Add 'is_callable' and 'is_nothrow_callable' traits and cleanup INVOKE.

The primary purpose of this patch is to add the 'is_callable' traits.
Since 'is_nothrow_callable' required making 'INVOKE' conditionally noexcept
I also took this oppertunity to implement a constexpr version of INVOKE.
This fixes 'std::experimental::apply' which required constexpr 'INVOKE support'.

This patch will be followed up with some cleanup. Primarly removing most
of "__member_function_traits" since it's no longer used by INVOKE (in C++11 at least).

llvm-svn: 266836

11 files changed, 488 insertions, 63 deletions

diff --git a/libcxx/test/std/experimental/utilities/tuple/tuple.apply/constexpr_types.pass.cpp b/libcxx/test/std/experimental/utilities/tuple/tuple.apply/constexpr_types.pass.cpp
index 2d700486f26..5b8a8f09d1e 100644
--- a/libcxx/test/std/experimental/utilities/tuple/tuple.apply/constexpr_types.pass.cpp
+++ b/libcxx/test/std/experimental/utilities/tuple/tuple.apply/constexpr_types.pass.cpp
@@ -9,11 +9,6 @@
 
 // UNSUPPORTED: c++98, c++03, c++11
 
-// TODO(ericwf)
-// constexpr support temporarily reverted due to bug:
-// https://llvm.org/bugs/show_bug.cgi?id=23141
-// XFAIL: *
-
 // <experimental/tuple>
 
 // template <class F, class T> constexpr decltype(auto) apply(F &&, T &&)
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp
new file mode 100644
index 00000000000..163b2d9afea
--- /dev/null
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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
+
+// <functional>
+
+// template<CopyConstructible Fn, CopyConstructible... Types>
+//   unspecified bind(Fn, Types...);
+// template<Returnable R, CopyConstructible Fn, CopyConstructible... Types>
+//   unspecified bind(Fn, Types...);
+
+// https://llvm.org/bugs/show_bug.cgi?id=23141
+#include <functional>
+#include <type_traits>
+
+struct Fun
+{
+  template<typename T, typename U>
+  void operator()(T && t, U && u) const
+  {
+    static_assert(std::is_same<U, int &>::value, "");
+  }
+};
+
+int main()
+{
+    std::bind(Fun{}, std::placeholders::_1, 42)("hello");
+}
diff --git a/libcxx/test/std/utilities/function.objects/func.require/bullet_1_2_3.pass.cpp b/libcxx/test/std/utilities/function.objects/func.require/bullet_1_2_3.pass.cpp
index 09e8e21137a..509c751b455 100644
--- a/libcxx/test/std/utilities/function.objects/func.require/bullet_1_2_3.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.require/bullet_1_2_3.pass.cpp
@@ -260,8 +260,11 @@ void test_derived_from_ref_wrap() {
     DerivedFromRefWrap<int> d(x);
     auto get_fn = &std::reference_wrapper<int>::get;
     auto& ret = std::__invoke(get_fn, r);
+    auto& cret = std::__invoke_constexpr(get_fn, r);
     assert(&ret == &x);
+    assert(&cret == &x);
     auto& ret2 = std::__invoke(get_fn, d);
+    auto& cret2 = std::__invoke_constexpr(get_fn, d);
     assert(&ret2 == &x);
     auto& ret3 = std::__invoke(get_fn, r2);
     assert(&ret3 == &x);
diff --git a/libcxx/test/std/utilities/function.objects/func.require/bullet_4_5_6.pass.cpp b/libcxx/test/std/utilities/function.objects/func.require/bullet_4_5_6.pass.cpp
index 2007c417a62..803c501f8c9 100644
--- a/libcxx/test/std/utilities/function.objects/func.require/bullet_4_5_6.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.require/bullet_4_5_6.pass.cpp
@@ -185,11 +185,22 @@ private:
 #else
     void runTest(Fn M, T& obj, ObjectType* expect ) {
 #endif
-        static_assert((std::is_same<
-            decltype(std::__invoke(M, std::forward<T>(obj))), Expect
-          >::value), "");
-        Expect e = std::__invoke(M, std::forward<T>(obj));
-        assert(&e == expect);
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke(M, std::forward<T>(obj))), Expect
+              >::value), "");
+            Expect e = std::__invoke(M, std::forward<T>(obj));
+            assert(&e == expect);
+        }
+#if TEST_STD_VER >= 11
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke_constexpr(M, std::forward<T>(obj))), Expect
+              >::value), "");
+            Expect e = std::__invoke_constexpr(M, std::forward<T>(obj));
+            assert(&e == expect);
+        }
+#endif
     }
 };
 
