+template <class ...ExpectArgs, class Tuple>
+void check_apply_quals_and_types(Tuple&& t) {
+    TypeID const* const expect_args = &makeArgumentID<ExpectArgs...>();
+    TrackedCallable obj;
+    TrackedCallable const& cobj = obj;
+    {
+        auto ret = std::apply(obj, std::forward<Tuple>(t));
+        assert(ret.quals == CQ_LValue);
+        assert(ret.arg_types == expect_args);
+        assert(ret.args == t);
+    }
+    {
+        auto ret = std::apply(cobj, std::forward<Tuple>(t));
+        assert(ret.quals == CQ_ConstLValue);
+        assert(ret.arg_types == expect_args);
+        assert(ret.args == t);
+    }
+    {
+        auto ret = std::apply(std::move(obj), std::forward<Tuple>(t));
+        assert(ret.quals == CQ_RValue);
+        assert(ret.arg_types == expect_args);
+        assert(ret.args == t);
+    }
+    {
+        auto ret = std::apply(std::move(cobj), std::forward<Tuple>(t));
+        assert(ret.quals == CQ_ConstRValue);
+        assert(ret.arg_types == expect_args);
+        assert(ret.args == t);
+    }
+}
+
+void test_call_quals_and_arg_types()
+{
+    TrackedCallable obj;
+    using Tup = std::tuple<int, int const&, unsigned&&>;
+    const int x = 42;
+    unsigned y = 101;
+    Tup t(-1, x, std::move(y));
+    Tup const& ct = t;
+    check_apply_quals_and_types<int&, int const&, unsigned&>(t);
+    check_apply_quals_and_types<int const&, int const&, unsigned&>(ct);
+    check_apply_quals_and_types<int&&, int const&, unsigned&&>(std::move(t));
+    check_apply_quals_and_types<int const&&, int const&, unsigned&&>(std::move(ct));
+}
+
+
+struct NothrowMoveable {
+  NothrowMoveable() noexcept = default;
+  NothrowMoveable(NothrowMoveable const&) noexcept(false) {}
+  NothrowMoveable(NothrowMoveable&&) noexcept {}
+};
+
+template <bool IsNoexcept>
+struct TestNoexceptCallable {
+  template <class ...Args>
+  NothrowMoveable operator()(Args...) const noexcept(IsNoexcept) { return {}; }
+};
+
+void test_noexcept()
+{
+    TestNoexceptCallable<true> nec;
+    TestNoexceptCallable<false> tc;
+    {
+        // test that the functions noexcept-ness is propagated
+        using Tup = std::tuple<int, const char*, long>;
+        Tup t;
+        ASSERT_NOEXCEPT(std::apply(nec, t));
+        ASSERT_NOT_NOEXCEPT(std::apply(tc, t));
+    }
+    {
+        // test that the noexcept-ness of the argument conversions is checked.
+        using Tup = std::tuple<NothrowMoveable, int>;
+        Tup t;
+        ASSERT_NOT_NOEXCEPT(std::apply(nec, t));
+        ASSERT_NOEXCEPT(std::apply(nec, std::move(t)));
+    }
+}
+
+namespace ReturnTypeTest {
+    static int my_int = 42;
+
+    template <int N> struct index {};
+
+    void f(index<0>) {}
+
+    int f(index<1>) { return 0; }
+
+    int & f(index<2>) { return static_cast<int &>(my_int); }
+    int const & f(index<3>) { return static_cast<int const &>(my_int); }
+    int volatile & f(index<4>) { return static_cast<int volatile &>(my_int); }
+    int const volatile & f(index<5>) { return static_cast<int const volatile &>(my_int); }
+
+    int && f(index<6>) { return static_cast<int &&>(my_int); }
+    int const && f(index<7>) { return static_cast<int const &&>(my_int); }
+    int volatile && f(index<8>) { return static_cast<int volatile &&>(my_int); }
+    int const volatile && f(index<9>) { return static_cast<int const volatile &&>(my_int); }
+
+    int * f(index<10>) { return static_cast<int *>(&my_int); }
+    int const * f(index<11>) { return static_cast<int const *>(&my_int); }
+    int volatile * f(index<12>) { return static_cast<int volatile *>(&my_int); }
+    int const volatile * f(index<13>) { return static_cast<int const volatile *>(&my_int); }
+
+    template <int Func, class Expect>
+    void test()
+    {
+        using RawInvokeResult = decltype(f(index<Func>{}));
+        static_assert(std::is_same<RawInvokeResult, Expect>::value, "");
