1 files changed, 72 insertions, 16 deletions

diff --git a/clang/test/SemaCXX/coroutines.cpp b/clang/test/SemaCXX/coroutines.cpp
index ae24dd2979f..3e18187295d 100644
--- a/clang/test/SemaCXX/coroutines.cpp
+++ b/clang/test/SemaCXX/coroutines.cpp
@@ -1,37 +1,68 @@
 // RUN: %clang_cc1 -std=c++14 -fcoroutines -verify %s
 
+struct awaitable {
+  bool await_ready();
+  void await_suspend(); // FIXME: coroutine_handle
+  void await_resume();
+} a;
+
+void no_coroutine_traits() {
+  co_await a; // expected-error {{need to include <coroutine>}}
+}
+
+namespace std {
+  template<typename ...T> struct coroutine_traits; // expected-note {{declared here}}
+};
+
+void no_specialization() {
+  co_await a; // expected-error {{implicit instantiation of undefined template 'std::coroutine_traits<void>'}}
+}
+
+template<typename ...T> struct std::coroutine_traits<int, T...> {};
+
+int no_promise_type() {
+  co_await a; // expected-error {{this function cannot be a coroutine: 'coroutine_traits<int>' has no member named 'promise_type'}}
+}
+
+struct promise; // expected-note {{forward declaration}}
+template<typename ...T> struct std::coroutine_traits<void, T...> { using promise_type = promise; };
+
+  // FIXME: This diagnostic is terrible.
+void undefined_promise() { // expected-error {{variable has incomplete type 'promise_type'}}
+  co_await a;
+}
+
+struct promise {};
+
 void mixed_yield() {
-  // FIXME: diagnose
-  co_yield 0;
-  return;
+  co_yield 0; // expected-note {{use of 'co_yield'}}
+  return; // expected-error {{not allowed in coroutine}}
 }
 
 void mixed_await() {
-  // FIXME: diagnose
-  co_await 0;
-  return;
+  co_await a; // expected-note {{use of 'co_await'}}
+  return; // expected-error {{not allowed in coroutine}}
 }
 
 void only_coreturn() {
-  // FIXME: diagnose
-  co_return;
+  co_return; // expected-warning {{'co_return' used in a function that uses neither 'co_await' nor 'co_yield'}}
 }
 
 void mixed_coreturn(bool b) {
-  // FIXME: diagnose
   if (b)
-    co_return;
+    // expected-warning@+1 {{'co_return' used in a function that uses neither}}
+    co_return; // expected-note {{use of 'co_return'}}
   else
-    return;
+    return; // expected-error {{not allowed in coroutine}}
 }
 
 struct CtorDtor {
   CtorDtor() {
     co_yield 0; // expected-error {{'co_yield' cannot be used in a constructor}}
   }
-  CtorDtor(int n) {
+  CtorDtor(awaitable a) {
     // The spec doesn't say this is ill-formed, but it must be.
-    co_await n; // expected-error {{'co_await' cannot be used in a constructor}}
+    co_await a; // expected-error {{'co_await' cannot be used in a constructor}}
   }
   ~CtorDtor() {
     co_return 0; // expected-error {{'co_return' cannot be used in a destructor}}
@@ -42,10 +73,35 @@ struct CtorDtor {
   }
 };
 
-constexpr void constexpr_coroutine() {
-  co_yield 0; // expected-error {{'co_yield' cannot be used in a constexpr function}}
+constexpr void constexpr_coroutine() { // expected-error {{never produces a constant expression}}
+  co_yield 0; // expected-error {{'co_yield' cannot be used in a constexpr function}} expected-note {{subexpression}}
 }
 
 void varargs_coroutine(const char *, ...) {
-  co_await 0; // expected-error {{'co_await' cannot be used in a varargs function}}
+  co_await a; // expected-error {{'co_await' cannot be used in a varargs function}}
+}
+
+struct outer {};
+
+namespace dependent_operator_co_await_lookup {
+  template<typename T> void await_template(T t) {
+    // no unqualified lookup results
+    co_await t; // expected-error {{no member named 'await_ready' in 'dependent_operator_co_await_lookup::not_awaitable'}}
+    // expected-error@-1 {{call to function 'operator co_await' that is neither visible in the template definition nor found by argument-dependent lookup}}
+  };
+  template void await_template(awaitable);
+
+  struct indirectly_awaitable { indirectly_awaitable(outer); };
+  awaitable operator co_await(indirectly_awaitable); // expected-note {{should be declared prior to}}
+  template void await_template(indirectly_awaitable);
+
+  struct not_awaitable {};
+  template void await_template(not_awaitable); // expected-note {{instantiation}}
+
+  template<typename T> void await_template_2(T t) {
+    // one unqualified lookup result
+    co_await t;
+  };
+  template void await_template(outer); // expected-note {{instantiation}}
+  template void await_template_2(outer);
 }