diff --git a/libcxx/test/std/utilities/function.objects/func.require/invoke_helpers.h b/libcxx/test/std/utilities/function.objects/func.require/invoke_helpers.h
index 495703d0e32..7e7a5fd24a6 100644
--- a/libcxx/test/std/utilities/function.objects/func.require/invoke_helpers.h
+++ b/libcxx/test/std/utilities/function.objects/func.require/invoke_helpers.h
@@ -271,89 +271,185 @@ private:
     ArgType a0, a1, a2;
 
     //==========================================================================
-    //                       BULLET 1 AND 2 TEST METHODS
+    //                       BULLET 1, 2 AND 3 TEST METHODS
     //==========================================================================
     template <class MethodPtr, class ObjectT>
     void runTestImp(Int<0>, MethodPtr ptr, ObjectT& object) {
-        static_assert((std::is_same<
-            decltype(std::__invoke(ptr, object_cast(object)))
-          , CallRet>::value), "");
-        assert(ID::unchecked_call == false);
-        CallRet ret = std::__invoke(ptr, object_cast(object));
-        assert(ID::checkCalled(ret));
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke(ptr, object_cast(object)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke(ptr, object_cast(object));
+            assert(ID::checkCalled(ret));
+        }
+#if TEST_STD_VER >= 11
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke_constexpr(ptr, object_cast(object)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke_constexpr(ptr, object_cast(object));
+            assert(ID::checkCalled(ret));
+        }
+#endif
     }
 
     template <class MethodPtr, class ObjectT>
     void runTestImp(Int<1>, MethodPtr ptr, ObjectT& object) {
-        static_assert((std::is_same<
-            decltype(std::__invoke(ptr, object_cast(object), arg_cast(a0)))
-          , CallRet>::value), "");
-        assert(ID::unchecked_call == false);
-        CallRet ret = std::__invoke(ptr, object_cast(object), arg_cast(a0));
-        assert(ID::checkCalled(ret));
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke(ptr, object_cast(object), arg_cast(a0)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke(ptr, object_cast(object), arg_cast(a0));
+            assert(ID::checkCalled(ret));
+        }
+#if TEST_STD_VER >= 11
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke_constexpr(ptr, object_cast(object), arg_cast(a0)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke_constexpr(ptr, object_cast(object), arg_cast(a0));
+            assert(ID::checkCalled(ret));
+        }
+#endif
     }
 
     template <class MethodPtr, class ObjectT>
     void runTestImp(Int<2>, MethodPtr ptr, ObjectT& object) {
-        static_assert((std::is_same<
-            decltype(std::__invoke(ptr, object_cast(object), arg_cast(a0), arg_cast(a1)))
-          , CallRet>::value), "");
-        assert(ID::unchecked_call == false);
-        CallRet ret = std::__invoke(ptr, object_cast(object), arg_cast(a0), arg_cast(a1));
-        assert(ID::checkCalled(ret));
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke(ptr, object_cast(object), arg_cast(a0), arg_cast(a1)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke(ptr, object_cast(object), arg_cast(a0), arg_cast(a1));
+            assert(ID::checkCalled(ret));
+        }
+#if TEST_STD_VER >= 11
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke_constexpr(ptr, object_cast(object), arg_cast(a0), arg_cast(a1)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke_constexpr(ptr, object_cast(object), arg_cast(a0), arg_cast(a1));
+            assert(ID::checkCalled(ret));
+        }
+#endif
     }
 
     template <class MethodPtr, class ObjectT>
     void runTestImp(Int<3>, MethodPtr ptr, ObjectT& object) {
-        static_assert((std::is_same<
-            decltype(std::__invoke(ptr, object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2)))
-          , CallRet>::value), "");
-        assert(ID::unchecked_call == false);
-        CallRet ret = std::__invoke(ptr, object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2));
-        assert(ID::checkCalled(ret));
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke(ptr, object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke(ptr, object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2));
+            assert(ID::checkCalled(ret));
+        }
+#if TEST_STD_VER >= 11
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke_constexpr(ptr, object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke_constexpr(ptr, object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2));
+            assert(ID::checkCalled(ret));
+        }
+#endif
     }
 