+        using FnType = RawInvokeResult (*) (index<Func>);
+        FnType fn = f;
+        std::tuple<index<Func>> t; ((void)t);
+        using InvokeResult = decltype(std::apply(fn, t));
+        static_assert(std::is_same<InvokeResult, Expect>::value, "");
+    }
+} // end namespace ReturnTypeTest
+
+void test_return_type()
+{
+    using ReturnTypeTest::test;
+    test<0, void>();
+    test<1, int>();
+    test<2, int &>();
+    test<3, int const &>();
+    test<4, int volatile &>();
+    test<5, int const volatile &>();
+    test<6, int &&>();
+    test<7, int const &&>();
+    test<8, int volatile &&>();
+    test<9, int const volatile &&>();
+    test<10, int *>();
+    test<11, int const *>();
+    test<12, int volatile *>();
+    test<13, int const volatile *>();
+}
+
+int main() {
+    test_constexpr_evaluation();
+    test_call_quals_and_arg_types();
+    test_return_type();
+    test_noexcept();
+}

test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_extended_types.pass.cpp

@@ -0,0 +1,426 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <tuple>
+
+// template <class F, class T> constexpr decltype(auto) apply(F &&, T &&)
+
+// Testing extended function types. The extended function types are those
+// named by INVOKE but that are not actual callable objects. These include
+// bullets 1-4 of invoke.
+
+#include <tuple>
+#include <array>
+#include <utility>
+#include <cassert>
+
+// std::array is explicitly allowed to be initialized with A a = { init-list };.
+// Disable the missing braces warning for this reason.
+#include "disable_missing_braces_warning.h"
+
+int count = 0;
+
+struct A_int_0
+{
+    A_int_0() : obj1(0){}
+    A_int_0(int x) : obj1(x) {}
+    int mem1() { return ++count; }
+    int mem2() const { return ++count; }
+    int const obj1;
+};
+
+struct A_int_1
+{
+    A_int_1() {}
+    A_int_1(int) {}
+    int mem1(int x) { return count += x; }
+    int mem2(int x) const { return count += x; }
+};
+
+struct A_int_2
+{
+    A_int_2() {}
+    A_int_2(int) {}
+    int mem1(int x, int y) { return count += (x + y); }
+    int mem2(int x, int y) const { return count += (x + y); }
+};
+
+template <class A>
+struct A_wrap
+{
+    A_wrap() {}
+    A_wrap(int x) : m_a(x) {}
+    A & operator*() { return m_a; }
+    A const & operator*() const { return m_a; }
+    A m_a;
+};
+
+typedef A_wrap<A_int_0> A_wrap_0;
+typedef A_wrap<A_int_1> A_wrap_1;
+typedef A_wrap<A_int_2> A_wrap_2;
+
+
+template <class A>
+struct A_base : public A
+{
+    A_base() : A() {}
+    A_base(int x) : A(x) {}
+};
+
+typedef A_base<A_int_0> A_base_0;
+typedef A_base<A_int_1> A_base_1;
+typedef A_base<A_int_2> A_base_2;
+
+
+template <
+    class Tuple, class ConstTuple
+  , class TuplePtr, class ConstTuplePtr
+  , class TupleWrap, class ConstTupleWrap
+  , class TupleBase, class ConstTupleBase
+  >
+void test_ext_int_0()
+{
+    count = 0;
+    typedef A_int_0 T;
+    typedef A_wrap_0 Wrap;
+    typedef A_base_0 Base;
+
+    typedef int(T::*mem1_t)();
+    mem1_t mem1 = &T::mem1;
+
+    typedef int(T::*mem2_t)() const;
+    mem2_t mem2 = &T::mem2;
+
+    typedef int const T::*obj1_t;
+    obj1_t obj1 = &T::obj1;
+
+    // member function w/ref
+    {
+        T a;
+        Tuple t{a};
+        assert(1 == std::apply(mem1, t));
+        assert(count == 1);
+    }
+    count = 0;
+    // member function w/pointer
+    {
+        T a;
+        TuplePtr t{&a};
+        assert(1 == std::apply(mem1, t));
+        assert(count == 1);
+    }
+    count = 0;
+    // member function w/base
+    {
+        Base a;
+        TupleBase t{a};
+        assert(1 == std::apply(mem1, t));
+        assert(count == 1);
+    }
+    count = 0;
+    // member function w/wrap
+    {
+        Wrap a;
+        TupleWrap t{a};
+        assert(1 == std::apply(mem1, t));
+        assert(count == 1);
