1 files changed, 77 insertions, 0 deletions
diff --git a/test/std/experimental/language.support/support.coroutines/coroutine.traits/promise_type.pass.cpp b/test/std/experimental/language.support/support.coroutines/coroutine.traits/promise_type.pass.cpp
new file mode 100644
index 000000000000..e26f333aa407
--- /dev/null
+++ b/test/std/experimental/language.support/support.coroutines/coroutine.traits/promise_type.pass.cpp
@@ -0,0 +1,77 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+//                     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
+
+#include <experimental/coroutine>
+
+namespace coro = std::experimental;
+
+template <class T, class = typename T::promise_type>
+constexpr bool has_promise_type(int) { return true; }
+template <class>
+constexpr bool has_promise_type(long) { return false; }
+template <class T>
+constexpr bool has_promise_type() { return has_promise_type<T>(0); }
+
+struct A {
+  using promise_type = A*;
+};
+
+struct B {};
+struct C {};
+struct D {
+private:
+  using promise_type = void;
+};
+struct E {};
+
+namespace std { namespace experimental {
+  template <>
+  struct coroutine_traits<::A, int> {
+    using promise_type = int*;
+  };
+  template <class ...Args>
+  struct coroutine_traits<::B, Args...> {
+    using promise_type = B*;
+  };
+  template <>
+  struct coroutine_traits<::C> {
+    using promise_type = void;
+  };
+}}
+
+template <class Expect, class T, class ...Args>
+void check_type() {
+  using Traits = coro::coroutine_traits<T, Args...>;
+  static_assert(has_promise_type<Traits>(), "");
+  static_assert(std::is_same<typename Traits::promise_type, Expect>::value, "");
+}
+
+template <class T, class ...Args>
+void check_no_type() {
+  using Traits = coro::coroutine_traits<T, Args...>;
+  static_assert(!has_promise_type<Traits>(), "");
+}
+
+int main()
+{
+  {
+    check_type<A*, A>();
+    check_type<int*, A, int>();
+    check_type<B*, B>();
+    check_type<void, C>();
+  }
+  {
+    check_no_type<D>();
+    check_no_type<E>();
+    check_no_type<C, int>();
+  }
+}