     //==========================================================================
-    //                       BULLET 5 TEST METHODS
+    //                       BULLET 7 TEST METHODS
     //==========================================================================
     template <class ObjectT>
     void runTestImp(Int<0>, ObjectT& object) {
-        static_assert((std::is_same<
-            decltype(std::__invoke(object_cast(object)))
-          , CallRet>::value), "");
-        assert(ID::unchecked_call == false);
-        CallRet ret = std::__invoke(object_cast(object));
-        assert(ID::checkCalled(ret));
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke(object_cast(object)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke(object_cast(object));
+            assert(ID::checkCalled(ret));
+        }
+#if TEST_STD_VER >= 11
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke_constexpr(object_cast(object)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke_constexpr(object_cast(object));
+            assert(ID::checkCalled(ret));
+        }
+#endif
     }
 
     template <class ObjectT>
     void runTestImp(Int<1>, ObjectT& object) {
-        static_assert((std::is_same<
-            decltype(std::__invoke(object_cast(object), arg_cast(a0)))
-          , CallRet>::value), "");
-        assert(ID::unchecked_call == false);
-        CallRet ret = std::__invoke(object_cast(object), arg_cast(a0));
-        assert(ID::checkCalled(ret));
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke(object_cast(object), arg_cast(a0)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke(object_cast(object), arg_cast(a0));
+            assert(ID::checkCalled(ret));
+        }
+#if TEST_STD_VER >= 11
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke_constexpr(object_cast(object), arg_cast(a0)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke_constexpr(object_cast(object), arg_cast(a0));
+            assert(ID::checkCalled(ret));
+        }
+#endif
     }
 
     template <class ObjectT>
     void runTestImp(Int<2>, ObjectT& object) {
-        static_assert((std::is_same<
-            decltype(std::__invoke(object_cast(object), arg_cast(a0), arg_cast(a1)))
-          , CallRet>::value), "");
-        assert(ID::unchecked_call == false);
-        CallRet ret = std::__invoke(object_cast(object), arg_cast(a0), arg_cast(a1));
-        assert(ID::checkCalled(ret));
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke(object_cast(object), arg_cast(a0), arg_cast(a1)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke(object_cast(object), arg_cast(a0), arg_cast(a1));
+            assert(ID::checkCalled(ret));
+        }
+#if TEST_STD_VER >= 11
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke_constexpr(object_cast(object), arg_cast(a0), arg_cast(a1)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke_constexpr(object_cast(object), arg_cast(a0), arg_cast(a1));
+            assert(ID::checkCalled(ret));
+        }
+#endif
     }
 
     template <class ObjectT>
     void runTestImp(Int<3>, ObjectT& object) {
-        static_assert((std::is_same<
-            decltype(std::__invoke(object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2)))
-          , CallRet>::value), "");
-        assert(ID::unchecked_call == false);
-        CallRet ret = std::__invoke(object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2));
-        assert(ID::checkCalled(ret));
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke(object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke(object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2));
+            assert(ID::checkCalled(ret));
+        }
+#if TEST_STD_VER >= 11
+        {
+            static_assert((std::is_same<
+                decltype(std::__invoke_constexpr(object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2)))
+              , CallRet>::value), "");
+            assert(ID::unchecked_call == false);
+            CallRet ret = std::__invoke_constexpr(object_cast(object), arg_cast(a0), arg_cast(a1), arg_cast(a2));
+            assert(ID::checkCalled(ret));
+        }
+#endif
     }
 };
 
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp
index aa77dab5151..3e4a99e981d 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// UNSUPPORTED: c++98, c++03
+
 // <memory>
 