+    }
+    count = 0;
+    // const member function w/ref
+    {
+        T const a;
+        ConstTuple t{a};
+        assert(1 == std::apply(mem2, t));
+        assert(count == 1);
+    }
+    count = 0;
+    // const member function w/pointer
+    {
+        T const a;
+        ConstTuplePtr t{&a};
+        assert(1 == std::apply(mem2, t));
+        assert(count == 1);
+    }
+    count = 0;
+    // const member function w/base
+    {
+        Base const a;
+        ConstTupleBase t{a};
+        assert(1 == std::apply(mem2, t));
+        assert(count == 1);
+    }
+    count = 0;
+    // const member function w/wrapper
+    {
+        Wrap const a;
+        ConstTupleWrap t{a};
+        assert(1 == std::apply(mem2, t));
+        assert(1 == count);
+    }
+    // member object w/ref
+    {
+        T a{42};
+        Tuple t{a};
+        assert(42 == std::apply(obj1, t));
+    }
+    // member object w/pointer
+    {
+        T a{42};
+        TuplePtr t{&a};
+        assert(42 == std::apply(obj1, t));
+    }
+    // member object w/base
+    {
+        Base a{42};
+        TupleBase t{a};
+        assert(42 == std::apply(obj1, t));
+    }
+    // member object w/wrapper
+    {
+        Wrap a{42};
+        TupleWrap t{a};
+        assert(42 == std::apply(obj1, t));
+    }
+}
+
+
+template <
+    class Tuple, class ConstTuple
+  , class TuplePtr, class ConstTuplePtr
+  , class TupleWrap, class ConstTupleWrap
+  , class TupleBase, class ConstTupleBase
+  >
+void test_ext_int_1()
+{
+    count = 0;
+    typedef A_int_1 T;
+    typedef A_wrap_1 Wrap;
+    typedef A_base_1 Base;
+
+    typedef int(T::*mem1_t)(int);
+    mem1_t mem1 = &T::mem1;
+
+    typedef int(T::*mem2_t)(int) const;
+    mem2_t mem2 = &T::mem2;
+
+    // member function w/ref
+    {
+        T a;
+        Tuple t{a, 2};
+        assert(2 == std::apply(mem1, t));
+        assert(count == 2);
+    }
+    count = 0;
+    // member function w/pointer
+    {
+        T a;
+        TuplePtr t{&a, 3};
+        assert(3 == std::apply(mem1, t));
+        assert(count == 3);
+    }
+    count = 0;
+    // member function w/base
+    {
+        Base a;
+        TupleBase t{a, 4};
+        assert(4 == std::apply(mem1, t));
+        assert(count == 4);
+    }
+    count = 0;
+    // member function w/wrap
+    {
+        Wrap a;
+        TupleWrap t{a, 5};
+        assert(5 == std::apply(mem1, t));
+        assert(count == 5);
+    }
+    count = 0;
+    // const member function w/ref
+    {
+        T const a;
+        ConstTuple t{a, 6};
+        assert(6 == std::apply(mem2, t));
+        assert(count == 6);
+    }
+    count = 0;
+    // const member function w/pointer
+    {
+        T const a;
+        ConstTuplePtr t{&a, 7};
+        assert(7 == std::apply(mem2, t));
+        assert(count == 7);
+    }
+    count = 0;
+    // const member function w/base
+    {
+        Base const a;
+        ConstTupleBase t{a, 8};
+        assert(8 == std::apply(mem2, t));
+        assert(count == 8);
+    }
+    count = 0;
+    // const member function w/wrapper
+    {
+        Wrap const a;
+        ConstTupleWrap t{a, 9};
+        assert(9 == std::apply(mem2, t));
+        assert(9 == count);
+    }
+}
+
+
+template <
+    class Tuple, class ConstTuple
+  , class TuplePtr, class ConstTuplePtr
+  , class TupleWrap, class ConstTupleWrap
+  , class TupleBase, class ConstTupleBase
+  >
+void test_ext_int_2()
+{
+    count = 0;
+    typedef A_int_2 T;
+    typedef A_wrap_2 Wrap;
+    typedef A_base_2 Base;
+
+    typedef int(T::*mem1_t)(int, int);
+    mem1_t mem1 = &T::mem1;
+
+    typedef int(T::*mem2_t)(int, int) const;
+    mem2_t mem2 = &T::mem2;
+
+    // member function w/ref
+    {
+        T a;
+        Tuple t{a, 1, 1};
+        assert(2 == std::apply(mem1, t));
+        assert(count == 2);
+    }
+    count = 0;
