[libc++] Use std::is_nothrow_callable for std::invoke according to LWG 2807

Thanks to Zoe Carver for the patch.
Differential Revision: https://reviews.llvm.org/D58097

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@357616 91177308-0d34-0410-b5e6-96231b3b80d8

include/functional

@@ -230,6 +230,10 @@ template<class Fn, class... BoundArgs>
 template<class R, class Fn, class... BoundArgs>
   unspecified bind(Fn&&, BoundArgs&&...);
 
+template<class F, class... Args>
+ invoke_result_t<F, Args...> invoke(F&& f, Args&&... args) // C++17
+    noexcept(is_nothrow_invocable_v<F, Args...>);
+
 namespace placeholders {
   // M is the implementation-defined number of placeholders
   extern unspecified _1;
@@ -2769,9 +2773,9 @@ bind(_Fp&& __f, _BoundArgs&&... __bound_args)
 #if _LIBCPP_STD_VER > 14
 
 template <class _Fn, class ..._Args>
-result_of_t<_Fn&&(_Args&&...)>
+invoke_result_t<_Fn, _Args...>
 invoke(_Fn&& __f, _Args&&... __args)
-    noexcept(noexcept(_VSTD::__invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...)))
+    noexcept(is_nothrow_invocable_v<_Fn, _Args...>)
 {
     return _VSTD::__invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
 }

test/std/utilities/function.objects/func.invoke/invoke.pass.cpp

@@ -10,8 +10,9 @@
 
 // <functional>
 
-// template <class F, class ...Args>
-// result_of_t<F&&(Args&&...)> invoke(F&&, Args&&...);
+// template<class F, class... Args>
+// invoke_result_t<F, Args...> invoke(F&& f, Args&&... args) // C++17
+//     noexcept(is_nothrow_invocable_v<_Fn, _Args...>);
 
 /// C++14 [func.def] 20.9.0
 /// (1) The following definitions apply to this Clause:

www/cxx1z_status.html

@@ -461,7 +461,7 @@
 	<tr><td><a href="https://wg21.link/LWG2802">2802</a></td><td>shared_ptr constructor requirements for a deleter</td><td>Kona</td><td></td></tr>
 	<tr><td><a href="https://wg21.link/LWG2804">2804</a></td><td>Unconditional constexpr default constructor for istream_iterator</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2806">2806</a></td><td>Base class of bad_optional_access</td><td>Kona</td><td>Complete</td></tr>
-	<tr><td><a href="https://wg21.link/LWG2807">2807</a></td><td>std::invoke should use std::is_nothrow_callable</td><td>Kona</td><td></td></tr>
+	<tr><td><a href="https://wg21.link/LWG2807">2807</a></td><td>std::invoke should use std::is_nothrow_callable</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2812">2812</a></td><td>Range access is available with &lt;string_view&gt;</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2824">2824</a></td><td>list::sort should say that the order of elements is unspecified if an exception is thrown</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2826">2826</a></td><td>string_view iterators use old wording</td><td>Kona</td><td>Complete</td></tr>