 // shared_ptr
@@ -55,7 +57,6 @@ int main()
     }
     assert(A::count == 0);
     assert(test_allocator<A>::alloc_count == 0);
-#if __cplusplus >= 201103L
     {
     int i = 67;
     char c = 'e';
@@ -74,5 +75,4 @@ int main()
     assert(p->get_char() == 'f');
     }
     assert(A::count == 0);
-#endif
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_no_variadics.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_cxx03.pass.cpp
index 8dcd50e4941..f6350c72bcc 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_no_variadics.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_cxx03.pass.cpp
@@ -14,7 +14,7 @@
 // template<class T, class A, class... Args>
 //    shared_ptr<T> allocate_shared(const A& a, Args&&... args);
 
-#define _LIBCPP_HAS_NO_VARIADICS
+
 #include <memory>
 #include <new>
 #include <cstdlib>
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_callable.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_callable.pass.cpp
new file mode 100644
index 00000000000..7de65835f73
--- /dev/null
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_callable.pass.cpp
@@ -0,0 +1,159 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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
+
+// type_traits
+
+// is_callable
+
+// Most testing of is_callable is done within the [meta.trans.other] result_of
+// tests.
+
+#include <type_traits>
+#include <functional>
+
+#include "test_macros.h"
+
+struct Tag {};
+struct DerFromTag : Tag {};
+
+struct Implicit {
+  Implicit(int) {}
+};
+
+struct Explicit {
+  explicit Explicit(int) {}
+};
+
+struct NotCallableWithInt {
+  int operator()(int) = delete;
+  int operator()(Tag) { return 42; }
+};
+
+int main()
+{
+    {
+        using Fn = int(Tag::*)(int);
+        using RFn = int(Tag::*)(int) &&;
+        // INVOKE bullet 1, 2 and 3
+        {
+            // Bullet 1
+            static_assert(std::is_callable<Fn(Tag&, int)>::value);
+            static_assert(std::is_callable<Fn(DerFromTag&, int)>::value);
+            static_assert(std::is_callable<RFn(Tag&&, int)>::value);
+            static_assert(!std::is_callable<RFn(Tag&, int)>::value);
+            static_assert(!std::is_callable<Fn(Tag&)>::value);
+            static_assert(!std::is_callable<Fn(Tag const&, int)>::value);
+        }
+        {
+            // Bullet 2
+            using T = std::reference_wrapper<Tag>;
+            using DT = std::reference_wrapper<DerFromTag>;
+            using CT = std::reference_wrapper<const Tag>;
+            static_assert(std::is_callable<Fn(T&, int)>::value);
+            static_assert(std::is_callable<Fn(DT&, int)>::value);
+            static_assert(std::is_callable<Fn(const T&, int)>::value);
+            static_assert(std::is_callable<Fn(T&&, int)>::value);
+            static_assert(!std::is_callable<Fn(CT&, int)>::value);
+            static_assert(!std::is_callable<RFn(T, int)>::value);
+        }
+        {
+            // Bullet 3
+            using T = Tag*;
+            using DT = DerFromTag*;
+            using CT = const Tag*;
+            using ST = std::unique_ptr<Tag>;
+            static_assert(std::is_callable<Fn(T&, int)>::value);
+            static_assert(std::is_callable<Fn(DT&, int)>::value);
+            static_assert(std::is_callable<Fn(const T&, int)>::value);
+            static_assert(std::is_callable<Fn(T&&, int)>::value);
+            static_assert(std::is_callable<Fn(ST, int)>::value);
+            static_assert(!std::is_callable<Fn(CT&, int)>::value);
+            static_assert(!std::is_callable<RFn(T, int)>::value);
+        }
+    }
+    {
+        // Bullets 4, 5 and 6
+        using Fn = int (Tag::*);
+        static_assert(!std::is_callable<Fn()>::value);
+        {
+            // Bullet 4
+            static_assert(std::is_callable<Fn(Tag&)>::value);
+            static_assert(std::is_callable<Fn(DerFromTag&)>::value);
+            static_assert(std::is_callable<Fn(Tag&&)>::value);
+            static_assert(std::is_callable<Fn(Tag const&)>::value);