+    // member function w/pointer
+    {
+        T a;
+        TuplePtr t{&a, 1, 2};
+        assert(3 == std::apply(mem1, t));
+        assert(count == 3);
+    }
+    count = 0;
+    // member function w/base
+    {
+        Base a;
+        TupleBase t{a, 2, 2};
+        assert(4 == std::apply(mem1, t));
+        assert(count == 4);
+    }
+    count = 0;
+    // member function w/wrap
+    {
+        Wrap a;
+        TupleWrap t{a, 2, 3};
+        assert(5 == std::apply(mem1, t));
+        assert(count == 5);
+    }
+    count = 0;
+    // const member function w/ref
+    {
+        T const a;
+        ConstTuple t{a, 3, 3};
+        assert(6 == std::apply(mem2, t));
+        assert(count == 6);
+    }
+    count = 0;
+    // const member function w/pointer
+    {
+        T const a;
+        ConstTuplePtr t{&a, 3, 4};
+        assert(7 == std::apply(mem2, t));
+        assert(count == 7);
+    }
+    count = 0;
+    // const member function w/base
+    {
+        Base const a;
+        ConstTupleBase t{a, 4, 4};
+        assert(8 == std::apply(mem2, t));
+        assert(count == 8);
+    }
+    count = 0;
+    // const member function w/wrapper
+    {
+        Wrap const a;
+        ConstTupleWrap t{a, 4, 5};
+        assert(9 == std::apply(mem2, t));
+        assert(9 == count);
+    }
+}
+
+int main()
+{
+    {
+        test_ext_int_0<
+            std::tuple<A_int_0 &>, std::tuple<A_int_0 const &>
+          , std::tuple<A_int_0 *>, std::tuple<A_int_0 const *>
+          , std::tuple<A_wrap_0 &>, std::tuple<A_wrap_0 const &>
+          , std::tuple<A_base_0 &>, std::tuple<A_base_0 const &>
+          >();
+        test_ext_int_0<
+            std::tuple<A_int_0>, std::tuple<A_int_0 const>
+          , std::tuple<A_int_0 *>, std::tuple<A_int_0 const *>
+          , std::tuple<A_wrap_0>, std::tuple<A_wrap_0 const>
+          , std::tuple<A_base_0>, std::tuple<A_base_0 const>
+          >();
+        test_ext_int_0<
+            std::array<A_int_0, 1>, std::array<A_int_0 const, 1>
+          , std::array<A_int_0*, 1>, std::array<A_int_0 const*, 1>
+          , std::array<A_wrap_0, 1>, std::array<A_wrap_0 const, 1>
+          , std::array<A_base_0, 1>, std::array<A_base_0 const, 1>
+          >();
+    }
+    {
+        test_ext_int_1<
+            std::tuple<A_int_1 &, int>, std::tuple<A_int_1 const &, int>
+          , std::tuple<A_int_1 *, int>, std::tuple<A_int_1 const *, int>
+          , std::tuple<A_wrap_1 &, int>, std::tuple<A_wrap_1 const &, int>
+          , std::tuple<A_base_1 &, int>, std::tuple<A_base_1 const &, int>
+          >();
+        test_ext_int_1<
+            std::tuple<A_int_1, int>, std::tuple<A_int_1 const, int>
+          , std::tuple<A_int_1 *, int>, std::tuple<A_int_1 const *, int>
+          , std::tuple<A_wrap_1, int>, std::tuple<A_wrap_1 const, int>
+          , std::tuple<A_base_1, int>, std::tuple<A_base_1 const, int>
+          >();
+        test_ext_int_1<
+            std::pair<A_int_1 &, int>, std::pair<A_int_1 const &, int>
+          , std::pair<A_int_1 *, int>, std::pair<A_int_1 const *, int>
+          , std::pair<A_wrap_1 &, int>, std::pair<A_wrap_1 const &, int>
+          , std::pair<A_base_1 &, int>, std::pair<A_base_1 const &, int>
+          >();
+        test_ext_int_1<
+            std::pair<A_int_1, int>, std::pair<A_int_1 const, int>
+          , std::pair<A_int_1 *, int>, std::pair<A_int_1 const *, int>
+          , std::pair<A_wrap_1, int>, std::pair<A_wrap_1 const, int>
+          , std::pair<A_base_1, int>, std::pair<A_base_1 const, int>
+          >();
+    }
+    {
+        test_ext_int_2<
+            std::tuple<A_int_2 &, int, int>, std::tuple<A_int_2 const &, int, int>
+          , std::tuple<A_int_2 *, int, int>, std::tuple<A_int_2 const *, int, int>
+          , std::tuple<A_wrap_2 &, int, int>, std::tuple<A_wrap_2 const &, int, int>
+          , std::tuple<A_base_2 &, int, int>, std::tuple<A_base_2 const &, int, int>
+          >();
+        test_ext_int_2<
+            std::tuple<A_int_2, int, int>, std::tuple<A_int_2 const, int, int>
+          , std::tuple<A_int_2 *, int, int>, std::tuple<A_int_2 const *, int, int>
+          , std::tuple<A_wrap_2, int, int>, std::tuple<A_wrap_2 const, int, int>
+          , std::tuple<A_base_2, int, int>, std::tuple<A_base_2 const, int, int>
+          >();
+    }
+}

test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_large_arity.pass.cpp

@@ -0,0 +1,144 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <tuple>
+
+// template <class F, class T> constexpr decltype(auto) apply(F &&, T &&)
+
+// Stress testing large arities with tuple and array.
+
+#include <tuple>
+#include <array>
+#include <utility>
+#include <cassert>
+
+////////////////////////////////////////////////////////////////////////////////
+template <class T, std::size_t Dummy = 0>
+struct always_imp
+{
+    typedef T type;
+};
+
+template <class T, std::size_t Dummy = 0>
+using always_t = typename always_imp<T, Dummy>::type;
+
+////////////////////////////////////////////////////////////////////////////////
+template <class Tuple, class Idx>
+struct make_function;
+
+template <class Tp, std::size_t ...Idx>
+struct make_function<Tp, std::integer_sequence<std::size_t, Idx...>>
+{
+    using type = bool (*)(always_t<Tp, Idx>...);
+};
+
+template <class Tp, std::size_t Size>
+using make_function_t = typename make_function<Tp, std::make_index_sequence<Size>>::type;
+
+////////////////////////////////////////////////////////////////////////////////
+template <class Tp, class Idx>
+struct make_tuple_imp;
+
+////////////////////////////////////////////////////////////////////////////////
+template <class Tp, std::size_t ...Idx>
+struct make_tuple_imp<Tp, std::integer_sequence<std::size_t, Idx...>>
+{
+    using type = std::tuple<always_t<Tp, Idx>...>;
+};
+
+template <class Tp, std::size_t Size>
+using make_tuple_t = typename make_tuple_imp<Tp, std::make_index_sequence<Size>>::type;
+
+template <class ...Types>
+bool test_apply_fn(Types...) { return true; }
+
+
+template <std::size_t Size>
+void test_all()
+{
+
+    using A = std::array<int, Size>;
+    using ConstA = std::array<int const, Size>;
+
+    using Tuple = make_tuple_t<int, Size>;
+    using CTuple = make_tuple_t<const int, Size>;
+
+    using ValFn  = make_function_t<int, Size>;
+    ValFn val_fn = &test_apply_fn;
+
+    using RefFn  = make_function_t<int &, Size>;
+    RefFn ref_fn = &test_apply_fn;
+
+    using CRefFn = make_function_t<int const &, Size>;
+    CRefFn cref_fn = &test_apply_fn;
+
+    using RRefFn = make_function_t<int &&, Size>;
+    RRefFn rref_fn = &test_apply_fn;
+
+    {
+        A a{};
+        assert(std::apply(val_fn, a));
+        assert(std::apply(ref_fn, a));
+        assert(std::apply(cref_fn, a));
+        assert(std::apply(rref_fn, std::move(a)));
+    }
+    {
+        ConstA a{};
+        assert(std::apply(val_fn, a));
+        assert(std::apply(cref_fn, a));
+    }
+    {
+        Tuple a{};
+        assert(std::apply(val_fn, a));
+        assert(std::apply(ref_fn, a));
+        assert(std::apply(cref_fn, a));
+        assert(std::apply(rref_fn, std::move(a)));
+    }
+    {
+        CTuple a{};
+        assert(std::apply(val_fn, a));
+        assert(std::apply(cref_fn, a));
+    }
+
+}
+
+
+template <std::size_t Size>
+void test_one()
+{
+    using A = std::array<int, Size>;
+    using Tuple = make_tuple_t<int, Size>;
+
+    using ValFn  = make_function_t<int, Size>;
+    ValFn val_fn = &test_apply_fn;
+
+    {
+        A a{};
+        assert(std::apply(val_fn, a));
+    }
+    {
+        Tuple a{};
+        assert(std::apply(val_fn, a));
+    }
+}
+
+int main()
+{
+    // Instantiate with 1-5 arguments.