+        }
+        {
+            // Bullet 5
+            using T = std::reference_wrapper<Tag>;
+            using DT = std::reference_wrapper<DerFromTag>;
+            using CT = std::reference_wrapper<const Tag>;
+            static_assert(std::is_callable<Fn(T&)>::value);
+            static_assert(std::is_callable<Fn(DT&)>::value);
+            static_assert(std::is_callable<Fn(const T&)>::value);
+            static_assert(std::is_callable<Fn(T&&)>::value);
+            static_assert(std::is_callable<Fn(CT&)>::value);
+        }
+        {
+            // Bullet 6
+            using T = Tag*;
+            using DT = DerFromTag*;
+            using CT = const Tag*;
+            using ST = std::unique_ptr<Tag>;
+            static_assert(std::is_callable<Fn(T&)>::value);
+            static_assert(std::is_callable<Fn(DT&)>::value);
+            static_assert(std::is_callable<Fn(const T&)>::value);
+            static_assert(std::is_callable<Fn(T&&)>::value);
+            static_assert(std::is_callable<Fn(ST)>::value);
+            static_assert(std::is_callable<Fn(CT&)>::value);
+        }
+    }
+    {
+        // INVOKE bullet 7
+        {
+            // Function pointer
+            using Fp = void(*)(Tag&, int);
+            static_assert(std::is_callable<Fp(Tag&, int)>::value);
+            static_assert(std::is_callable<Fp(DerFromTag&, int)>::value);
+            static_assert(!std::is_callable<Fp(const Tag&, int)>::value);
+            static_assert(!std::is_callable<Fp()>::value);
+            static_assert(!std::is_callable<Fp(Tag&)>::value);
+        }
+        {
+            // Function reference
+            using Fp = void(&)(Tag&, int);
+            static_assert(std::is_callable<Fp(Tag&, int)>::value);
+            static_assert(std::is_callable<Fp(DerFromTag&, int)>::value);
+            static_assert(!std::is_callable<Fp(const Tag&, int)>::value);
+            static_assert(!std::is_callable<Fp()>::value);
+            static_assert(!std::is_callable<Fp(Tag&)>::value);
+        }
+        {
+            // Function object
+            using Fn = NotCallableWithInt;
+            static_assert(std::is_callable<Fn(Tag)>::value, "");
+            static_assert(!std::is_callable<Fn(int)>::value, "");
+        }
+    }
+    {
+        // Check that the conversion to the return type is properly checked
+        using Fn = int(*)();
+        static_assert(std::is_callable<Fn(), Implicit>::value);
+        static_assert(std::is_callable<Fn(), double>::value);
+        static_assert(std::is_callable<Fn(), const volatile void>::value);
+        static_assert(!std::is_callable<Fn(), Explicit>::value);
+    }
+    {
+        // Check for is_callable_v
+        using Fn = void(*)();
+        static_assert(std::is_callable_v<Fn()>);
+        static_assert(!std::is_callable_v<Fn(int)>);
+    }
+}
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_callable.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_callable.pass.cpp
new file mode 100644
index 00000000000..c36a460af34
--- /dev/null
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_callable.pass.cpp
@@ -0,0 +1,115 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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
+
+// type_traits
+
+// is_nothrow_callable
+
+#include <type_traits>
+#include <functional>
+
+#include "test_macros.h"
+
+struct Tag {};
+
+struct Implicit {
+  Implicit(int) noexcept {}
+};
+
+struct ThrowsImplicit {
+  ThrowsImplicit(int) {}
+};
+
+struct Explicit {
+  explicit Explicit(int) noexcept {}
+};
+
+template <bool IsNoexcept, class Ret, class ...Args>
+struct CallObject {
+  Ret operator()(Args&&...) const noexcept(IsNoexcept);
+};
+
+template <class Fn>
+constexpr bool throws_callable() {
+    return std::is_callable<Fn>::value &&
+        !std::is_nothrow_callable<Fn>::value;
+}
+
+template <class Fn, class Ret>
+constexpr bool throws_callable() {
+    return std::is_callable<Fn, Ret>::value &&
+        !std::is_nothrow_callable<Fn, Ret>::value;
+}
+