+    test_all<1>();
+    test_all<2>();
+    test_all<3>();
+    test_all<4>();
+    test_all<5>();
+
+    // Stress test with 256
+    test_one<256>();
+}

test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp

@@ -0,0 +1,210 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <tuple>
+
+// template <class T, class Tuple> constexpr T make_from_tuple(Tuple&&);
+
+#include <tuple>
+#include <array>
+#include <utility>
+#include <string>
+#include <cassert>
+
+#include "test_macros.h"
+#include "type_id.h"
+
+template <class Tuple>
+struct ConstexprConstructibleFromTuple {
+  template <class ...Args>
+  explicit constexpr ConstexprConstructibleFromTuple(Args&&... xargs)
+      : args{std::forward<Args>(xargs)...} {}
+  Tuple args;
+};
+
+template <class TupleLike>
+struct ConstructibleFromTuple;
+
+template <template <class ...> class Tuple, class ...Types>
+struct ConstructibleFromTuple<Tuple<Types...>> {
+  template <class ...Args>
+  explicit ConstructibleFromTuple(Args&&... xargs)
+      : args(xargs...),
+        arg_types(&makeArgumentID<Args&&...>())
+  {}
+  Tuple<std::decay_t<Types>...> args;
+  TypeID const* arg_types;
+};
+
+template <class Tp, size_t N>
+struct ConstructibleFromTuple<std::array<Tp, N>> {
+template <class ...Args>
+  explicit ConstructibleFromTuple(Args&&... xargs)
+      : args{xargs...},
+        arg_types(&makeArgumentID<Args&&...>())
+  {}
+  std::array<Tp, N> args;
+  TypeID const* arg_types;
+};
+
+template <class Tuple>
+constexpr bool do_constexpr_test(Tuple&& tup) {
+    using RawTuple = std::decay_t<Tuple>;
+    using Tp = ConstexprConstructibleFromTuple<RawTuple>;
+    return std::make_from_tuple<Tp>(std::forward<Tuple>(tup)).args == tup;
+}
+
+// Needed by do_forwarding_test() since it compare pairs of different types.
+template <class T1, class T2, class U1, class U2>
+inline bool operator==(const std::pair<T1, T2>& lhs, const std::pair<U1, U2>& rhs) {
+    return lhs.first == rhs.first && lhs.second == rhs.second;
+}
+
+template <class ...ExpectTypes, class Tuple>
+bool do_forwarding_test(Tuple&& tup) {
+    using RawTuple = std::decay_t<Tuple>;
+    using Tp = ConstructibleFromTuple<RawTuple>;
+    const Tp value = std::make_from_tuple<Tp>(std::forward<Tuple>(tup));
+    return value.args == tup
+        && value.arg_types == &makeArgumentID<ExpectTypes...>();
+}
+
+void test_constexpr_construction() {
+    {
+        constexpr std::tuple<> tup;
+        static_assert(do_constexpr_test(tup), "");
+    }
+    {
+        constexpr std::tuple<int> tup(42);
+        static_assert(do_constexpr_test(tup), "");
+    }
+    {
+        constexpr std::tuple<int, long, void*> tup(42, 101, nullptr);
+        static_assert(do_constexpr_test(tup), "");
+    }
+    {
+        constexpr std::pair<int, const char*> p(42, "hello world");
+        static_assert(do_constexpr_test(p), "");
+    }
+    {
+        using Tuple = std::array<int, 3>;
+        using ValueTp = ConstexprConstructibleFromTuple<Tuple>;
+        constexpr Tuple arr = {42, 101, -1};
+        constexpr ValueTp value = std::make_from_tuple<ValueTp>(arr);
+        static_assert(value.args[0] == arr[0] && value.args[1] == arr[1]
+            && value.args[2] == arr[2], "");
+    }
+}
+
+void test_perfect_forwarding() {
+    {
+        using Tup = std::tuple<>;
+        Tup tup;
+        Tup const& ctup = tup;
+        assert(do_forwarding_test<>(tup));
+        assert(do_forwarding_test<>(ctup));
+    }
+    {
+        using Tup = std::tuple<int>;
+        Tup tup(42);
+        Tup const& ctup = tup;
+        assert(do_forwarding_test<int&>(tup));
+        assert(do_forwarding_test<int const&>(ctup));
+        assert(do_forwarding_test<int&&>(std::move(tup)));
+        assert(do_forwarding_test<int const&&>(std::move(ctup)));
+    }
+    {
+        using Tup = std::tuple<int&, const char*, unsigned&&>;
+        int x = 42;
+        unsigned y = 101;
+        Tup tup(x, "hello world", std::move(y));
+        Tup const& ctup = tup;
+        assert((do_forwarding_test<int&, const char*&, unsigned&>(tup)));
+        assert((do_forwarding_test<int&, const char* const&, unsigned &>(ctup)));
+        assert((do_forwarding_test<int&, const char*&&, unsigned&&>(std::move(tup))));
+        assert((do_forwarding_test<int&, const char* const&&, unsigned &&>(std::move(ctup))));
+    }
+    // test with pair<T, U>
+    {
+        using Tup = std::pair<int&, const char*>;
+        int x = 42;
+        Tup tup(x, "hello world");
+        Tup const& ctup = tup;
+        assert((do_forwarding_test<int&, const char*&>(tup)));
+        assert((do_forwarding_test<int&, const char* const&>(ctup)));
+        assert((do_forwarding_test<int&, const char*&&>(std::move(tup))));
+        assert((do_forwarding_test<int&, const char* const&&>(std::move(ctup))));
+    }
+    // test with array<T, I>
+    {
+        using Tup = std::array<int, 3>;
+        Tup tup = {42, 101, -1};
+        Tup const& ctup = tup;
+        assert((do_forwarding_test<int&, int&, int&>(tup)));
+        assert((do_forwarding_test<int const&, int const&, int const&>(ctup)));
+        assert((do_forwarding_test<int&&, int&&, int&&>(std::move(tup))));
+        assert((do_forwarding_test<int const&&, int const&&, int const&&>(std::move(ctup))));
+    }
+}
+
+void test_noexcept() {
+    struct NothrowMoveable {
+      NothrowMoveable() = default;
+      NothrowMoveable(NothrowMoveable const&) {}
+      NothrowMoveable(NothrowMoveable&&) noexcept {}
+    };
+    struct TestType {
+      TestType(int, NothrowMoveable) noexcept {}
+      TestType(int, int, int) noexcept(false) {}
+      TestType(long, long, long) noexcept {}
+    };
+    {
+        using Tuple = std::tuple<int, NothrowMoveable>;
+        Tuple tup; ((void)tup);
+        Tuple const& ctup = tup; ((void)ctup);
+        ASSERT_NOT_NOEXCEPT(std::make_from_tuple<TestType>(ctup));
+        ASSERT_NOEXCEPT(std::make_from_tuple<TestType>(std::move(tup)));
+    }
+    {
+        using Tuple = std::pair<int, NothrowMoveable>;
+        Tuple tup; ((void)tup);
+        Tuple const& ctup = tup; ((void)ctup);
+        ASSERT_NOT_NOEXCEPT(std::make_from_tuple<TestType>(ctup));
+        ASSERT_NOEXCEPT(std::make_from_tuple<TestType>(std::move(tup)));
+    }
+    {
+        using Tuple = std::tuple<int, int, int>;
+        Tuple tup; ((void)tup);
+        ASSERT_NOT_NOEXCEPT(std::make_from_tuple<TestType>(tup));
+    }
+    {
+        using Tuple = std::tuple<long, long, long>;
+        Tuple tup; ((void)tup);
+        ASSERT_NOEXCEPT(std::make_from_tuple<TestType>(tup));
+    }
+    {
+        using Tuple = std::array<int, 3>;
+        Tuple tup; ((void)tup);
+        ASSERT_NOT_NOEXCEPT(std::make_from_tuple<TestType>(tup));
+    }
+    {
+        using Tuple = std::array<long, 3>;
+        Tuple tup; ((void)tup);
+        ASSERT_NOEXCEPT(std::make_from_tuple<TestType>(tup));
+    }
+}
+
+int main()
+{
+    test_constexpr_construction();
+    test_perfect_forwarding();
+    test_noexcept();
+}

test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp

@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03
+
+// <tuple>
+
+// template <class... Types>
+//   class tuple_size<tuple<Types...>>
+//     : public integral_constant<size_t, sizeof...(Types)> { };
+
+// Expect failures with a reference type, pointer type, and a non-tuple type.