+// FIXME(EricWF) Don't test the where noexcept is *not* part of the type system
+// once implementations have caught up.
+void test_noexcept_function_pointers()
+{
+    struct Dummy { void foo() noexcept; static void bar() noexcept; };
+#if !defined(__cpp_noexcept_function_type)
+    {
+        // Check that PMF's and function pointers *work*. is_nothrow_callable will always
+        // return false because 'noexcept' is not part of the function type.
+        static_assert(throws_callable<decltype(&Dummy::foo)(Dummy&)>());
+        static_assert(throws_callable<decltype(&Dummy::bar)()>());
+    }
+#else
+    {
+        // Check that PMF's and function pointers actually work and that
+        // is_nothrow_callable returns true for noexcept PMF's and function
+        // pointers.
+        static_assert(std::is_nothrow_callable<decltype(&Dummy::foo)(Dummy&)>::value);
+        static_assert(std::is_nothrow_callable<decltype(&Dummy::bar)()>::value);
+    }
+#endif
+}
+
+int main()
+{
+    {
+        // Check that the conversion to the return type is properly checked
+        using Fn = CallObject<true, int>;
+        static_assert(std::is_nothrow_callable<Fn(), Implicit>::value);
+        static_assert(std::is_nothrow_callable<Fn(), double>::value);
+        static_assert(std::is_nothrow_callable<Fn(), const volatile void>::value);
+        static_assert(throws_callable<Fn(), ThrowsImplicit>());
+        static_assert(!std::is_nothrow_callable<Fn(), Explicit>());
+    }
+    {
+        // Check that the conversion to the parameters is properly checked
+        using Fn = CallObject<true, void, const Implicit&, const ThrowsImplicit&>;
+        static_assert(std::is_nothrow_callable<Fn(Implicit&, ThrowsImplicit&)>::value);
+        static_assert(std::is_nothrow_callable<Fn(int, ThrowsImplicit&)>::value);
+        static_assert(throws_callable<Fn(int, int)>());
+        static_assert(!std::is_nothrow_callable<Fn()>::value);
+    }
+    {
+        // Check that the noexcept-ness of function objects is checked.
+        using Fn = CallObject<true, void>;
+        using Fn2 = CallObject<false, void>;
+        static_assert(std::is_nothrow_callable<Fn()>::value);
+        static_assert(throws_callable<Fn2()>());
+    }
+    {
+        // Check that PMD derefs are noexcept
+        using Fn = int (Tag::*);
+        static_assert(std::is_nothrow_callable<Fn(Tag&)>::value);
+        static_assert(std::is_nothrow_callable<Fn(Tag&), Implicit>::value);
+        static_assert(throws_callable<Fn(Tag&), ThrowsImplicit>());
+    }
+    {
+        // Check for is_nothrow_callable_v
+        using Fn = CallObject<true, int>;
+        static_assert(std::is_nothrow_callable_v<Fn()>);
+        static_assert(!std::is_nothrow_callable_v<Fn(int)>);
+    }
+    test_noexcept_function_pointers();
+}
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp
index 3ac7d1bc9df..fc01b22c36a 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp
@@ -45,6 +45,10 @@ struct HasType<T, typename Voider<typename T::type>::type> : std::true_type {};
 template <class T, class U>
 void test_result_of()
 {
+#if TEST_STD_VER > 14
+    static_assert(std::is_callable<T>::value, "");
+    static_assert(std::is_callable<T, U>::value, "");
+#endif
     static_assert((std::is_same<typename std::result_of<T>::type, U>::value), "");
 }
 
@@ -54,6 +58,9 @@ void test_no_result()
 #if TEST_STD_VER >= 11
     static_assert((!HasType<std::result_of<T> >::value), "");
 #endif
+#if TEST_STD_VER > 14
+    static_assert(std::is_callable<T>::value == false, "");
+#endif
 }
 
 int main()
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
index a00887384d4..8cb5853bbc6 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
@@ -35,6 +35,10 @@ void test_result_of_imp()
 #if TEST_STD_VER > 11
     static_assert((std::is_same<std::result_of_t<T>, U>::value), "");
 #endif
+#if TEST_STD_VER > 14
+    static_assert(std::is_callable<T>::value, "");
+    static_assert(std::is_callable<T, U>::value, "");
+#endif
 }
 
 int main()