+
+#include <tuple>
+
+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}}
+}

test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp

@@ -0,0 +1,26 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <tuple>
+
+// template <class T> constexpr size_t tuple_size_v = tuple_size<T>::value;
+
+// Expect failures with a reference type, pointer type, and a non-tuple type.
+
+#include <tuple>
+
+int main()
+{
+    (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}}
+}

test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.pass.cpp

@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <tuple>
+
+// template <class T> constexpr size_t tuple_size_v = tuple_size<T>::value;
+
+#include <tuple>
+#include <utility>
+#include <array>
+
+template <class Tuple, int Expect>
+void test()
+{
+    static_assert(std::tuple_size_v<Tuple> == Expect, "");
+    static_assert(std::tuple_size_v<Tuple> == std::tuple_size<Tuple>::value, "");
+    static_assert(std::tuple_size_v<Tuple const> == std::tuple_size<Tuple>::value, "");
+    static_assert(std::tuple_size_v<Tuple volatile> == std::tuple_size<Tuple>::value, "");
+    static_assert(std::tuple_size_v<Tuple const volatile> == std::tuple_size<Tuple>::value, "");
+}
+
+int main()
+{
+    test<std::tuple<>, 0>();
+
+    test<std::tuple<int>, 1>();
+    test<std::array<int, 1>, 1>();
+
+    test<std::tuple<int, int>, 2>();
+    test<std::pair<int, int>, 2>();
+    test<std::array<int, 2>, 2>();
+
+    test<std::tuple<int, int, int>, 3>();
+    test<std::array<int, 3>, 3>();
+}

www/cxx1z_status.html

@@ -106,7 +106,7 @@
 	<tr><td><a href="http://wg21.link/p0175r1">p0175r1</a></td><td>LWG</td><td>Synopses for the C library</td><td>Oulu</td><td></td><td></td></tr>
 	<tr><td><a href="http://wg21.link/p0180r2">p0180r2</a></td><td>LWG</td><td>Reserve a New Library Namespace for Future Standardization</td><td>Oulu</td><td></td><td></td></tr>
 	<tr><td><a href="http://wg21.link/p0181r1">p0181r1</a></td><td>LWG</td><td>Ordered by Default</td><td>Oulu</td><td></td><td></td></tr>
-	<tr><td><a href="http://wg21.link/p0209r2">p0209r2</a></td><td>LWG</td><td>make_from_tuple: apply for construction</td><td>Oulu</td><td></td><td></td></tr>
+	<tr><td><a href="http://wg21.link/p0209r2">p0209r2</a></td><td>LWG</td><td>make_from_tuple: apply for construction</td><td>Oulu</td><td>Complete</td><td>3.9</td></tr>
 	<tr><td><a href="http://wg21.link/p0219r1">p0219r1</a></td><td>LWG</td><td>Relative Paths for Filesystem</td><td>Oulu</td><td></td><td></td></tr>
 	<tr><td><a href="http://wg21.link/p0254r2">p0254r2</a></td><td>LWG</td><td>Integrating std::string_view and std::string</td><td>Oulu</td><td></td><td></td></tr>
 	<tr><td><a href="http://wg21.link/p0258r2">p0258r2</a></td><td>LWG</td><td>has_unique_object_representations</td><td>Oulu</td><td></td><td></td></tr>